2005-04-16 22:20:36 +00:00
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/*
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* Directory notifications for Linux.
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*
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* Copyright (C) 2000,2001,2002 Stephen Rothwell
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*
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2009-05-21 21:01:33 +00:00
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* Copyright (C) 2009 Eric Paris <Red Hat Inc>
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* dnotify was largly rewritten to use the new fsnotify infrastructure
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*
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2005-04-16 22:20:36 +00:00
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/dnotify.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/slab.h>
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2008-04-24 11:44:08 +00:00
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#include <linux/fdtable.h>
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2009-05-21 21:01:33 +00:00
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#include <linux/fsnotify_backend.h>
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2005-04-16 22:20:36 +00:00
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2006-03-26 09:37:24 +00:00
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int dir_notify_enable __read_mostly = 1;
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2005-04-16 22:20:36 +00:00
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2009-05-21 21:01:33 +00:00
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static struct kmem_cache *dnotify_struct_cache __read_mostly;
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2009-12-18 02:24:24 +00:00
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static struct kmem_cache *dnotify_mark_cache __read_mostly;
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2009-05-21 21:01:33 +00:00
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static struct fsnotify_group *dnotify_group __read_mostly;
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/*
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2009-12-18 02:24:24 +00:00
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* dnotify will attach one of these to each inode (i_fsnotify_marks) which
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2009-05-21 21:01:33 +00:00
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* is being watched by dnotify. If multiple userspace applications are watching
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* the same directory with dnotify their information is chained in dn
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*/
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2009-12-18 02:24:24 +00:00
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struct dnotify_mark {
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struct fsnotify_mark fsn_mark;
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2009-05-21 21:01:33 +00:00
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struct dnotify_struct *dn;
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};
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2005-04-16 22:20:36 +00:00
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2009-05-21 21:01:33 +00:00
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/*
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* When a process starts or stops watching an inode the set of events which
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* dnotify cares about for that inode may change. This function runs the
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* list of everything receiving dnotify events about this directory and calculates
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* the set of all those events. After it updates what dnotify is interested in
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* it calls the fsnotify function so it can update the set of all events relevant
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* to this inode.
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*/
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2009-12-18 02:24:24 +00:00
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static void dnotify_recalc_inode_mask(struct fsnotify_mark *fsn_mark)
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2005-04-16 22:20:36 +00:00
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{
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2009-05-21 21:01:33 +00:00
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__u32 new_mask, old_mask;
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2005-04-16 22:20:36 +00:00
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struct dnotify_struct *dn;
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2009-12-18 02:24:24 +00:00
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struct dnotify_mark *dn_mark = container_of(fsn_mark,
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struct dnotify_mark,
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fsn_mark);
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2009-05-21 21:01:33 +00:00
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2009-12-18 02:24:24 +00:00
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assert_spin_locked(&fsn_mark->lock);
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2005-04-16 22:20:36 +00:00
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2009-12-18 02:24:24 +00:00
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old_mask = fsn_mark->mask;
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2005-04-16 22:20:36 +00:00
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new_mask = 0;
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2009-12-18 02:24:24 +00:00
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for (dn = dn_mark->dn; dn != NULL; dn = dn->dn_next)
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2009-05-21 21:01:33 +00:00
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new_mask |= (dn->dn_mask & ~FS_DN_MULTISHOT);
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2009-12-18 02:24:33 +00:00
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fsnotify_set_mark_mask_locked(fsn_mark, new_mask);
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2009-05-21 21:01:33 +00:00
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if (old_mask == new_mask)
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return;
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2014-12-13 00:58:36 +00:00
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if (fsn_mark->inode)
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fsnotify_recalc_inode_mask(fsn_mark->inode);
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2005-04-16 22:20:36 +00:00
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}
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2009-05-21 21:01:33 +00:00
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/*
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* Mains fsnotify call where events are delivered to dnotify.
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* Find the dnotify mark on the relevant inode, run the list of dnotify structs
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* on that mark and determine which of them has expressed interest in receiving
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* events of this type. When found send the correct process and signal and
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* destroy the dnotify struct if it was not registered to receive multiple
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* events.
