linux/fs/devpts/inode.c
Tejun Heo 5a0e3ad6af 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>
2010-03-30 22:02:32 +09:00

579 lines
14 KiB
C

/* -*- linux-c -*- --------------------------------------------------------- *
*
* linux/fs/devpts/inode.c
*
* Copyright 1998-2004 H. Peter Anvin -- All Rights Reserved
*
* This file is part of the Linux kernel and is made available under
* the terms of the GNU General Public License, version 2, or at your
* option, any later version, incorporated herein by reference.
*
* ------------------------------------------------------------------------- */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/namei.h>
#include <linux/slab.h>
#include <linux/mount.h>
#include <linux/tty.h>
#include <linux/mutex.h>
#include <linux/magic.h>
#include <linux/idr.h>
#include <linux/devpts_fs.h>
#include <linux/parser.h>
#include <linux/fsnotify.h>
#include <linux/seq_file.h>
#define DEVPTS_DEFAULT_MODE 0600
/*
* ptmx is a new node in /dev/pts and will be unused in legacy (single-
* instance) mode. To prevent surprises in user space, set permissions of
* ptmx to 0. Use 'chmod' or remount with '-o ptmxmode' to set meaningful
* permissions.
*/
#define DEVPTS_DEFAULT_PTMX_MODE 0000
#define PTMX_MINOR 2
extern int pty_limit; /* Config limit on Unix98 ptys */
static DEFINE_MUTEX(allocated_ptys_lock);
static struct vfsmount *devpts_mnt;
struct pts_mount_opts {
int setuid;
int setgid;
uid_t uid;
gid_t gid;
umode_t mode;
umode_t ptmxmode;
int newinstance;
};
enum {
Opt_uid, Opt_gid, Opt_mode, Opt_ptmxmode, Opt_newinstance,
Opt_err
};
static const match_table_t tokens = {
{Opt_uid, "uid=%u"},
{Opt_gid, "gid=%u"},
{Opt_mode, "mode=%o"},
#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
{Opt_ptmxmode, "ptmxmode=%o"},
{Opt_newinstance, "newinstance"},
#endif
{Opt_err, NULL}
};
struct pts_fs_info {
struct ida allocated_ptys;
struct pts_mount_opts mount_opts;
struct dentry *ptmx_dentry;
};
static inline struct pts_fs_info *DEVPTS_SB(struct super_block *sb)
{
return sb->s_fs_info;
}
static inline struct super_block *pts_sb_from_inode(struct inode *inode)
{
#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
if (inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC)
return inode->i_sb;
#endif
return devpts_mnt->mnt_sb;
}
#define PARSE_MOUNT 0
#define PARSE_REMOUNT 1
/*
* parse_mount_options():
* Set @opts to mount options specified in @data. If an option is not
* specified in @data, set it to its default value. The exception is
* 'newinstance' option which can only be set/cleared on a mount (i.e.
* cannot be changed during remount).
*
* Note: @data may be NULL (in which case all options are set to default).
