linux/drivers/net/netconsole.c

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/*
* linux/drivers/net/netconsole.c
*
* Copyright (C) 2001 Ingo Molnar <mingo@redhat.com>
*
* This file contains the implementation of an IRQ-safe, crash-safe
* kernel console implementation that outputs kernel messages to the
* network.
*
* Modification history:
*
* 2001-09-17 started by Ingo Molnar.
* 2003-08-11 2.6 port by Matt Mackall
* simplified options
* generic card hooks
* works non-modular
* 2003-09-07 rewritten with netpoll api
*/
/****************************************************************
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
****************************************************************/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/module.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <linux/console.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/netpoll.h>
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
#include <linux/inet.h>
#include <linux/configfs.h>
#include <linux/etherdevice.h>
MODULE_AUTHOR("Maintainer: Matt Mackall <mpm@selenic.com>");
MODULE_DESCRIPTION("Console driver for network interfaces");
MODULE_LICENSE("GPL");
#define MAX_PARAM_LENGTH 256
#define MAX_PRINT_CHUNK 1000
static char config[MAX_PARAM_LENGTH];
module_param_string(netconsole, config, MAX_PARAM_LENGTH, 0);
MODULE_PARM_DESC(netconsole, " netconsole=[src-port]@[src-ip]/[dev],[tgt-port]@<tgt-ip>/[tgt-macaddr]");
static bool oops_only = false;
module_param(oops_only, bool, 0600);
MODULE_PARM_DESC(oops_only, "Only log oops messages");
#ifndef MODULE
static int __init option_setup(char *opt)
{
strlcpy(config, opt, MAX_PARAM_LENGTH);
return 1;
}
__setup("netconsole=", option_setup);
#endif /* MODULE */
/* Linked list of all configured targets */
static LIST_HEAD(target_list);
/* This needs to be a spinlock because write_msg() cannot sleep */
static DEFINE_SPINLOCK(target_list_lock);
/**
* struct netconsole_target - Represents a configured netconsole target.
* @list: Links this target into the target_list.
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
* @item: Links us into the configfs subsystem hierarchy.
* @enabled: On / off knob to enable / disable target.
* Visible from userspace (read-write).
* We maintain a strict 1:1 correspondence between this and
* whether the corresponding netpoll is active or inactive.
* Also, other parameters of a target may be modified at
* runtime only when it is disabled (enabled == 0).
* @np: The netpoll structure for this target.
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
* Contains the other userspace visible parameters:
* dev_name (read-write)
* local_port (read-write)
* remote_port (read-write)
* local_ip (read-write)
* remote_ip (read-write)
* local_mac (read-only)
* remote_mac (read-write)
*/
struct netconsole_target {
struct list_head list;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
#ifdef CONFIG_NETCONSOLE_DYNAMIC
struct config_item item;
#endif
int enabled;
netconsole: avoid a crash with multiple sysfs writers When my 'ifup eth' script was fired multiple times and ran concurrent on my laptop, for some obscure /etc scripting reason, it was revealed that the store_enabled() function in netconsole doesn't handle it nicely, as recorded by the Oops below (a syslog paste, but not mangled too much to prevent from discerning the traceback). On Linux 3.10.4, this patch seeks to remedy the problem, and it has been running stable on my laptop for a few days. [52608.609325] BUG: unable to handle kernel NULL pointer dereference at 00000000000003e0 [52608.609331] IP: [<ffffffff81532a17>] __netpoll_cleanup+0x27/0xe0 [52608.609339] PGD 15e51a067 PUD 15433e067 PMD 0 [52608.609343] Oops: 0000 [#1] SMP re firewire_ohci firewire_core crc_itu_t [last unloaded: kvm_intel] [52608.609347] Modules linked in: kvm_intel tun vfat fat ppdev parport_pc parport fuse ipt_MASQUERADE usb_storage nf_conntrack_netbios_ns nf_conn [..garbled..] [52608.609433] RAX: 0000000000000000 RBX: ffff880210bbcc68 RCX: 0000000000000000 [52608.609435] RDX: 0000000000000000 RSI: ffff8801ba447da0 RDI: ffff880210bbcc68 [52608.609437] RBP: ffff8801ba447e18 R08: 0000000000000000 R09: 0000000000000001 [52608.609439] R10: 000000000000000a R11: f000000000000000 R12: ffff880210bbcc68 [52608.609441] R13: ffff88020bc41000 R14: 0000000000000002 R15: 000000000000000200000000000 [52608.609443] FS: 00007f38d7bff740(0000) GS:ffff88021dc40000(0000) knlGS:0000000000000000 [52608.609446] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003300000000001427e0 [52608.609448] CR2: 00000000000003e0 CR3: 0000000154103000 CR4: 00000000001427e0 [52608.609450] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [52608.609452] netpoll: netconsole: local port 6665ess 10.0.0.27 [52608.609454] netpoll: netconsole: local IPv4 address 10.0.0.27 [52608.609456] netpoll: netconsole: interface 'em1' [52608.609457] netpoll: netconsole: remote port 514ress 10.0.0.15 [52608.609459] netpoll: netconsole: remote IPv4 address 10.0.0.15:65:a8:9a:c7 [52608.609461] netpoll: netconsole: remote ethernet address 1c:6f:65:a8:9a:c7 [52608.609463] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [52608.609464] Stack:801ba447e08 ffff880210bbcc68 ffffffffffffffea ffff88020bc41000 [52608.609466] ffff8801ba447e08 ffff880210bbcc68 ffffffffffffffea