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*/
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static int dnotify_handle_event(struct fsnotify_group *group,
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2014-01-21 23:48:14 +00:00
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struct inode *inode,
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2010-07-28 14:18:39 +00:00
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struct fsnotify_mark *inode_mark,
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struct fsnotify_mark *vfsmount_mark,
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2016-11-21 01:19:09 +00:00
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u32 mask, const void *data, int data_type,
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2014-02-17 12:09:50 +00:00
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const unsigned char *file_name, u32 cookie)
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2009-05-21 21:01:33 +00:00
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{
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2009-12-18 02:24:24 +00:00
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struct dnotify_mark *dn_mark;
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2009-05-21 21:01:33 +00:00
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struct dnotify_struct *dn;
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struct dnotify_struct **prev;
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struct fown_struct *fown;
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2014-01-21 23:48:14 +00:00
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__u32 test_mask = mask & ~FS_EVENT_ON_CHILD;
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2009-05-21 21:01:33 +00:00
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2014-01-21 23:48:15 +00:00
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/* not a dir, dnotify doesn't care */
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if (!S_ISDIR(inode->i_mode))
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return 0;
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2010-07-28 14:18:39 +00:00
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BUG_ON(vfsmount_mark);
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dn_mark = container_of(inode_mark, struct dnotify_mark, fsn_mark);
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2009-05-21 21:01:33 +00:00
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2010-07-28 14:18:39 +00:00
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spin_lock(&inode_mark->lock);
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2009-12-18 02:24:24 +00:00
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prev = &dn_mark->dn;
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2009-05-21 21:01:33 +00:00
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while ((dn = *prev) != NULL) {
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dnotify: ignore FS_EVENT_ON_CHILD
Mask off FS_EVENT_ON_CHILD in dnotify_handle_event(). Otherwise, when there
is more than one watch on a directory and dnotify_should_send_event()
succeeds, events with FS_EVENT_ON_CHILD set will trigger all watches and cause
spurious events.
This case was overlooked in commit e42e2773.
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
static void create_event(int s, siginfo_t* si, void* p)
{
printf("create\n");
}
static void delete_event(int s, siginfo_t* si, void* p)
{
printf("delete\n");
}
int main (void) {
struct sigaction action;
char *tmpdir, *file;
int fd1, fd2;
sigemptyset (&action.sa_mask);
action.sa_flags = SA_SIGINFO;
action.sa_sigaction = create_event;
sigaction (SIGRTMIN + 0, &action, NULL);
action.sa_sigaction = delete_event;
sigaction (SIGRTMIN + 1, &action, NULL);
# define TMPDIR "/tmp/test.XXXXXX"
tmpdir = malloc(strlen(TMPDIR) + 1);
strcpy(tmpdir, TMPDIR);
mkdtemp(tmpdir);
# define TMPFILE "/file"
file = malloc(strlen(tmpdir) + strlen(TMPFILE) + 1);
sprintf(file, "%s/%s", tmpdir, TMPFILE);
fd1 = open (tmpdir, O_RDONLY);
fcntl(fd1, F_SETSIG, SIGRTMIN);
fcntl(fd1, F_NOTIFY, DN_MULTISHOT | DN_CREATE);
fd2 = open (tmpdir, O_RDONLY);
fcntl(fd2, F_SETSIG, SIGRTMIN + 1);
fcntl(fd2, F_NOTIFY, DN_MULTISHOT | DN_DELETE);
if (fork()) {
/* This triggers a create event */
creat(file, 0600);
/* This triggers a create and delete event (!) */
unlink(file);
} else {
sleep(1);
rmdir(tmpdir);
}
return 0;
}
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: Eric Paris <eparis@redhat.com>
2009-10-14 22:13:23 +00:00
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if ((dn->dn_mask & test_mask) == 0) {
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2009-05-21 21:01:33 +00:00
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prev = &dn->dn_next;
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continue;
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}
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fown = &dn->dn_filp->f_owner;
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send_sigio(fown, dn->dn_fd, POLL_MSG);
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if (dn->dn_mask & FS_DN_MULTISHOT)
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prev = &dn->dn_next;
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else {
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*prev = dn->dn_next;
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kmem_cache_free(dnotify_struct_cache, dn);
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2010-07-28 14:18:39 +00:00
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dnotify_recalc_inode_mask(inode_mark);
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2009-05-21 21:01:33 +00:00
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}
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}
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2010-07-28 14:18:39 +00:00
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spin_unlock(&inode_mark->lock);
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2009-05-21 21:01:33 +00:00
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return 0;
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}
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2009-12-18 02:24:24 +00:00
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static void dnotify_free_mark(struct fsnotify_mark *fsn_mark)