*/
static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)
{
char *p;
opts->setuid = 0;
opts->setgid = 0;
opts->uid = 0;
opts->gid = 0;
opts->mode = DEVPTS_DEFAULT_MODE;
opts->ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
/* newinstance makes sense only on initial mount */
if (op == PARSE_MOUNT)
opts->newinstance = 0;
while ((p = strsep(&data, ",")) != NULL) {
substring_t args[MAX_OPT_ARGS];
int token;
int option;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_uid:
if (match_int(&args[0], &option))
return -EINVAL;
opts->uid = option;
opts->setuid = 1;
break;
case Opt_gid:
if (match_int(&args[0], &option))
return -EINVAL;
opts->gid = option;
opts->setgid = 1;
break;
case Opt_mode:
if (match_octal(&args[0], &option))
return -EINVAL;
opts->mode = option & S_IALLUGO;
break;
#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
case Opt_ptmxmode:
if (match_octal(&args[0], &option))
return -EINVAL;
opts->ptmxmode = option & S_IALLUGO;
break;
case Opt_newinstance:
/* newinstance makes sense only on initial mount */
if (op == PARSE_MOUNT)
opts->newinstance = 1;
break;
#endif
default:
printk(KERN_ERR "devpts: called with bogus options\n");
return -EINVAL;
}
}
return 0;
}
#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
static int mknod_ptmx(struct super_block *sb)
{
int mode;
int rc = -ENOMEM;
struct dentry *dentry;
struct inode *inode;
struct dentry *root = sb->s_root;
struct pts_fs_info *fsi = DEVPTS_SB(sb);
struct pts_mount_opts *opts = &fsi->mount_opts;
mutex_lock(&root->d_inode->i_mutex);
/* If we have already created ptmx node, return */
if (fsi->ptmx_dentry) {
rc = 0;
goto out;
}
dentry = d_alloc_name(root, "ptmx");
if (!dentry) {
printk(KERN_NOTICE "Unable to alloc dentry for ptmx node\n");
goto out;
}
/*
* Create a new 'ptmx' node in this mount of devpts.
*/
inode = new_inode(sb);
if (!inode) {
printk(KERN_ERR "Unable to alloc inode for ptmx node\n");
dput(dentry);
goto out;
}
inode->i_ino = 2;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
mode = S_IFCHR|opts->ptmxmode;
init_special_inode(inode, mode, MKDEV(TTYAUX_MAJOR, 2));
d_add(dentry, inode);
fsi->ptmx_dentry = dentry;
rc = 0;
out:
mutex_unlock(&root->d_inode->i_mutex);
return rc;
}
static void update_ptmx_mode(struct pts_fs_info *fsi)
{
struct inode *inode;
if (fsi->ptmx_dentry) {
inode = fsi->ptmx_dentry->d_inode;
inode->i_mode = S_IFCHR|fsi->mount_opts.ptmxmode;
}
}
#else
static inline void update_ptmx_mode(struct pts_fs_info *fsi)
{
return;
}
#endif
static int devpts_remount(struct super_block *sb, int *flags, char *data)
{
int err;
struct pts_fs_info *fsi = DEVPTS_SB(sb);
struct pts_mount_opts *opts = &fsi->mount_opts;
err = parse_mount_options(data, PARSE_REMOUNT, opts);
/*
* parse_mount_options() restores options to default values
* before parsing and may have changed ptmxmode. So, update the
* mode in the inode too. Bogus options don't fail the remount,
* so do this even on error return.
*/
update_ptmx_mode(fsi);
return err;
}
static int devpts_show_options(struct seq_file *seq, struct vfsmount *vfs)
{
struct pts_fs_info *fsi = DEVPTS_SB(vfs->mnt_sb);
struct pts_mount_opts *opts = &fsi->mount_opts;
if (opts->setuid)
seq_printf(seq, ",uid=%u", opts->uid);
if (opts->setgid)
seq_printf(seq, ",gid=%u", opts->gid);
seq_printf(seq, ",mode=%03o", opts->mode);
#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
seq_printf(seq, ",ptmxmode=%03o", opts->ptmxmode);
#endif
return 0;
}
static const struct super_operations devpts_sops = {
.statfs = simple_statfs,
.remount_fs = devpts_remount,
.show_options = devpts_show_options,
};
static void *new_pts_fs_info(void)
{
struct pts_fs_info *fsi;
fsi = kzalloc(sizeof(struct pts_fs_info), GFP_KERNEL);
if (!fsi)
return NULL;
ida_init(&fsi->allocated_ptys);
fsi->mount_opts.mode = DEVPTS_DEFAULT_MODE;
fsi->mount_opts.ptmxmode = DEVPTS_DEFAULT_PTMX_MODE;
return fsi;
}
static int
devpts_fill_super(struct super_block *s, void *data, int silent)
{
struct inode *inode;
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
s->s_magic = DEVPTS_SUPER_MAGIC;
s->s_op = &devpts_sops;
s->s_time_gran = 1;
s->s_fs_info = new_pts_fs_info();
if (!s->s_fs_info)
goto fail;
inode = new_inode(s);
if (!inode)
goto free_fsi;
inode->i_ino = 1;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
inode->i_mode = S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR;
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = &simple_dir_operations;
inode->i_nlink = 2;
s->s_root = d_alloc_root(inode);
if (s->s_root)
return 0;
printk(KERN_ERR "devpts: get root dentry failed\n");
iput(inode);
free_fsi:
kfree(s->s_fs_info);
fail:
return -ENOMEM;
}
#ifdef CONFIG_DEVPTS_MULTIPLE_INSTANCES
static int compare_init_pts_sb(struct super_block *s, void *p)
{
if (devpts_mnt)
return devpts_mnt->mnt_sb == s;
return 0;
}
/*
* devpts_get_sb()
*
* If the '-o newinstance' mount option was specified, mount a new
* (private) instance of devpts. PTYs created in this instance are
* independent of the PTYs in other devpts instances.
