mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-25 02:09:42 +00:00
![Jan Blunck](/assets/img/avatar_default.png)
* Add path_put() functions for releasing a reference to the dentry and vfsmount of a struct path in the right order * Switch from path_release(nd) to path_put(&nd->path) * Rename dput_path() to path_put_conditional() [akpm@linux-foundation.org: fix cifs] Signed-off-by: Jan Blunck <jblunck@suse.de> Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Acked-by: Christoph Hellwig <hch@lst.de> Cc: <linux-fsdevel@vger.kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Steven French <sfrench@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
756 lines
18 KiB
C
756 lines
18 KiB
C
/*
|
|
* fs/inotify_user.c - inotify support for userspace
|
|
*
|
|
* Authors:
|
|
* John McCutchan <ttb@tentacle.dhs.org>
|
|
* Robert Love <rml@novell.com>
|
|
*
|
|
* Copyright (C) 2005 John McCutchan
|
|
* Copyright 2006 Hewlett-Packard Development Company, L.P.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/file.h>
|
|
#include <linux/mount.h>
|
|
#include <linux/namei.h>
|
|
#include <linux/poll.h>
|
|
#include <linux/init.h>
|
|
#include <linux/list.h>
|
|
#include <linux/inotify.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/magic.h>
|
|
|
|
#include <asm/ioctls.h>
|
|
|
|
static struct kmem_cache *watch_cachep __read_mostly;
|
|
static struct kmem_cache *event_cachep __read_mostly;
|
|
|
|
static struct vfsmount *inotify_mnt __read_mostly;
|
|
|
|
/* these are configurable via /proc/sys/fs/inotify/ */
|
|
static int inotify_max_user_instances __read_mostly;
|
|
static int inotify_max_user_watches __read_mostly;
|
|
static int inotify_max_queued_events __read_mostly;
|
|
|
|
/*
|
|
* Lock ordering:
|
|
*
|
|
* inotify_dev->up_mutex (ensures we don't re-add the same watch)
|
|
* inode->inotify_mutex (protects inode's watch list)
|
|
* inotify_handle->mutex (protects inotify_handle's watch list)
|
|
* inotify_dev->ev_mutex (protects device's event queue)
|
|
*/
|
|
|
|
/*
|
|
* Lifetimes of the main data structures:
|
|
*
|
|
* inotify_device: Lifetime is managed by reference count, from
|
|
* sys_inotify_init() until release. Additional references can bump the count
|
|
* via get_inotify_dev() and drop the count via put_inotify_dev().
|
|
*
|
|
* inotify_user_watch: Lifetime is from create_watch() to the receipt of an
|
|
* IN_IGNORED event from inotify, or when using IN_ONESHOT, to receipt of the
|
|
* first event, or to inotify_destroy().
|
|
*/
|
|
|
|
/*
|
|
* struct inotify_device - represents an inotify instance
|
|
*
|
|
* This structure is protected by the mutex 'mutex'.
|
|
*/
|
|
struct inotify_device {
|
|
wait_queue_head_t wq; /* wait queue for i/o */
|
|
struct mutex ev_mutex; /* protects event queue */
|
|
struct mutex up_mutex; /* synchronizes watch updates */
|
|
struct list_head events; /* list of queued events */
|
|
atomic_t count; /* reference count */
|
|
struct user_struct *user; /* user who opened this dev */
|
|
struct inotify_handle *ih; /* inotify handle */
|
|
struct fasync_struct *fa; /* async notification */
|
|
unsigned int queue_size; /* size of the queue (bytes) */
|
|
unsigned int event_count; /* number of pending events */
|
|
unsigned int max_events; /* maximum number of events */
|
|
};
|
|
|
|
/*
|
|
* struct inotify_kernel_event - An inotify event, originating from a watch and
|
|
* queued for user-space. A list of these is attached to each instance of the
|
|
* device. In read(), this list is walked and all events that can fit in the
|
|
* buffer are returned.
|
|
*
|
|
* Protected by dev->ev_mutex of the device in which we are queued.
|
|
*/
|
|
struct inotify_kernel_event {
|
|
struct inotify_event event; /* the user-space event */
|
|
struct list_head list; /* entry in inotify_device's list */
|
|
char *name; /* filename, if any */
|
|
};
|
|
|
|
/*
|
|
* struct inotify_user_watch - our version of an inotify_watch, we add
|
|
* a reference to the associated inotify_device.