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2009-05-21 21:01:33 +00:00
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{
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2009-12-18 02:24:24 +00:00
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struct dnotify_mark *dn_mark = container_of(fsn_mark,
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struct dnotify_mark,
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fsn_mark);
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2009-05-21 21:01:33 +00:00
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2009-12-18 02:24:24 +00:00
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BUG_ON(dn_mark->dn);
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2009-05-21 21:01:33 +00:00
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2009-12-18 02:24:24 +00:00
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kmem_cache_free(dnotify_mark_cache, dn_mark);
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2009-05-21 21:01:33 +00:00
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}
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static struct fsnotify_ops dnotify_fsnotify_ops = {
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.handle_event = dnotify_handle_event,
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};
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/*
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* Called every time a file is closed. Looks first for a dnotify mark on the
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2009-12-18 02:24:24 +00:00
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* inode. If one is found run all of the ->dn structures attached to that
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2009-05-21 21:01:33 +00:00
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* mark for one relevant to this process closing the file and remove that
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* dnotify_struct. If that was the last dnotify_struct also remove the
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2009-12-18 02:24:24 +00:00
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* fsnotify_mark.
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2009-05-21 21:01:33 +00:00
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*/
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2005-04-16 22:20:36 +00:00
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void dnotify_flush(struct file *filp, fl_owner_t id)
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{
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2009-12-18 02:24:24 +00:00
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struct fsnotify_mark *fsn_mark;
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struct dnotify_mark *dn_mark;
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2005-04-16 22:20:36 +00:00
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struct dnotify_struct *dn;
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struct dnotify_struct **prev;
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struct inode *inode;
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2015-09-04 22:43:12 +00:00
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bool free = false;
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2005-04-16 22:20:36 +00:00
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2013-01-23 22:07:38 +00:00
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inode = file_inode(filp);
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2005-04-16 22:20:36 +00:00
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if (!S_ISDIR(inode->i_mode))
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return;
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2009-05-21 21:01:33 +00:00
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2009-12-18 02:24:27 +00:00
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fsn_mark = fsnotify_find_inode_mark(dnotify_group, inode);
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2009-12-18 02:24:24 +00:00
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if (!fsn_mark)
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2009-05-21 21:01:33 +00:00
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return;
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2009-12-18 02:24:24 +00:00
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dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
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2009-05-21 21:01:33 +00:00
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2013-07-08 22:59:44 +00:00
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mutex_lock(&dnotify_group->mark_mutex);
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2009-05-21 21:01:33 +00:00
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2009-12-18 02:24:24 +00:00
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spin_lock(&fsn_mark->lock);
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prev = &dn_mark->dn;
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2005-04-16 22:20:36 +00:00
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while ((dn = *prev) != NULL) {
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if ((dn->dn_owner == id) && (dn->dn_filp == filp)) {
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*prev = dn->dn_next;
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2009-05-21 21:01:33 +00:00
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kmem_cache_free(dnotify_struct_cache, dn);
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2009-12-18 02:24:24 +00:00
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dnotify_recalc_inode_mask(fsn_mark);
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2005-04-16 22:20:36 +00:00
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break;
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}
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prev = &dn->dn_next;
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}
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2009-05-21 21:01:33 +00:00
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2009-12-18 02:24:24 +00:00
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spin_unlock(&fsn_mark->lock);
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2009-05-21 21:01:33 +00:00
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2013-07-08 22:59:44 +00:00
