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linux/fs/nfs/nfsroot.c
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2 
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

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/*
* $Id: nfsroot.c,v 1.45 1998/03/07 10:44:46 mj Exp $
*
* Copyright (C) 1995, 1996 Gero Kuhlmann <gero@gkminix.han.de>
*
* Allow an NFS filesystem to be mounted as root. The way this works is:
* (1) Use the IP autoconfig mechanism to set local IP addresses and routes.
* (2) Handle RPC negotiation with the system which replied to RARP or
* was reported as a boot server by BOOTP or manually.
* (3) The actual mounting is done later, when init() is running.
*
*
* Changes:
*
* Alan Cox : Removed get_address name clash with FPU.
* Alan Cox : Reformatted a bit.
* Gero Kuhlmann : Code cleanup
* Michael Rausch : Fixed recognition of an incoming RARP answer.
* Martin Mares : (2.0) Auto-configuration via BOOTP supported.
* Martin Mares : Manual selection of interface & BOOTP/RARP.
* Martin Mares : Using network routes instead of host routes,
* allowing the default configuration to be used
* for normal operation of the host.
* Martin Mares : Randomized timer with exponential backoff
* installed to minimize network congestion.
* Martin Mares : Code cleanup.
* Martin Mares : (2.1) BOOTP and RARP made configuration options.
* Martin Mares : Server hostname generation fixed.
* Gerd Knorr : Fixed wired inode handling
* Martin Mares : (2.2) "0.0.0.0" addresses from command line ignored.
* Martin Mares : RARP replies not tested for server address.
* Gero Kuhlmann : (2.3) Some bug fixes and code cleanup again (please
* send me your new patches _before_ bothering
* Linus so that I don' always have to cleanup
* _afterwards_ - thanks)
* Gero Kuhlmann : Last changes of Martin Mares undone.
* Gero Kuhlmann : RARP replies are tested for specified server
* again. However, it's now possible to have
* different RARP and NFS servers.
* Gero Kuhlmann : "0.0.0.0" addresses from command line are
* now mapped to INADDR_NONE.
* Gero Kuhlmann : Fixed a bug which prevented BOOTP path name
* from being used (thanks to Leo Spiekman)
* Andy Walker : Allow to specify the NFS server in nfs_root
* without giving a path name
* Swen Th<54>mmler : Allow to specify the NFS options in nfs_root
* without giving a path name. Fix BOOTP request
* for domainname (domainname is NIS domain, not
* DNS domain!). Skip dummy devices for BOOTP.
* Jacek Zapala : Fixed a bug which prevented server-ip address
* from nfsroot parameter from being used.
* Olaf Kirch : Adapted to new NFS code.
* Jakub Jelinek : Free used code segment.
* Marko Kohtala : Fixed some bugs.
* Martin Mares : Debug message cleanup
* Martin Mares : Changed to use the new generic IP layer autoconfig
* code. BOOTP and RARP moved there.
* Martin Mares : Default path now contains host name instead of
* host IP address (but host name defaults to IP
* address anyway).
* Martin Mares : Use root_server_addr appropriately during setup.
* Martin Mares : Rewrote parameter parsing, now hopefully giving
* correct overriding.
* Trond Myklebust : Add in preliminary support for NFSv3 and TCP.
* Fix bug in root_nfs_addr(). nfs_data.namlen
* is NOT for the length of the hostname.
* Hua Qin : Support for mounting root file system via
* NFS over TCP.