ffff88020bc41000 [52608.609471] 0000000000000002 0000000000000002 ffff8801ba447e38 ffffffff81532af4 [52608.609475] 0000000000000000 ffff880210bbcc00 ffff8801ba447e78 ffffffff81420e7c [52608.609479] Call Trace: [52608.609484] [<ffffffff81532af4>] netpoll_cleanup+0x24/0x50 [52608.609489] [<ffffffff81420e7c>] store_enabled+0x5c/0xe0 [52608.609492] [<ffffffff81420abe>] netconsole_target_attr_store+0x2e/0x40 [52608.609498] [<ffffffff811ff2a2>] configfs_write_file+0xd2/0x130 [52608.609503] [<ffffffff81188f95>] vfs_write+0xc5/0x1f0 [52608.609506] [<ffffffff81189482>] SyS_write+0x52/0xa0/0x10 [52608.609511] [<ffffffff81628c2e>] ? do_page_fault+0xe/0x10 [52608.609516] [<ffffffff8162d402>] system_call_fastpath+0x16/0x1b [52608.609517] Code: 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 30 4c 89 65 e0 48 89 5d d8 49 89 fc 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 48 8 [..garbled..] [52608.609559] RIP [<ffffffff81532a17>] __netpoll_cleanup+0x27/0xe0 [52608.609563] RSP <ffff8801ba447de8> [52608.609564] CR2: 00000000000003e0 [52608.609567] ---[ end trace d25ec343349b61d2 ]--- Signed-off-by: Dan Aloni <alonid@postram.com> Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: David S. Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-30 10:59:46 +00:00
struct mutex mutex;
struct netpoll np;
};
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
#ifdef CONFIG_NETCONSOLE_DYNAMIC
static struct configfs_subsystem netconsole_subsys;
static int __init dynamic_netconsole_init(void)
{
config_group_init(&netconsole_subsys.su_group);
mutex_init(&netconsole_subsys.su_mutex);
return configfs_register_subsystem(&netconsole_subsys);
}
static void __exit dynamic_netconsole_exit(void)
{
configfs_unregister_subsystem(&netconsole_subsys);
}
/*
* Targets that were created by parsing the boot/module option string
* do not exist in the configfs hierarchy (and have NULL names) and will
* never go away, so make these a no-op for them.
*/
static void netconsole_target_get(struct netconsole_target *nt)
{
if (config_item_name(&nt->item))
config_item_get(&nt->item);
}
static void netconsole_target_put(struct netconsole_target *nt)
{
if (config_item_name(&nt->item))
config_item_put(&nt->item);
}
#else /* !CONFIG_NETCONSOLE_DYNAMIC */
static int __init dynamic_netconsole_init(void)
{
return 0;
}
static void __exit dynamic_netconsole_exit(void)
{
}
/*
* No danger of targets going away from under us when dynamic
* reconfigurability is off.
*/
static void netconsole_target_get(struct netconsole_target *nt)
{
}
static void netconsole_target_put(struct netconsole_target *nt)
{
}
#endif /* CONFIG_NETCONSOLE_DYNAMIC */
/* Allocate new target (from boot/module param) and setup netpoll for it */
static struct netconsole_target *alloc_param_target(char *target_config)
{
int err = -ENOMEM;
struct netconsole_target *nt;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
/*
* Allocate and initialize with defaults.
* Note that these targets get their config_item fields zeroed-out.
*/
nt = kzalloc(sizeof(*nt), GFP_KERNEL);
if (!nt)
goto fail;
nt->np.name = "netconsole";
strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
nt->np.local_port = 6665;
nt->np.remote_port = 6666;
netconsole: avoid a crash with multiple sysfs writers When my 'ifup eth' script was fired multiple times and ran concurrent on my laptop, for some obscure /etc scripting reason, it was revealed that the store_enabled() function in netconsole doesn't handle it nicely, as recorded by the Oops below (a syslog paste, but not mangled too much to prevent from discerning the traceback). On Linux 3.10.4, this patch seeks to remedy the problem, and it has been running stable on my laptop for a few days. [52608.609325] BUG: unable to handle kernel NULL pointer dereference at 00000000000003e0 [52608.609331] IP: [<ffffffff81532a17>] __netpoll_cleanup+0x27/0xe0 [52608.609339] PGD 15e51a067 PUD 15433e067 PMD 0 [52608.609343] Oops: 0000 [#1] SMP re firewire_ohci firewire_core crc_itu_t [last unloaded: kvm_intel] [52608.609347] Modules linked in: kvm_intel tun vfat fat ppdev parport_pc parport fuse ipt_MASQUERADE usb_storage nf_conntrack_netbios_ns nf_conn [..garbled..] [52608.609433] RAX: 0000000000000000 RBX: ffff880210bbcc68 RCX: 0000000000000000 [52608.609435] RDX: 0000000000000000 RSI: ffff8801ba447da0 RDI: ffff880210bbcc68 [52608.609437] RBP: ffff8801ba447e18 R08: 0000000000000000 R09: 0000000000000001 [52608.609439] R10: 000000000000000a R11: f000000000000000 R12: ffff880210bbcc68 [52608.609441] R13: ffff88020bc41000 R14: 0000000000000002 R15: 000000000000000200000000000 [52608.609443] FS: 00007f38d7bff740(0000) GS:ffff88021dc40000(0000) knlGS:0000000000000000 [52608.609446] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003300000000001427e0 [52608.609448] CR2: 00000000000003e0 CR3: 0000000154103000 CR4: 00000000001427e0 [52608.609450] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [52608.609452] netpoll: netconsole: local port 6665ess 10.0.0.27 [52608.609454] netpoll: netconsole: local IPv4 address 10.0.0.27 [52608.609456] netpoll: netconsole: interface 'em1' [52608.609457] netpoll: netconsole: remote port 514ress 10.0.0.15 [52608.609459] netpoll: netconsole: remote IPv4 address 10.0.0.15:65:a8:9a:c7 [52608.609461] netpoll: netconsole: remote ethernet address 1c:6f:65:a8:9a:c7 [52608.609463] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [52608.609464] Stack:801ba447e08 ffff880210bbcc68 ffffffffffffffea ffff88020bc41000 [52608.609466] ffff8801ba447e08 ffff880210bbcc68 ffffffffffffffea ffff88020bc41000 [52608.609471] 0000000000000002 0000000000000002 ffff8801ba447e38 ffffffff81532af4 [52608.609475] 0000000000000000 ffff880210bbcc00 ffff8801ba447e78 ffffffff81420e7c [52608.609479] Call Trace: [52608.609484] [<ffffffff81532af4>] netpoll_cleanup+0x24/0x50 [52608.609489] [<ffffffff81420e7c>] store_enabled+0x5c/0xe0 [52608.609492] [<ffffffff81420abe>] netconsole_target_attr_store+0x2e/0x40 [52608.609498] [<ffffffff811ff2a2>] configfs_write_file+0xd2/0x130 [52608.609503] [<ffffffff81188f95>] vfs_write+0xc5/0x1f0 [52608.609506] [<ffffffff81189482>] SyS_write+0x52/0xa0/0x10 [52608.609511] [<ffffffff81628c2e>] ? do_page_fault+0xe/0x10 [52608.609516] [<ffffffff8162d402>] system_call_fastpath+0x16/0x1b [52608.609517] Code: 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 30 4c 89 65 e0 48 89 5d d8 49 89 fc 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 48 8 [..garbled..] [52608.609559] RIP [<ffffffff81532a17>] __netpoll_cleanup+0x27/0xe0 [52608.609563] RSP <ffff8801ba447de8> [52608.609564] CR2: 00000000000003e0 [52608.609567] ---[ end trace d25ec343349b61d2 ]--- Signed-off-by: Dan Aloni <alonid@postram.com> Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: David S. Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-30 10:59:46 +00:00
mutex_init(&nt->mutex);
eth_broadcast_addr(nt->np.remote_mac);
/* Parse parameters and setup netpoll */
err = netpoll_parse_options(&nt->np, target_config);
if (err)
goto fail;
err = netpoll_setup(&nt->np);
if (err)
goto fail;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
nt->enabled = 1;
return nt;
fail:
kfree(nt);
return ERR_PTR(err);
}
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
/* Cleanup netpoll for given target (from boot/module param) and free it */
static void free_param_target(struct netconsole_target *nt)
{
netpoll_cleanup(&nt->np);
kfree(nt);
}
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
#ifdef CONFIG_NETCONSOLE_DYNAMIC
/*
* Our subsystem hierarchy is:
*
* /sys/kernel/config/netconsole/
* |
* <target>/
* | enabled
* | dev_name
* | local_port
* | remote_port
* | local_ip
* | remote_ip
* | local_mac
* | remote_mac
* |
* <target>/...
*/
struct netconsole_target_attr {
struct configfs_attribute attr;
ssize_t (*show)(struct netconsole_target *nt,
char *buf);
ssize_t (*store)(struct netconsole_target *nt,
const char *buf,
size_t count);
};
static struct netconsole_target *to_target(struct config_item *item)
{
return item ?
container_of(item, struct netconsole_target, item) :
NULL;
}
/*
* Attribute operations for netconsole_target.
*/
static ssize_t show_enabled(struct netconsole_target *nt, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%d\n", nt->enabled);
}
static ssize_t show_dev_name(struct netconsole_target *nt, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%s\n", nt->np.dev_name);
}
static ssize_t show_local_port(struct netconsole_target *nt, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.local_port);
}
static ssize_t show_remote_port(struct netconsole_target *nt, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%d\n", nt->np.remote_port);
}
static ssize_t show_local_ip(struct netconsole_target *nt, char *buf)
{
if (nt->np.ipv6)
return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.local_ip.in6);
else
return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.local_ip);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
}
static ssize_t show_remote_ip(struct netconsole_target *nt, char *buf)
{
if (nt->np.ipv6)
return snprintf(buf, PAGE_SIZE, "%pI6c\n", &nt->np.remote_ip.in6);
else
return snprintf(buf, PAGE_SIZE, "%pI4\n", &nt->np.remote_ip);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
}
static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
{
struct net_device *dev = nt->np.dev;
static const u8 bcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
return snprintf(buf, PAGE_SIZE, "%pM\n", dev ? dev->dev_addr : bcast);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
}
static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)
{
return snprintf(buf, PAGE_SIZE, "%pM\n", nt->np.remote_mac);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
}
/*
* This one is special -- targets created through the configfs interface
* are not enabled (and the corresponding netpoll activated) by default.
* The user is expected to set the desired parameters first (which
* would enable him to dynamically add new netpoll targets for new
* network interfaces as and when they come up).
*/
static ssize_t store_enabled(struct netconsole_target *nt,
const char *buf,
size_t count)
{
unsigned long flags;
int enabled;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
int err;
err = kstrtoint(buf, 10, &enabled);
if (err < 0)
return err;
if (enabled < 0 || enabled > 1)
return -EINVAL;
if (enabled == nt->enabled) {
pr_info("network logging has already %s\n",
nt->enabled ? "started" : "stopped");
return -EINVAL;
}
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
if (enabled) { /* 1 */
/*
* Skip netpoll_parse_options() -- all the attributes are
* already configured via configfs. Just print them out.