|
|
*/
|
|
struct inotify_user_watch {
|
|
struct inotify_device *dev; /* associated device */
|
|
struct inotify_watch wdata; /* inotify watch data */
|
|
};
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
|
|
#include <linux/sysctl.h>
|
|
|
|
static int zero;
|
|
|
|
ctl_table inotify_table[] = {
|
|
{
|
|
.ctl_name = INOTIFY_MAX_USER_INSTANCES,
|
|
.procname = "max_user_instances",
|
|
.data = &inotify_max_user_instances,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &proc_dointvec_minmax,
|
|
.strategy = &sysctl_intvec,
|
|
.extra1 = &zero,
|
|
},
|
|
{
|
|
.ctl_name = INOTIFY_MAX_USER_WATCHES,
|
|
.procname = "max_user_watches",
|
|
.data = &inotify_max_user_watches,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &proc_dointvec_minmax,
|
|
.strategy = &sysctl_intvec,
|
|
.extra1 = &zero,
|
|
},
|
|
{
|
|
.ctl_name = INOTIFY_MAX_QUEUED_EVENTS,
|
|
.procname = "max_queued_events",
|
|
.data = &inotify_max_queued_events,
|
|
.maxlen = sizeof(int),
|
|
.mode = 0644,
|
|
.proc_handler = &proc_dointvec_minmax,
|
|
.strategy = &sysctl_intvec,
|
|
.extra1 = &zero
|
|
},
|
|
{ .ctl_name = 0 }
|
|
};
|
|
#endif /* CONFIG_SYSCTL */
|
|
|
|
static inline void get_inotify_dev(struct inotify_device *dev)
|
|
{
|
|
atomic_inc(&dev->count);
|
|
}
|
|
|
|
static inline void put_inotify_dev(struct inotify_device *dev)
|
|
{
|
|
if (atomic_dec_and_test(&dev->count)) {
|
|
atomic_dec(&dev->user->inotify_devs);
|
|
free_uid(dev->user);
|
|
kfree(dev);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* free_inotify_user_watch - cleans up the watch and its references
|
|
*/
|
|
static void free_inotify_user_watch(struct inotify_watch *w)
|
|
{
|
|
struct inotify_user_watch *watch;
|
|
struct inotify_device *dev;
|
|
|
|
watch = container_of(w, struct inotify_user_watch, wdata);
|
|
dev = watch->dev;
|
|
|
|
atomic_dec(&dev->user->inotify_watches);
|
|
put_inotify_dev(dev);
|
|
kmem_cache_free(watch_cachep, watch);
|
|
}
|
|
|
|
/*
|
|
* kernel_event - create a new kernel event with the given parameters
|
|
*
|
|
* This function can sleep.
|
|
*/
|
|
static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
|
|
const char *name)
|
|
{
|
|
struct inotify_kernel_event *kevent;
|
|
|
|
kevent = kmem_cache_alloc(event_cachep, GFP_NOFS);
|
|
if (unlikely(!kevent))
|
|
return NULL;
|
|
|
|
/* we hand this out to user-space, so zero it just in case */
|
|
memset(&kevent->event, 0, sizeof(struct inotify_event));
|
|
|
|
kevent->event.wd = wd;
|
|
kevent->event.mask = mask;
|
|
kevent->event.cookie = cookie;
|
|
|
|
INIT_LIST_HEAD(&kevent->list);
|
|
|
|
if (name) {
|
|
size_t len, rem, event_size = sizeof(struct inotify_event);
|
|
|
|
/*
|
|
* We need to pad the filename so as to properly align an
|
|
* array of inotify_event structures. Because the structure is
|
|
* small and the common case is a small filename, we just round
|
|
* up to the next multiple of the structure's sizeof. This is
|
|
* simple and safe for all architectures.
|
|
*/
|
|
len = strlen(name) + 1;
|
|
rem = event_size - len;
|
|
if (len > event_size) {
|
|
rem = event_size - (len % event_size);
|
|
if (len % event_size == 0)
|
|
rem = 0;
|
|
}
|
|
|
|
kevent->name = kmalloc(len + rem, GFP_KERNEL);
|
|
if (unlikely(!kevent->name)) {
|
|
kmem_cache_free(event_cachep, kevent);
|
|
return NULL;
|
|
}
|
|
memcpy(kevent->name, name, len);
|
|
if (rem)
|
|
memset(kevent->name + len, 0, rem);
|
|
kevent->event.len = len + rem;
|
|
} else {
|
|
kevent->event.len = 0;
|
|
kevent->name = NULL;
|
|
}
|
|
|
|
return kevent;
|
|
}
|
|
|
|
/*
|
|
* inotify_dev_get_event - return the next event in the given dev's queue
|
|
*
|
|
* Caller must hold dev->ev_mutex.