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/* nothing else could have found us thanks to the dnotify_groups
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mark_mutex */
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2015-09-04 22:43:12 +00:00
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if (dn_mark->dn == NULL) {
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fsnotify_detach_mark(fsn_mark);
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free = true;
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}
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2009-05-21 21:01:33 +00:00
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2013-07-08 22:59:44 +00:00
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mutex_unlock(&dnotify_group->mark_mutex);
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2009-05-21 21:01:33 +00:00
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2015-09-04 22:43:12 +00:00
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if (free)
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fsnotify_free_mark(fsn_mark);
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2009-12-18 02:24:24 +00:00
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fsnotify_put_mark(fsn_mark);
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2009-05-21 21:01:33 +00:00
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}
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/* this conversion is done only at watch creation */
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static __u32 convert_arg(unsigned long arg)
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{
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__u32 new_mask = FS_EVENT_ON_CHILD;
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if (arg & DN_MULTISHOT)
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new_mask |= FS_DN_MULTISHOT;
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if (arg & DN_DELETE)
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new_mask |= (FS_DELETE | FS_MOVED_FROM);
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if (arg & DN_MODIFY)
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new_mask |= FS_MODIFY;
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if (arg & DN_ACCESS)
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new_mask |= FS_ACCESS;
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if (arg & DN_ATTRIB)
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new_mask |= FS_ATTRIB;
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if (arg & DN_RENAME)
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new_mask |= FS_DN_RENAME;
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if (arg & DN_CREATE)
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new_mask |= (FS_CREATE | FS_MOVED_TO);
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return new_mask;
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2005-04-16 22:20:36 +00:00
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}
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2009-05-21 21:01:33 +00:00
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/*
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* If multiple processes watch the same inode with dnotify there is only one
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2009-12-18 02:24:24 +00:00
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* dnotify mark in inode->i_fsnotify_marks but we chain a dnotify_struct
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2009-05-21 21:01:33 +00:00
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* onto that mark. This function either attaches the new dnotify_struct onto
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* that list, or it |= the mask onto an existing dnofiy_struct.
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*/
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2009-12-18 02:24:24 +00:00
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static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark *dn_mark,
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2009-05-21 21:01:33 +00:00
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fl_owner_t id, int fd, struct file *filp, __u32 mask)
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{
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struct dnotify_struct *odn;
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2009-12-18 02:24:24 +00:00
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odn = dn_mark->dn;
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2009-05-21 21:01:33 +00:00
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while (odn != NULL) {
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/* adding more events to existing dnofiy_struct? */
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if ((odn->dn_owner == id) && (odn->dn_filp == filp)) {
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odn->dn_fd = fd;
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odn->dn_mask |= mask;
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return -EEXIST;
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}
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odn = odn->dn_next;
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}
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dn->dn_mask = mask;
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dn->dn_fd = fd;
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dn->dn_filp = filp;
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dn->dn_owner = id;
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2009-12-18 02:24:24 +00:00
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dn->dn_next = dn_mark->dn;
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dn_mark->dn = dn;
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2009-05-21 21:01:33 +00:00
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return 0;
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}
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/*
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* When a process calls fcntl to attach a dnotify watch to a directory it ends
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* up here. Allocate both a mark for fsnotify to add and a dnotify_struct to be
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* attached to the fsnotify_mark.