*
* If the '-o newinstance' option was not specified, mount/remount the
* initial kernel mount of devpts. This type of mount gives the
* legacy, single-instance semantics.
*
* The 'newinstance' option is needed to support multiple namespace
* semantics in devpts while preserving backward compatibility of the
* current 'single-namespace' semantics. i.e all mounts of devpts
* without the 'newinstance' mount option should bind to the initial
* kernel mount, like get_sb_single().
*
* Mounts with 'newinstance' option create a new, private namespace.
*
* NOTE:
*
* For single-mount semantics, devpts cannot use get_sb_single(),
* because get_sb_single()/sget() find and use the super-block from
* the most recent mount of devpts. But that recent mount may be a
* 'newinstance' mount and get_sb_single() would pick the newinstance
* super-block instead of the initial super-block.
*/
static int devpts_get_sb(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data, struct vfsmount *mnt)
{
int error;
struct pts_mount_opts opts;
struct super_block *s;
error = parse_mount_options(data, PARSE_MOUNT, &opts);
if (error)
return error;
if (opts.newinstance)
s = sget(fs_type, NULL, set_anon_super, NULL);
else
s = sget(fs_type, compare_init_pts_sb, set_anon_super, NULL);
if (IS_ERR(s))
return PTR_ERR(s);
if (!s->s_root) {
s->s_flags = flags;
error = devpts_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
if (error)
goto out_undo_sget;
s->s_flags |= MS_ACTIVE;
}
simple_set_mnt(mnt, s);
memcpy(&(DEVPTS_SB(s))->mount_opts, &opts, sizeof(opts));
error = mknod_ptmx(s);
if (error)
goto out_dput;
return 0;
out_dput:
dput(s->s_root); /* undo dget() in simple_set_mnt() */
out_undo_sget:
deactivate_locked_super(s);
return error;
}
#else
/*
* This supports only the legacy single-instance semantics (no
* multiple-instance semantics)
*/
static int devpts_get_sb(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data, struct vfsmount *mnt)
{
return get_sb_single(fs_type, flags, data, devpts_fill_super, mnt);
}
#endif
static void devpts_kill_sb(struct super_block *sb)
{
struct pts_fs_info *fsi = DEVPTS_SB(sb);
kfree(fsi);
kill_litter_super(sb);
}
static struct file_system_type devpts_fs_type = {
.name = "devpts",
.get_sb = devpts_get_sb,
.kill_sb = devpts_kill_sb,
};
/*
* The normal naming convention is simply /dev/pts/<number>; this conforms
* to the System V naming convention
*/
int devpts_new_index(struct inode *ptmx_inode)
{
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
struct pts_fs_info *fsi = DEVPTS_SB(sb);
int index;
int ida_ret;
retry:
if (!ida_pre_get(&fsi->allocated_ptys, GFP_KERNEL))
return -ENOMEM;
mutex_lock(&allocated_ptys_lock);
ida_ret = ida_get_new(&fsi->allocated_ptys, &index);
if (ida_ret < 0) {
mutex_unlock(&allocated_ptys_lock);
if (ida_ret == -EAGAIN)
goto retry;
return -EIO;
}
if (index >= pty_limit) {