|
|
*/
|
|
static inline struct inotify_kernel_event *
|
|
inotify_dev_get_event(struct inotify_device *dev)
|
|
{
|
|
return list_entry(dev->events.next, struct inotify_kernel_event, list);
|
|
}
|
|
|
|
/*
|
|
* inotify_dev_get_last_event - return the last event in the given dev's queue
|
|
*
|
|
* Caller must hold dev->ev_mutex.
|
|
*/
|
|
static inline struct inotify_kernel_event *
|
|
inotify_dev_get_last_event(struct inotify_device *dev)
|
|
{
|
|
if (list_empty(&dev->events))
|
|
return NULL;
|
|
return list_entry(dev->events.prev, struct inotify_kernel_event, list);
|
|
}
|
|
|
|
/*
|
|
* inotify_dev_queue_event - event handler registered with core inotify, adds
|
|
* a new event to the given device
|
|
*
|
|
* Can sleep (calls kernel_event()).
|
|
*/
|
|
static void inotify_dev_queue_event(struct inotify_watch *w, u32 wd, u32 mask,
|
|
u32 cookie, const char *name,
|
|
struct inode *ignored)
|
|
{
|
|
struct inotify_user_watch *watch;
|
|
struct inotify_device *dev;
|
|
struct inotify_kernel_event *kevent, *last;
|
|
|
|
watch = container_of(w, struct inotify_user_watch, wdata);
|
|
dev = watch->dev;
|
|
|
|
mutex_lock(&dev->ev_mutex);
|
|
|
|
/* we can safely put the watch as we don't reference it while
|
|
* generating the event
|
|
*/
|
|
if (mask & IN_IGNORED || w->mask & IN_ONESHOT)
|
|
put_inotify_watch(w); /* final put */
|
|
|
|
/* coalescing: drop this event if it is a dupe of the previous */
|
|
last = inotify_dev_get_last_event(dev);
|
|
if (last && last->event.mask == mask && last->event.wd == wd &&
|
|
last->event.cookie == cookie) {
|
|
const char *lastname = last->name;
|
|
|
|
if (!name && !lastname)
|
|
goto out;
|
|
if (name && lastname && !strcmp(lastname, name))
|
|
goto out;
|
|
}
|
|
|
|
/* the queue overflowed and we already sent the Q_OVERFLOW event */
|
|
if (unlikely(dev->event_count > dev->max_events))
|
|
goto out;
|
|
|
|
/* if the queue overflows, we need to notify user space */
|
|
if (unlikely(dev->event_count == dev->max_events))
|
|
kevent = kernel_event(-1, IN_Q_OVERFLOW, cookie, NULL);
|
|
else
|
|
kevent = kernel_event(wd, mask, cookie, name);
|
|
|
|
if (unlikely(!kevent))
|
|
goto out;
|
|
|
|
/* queue the event and wake up anyone waiting */
|
|
dev->event_count++;
|
|
dev->queue_size += sizeof(struct inotify_event) + kevent->event.len;
|
|
list_add_tail(&kevent->list, &dev->events);
|
|
wake_up_interruptible(&dev->wq);
|
|
kill_fasync(&dev->fa, SIGIO, POLL_IN);
|
|
|
|
out:
|
|
mutex_unlock(&dev->ev_mutex);
|
|
}
|
|
|
|
/*
|
|
* remove_kevent - cleans up and ultimately frees the given kevent
|
|
*
|
|
* Caller must hold dev->ev_mutex.
|
|
*/
|
|
static void remove_kevent(struct inotify_device *dev,
|
|
struct inotify_kernel_event *kevent)
|
|
{
|
|
list_del(&kevent->list);
|
|
|
|
dev->event_count--;
|
|
dev->queue_size -= sizeof(struct inotify_event) + kevent->event.len;
|
|
|
|
kfree(kevent->name);
|
|
kmem_cache_free(event_cachep, kevent);
|
|
}
|
|
|
|
/*
|
|
* inotify_dev_event_dequeue - destroy an event on the given device
|
|
*
|
|
* Caller must hold dev->ev_mutex.