* Fabian Frederick: Option parser rebuilt (using parser lib)
*/
#include <linux/config.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/sunrpc/clnt.h>
#include <linux/nfs.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/in.h>
#include <linux/major.h>
#include <linux/utsname.h>
#include <linux/inet.h>
#include <linux/root_dev.h>
#include <net/ipconfig.h>
#include <linux/parser.h>
/* Define this to allow debugging output */
#undef NFSROOT_DEBUG
#define NFSDBG_FACILITY NFSDBG_ROOT
/* Default path we try to mount. "%s" gets replaced by our IP address */
#define NFS_ROOT "/tftpboot/%s"
/* Parameters passed from the kernel command line */
static char nfs_root_name[256] __initdata = "";
/* Address of NFS server */
static __u32 servaddr __initdata = 0;
/* Name of directory to mount */
static char nfs_path[NFS_MAXPATHLEN] __initdata = { 0, };
/* NFS-related data */
static struct nfs_mount_data nfs_data __initdata = { 0, };/* NFS mount info */
static int nfs_port __initdata = 0; /* Port to connect to for NFS */
static int mount_port __initdata = 0; /* Mount daemon port number */
/***************************************************************************
Parsing of options
***************************************************************************/
enum {
/* Options that take integer arguments */
Opt_port, Opt_rsize, Opt_wsize, Opt_timeo, Opt_retrans, Opt_acregmin,
Opt_acregmax, Opt_acdirmin, Opt_acdirmax,
/* Options that take no arguments */
Opt_soft, Opt_hard, Opt_intr,
Opt_nointr, Opt_posix, Opt_noposix, Opt_cto, Opt_nocto, Opt_ac,
Opt_noac, Opt_lock, Opt_nolock, Opt_v2, Opt_v3, Opt_udp, Opt_tcp,
/* Error token */
Opt_err
};
static match_table_t __initdata tokens = {
{Opt_port, "port=%u"},
{Opt_rsize, "rsize=%u"},
{Opt_wsize, "wsize=%u"},
{Opt_timeo, "timeo=%u"},
{Opt_retrans, "retrans=%u"},
{Opt_acregmin, "acregmin=%u"},
{Opt_acregmax, "acregmax=%u"},
{Opt_acdirmin, "acdirmin=%u"},
{Opt_acdirmax, "acdirmax=%u"},
{Opt_soft, "soft"},
{Opt_hard, "hard"},
{Opt_intr, "intr"},
{Opt_nointr, "nointr"},
{Opt_posix, "posix"},
{Opt_noposix, "noposix"},
{Opt_cto, "cto"},
{Opt_nocto, "nocto"},
{Opt_ac, "ac"},
{Opt_noac, "noac"},
{Opt_lock, "lock"},
{Opt_nolock, "nolock"},
{Opt_v2, "nfsvers=2"},
{Opt_v2, "v2"},
{Opt_v3, "nfsvers=3"},
{Opt_v3, "v3"},
{Opt_udp, "proto=udp"},
{Opt_udp, "udp"},
{Opt_tcp, "proto=tcp"},
{Opt_tcp, "tcp"},
{Opt_err, NULL}
};
/*
* Parse option string.
*/
static int __init root_nfs_parse(char *name, char *buf)
{
char *p;
substring_t args[MAX_OPT_ARGS];
int option;
if (!name)
return 1;
/* Set the NFS remote path */
p = strsep(&name, ",");
if (p[0] != '\0' && strcmp(p, "default") != 0)
strlcpy(buf, p, NFS_MAXPATHLEN);
while ((p = strsep (&name, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
/* %u tokens only. Beware if you add new tokens! */
if (token < Opt_soft && match_int(&args[0], &option))
return 0;
switch (token) {
case Opt_port:
nfs_port = option;
break;
case Opt_rsize:
nfs_data.rsize = option;
break;
case Opt_wsize:
nfs_data.wsize = option;
break;
case Opt_timeo:
nfs_data.timeo = option;
break;
case Opt_retrans:
nfs_data.retrans = option;
break;
case Opt_acregmin:
nfs_data.acregmin = option;
break;
case Opt_acregmax:
nfs_data.acregmax = option;
break;
case Opt_acdirmin:
nfs_data.acdirmin = option;
break;
case Opt_acdirmax:
nfs_data.acdirmax = option;
break;
case Opt_soft:
nfs_data.flags |= NFS_MOUNT_SOFT;
break;
case Opt_hard:
nfs_data.flags &= ~NFS_MOUNT_SOFT;
break;
case Opt_intr:
nfs_data.flags |= NFS_MOUNT_INTR;
break;
case Opt_nointr:
nfs_data.flags &= ~NFS_MOUNT_INTR;
break;
case Opt_posix:
nfs_data.flags |= NFS_MOUNT_POSIX;
break;
case Opt_noposix:
nfs_data.flags &= ~NFS_MOUNT_POSIX;
break;
case Opt_cto:
nfs_data.flags &= ~NFS_MOUNT_NOCTO;
break;
case Opt_nocto:
nfs_data.flags |= NFS_MOUNT_NOCTO;
break;
case Opt_ac:
nfs_data.flags &= ~NFS_MOUNT_NOAC;
break;
case Opt_noac:
nfs_data.flags |= NFS_MOUNT_NOAC;
break;
case Opt_lock:
nfs_data.flags &= ~NFS_MOUNT_NONLM;
break;
case Opt_nolock:
nfs_data.flags |= NFS_MOUNT_NONLM;
break;
case Opt_v2:
nfs_data.flags &= ~NFS_MOUNT_VER3;
break;
case Opt_v3:
nfs_data.flags |= NFS_MOUNT_VER3;
break;
case Opt_udp:
nfs_data.flags &= ~NFS_MOUNT_TCP;
break;
case Opt_tcp:
nfs_data.flags |= NFS_MOUNT_TCP;
break;
default :
return 0;
}
}
return 1;
}
/*
* Prepare the NFS data structure and parse all options.