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*/
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2005-04-16 22:20:36 +00:00
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int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
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{
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2009-12-18 02:24:24 +00:00
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struct dnotify_mark *new_dn_mark, *dn_mark;
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struct fsnotify_mark *new_fsn_mark, *fsn_mark;
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2005-04-16 22:20:36 +00:00
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struct dnotify_struct *dn;
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struct inode *inode;
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fl_owner_t id = current->files;
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2008-05-01 02:52:22 +00:00
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struct file *f;
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2009-05-21 21:01:33 +00:00
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int destroy = 0, error = 0;
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__u32 mask;
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/* we use these to tell if we need to kfree */
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2009-12-18 02:24:24 +00:00
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new_fsn_mark = NULL;
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2009-05-21 21:01:33 +00:00
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dn = NULL;
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2005-04-16 22:20:36 +00:00
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2009-05-21 21:01:33 +00:00
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if (!dir_notify_enable) {
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error = -EINVAL;
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goto out_err;
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}
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/* a 0 mask means we are explicitly removing the watch */
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2005-04-16 22:20:36 +00:00
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if ((arg & ~DN_MULTISHOT) == 0) {
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dnotify_flush(filp, id);
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2009-05-21 21:01:33 +00:00
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error = 0;
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goto out_err;
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2005-04-16 22:20:36 +00:00
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}
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2009-05-21 21:01:33 +00:00
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/* dnotify only works on directories */
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2013-01-23 22:07:38 +00:00
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inode = file_inode(filp);
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2009-05-21 21:01:33 +00:00
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if (!S_ISDIR(inode->i_mode)) {
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error = -ENOTDIR;
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goto out_err;
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2005-04-16 22:20:36 +00:00
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}
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2009-05-21 21:01:33 +00:00
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/* expect most fcntl to add new rather than augment old */
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dn = kmem_cache_alloc(dnotify_struct_cache, GFP_KERNEL);
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if (!dn) {
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error = -ENOMEM;
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goto out_err;
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}
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2008-05-01 02:52:22 +00:00
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2009-05-21 21:01:33 +00:00
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/* new fsnotify mark, we expect most fcntl calls to add a new mark */
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2009-12-18 02:24:24 +00:00
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new_dn_mark = kmem_cache_alloc(dnotify_mark_cache, GFP_KERNEL);
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if (!new_dn_mark) {
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2009-05-21 21:01:33 +00:00
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error = -ENOMEM;
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goto out_err;
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}
|
2005-04-16 22:20:36 +00:00
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|
2009-05-21 21:01:33 +00:00
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/* convert the userspace DN_* "arg" to the internal FS_* defines in fsnotify */
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mask = convert_arg(arg);
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2005-04-16 22:20:36 +00:00
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2009-12-18 02:24:24 +00:00
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/* set up the new_fsn_mark and new_dn_mark */
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new_fsn_mark = &new_dn_mark->fsn_mark;
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fsnotify_init_mark(new_fsn_mark, dnotify_free_mark);
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new_fsn_mark->mask = mask;
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new_dn_mark->dn = NULL;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-05-21 21:01:33 +00:00
|
|
|
/* this is needed to prevent the fcntl/close race described below */
|
2013-07-08 22:59:44 +00:00
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|
|
mutex_lock(&dnotify_group->mark_mutex);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-12-18 02:24:24 +00:00
|
|
|
/* add the new_fsn_mark or find an old one. */
|
2009-12-18 02:24:27 +00:00
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|
fsn_mark = fsnotify_find_inode_mark(dnotify_group, inode);
|
2009-12-18 02:24:24 +00:00
|
|
|
if (fsn_mark) {
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|
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dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark);
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|
|
|
spin_lock(&fsn_mark->lock);
|
2009-05-21 21:01:33 +00:00
|
|
|
} else {
|
2013-07-08 22:59:44 +00:00
|
|
|
fsnotify_add_mark_locked(new_fsn_mark, dnotify_group, inode,
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|
|
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NULL, 0);
|
2009-12-18 02:24:24 +00:00
|
|
|
spin_lock(&new_fsn_mark->lock);
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|
|
|
fsn_mark = new_fsn_mark;
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|
|
|
dn_mark = new_dn_mark;
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|
|
|
/* we used new_fsn_mark, so don't free it */
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|
|
|
new_fsn_mark = NULL;
|
2009-05-21 21:01:33 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-05-21 21:01:33 +00:00
|
|
|
rcu_read_lock();
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|
|
|
f = fcheck(fd);
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|
|
|
rcu_read_unlock();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2009-05-21 21:01:33 +00:00
|
|
|
/* if (f != filp) means that we lost a race and another task/thread
|
|
|
|
* actually closed the fd we are still playing with before we grabbed
|
2013-07-08 22:59:44 +00:00
|
|
|
* the dnotify_groups mark_mutex and fsn_mark->lock. Since closing the
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|
|
|
* fd is the only time we clean up the marks we need to get our mark
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|
|
|
* off the list. */
|
2009-05-21 21:01:33 +00:00
|
|
|
if (f != filp) {
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|
|
|
/* if we added ourselves, shoot ourselves, it's possible that
|
2009-12-18 02:24:24 +00:00
|
|
|
* the flush actually did shoot this fsn_mark. That's fine too
|
2009-05-21 21:01:33 +00:00
|
|
|
* since multiple calls to destroy_mark is perfectly safe, if
|
2009-12-18 02:24:24 +00:00
|
|
|
* we found a dn_mark already attached to the inode, just sod
|
2009-05-21 21:01:33 +00:00
|
|
|
* off silently as the flush at close time dealt with it.