*/
netpoll_print_options(&nt->np);
err = netpoll_setup(&nt->np);
if (err)
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return err;
pr_info("netconsole: network logging started\n");
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
} else { /* 0 */
/* We need to disable the netconsole before cleaning it up
* otherwise we might end up in write_msg() with
* nt->np.dev == NULL and nt->enabled == 1
*/
spin_lock_irqsave(&target_list_lock, flags);
nt->enabled = 0;
spin_unlock_irqrestore(&target_list_lock, flags);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
netpoll_cleanup(&nt->np);
}
nt->enabled = enabled;
return strnlen(buf, count);
}
static ssize_t store_dev_name(struct netconsole_target *nt,
const char *buf,
size_t count)
{
size_t len;
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->item));
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return -EINVAL;
}
strlcpy(nt->np.dev_name, buf, IFNAMSIZ);
/* Get rid of possible trailing newline from echo(1) */
len = strnlen(nt->np.dev_name, IFNAMSIZ);
if (nt->np.dev_name[len - 1] == '\n')
nt->np.dev_name[len - 1] = '\0';
return strnlen(buf, count);
}
static ssize_t store_local_port(struct netconsole_target *nt,
const char *buf,
size_t count)
{
int rv;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->item));
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return -EINVAL;
}
rv = kstrtou16(buf, 10, &nt->np.local_port);
if (rv < 0)
return rv;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return strnlen(buf, count);
}
static ssize_t store_remote_port(struct netconsole_target *nt,
const char *buf,
size_t count)
{
int rv;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->item));
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return -EINVAL;
}
rv = kstrtou16(buf, 10, &nt->np.remote_port);
if (rv < 0)
return rv;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return strnlen(buf, count);
}
static ssize_t store_local_ip(struct netconsole_target *nt,
const char *buf,
size_t count)
{
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->item));
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return -EINVAL;
}
if (strnchr(buf, count, ':')) {
const char *end;
if (in6_pton(buf, count, nt->np.local_ip.in6.s6_addr, -1, &end) > 0) {
if (*end && *end != '\n') {
pr_err("invalid IPv6 address at: <%c>\n", *end);
return -EINVAL;
}
nt->np.ipv6 = true;
} else
return -EINVAL;
} else {
if (!nt->np.ipv6) {
nt->np.local_ip.ip = in_aton(buf);
} else
return -EINVAL;
}
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return strnlen(buf, count);
}
static ssize_t store_remote_ip(struct netconsole_target *nt,
const char *buf,
size_t count)
{
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->item));
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return -EINVAL;
}
if (strnchr(buf, count, ':')) {
const char *end;
if (in6_pton(buf, count, nt->np.remote_ip.in6.s6_addr, -1, &end) > 0) {
if (*end && *end != '\n') {
pr_err("invalid IPv6 address at: <%c>\n", *end);
return -EINVAL;
}
nt->np.ipv6 = true;
} else
return -EINVAL;
} else {
if (!nt->np.ipv6) {
nt->np.remote_ip.ip = in_aton(buf);
} else
return -EINVAL;
}
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return strnlen(buf, count);
}
static ssize_t store_remote_mac(struct netconsole_target *nt,
const char *buf,
size_t count)
{
u8 remote_mac[ETH_ALEN];
if (nt->enabled) {
pr_err("target (%s) is enabled, disable to update parameters\n",
config_item_name(&nt->item));
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return -EINVAL;
}
if (!mac_pton(buf, remote_mac))
return -EINVAL;
if (buf[3 * ETH_ALEN - 1] && buf[3 * ETH_ALEN - 1] != '\n')
return -EINVAL;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);
return strnlen(buf, count);
}
/*
* Attribute definitions for netconsole_target.
*/
#define NETCONSOLE_TARGET_ATTR_RO(_name) \
static struct netconsole_target_attr netconsole_target_##_name = \
__CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)
#define NETCONSOLE_TARGET_ATTR_RW(_name) \
static struct netconsole_target_attr netconsole_target_##_name = \
__CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)
NETCONSOLE_TARGET_ATTR_RW(enabled);
NETCONSOLE_TARGET_ATTR_RW(dev_name);
NETCONSOLE_TARGET_ATTR_RW(local_port);
NETCONSOLE_TARGET_ATTR_RW(remote_port);
NETCONSOLE_TARGET_ATTR_RW(local_ip);
NETCONSOLE_TARGET_ATTR_RW(remote_ip);
NETCONSOLE_TARGET_ATTR_RO(local_mac);
NETCONSOLE_TARGET_ATTR_RW(remote_mac);
static struct configfs_attribute *netconsole_target_attrs[] = {
&netconsole_target_enabled.attr,
&netconsole_target_dev_name.attr,
&netconsole_target_local_port.attr,
&netconsole_target_remote_port.attr,
&netconsole_target_local_ip.attr,
&netconsole_target_remote_ip.attr,
&netconsole_target_local_mac.attr,
&netconsole_target_remote_mac.attr,
NULL,
};
/*
* Item operations and type for netconsole_target.
*/
static void netconsole_target_release(struct config_item *item)
{
kfree(to_target(item));
}
static ssize_t netconsole_target_attr_show(struct config_item *item,
struct configfs_attribute *attr,
char *buf)
{
ssize_t ret = -EINVAL;
struct netconsole_target *nt = to_target(item);
struct netconsole_target_attr *na =
container_of(attr, struct netconsole_target_attr, attr);
if (na->show)
ret = na->show(nt, buf);
return ret;
}
static ssize_t netconsole_target_attr_store(struct config_item *item,
struct configfs_attribute *attr,
const char *buf,
size_t count)
{
ssize_t ret = -EINVAL;
struct netconsole_target *nt = to_target(item);
struct netconsole_target_attr *na =
container_of(attr, struct netconsole_target_attr, attr);
mutex_lock(&nt->mutex);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
if (na->store)
ret = na->store(nt, buf, count);
mutex_unlock(&nt->mutex);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
return ret;
}
static struct configfs_item_operations netconsole_target_item_ops = {
.release = netconsole_target_release,
.show_attribute = netconsole_target_attr_show,
.store_attribute = netconsole_target_attr_store,
};
static struct config_item_type netconsole_target_type = {
.ct_attrs = netconsole_target_attrs,
.ct_item_ops = &netconsole_target_item_ops,
.ct_owner = THIS_MODULE,
};
/*
* Group operations and type for netconsole_subsys.