*/
static int __init root_nfs_name(char *name)
{
static char buf[NFS_MAXPATHLEN] __initdata;
char *cp;
/* Set some default values */
memset(&nfs_data, 0, sizeof(nfs_data));
nfs_port = -1;
nfs_data.version = NFS_MOUNT_VERSION;
nfs_data.flags = NFS_MOUNT_NONLM; /* No lockd in nfs root yet */
nfs_data.rsize = NFS_DEF_FILE_IO_BUFFER_SIZE;
nfs_data.wsize = NFS_DEF_FILE_IO_BUFFER_SIZE;
nfs_data.acregmin = 3;
nfs_data.acregmax = 60;
nfs_data.acdirmin = 30;
nfs_data.acdirmax = 60;
strcpy(buf, NFS_ROOT);
/* Process options received from the remote server */
root_nfs_parse(root_server_path, buf);
/* Override them by options set on kernel command-line */
root_nfs_parse(name, buf);
cp = system_utsname.nodename;
if (strlen(buf) + strlen(cp) > NFS_MAXPATHLEN) {
printk(KERN_ERR "Root-NFS: Pathname for remote directory too long.\n");
return -1;
}
sprintf(nfs_path, buf, cp);
return 1;
}
/*
* Get NFS server address.
*/
static int __init root_nfs_addr(void)
{
if ((servaddr = root_server_addr) == INADDR_NONE) {
printk(KERN_ERR "Root-NFS: No NFS server available, giving up.\n");
return -1;
}
snprintf(nfs_data.hostname, sizeof(nfs_data.hostname),
"%u.%u.%u.%u", NIPQUAD(servaddr));
return 0;
}
/*
* Tell the user what's going on.
*/
#ifdef NFSROOT_DEBUG
static void __init root_nfs_print(void)
{
printk(KERN_NOTICE "Root-NFS: Mounting %s on server %s as root\n",
nfs_path, nfs_data.hostname);
printk(KERN_NOTICE "Root-NFS: rsize = %d, wsize = %d, timeo = %d, retrans = %d\n",
nfs_data.rsize, nfs_data.wsize, nfs_data.timeo, nfs_data.retrans);
printk(KERN_NOTICE "Root-NFS: acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
nfs_data.acregmin, nfs_data.acregmax,
nfs_data.acdirmin, nfs_data.acdirmax);
printk(KERN_NOTICE "Root-NFS: nfsd port = %d, mountd port = %d, flags = %08x\n",
nfs_port, mount_port, nfs_data.flags);
}
#endif
static int __init root_nfs_init(void)
{
#ifdef NFSROOT_DEBUG
nfs_debug |= NFSDBG_ROOT;
#endif
/*
* Decode the root directory path name and NFS options from
* the kernel command line. This has to go here in order to
* be able to use the client IP address for the remote root
* directory (necessary for pure RARP booting).
*/
if (root_nfs_name(nfs_root_name) < 0 ||
root_nfs_addr() < 0)
return -1;
#ifdef NFSROOT_DEBUG
root_nfs_print();
#endif
return 0;
}
/*
* Parse NFS server and directory information passed on the kernel
* command line.