|
|
*/
|
|
static void inotify_dev_event_dequeue(struct inotify_device *dev)
|
|
{
|
|
if (!list_empty(&dev->events)) {
|
|
struct inotify_kernel_event *kevent;
|
|
kevent = inotify_dev_get_event(dev);
|
|
remove_kevent(dev, kevent);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* find_inode - resolve a user-given path to a specific inode and return a nd
|
|
*/
|
|
static int find_inode(const char __user *dirname, struct nameidata *nd,
|
|
unsigned flags)
|
|
{
|
|
int error;
|
|
|
|
error = __user_walk(dirname, flags, nd);
|
|
if (error)
|
|
return error;
|
|
/* you can only watch an inode if you have read permissions on it */
|
|
error = vfs_permission(nd, MAY_READ);
|
|
if (error)
|
|
path_put(&nd->path);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* create_watch - creates a watch on the given device.
|
|
*
|
|
* Callers must hold dev->up_mutex.
|
|
*/
|
|
static int create_watch(struct inotify_device *dev, struct inode *inode,
|
|
u32 mask)
|
|
{
|
|
struct inotify_user_watch *watch;
|
|
int ret;
|
|
|
|
if (atomic_read(&dev->user->inotify_watches) >=
|
|
inotify_max_user_watches)
|
|
return -ENOSPC;
|
|
|
|
watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL);
|
|
if (unlikely(!watch))
|
|
return -ENOMEM;
|
|
|
|
/* save a reference to device and bump the count to make it official */
|
|
get_inotify_dev(dev);
|
|
watch->dev = dev;
|
|
|
|
atomic_inc(&dev->user->inotify_watches);
|
|
|
|
inotify_init_watch(&watch->wdata);
|
|
ret = inotify_add_watch(dev->ih, &watch->wdata, inode, mask);
|
|
if (ret < 0)
|
|
free_inotify_user_watch(&watch->wdata);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Device Interface */
|
|
|
|
static unsigned int inotify_poll(struct file *file, poll_table *wait)
|
|
{
|
|
struct inotify_device *dev = file->private_data;
|
|
int ret = 0;
|
|
|
|
poll_wait(file, &dev->wq, wait);
|
|
mutex_lock(&dev->ev_mutex);
|
|
if (!list_empty(&dev->events))
|
|
ret = POLLIN | POLLRDNORM;
|
|
mutex_unlock(&dev->ev_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t inotify_read(struct file *file, char __user *buf,
|
|
size_t count, loff_t *pos)
|
|
{
|
|
size_t event_size = sizeof (struct inotify_event);
|
|
struct inotify_device *dev;
|
|
char __user *start;
|
|
int ret;
|
|
DEFINE_WAIT(wait);
|
|
|
|
start = buf;
|
|
dev = file->private_data;
|
|
|
|
while (1) {
|
|
int events;
|
|
|
|
prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE);
|
|
|
|
mutex_lock(&dev->ev_mutex);
|
|
events = !list_empty(&dev->events);
|
|
mutex_unlock(&dev->ev_mutex);
|
|
if (events) {
|
|
ret = 0;
|
|
break;
|
|
}
|
|
|
|
if (file->f_flags & O_NONBLOCK) {
|
|
ret = -EAGAIN;
|
|
break;
|
|
}
|
|
|
|
if (signal_pending(current)) {
|
|
ret = -EINTR;
|
|
break;
|
|
}
|
|
|
|
schedule();
|
|
}
|
|
|
|
finish_wait(&dev->wq, &wait);
|
|
if (ret)
|
|
return ret;
|
|
|
|
mutex_lock(&dev->ev_mutex);
|
|
while (1) {
|
|
struct inotify_kernel_event *kevent;
|
|
|
|
ret = buf - start;
|
|
if (list_empty(&dev->events))
|
|
break;
|
|
|
|
kevent = inotify_dev_get_event(dev);
|
|
if (event_size + kevent->event.len > count) {
|
|
if (ret == 0 && count > 0) {
|
|
/*
|
|
* could not get a single event because we
|
|
* didn't have enough buffer space.