*/
static struct config_item *make_netconsole_target(struct config_group *group,
const char *name)
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
{
unsigned long flags;
struct netconsole_target *nt;
/*
* Allocate and initialize with defaults.
* Target is disabled at creation (enabled == 0).
*/
nt = kzalloc(sizeof(*nt), GFP_KERNEL);
if (!nt)
return ERR_PTR(-ENOMEM);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
nt->np.name = "netconsole";
strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
nt->np.local_port = 6665;
nt->np.remote_port = 6666;
netconsole: avoid a crash with multiple sysfs writers When my 'ifup eth' script was fired multiple times and ran concurrent on my laptop, for some obscure /etc scripting reason, it was revealed that the store_enabled() function in netconsole doesn't handle it nicely, as recorded by the Oops below (a syslog paste, but not mangled too much to prevent from discerning the traceback). On Linux 3.10.4, this patch seeks to remedy the problem, and it has been running stable on my laptop for a few days. [52608.609325] BUG: unable to handle kernel NULL pointer dereference at 00000000000003e0 [52608.609331] IP: [<ffffffff81532a17>] __netpoll_cleanup+0x27/0xe0 [52608.609339] PGD 15e51a067 PUD 15433e067 PMD 0 [52608.609343] Oops: 0000 [#1] SMP re firewire_ohci firewire_core crc_itu_t [last unloaded: kvm_intel] [52608.609347] Modules linked in: kvm_intel tun vfat fat ppdev parport_pc parport fuse ipt_MASQUERADE usb_storage nf_conntrack_netbios_ns nf_conn [..garbled..] [52608.609433] RAX: 0000000000000000 RBX: ffff880210bbcc68 RCX: 0000000000000000 [52608.609435] RDX: 0000000000000000 RSI: ffff8801ba447da0 RDI: ffff880210bbcc68 [52608.609437] RBP: ffff8801ba447e18 R08: 0000000000000000 R09: 0000000000000001 [52608.609439] R10: 000000000000000a R11: f000000000000000 R12: ffff880210bbcc68 [52608.609441] R13: ffff88020bc41000 R14: 0000000000000002 R15: 000000000000000200000000000 [52608.609443] FS: 00007f38d7bff740(0000) GS:ffff88021dc40000(0000) knlGS:0000000000000000 [52608.609446] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003300000000001427e0 [52608.609448] CR2: 00000000000003e0 CR3: 0000000154103000 CR4: 00000000001427e0 [52608.609450] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [52608.609452] netpoll: netconsole: local port 6665ess 10.0.0.27 [52608.609454] netpoll: netconsole: local IPv4 address 10.0.0.27 [52608.609456] netpoll: netconsole: interface 'em1' [52608.609457] netpoll: netconsole: remote port 514ress 10.0.0.15 [52608.609459] netpoll: netconsole: remote IPv4 address 10.0.0.15:65:a8:9a:c7 [52608.609461] netpoll: netconsole: remote ethernet address 1c:6f:65:a8:9a:c7 [52608.609463] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [52608.609464] Stack:801ba447e08 ffff880210bbcc68 ffffffffffffffea ffff88020bc41000 [52608.609466] ffff8801ba447e08 ffff880210bbcc68 ffffffffffffffea ffff88020bc41000 [52608.609471] 0000000000000002 0000000000000002 ffff8801ba447e38 ffffffff81532af4 [52608.609475] 0000000000000000 ffff880210bbcc00 ffff8801ba447e78 ffffffff81420e7c [52608.609479] Call Trace: [52608.609484] [<ffffffff81532af4>] netpoll_cleanup+0x24/0x50 [52608.609489] [<ffffffff81420e7c>] store_enabled+0x5c/0xe0 [52608.609492] [<ffffffff81420abe>] netconsole_target_attr_store+0x2e/0x40 [52608.609498] [<ffffffff811ff2a2>] configfs_write_file+0xd2/0x130 [52608.609503] [<ffffffff81188f95>] vfs_write+0xc5/0x1f0 [52608.609506] [<ffffffff81189482>] SyS_write+0x52/0xa0/0x10 [52608.609511] [<ffffffff81628c2e>] ? do_page_fault+0xe/0x10 [52608.609516] [<ffffffff8162d402>] system_call_fastpath+0x16/0x1b [52608.609517] Code: 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 30 4c 89 65 e0 48 89 5d d8 49 89 fc 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 48 8 [..garbled..] [52608.609559] RIP [<ffffffff81532a17>] __netpoll_cleanup+0x27/0xe0 [52608.609563] RSP <ffff8801ba447de8> [52608.609564] CR2: 00000000000003e0 [52608.609567] ---[ end trace d25ec343349b61d2 ]--- Signed-off-by: Dan Aloni <alonid@postram.com> Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: David S. Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-30 10:59:46 +00:00
mutex_init(&nt->mutex);
eth_broadcast_addr(nt->np.remote_mac);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
/* Initialize the config_item member */
config_item_init_type_name(&nt->item, name, &netconsole_target_type);
/* Adding, but it is disabled */
spin_lock_irqsave(&target_list_lock, flags);
list_add(&nt->list, &target_list);
spin_unlock_irqrestore(&target_list_lock, flags);
return &nt->item;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
}
static void drop_netconsole_target(struct config_group *group,
struct config_item *item)
{
unsigned long flags;
struct netconsole_target *nt = to_target(item);
spin_lock_irqsave(&target_list_lock, flags);
list_del(&nt->list);
spin_unlock_irqrestore(&target_list_lock, flags);
/*
* The target may have never been enabled, or was manually disabled
* before being removed so netpoll may have already been cleaned up.