*/
static int __init nfs_root_setup(char *line)
{
ROOT_DEV = Root_NFS;
if (line[0] == '/' || line[0] == ',' || (line[0] >= '0' && line[0] <= '9')) {
strlcpy(nfs_root_name, line, sizeof(nfs_root_name));
} else {
int n = strlen(line) + sizeof(NFS_ROOT) - 1;
if (n >= sizeof(nfs_root_name))
line[sizeof(nfs_root_name) - sizeof(NFS_ROOT) - 2] = '\0';
sprintf(nfs_root_name, NFS_ROOT, line);
}
root_server_addr = root_nfs_parse_addr(nfs_root_name);
return 1;
}
__setup("nfsroot=", nfs_root_setup);
/***************************************************************************
Routines to actually mount the root directory
***************************************************************************/
/*
* Construct sockaddr_in from address and port number.
*/
static inline void
set_sockaddr(struct sockaddr_in *sin, __u32 addr, __u16 port)
{
sin->sin_family = AF_INET;
sin->sin_addr.s_addr = addr;
sin->sin_port = port;
}
/*
* Query server portmapper for the port of a daemon program.
*/
static int __init root_nfs_getport(int program, int version, int proto)
{
struct sockaddr_in sin;
printk(KERN_NOTICE "Looking up port of RPC %d/%d on %u.%u.%u.%u\n",
program, version, NIPQUAD(servaddr));
set_sockaddr(&sin, servaddr, 0);
return rpc_getport_external(&sin, program, version, proto);
}
/*
* Use portmapper to find mountd and nfsd port numbers if not overriden
* by the user. Use defaults if portmapper is not available.
* XXX: Is there any nfs server with no portmapper?
*/
static int __init root_nfs_ports(void)
{
int port;
int nfsd_ver, mountd_ver;
int nfsd_port, mountd_port;
int proto;
if (nfs_data.flags & NFS_MOUNT_VER3) {
nfsd_ver = NFS3_VERSION;
mountd_ver = NFS_MNT3_VERSION;
nfsd_port = NFS_PORT;
mountd_port = NFS_MNT_PORT;
} else {
nfsd_ver = NFS2_VERSION;
mountd_ver = NFS_MNT_VERSION;
nfsd_port = NFS_PORT;
mountd_port = NFS_MNT_PORT;
}
proto = (nfs_data.flags & NFS_MOUNT_TCP) ? IPPROTO_TCP : IPPROTO_UDP;
if (nfs_port < 0) {
if ((port = root_nfs_getport(NFS_PROGRAM, nfsd_ver, proto)) < 0) {
printk(KERN_ERR "Root-NFS: Unable to get nfsd port "
"number from server, using default\n");
port = nfsd_port;
}
nfs_port = htons(port);
dprintk("Root-NFS: Portmapper on server returned %d "
"as nfsd port\n", port);
}
if ((port = root_nfs_getport(NFS_MNT_PROGRAM, mountd_ver, proto)) < 0) {
printk(KERN_ERR "Root-NFS: Unable to get mountd port "
"number from server, using default\n");
port = mountd_port;
}
mount_port = htons(port);
dprintk("Root-NFS: mountd port is %d\n", port);
return 0;
}
/*
* Get a file handle from the server for the directory which is to be
* mounted.
*/
static int __init root_nfs_get_handle(void)
{
struct nfs_fh fh;
struct sockaddr_in sin;
int status;
int protocol = (nfs_data.flags & NFS_MOUNT_TCP) ?
IPPROTO_TCP : IPPROTO_UDP;
int version = (nfs_data.flags & NFS_MOUNT_VER3) ?
NFS_MNT3_VERSION : NFS_MNT_VERSION;
set_sockaddr(&sin, servaddr, mount_port);
status = nfsroot_mount(&sin, nfs_path, &fh, version, protocol);
if (status < 0)
printk(KERN_ERR "Root-NFS: Server returned error %d "
"while mounting %s\n", status, nfs_path);
else {
nfs_data.root.size = fh.size;
memcpy(nfs_data.root.data, fh.data, fh.size);
}
return status;
}
/*
* Get the NFS port numbers and file handle, and return the prepared 'data'
* argument for mount() if everything went OK. Return NULL otherwise.
*/
void * __init nfs_root_data(void)
{
if (root_nfs_init() < 0
|| root_nfs_ports() < 0
|| root_nfs_get_handle() < 0)
return NULL;
set_sockaddr((struct sockaddr_in *) &nfs_data.addr, servaddr, nfs_port);
return (void*)&nfs_data;
}
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