|
|
*/
|
|
ret = -EINVAL;
|
|
}
|
|
break;
|
|
}
|
|
|
|
if (copy_to_user(buf, &kevent->event, event_size)) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
buf += event_size;
|
|
count -= event_size;
|
|
|
|
if (kevent->name) {
|
|
if (copy_to_user(buf, kevent->name, kevent->event.len)){
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
buf += kevent->event.len;
|
|
count -= kevent->event.len;
|
|
}
|
|
|
|
remove_kevent(dev, kevent);
|
|
}
|
|
mutex_unlock(&dev->ev_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int inotify_fasync(int fd, struct file *file, int on)
|
|
{
|
|
struct inotify_device *dev = file->private_data;
|
|
|
|
return fasync_helper(fd, file, on, &dev->fa) >= 0 ? 0 : -EIO;
|
|
}
|
|
|
|
static int inotify_release(struct inode *ignored, struct file *file)
|
|
{
|
|
struct inotify_device *dev = file->private_data;
|
|
|
|
inotify_destroy(dev->ih);
|
|
|
|
/* destroy all of the events on this device */
|
|
mutex_lock(&dev->ev_mutex);
|
|
while (!list_empty(&dev->events))
|
|
inotify_dev_event_dequeue(dev);
|
|
mutex_unlock(&dev->ev_mutex);
|
|
|
|
if (file->f_flags & FASYNC)
|
|
inotify_fasync(-1, file, 0);
|
|
|
|
/* free this device: the put matching the get in inotify_init() */
|
|
put_inotify_dev(dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static long inotify_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
struct inotify_device *dev;
|
|
void __user *p;
|
|
int ret = -ENOTTY;
|
|
|
|
dev = file->private_data;
|
|
p = (void __user *) arg;
|
|
|
|
switch (cmd) {
|
|
case FIONREAD:
|
|
ret = put_user(dev->queue_size, (int __user *) p);
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const struct file_operations inotify_fops = {
|
|
.poll = inotify_poll,
|
|
.read = inotify_read,
|
|
.fasync = inotify_fasync,
|
|
.release = inotify_release,
|
|
.unlocked_ioctl = inotify_ioctl,
|
|
.compat_ioctl = inotify_ioctl,
|
|
};
|
|
|
|
static const struct inotify_operations inotify_user_ops = {
|
|
.handle_event = inotify_dev_queue_event,
|
|
.destroy_watch = free_inotify_user_watch,
|
|
};
|
|
|
|
asmlinkage long sys_inotify_init(void)
|
|
{
|
|
struct inotify_device *dev;
|
|
struct inotify_handle *ih;
|
|
struct user_struct *user;
|
|
struct file *filp;
|
|
int fd, ret;
|
|
|
|
fd = get_unused_fd();
|
|
if (fd < 0)
|
|
return fd;
|
|
|
|
filp = get_empty_filp();
|
|
if (!filp) {
|
|
ret = -ENFILE;
|
|
goto out_put_fd;
|
|
}
|
|
|
|
user = get_uid(current->user);
|
|
if (unlikely(atomic_read(&user->inotify_devs) >=
|
|
inotify_max_user_instances)) {
|
|
ret = -EMFILE;
|
|
goto out_free_uid;
|
|
}
|
|
|
|
dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL);
|
|
if (unlikely(!dev)) {
|
|
ret = -ENOMEM;
|
|
goto out_free_uid;
|
|
}
|
|
|
|
ih = inotify_init(&inotify_user_ops);
|
|
if (unlikely(IS_ERR(ih))) {
|
|
ret = PTR_ERR(ih);
|
|
goto out_free_dev;
|
|
}
|
|
dev->ih = ih;
|
|
dev->fa = NULL;
|
|
|
|
filp->f_op = &inotify_fops;
|
|
filp->f_path.mnt = mntget(inotify_mnt);
|
|
filp->f_path.dentry = dget(inotify_mnt->mnt_root);
|
|
filp->f_mapping = filp->f_path.dentry->d_inode->i_mapping;
|
|
filp->f_mode = FMODE_READ;
|
|
filp->f_flags = O_RDONLY;
|
|
filp->private_data = dev;
|
|
|
|
INIT_LIST_HEAD(&dev->events);
|
|
init_waitqueue_head(&dev->wq);
|
|
mutex_init(&dev->ev_mutex);
|
|
mutex_init(&dev->up_mutex);
|
|
dev->event_count = 0;
|
|
dev->queue_size = 0;
|
|
dev->max_events = inotify_max_queued_events;
|
|
dev->user = user;