|
|
|
|
*/
|
2009-12-18 02:24:24 +00:00
|
|
|
if (dn_mark == new_dn_mark)
|
2009-05-21 21:01:33 +00:00
|
|
|
destroy = 1;
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|
|
|
goto out;
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|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2014-08-22 15:27:32 +00:00
|
|
|
__f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
|
2009-05-21 21:01:33 +00:00
|
|
|
|
2009-12-18 02:24:24 +00:00
|
|
|
error = attach_dn(dn, dn_mark, id, fd, filp, mask);
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|
|
|
/* !error means that we attached the dn to the dn_mark, so don't free it */
|
2009-05-21 21:01:33 +00:00
|
|
|
if (!error)
|
|
|
|
dn = NULL;
|
|
|
|
/* -EEXIST means that we didn't add this new dn and used an old one.
|
|
|
|
* that isn't an error (and the unused dn should be freed) */
|
|
|
|
else if (error == -EEXIST)
|
|
|
|
error = 0;
|
|
|
|
|
2009-12-18 02:24:24 +00:00
|
|
|
dnotify_recalc_inode_mask(fsn_mark);
|
2009-05-21 21:01:33 +00:00
|
|
|
out:
|
2009-12-18 02:24:24 +00:00
|
|
|
spin_unlock(&fsn_mark->lock);
|
2009-05-21 21:01:33 +00:00
|
|
|
|
|
|
|
if (destroy)
|
2015-09-04 22:43:12 +00:00
|
|
|
fsnotify_detach_mark(fsn_mark);
|
2013-07-08 22:59:44 +00:00
|
|
|
mutex_unlock(&dnotify_group->mark_mutex);
|
2015-09-04 22:43:12 +00:00
|
|
|
if (destroy)
|
|
|
|
fsnotify_free_mark(fsn_mark);
|
2009-12-18 02:24:24 +00:00
|
|
|
fsnotify_put_mark(fsn_mark);
|
2009-05-21 21:01:33 +00:00
|
|
|
out_err:
|
2009-12-18 02:24:24 +00:00
|
|
|
if (new_fsn_mark)
|
|
|
|
fsnotify_put_mark(new_fsn_mark);
|
2009-05-21 21:01:33 +00:00
|
|
|
if (dn)
|
|
|
|
kmem_cache_free(dnotify_struct_cache, dn);
|
|
|
|
return error;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static int __init dnotify_init(void)
|
|
|
|
{
|
2009-05-21 21:01:33 +00:00
|
|
|
dnotify_struct_cache = KMEM_CACHE(dnotify_struct, SLAB_PANIC);
|
2009-12-18 02:24:24 +00:00
|
|
|
dnotify_mark_cache = KMEM_CACHE(dnotify_mark, SLAB_PANIC);
|
2009-05-21 21:01:33 +00:00
|
|
|
|
2009-12-18 02:24:22 +00:00
|
|
|
dnotify_group = fsnotify_alloc_group(&dnotify_fsnotify_ops);
|
2009-05-21 21:01:33 +00:00
|
|
|
if (IS_ERR(dnotify_group))
|
|
|
|
panic("unable to allocate fsnotify group for dnotify\n");
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
module_init(dnotify_init)
|