*/
if (nt->enabled)
netpoll_cleanup(&nt->np);
config_item_put(&nt->item);
}
static struct configfs_group_operations netconsole_subsys_group_ops = {
.make_item = make_netconsole_target,
.drop_item = drop_netconsole_target,
};
static struct config_item_type netconsole_subsys_type = {
.ct_group_ops = &netconsole_subsys_group_ops,
.ct_owner = THIS_MODULE,
};
/* The netconsole configfs subsystem */
static struct configfs_subsystem netconsole_subsys = {
.su_group = {
.cg_item = {
.ci_namebuf = "netconsole",
.ci_type = &netconsole_subsys_type,
},
},
};
#endif /* CONFIG_NETCONSOLE_DYNAMIC */
/* Handle network interface device notifications */
static int netconsole_netdev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
unsigned long flags;
struct netconsole_target *nt;
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
bool stopped = false;
if (!(event == NETDEV_CHANGENAME || event == NETDEV_UNREGISTER ||
event == NETDEV_RELEASE || event == NETDEV_JOIN))
goto done;
spin_lock_irqsave(&target_list_lock, flags);
restart:
list_for_each_entry(nt, &target_list, list) {
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
netconsole_target_get(nt);
if (nt->np.dev == dev) {
switch (event) {
case NETDEV_CHANGENAME:
strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
break;
case NETDEV_RELEASE:
case NETDEV_JOIN:
case NETDEV_UNREGISTER:
/* rtnl_lock already held
* we might sleep in __netpoll_cleanup()
*/
spin_unlock_irqrestore(&target_list_lock, flags);
netconsole: avoid a crash with multiple sysfs writers When my 'ifup eth' script was fired multiple times and ran concurrent on my laptop, for some obscure /etc scripting reason, it was revealed that the store_enabled() function in netconsole doesn't handle it nicely, as recorded by the Oops below (a syslog paste, but not mangled too much to prevent from discerning the traceback). On Linux 3.10.4, this patch seeks to remedy the problem, and it has been running stable on my laptop for a few days. [52608.609325] BUG: unable to handle kernel NULL pointer dereference at 00000000000003e0 [52608.609331] IP: [<ffffffff81532a17>] __netpoll_cleanup+0x27/0xe0 [52608.609339] PGD 15e51a067 PUD 15433e067 PMD 0 [52608.609343] Oops: 0000 [#1] SMP re firewire_ohci firewire_core crc_itu_t [last unloaded: kvm_intel] [52608.609347] Modules linked in: kvm_intel tun vfat fat ppdev parport_pc parport fuse ipt_MASQUERADE usb_storage nf_conntrack_netbios_ns nf_conn [..garbled..] [52608.609433] RAX: 0000000000000000 RBX: ffff880210bbcc68 RCX: 0000000000000000 [52608.609435] RDX: 0000000000000000 RSI: ffff8801ba447da0 RDI: ffff880210bbcc68 [52608.609437] RBP: ffff8801ba447e18 R08: 0000000000000000 R09: 0000000000000001 [52608.609439] R10: 000000000000000a R11: f000000000000000 R12: ffff880210bbcc68 [52608.609441] R13: ffff88020bc41000 R14: 0000000000000002 R15: 000000000000000200000000000 [52608.609443] FS: 00007f38d7bff740(0000) GS:ffff88021dc40000(0000) knlGS:0000000000000000 [52608.609446] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003300000000001427e0 [52608.609448] CR2: 00000000000003e0 CR3: 0000000154103000 CR4: 00000000001427e0 [52608.609450] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [52608.609452] netpoll: netconsole: local port 6665ess 10.0.0.27 [52608.609454] netpoll: netconsole: local IPv4 address 10.0.0.27 [52608.609456] netpoll: netconsole: interface 'em1' [52608.609457] netpoll: netconsole: remote port 514ress 10.0.0.15 [52608.609459] netpoll: netconsole: remote IPv4 address 10.0.0.15:65:a8:9a:c7 [52608.609461] netpoll: netconsole: remote ethernet address 1c:6f:65:a8:9a:c7 [52608.609463] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [52608.609464] Stack:801ba447e08 ffff880210bbcc68 ffffffffffffffea ffff88020bc41000 [52608.609466] ffff8801ba447e08 ffff880210bbcc68 ffffffffffffffea ffff88020bc41000 [52608.609471] 0000000000000002 0000000000000002 ffff8801ba447e38 ffffffff81532af4 [52608.609475] 0000000000000000 ffff880210bbcc00 ffff8801ba447e78 ffffffff81420e7c [52608.609479] Call Trace: [52608.609484] [<ffffffff81532af4>] netpoll_cleanup+0x24/0x50 [52608.609489] [<ffffffff81420e7c>] store_enabled+0x5c/0xe0 [52608.609492] [<ffffffff81420abe>] netconsole_target_attr_store+0x2e/0x40 [52608.609498] [<ffffffff811ff2a2>] configfs_write_file+0xd2/0x130 [52608.609503] [<ffffffff81188f95>] vfs_write+0xc5/0x1f0 [52608.609506] [<ffffffff81189482>] SyS_write+0x52/0xa0/0x10 [52608.609511] [<ffffffff81628c2e>] ? do_page_fault+0xe/0x10 [52608.609516] [<ffffffff8162d402>] system_call_fastpath+0x16/0x1b [52608.609517] Code: 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 30 4c 89 65 e0 48 89 5d d8 49 89 fc 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 48 8 [..garbled..] [52608.609559] RIP [<ffffffff81532a17>] __netpoll_cleanup+0x27/0xe0 [52608.609563] RSP <ffff8801ba447de8> [52608.609564] CR2: 00000000000003e0 [52608.609567] ---[ end trace d25ec343349b61d2 ]--- Signed-off-by: Dan Aloni <alonid@postram.com> Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: David S. Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-30 10:59:46 +00:00