|
|
atomic_set(&dev->count, 0);
|
|
|
|
get_inotify_dev(dev);
|
|
atomic_inc(&user->inotify_devs);
|
|
fd_install(fd, filp);
|
|
|
|
return fd;
|
|
out_free_dev:
|
|
kfree(dev);
|
|
out_free_uid:
|
|
free_uid(user);
|
|
put_filp(filp);
|
|
out_put_fd:
|
|
put_unused_fd(fd);
|
|
return ret;
|
|
}
|
|
|
|
asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask)
|
|
{
|
|
struct inode *inode;
|
|
struct inotify_device *dev;
|
|
struct nameidata nd;
|
|
struct file *filp;
|
|
int ret, fput_needed;
|
|
unsigned flags = 0;
|
|
|
|
filp = fget_light(fd, &fput_needed);
|
|
if (unlikely(!filp))
|
|
return -EBADF;
|
|
|
|
/* verify that this is indeed an inotify instance */
|
|
if (unlikely(filp->f_op != &inotify_fops)) {
|
|
ret = -EINVAL;
|
|
goto fput_and_out;
|
|
}
|
|
|
|
if (!(mask & IN_DONT_FOLLOW))
|
|
flags |= LOOKUP_FOLLOW;
|
|
if (mask & IN_ONLYDIR)
|
|
flags |= LOOKUP_DIRECTORY;
|
|
|
|
ret = find_inode(path, &nd, flags);
|
|
if (unlikely(ret))
|
|
goto fput_and_out;
|
|
|
|
/* inode held in place by reference to nd; dev by fget on fd */
|
|
inode = nd.path.dentry->d_inode;
|
|
dev = filp->private_data;
|
|
|
|
mutex_lock(&dev->up_mutex);
|
|
ret = inotify_find_update_watch(dev->ih, inode, mask);
|
|
if (ret == -ENOENT)
|
|
ret = create_watch(dev, inode, mask);
|
|
mutex_unlock(&dev->up_mutex);
|
|
|
|
path_put(&nd.path);
|
|
fput_and_out:
|
|
fput_light(filp, fput_needed);
|
|
return ret;
|
|
}
|
|
|
|
asmlinkage long sys_inotify_rm_watch(int fd, u32 wd)
|
|
{
|
|
struct file *filp;
|
|
struct inotify_device *dev;
|
|
int ret, fput_needed;
|
|
|
|
filp = fget_light(fd, &fput_needed);
|
|
if (unlikely(!filp))
|
|
return -EBADF;
|
|
|
|
/* verify that this is indeed an inotify instance */
|
|
if (unlikely(filp->f_op != &inotify_fops)) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
dev = filp->private_data;
|
|
|
|
/* we free our watch data when we get IN_IGNORED */
|
|
ret = inotify_rm_wd(dev->ih, wd);
|
|
|
|
out:
|
|
fput_light(filp, fput_needed);
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
inotify_get_sb(struct file_system_type *fs_type, int flags,
|
|
const char *dev_name, void *data, struct vfsmount *mnt)
|
|
{
|
|
return get_sb_pseudo(fs_type, "inotify", NULL,
|
|
INOTIFYFS_SUPER_MAGIC, mnt);
|
|
}
|
|
|
|
static struct file_system_type inotify_fs_type = {
|
|
.name = "inotifyfs",
|
|
.get_sb = inotify_get_sb,
|
|
.kill_sb = kill_anon_super,
|
|
};
|
|
|
|
/*
|
|
* inotify_user_setup - Our initialization function. Note that we cannnot return
|
|
* error because we have compiled-in VFS hooks. So an (unlikely) failure here
|
|
* must result in panic().
|
|
*/
|
|
static int __init inotify_user_setup(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = register_filesystem(&inotify_fs_type);
|
|
if (unlikely(ret))
|
|
panic("inotify: register_filesystem returned %d!\n", ret);
|
|
|
|
inotify_mnt = kern_mount(&inotify_fs_type);
|
|
if (IS_ERR(inotify_mnt))
|
|
panic("inotify: kern_mount ret %ld!\n", PTR_ERR(inotify_mnt));
|
|
|
|
inotify_max_queued_events = 16384;
|
|
inotify_max_user_instances = 128;
|
|
inotify_max_user_watches = 8192;
|
|
|
|
watch_cachep = kmem_cache_create("inotify_watch_cache",
|
|
sizeof(struct inotify_user_watch),
|
|
0, SLAB_PANIC, NULL);
|
|
event_cachep = kmem_cache_create("inotify_event_cache",
|
|
sizeof(struct inotify_kernel_event),
|
|
0, SLAB_PANIC, NULL);
|
|
|
|
return 0;
|
|
}
|
|
|
|
module_init(inotify_user_setup);
|