ida_remove(&fsi->allocated_ptys, index);
mutex_unlock(&allocated_ptys_lock);
return -EIO;
}
mutex_unlock(&allocated_ptys_lock);
return index;
}
void devpts_kill_index(struct inode *ptmx_inode, int idx)
{
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
struct pts_fs_info *fsi = DEVPTS_SB(sb);
mutex_lock(&allocated_ptys_lock);
ida_remove(&fsi->allocated_ptys, idx);
mutex_unlock(&allocated_ptys_lock);
}
int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
{
/* tty layer puts index from devpts_new_index() in here */
int number = tty->index;
struct tty_driver *driver = tty->driver;
dev_t device = MKDEV(driver->major, driver->minor_start+number);
struct dentry *dentry;
struct super_block *sb = pts_sb_from_inode(ptmx_inode);
struct inode *inode = new_inode(sb);
struct dentry *root = sb->s_root;
struct pts_fs_info *fsi = DEVPTS_SB(sb);
struct pts_mount_opts *opts = &fsi->mount_opts;
char s[12];
/* We're supposed to be given the slave end of a pty */
BUG_ON(driver->type != TTY_DRIVER_TYPE_PTY);
BUG_ON(driver->subtype != PTY_TYPE_SLAVE);
if (!inode)
return -ENOMEM;
inode->i_ino = number + 3;
inode->i_uid = opts->setuid ? opts->uid : current_fsuid();
inode->i_gid = opts->setgid ? opts->gid : current_fsgid();
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
init_special_inode(inode, S_IFCHR|opts->mode, device);
inode->i_private = tty;
tty->driver_data = inode;
sprintf(s, "%d", number);
mutex_lock(&root->d_inode->i_mutex);
dentry = d_alloc_name(root, s);
if (!IS_ERR(dentry)) {
d_add(dentry, inode);
fsnotify_create(root->d_inode, dentry);
}
mutex_unlock(&root->d_inode->i_mutex);
return 0;
}
struct tty_struct *devpts_get_tty(struct inode *pts_inode, int number)
{
struct dentry *dentry;
struct tty_struct *tty;
BUG_ON(pts_inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR));
/* Ensure dentry has not been deleted by devpts_pty_kill() */
dentry = d_find_alias(pts_inode);
if (!dentry)
return NULL;
tty = NULL;
if (pts_inode->i_sb->s_magic == DEVPTS_SUPER_MAGIC)
tty = (struct tty_struct *)pts_inode->i_private;
dput(dentry);
return tty;
}
void devpts_pty_kill(struct tty_struct *tty)
{
struct inode *inode = tty->driver_data;
struct super_block *sb = pts_sb_from_inode(inode);
struct dentry *root = sb->s_root;
struct dentry *dentry;
BUG_ON(inode->i_rdev == MKDEV(TTYAUX_MAJOR, PTMX_MINOR));
mutex_lock(&root->d_inode->i_mutex);
dentry = d_find_alias(inode);
if (IS_ERR(dentry))
goto out;
if (dentry) {
inode->i_nlink--;
d_delete(dentry);
dput(dentry); /* d_alloc_name() in devpts_pty_new() */
}
dput(dentry); /* d_find_alias above */
out:
mutex_unlock(&root->d_inode->i_mutex);
}
static int __init init_devpts_fs(void)
{
int err = register_filesystem(&devpts_fs_type);
if (!err) {
devpts_mnt = kern_mount(&devpts_fs_type);
if (IS_ERR(devpts_mnt)) {
err = PTR_ERR(devpts_mnt);
unregister_filesystem(&devpts_fs_type);
}
}
return err;
}
module_init(init_devpts_fs)