__netpoll_cleanup(&nt->np);
netconsole: avoid a crash with multiple sysfs writers When my 'ifup eth' script was fired multiple times and ran concurrent on my laptop, for some obscure /etc scripting reason, it was revealed that the store_enabled() function in netconsole doesn't handle it nicely, as recorded by the Oops below (a syslog paste, but not mangled too much to prevent from discerning the traceback). On Linux 3.10.4, this patch seeks to remedy the problem, and it has been running stable on my laptop for a few days. [52608.609325] BUG: unable to handle kernel NULL pointer dereference at 00000000000003e0 [52608.609331] IP: [<ffffffff81532a17>] __netpoll_cleanup+0x27/0xe0 [52608.609339] PGD 15e51a067 PUD 15433e067 PMD 0 [52608.609343] Oops: 0000 [#1] SMP re firewire_ohci firewire_core crc_itu_t [last unloaded: kvm_intel] [52608.609347] Modules linked in: kvm_intel tun vfat fat ppdev parport_pc parport fuse ipt_MASQUERADE usb_storage nf_conntrack_netbios_ns nf_conn [..garbled..] [52608.609433] RAX: 0000000000000000 RBX: ffff880210bbcc68 RCX: 0000000000000000 [52608.609435] RDX: 0000000000000000 RSI: ffff8801ba447da0 RDI: ffff880210bbcc68 [52608.609437] RBP: ffff8801ba447e18 R08: 0000000000000000 R09: 0000000000000001 [52608.609439] R10: 000000000000000a R11: f000000000000000 R12: ffff880210bbcc68 [52608.609441] R13: ffff88020bc41000 R14: 0000000000000002 R15: 000000000000000200000000000 [52608.609443] FS: 00007f38d7bff740(0000) GS:ffff88021dc40000(0000) knlGS:0000000000000000 [52608.609446] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003300000000001427e0 [52608.609448] CR2: 00000000000003e0 CR3: 0000000154103000 CR4: 00000000001427e0 [52608.609450] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [52608.609452] netpoll: netconsole: local port 6665ess 10.0.0.27 [52608.609454] netpoll: netconsole: local IPv4 address 10.0.0.27 [52608.609456] netpoll: netconsole: interface 'em1' [52608.609457] netpoll: netconsole: remote port 514ress 10.0.0.15 [52608.609459] netpoll: netconsole: remote IPv4 address 10.0.0.15:65:a8:9a:c7 [52608.609461] netpoll: netconsole: remote ethernet address 1c:6f:65:a8:9a:c7 [52608.609463] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [52608.609464] Stack:801ba447e08 ffff880210bbcc68 ffffffffffffffea ffff88020bc41000 [52608.609466] ffff8801ba447e08 ffff880210bbcc68 ffffffffffffffea ffff88020bc41000 [52608.609471] 0000000000000002 0000000000000002 ffff8801ba447e38 ffffffff81532af4 [52608.609475] 0000000000000000 ffff880210bbcc00 ffff8801ba447e78 ffffffff81420e7c [52608.609479] Call Trace: [52608.609484] [<ffffffff81532af4>] netpoll_cleanup+0x24/0x50 [52608.609489] [<ffffffff81420e7c>] store_enabled+0x5c/0xe0 [52608.609492] [<ffffffff81420abe>] netconsole_target_attr_store+0x2e/0x40 [52608.609498] [<ffffffff811ff2a2>] configfs_write_file+0xd2/0x130 [52608.609503] [<ffffffff81188f95>] vfs_write+0xc5/0x1f0 [52608.609506] [<ffffffff81189482>] SyS_write+0x52/0xa0/0x10 [52608.609511] [<ffffffff81628c2e>] ? do_page_fault+0xe/0x10 [52608.609516] [<ffffffff8162d402>] system_call_fastpath+0x16/0x1b [52608.609517] Code: 1f 44 00 00 0f 1f 44 00 00 55 48 89 e5 48 83 ec 30 4c 89 65 e0 48 89 5d d8 49 89 fc 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 48 8 [..garbled..] [52608.609559] RIP [<ffffffff81532a17>] __netpoll_cleanup+0x27/0xe0 [52608.609563] RSP <ffff8801ba447de8> [52608.609564] CR2: 00000000000003e0 [52608.609567] ---[ end trace d25ec343349b61d2 ]--- Signed-off-by: Dan Aloni <alonid@postram.com> Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: David S. Miller <davem@davemloft.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-08-30 10:59:46 +00:00
spin_lock_irqsave(&target_list_lock, flags);
dev_put(nt->np.dev);
nt->np.dev = NULL;
nt->enabled = 0;
stopped = true;
netconsole_target_put(nt);
goto restart;
}
}
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
netconsole_target_put(nt);
}
spin_unlock_irqrestore(&target_list_lock, flags);
if (stopped) {
const char *msg = "had an event";
switch (event) {
case NETDEV_UNREGISTER:
msg = "unregistered";
break;
case NETDEV_RELEASE:
msg = "released slaves";
break;
case NETDEV_JOIN:
msg = "is joining a master device";
break;
}
pr_info("network logging stopped on interface %s as it %s\n",
dev->name, msg);
}
done:
return NOTIFY_DONE;
}
static struct notifier_block netconsole_netdev_notifier = {
.notifier_call = netconsole_netdev_event,
};
static void write_msg(struct console *con, const char *msg, unsigned int len)
{
int frag, left;
unsigned long flags;
struct netconsole_target *nt;
const char *tmp;
if (oops_only && !oops_in_progress)
return;
/* Avoid taking lock and disabling interrupts unnecessarily */
if (list_empty(&target_list))
return;
spin_lock_irqsave(&target_list_lock, flags);
list_for_each_entry(nt, &target_list, list) {
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
netconsole_target_get(nt);
if (nt->enabled && netif_running(nt->np.dev)) {
/*
* We nest this inside the for-each-target loop above
* so that we're able to get as much logging out to
* at least one target if we die inside here, instead
* of unnecessarily keeping all targets in lock-step.
*/
tmp = msg;
for (left = len; left;) {
frag = min(left, MAX_PRINT_CHUNK);
netpoll_send_udp(&nt->np, tmp, frag);
tmp += frag;
left -= frag;
}
}
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
netconsole_target_put(nt);
}
spin_unlock_irqrestore(&target_list_lock, flags);
}
static struct console netconsole = {
.name = "netcon",
.flags = CON_ENABLED,
.write = write_msg,
};
static int __init init_netconsole(void)
{
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
int err;
struct netconsole_target *nt, *tmp;
unsigned long flags;
char *target_config;
char *input = config;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
if (strnlen(input, MAX_PARAM_LENGTH)) {
while ((target_config = strsep(&input, ";"))) {
nt = alloc_param_target(target_config);
if (IS_ERR(nt)) {
err = PTR_ERR(nt);
goto fail;
}
/* Dump existing printks when we register */
netconsole.flags |= CON_PRINTBUFFER;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
spin_lock_irqsave(&target_list_lock, flags);
list_add(&nt->list, &target_list);
spin_unlock_irqrestore(&target_list_lock, flags);
}
}
err = register_netdevice_notifier(&netconsole_netdev_notifier);
if (err)
goto fail;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
err = dynamic_netconsole_init();
if (err)
goto undonotifier;
register_console(&netconsole);
pr_info("network logging started\n");
return err;
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
undonotifier:
unregister_netdevice_notifier(&netconsole_netdev_notifier);
fail:
pr_err("cleaning up\n");
/*
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
* Remove all targets and destroy them (only targets created
* from the boot/module option exist here). Skipping the list
* lock is safe here, and netpoll_cleanup() will sleep.
*/
list_for_each_entry_safe(nt, tmp, &target_list, list) {
list_del(&nt->list);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
free_param_target(nt);
}
return err;
}
static void __exit cleanup_netconsole(void)
{
struct netconsole_target *nt, *tmp;
unregister_console(&netconsole);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
dynamic_netconsole_exit();
unregister_netdevice_notifier(&netconsole_netdev_notifier);
/*
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
* Targets created via configfs pin references on our module
* and would first be rmdir(2)'ed from userspace. We reach
* here only when they are already destroyed, and only those
* created from the boot/module option are left, so remove and
* destroy them. Skipping the list lock is safe here, and
* netpoll_cleanup() will sleep.
*/
list_for_each_entry_safe(nt, tmp, &target_list, list) {
list_del(&nt->list);
[NET] netconsole: Support dynamic reconfiguration using configfs Based upon initial work by Keiichi Kii <k-keiichi@bx.jp.nec.com>. This patch introduces support for dynamic reconfiguration (adding, removing and/or modifying parameters of netconsole targets at runtime) using a userspace interface exported via configfs. Documentation is also updated accordingly. Issues and brief design overview: (1) Kernel-initiated creation / destruction of kernel objects is not possible with configfs -- the lifetimes of the "config items" is managed exclusively from userspace. But netconsole must support boot/module params too, and these are parsed in kernel and hence netpolls must be setup from the kernel. Joel Becker suggested to separately manage the lifetimes of the two kinds of netconsole_target objects -- those created via configfs mkdir(2) from userspace and those specified from the boot/module option string. This adds complexity and some redundancy here and also means that boot/module param-created targets are not exposed through the configfs namespace (and hence cannot be updated / destroyed dynamically). However, this saves us from locking / refcounting complexities that would need to be introduced in configfs to support kernel-initiated item creation / destroy there. (2) In configfs, item creation takes place in the call chain of the mkdir(2) syscall in the driver subsystem. If we used an ioctl(2) to create / destroy objects from userspace, the special userspace program is able to fill out the structure to be passed into the ioctl and hence specify attributes such as local interface that are required at the time we set up the netpoll. For configfs, this information is not available at the time of mkdir(2). So, we keep all newly-created targets (via configfs) disabled by default. The user is expected to set various attributes appropriately (including the local network interface if required) and then write(2) "1" to the "enabled" attribute. Thus, netpoll_setup() is then called on the set parameters in the context of _this_ write(2) on the "enabled" attribute itself. This design enables the user to reconfigure existing netconsole targets at runtime to be attached to newly-come-up interfaces that may not have existed when netconsole was loaded or when the targets were actually created. All this effectively enables us to get rid of custom ioctls. (3) Ultra-paranoid configfs attribute show() and store() operations, with sanity and input range checking, using only safe string primitives, and compliant with the recommendations in Documentation/filesystems/sysfs.txt. (4) A new function netpoll_print_options() is created in the netpoll API, that just prints out the configured parameters for a netpoll structure. netpoll_parse_options() is modified to use that and it is also exported to be used from netconsole. Signed-off-by: Satyam Sharma <satyam@infradead.org> Acked-by: Keiichi Kii <k-keiichi@bx.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-08-10 22:35:05 +00:00
free_param_target(nt);
}
}
/*
* Use late_initcall to ensure netconsole is
* initialized after network device driver if built-in.
*
* late_initcall() and module_init() are identical if built as module.
*/
late_initcall(init_netconsole);
module_exit(cleanup_netconsole);