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| author |   John McCutchan <ttb@tentacle.dhs.org> | 2005-12-12 00:37:14 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@g5.osdl.org> | 2005-12-12 08:57:43 -0800 |
| commit | 8140a5005bc6f1c9d0fa103460d50d472e6e3426 (patch) | |
| tree | 9c5ae431bf1db43e3a1e7a4cceb472c76077ac18 | |
| parent | [PATCH] cciss: double put_disk() (diff) | |
| download | linux-dev-8140a5005bc6f1c9d0fa103460d50d472e6e3426.tar.xz linux-dev-8140a5005bc6f1c9d0fa103460d50d472e6e3426.zip | |
[PATCH] inotify: add two inotify_add_watch flags
The below patch lets userspace have more control over the inodes that
inotify will watch. It introduces two new flags.
IN_ONLYDIR -- only watch the inode if it is a directory.
This is needed to avoid the race that can occur when we want to be
sure that we are watching a directory.
IN_DONT_FOLLOW -- don't follow a symlink. In combination
with IN_ONLYDIR we can make sure that we don't watch the target of
symlinks.
The issues the flags fix came up when writing the gnome-vfs inotify
backend. Default behaviour is unchanged.
Signed-off-by: John McCutchan <ttb@tentacle.dhs.org>
Acked-by: Robert Love <rml@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | fs/inotify.c | 13 | ||||
| -rw-r--r-- | include/linux/inotify.h | 2 |
2 files changed, 12 insertions, 3 deletions
diff --git a/fs/inotify.c b/fs/inotify.c index bf7ce1d2412b..2fecb7af4a77 100644 --- a/fs/inotify.c +++ b/fs/inotify.c @@ -364,11 +364,12 @@ static int inotify_dev_get_wd(struct inotify_device *dev, /* * 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) +static int find_inode(const char __user *dirname, struct nameidata *nd, + unsigned flags) { int error; - error = __user_walk(dirname, LOOKUP_FOLLOW, nd); + error = __user_walk(dirname, flags, nd); if (error) return error; /* you can only watch an inode if you have read permissions on it */ @@ -933,6 +934,7 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) struct file *filp; int ret, fput_needed; int mask_add = 0; + unsigned flags = 0; filp = fget_light(fd, &fput_needed); if (unlikely(!filp)) @@ -944,7 +946,12 @@ asmlinkage long sys_inotify_add_watch(int fd, const char __user *path, u32 mask) goto fput_and_out; } - ret = find_inode(path, &nd); + 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; diff --git a/include/linux/inotify.h b/include/linux/inotify.h index ee5b239092ed..267c88b5f742 100644 --- a/include/linux/inotify.h +++ b/include/linux/inotify.h @@ -47,6 +47,8 @@ struct inotify_event { #define IN_MOVE (IN_MOVED_FROM | IN_MOVED_TO) /* moves */ /* special flags */ +#define IN_ONLYDIR 0x01000000 /* only watch the path if it is a directory */ +#define IN_DONT_FOLLOW 0x02000000 /* don't follow a sym link */ #define IN_MASK_ADD 0x20000000 /* add to the mask of an already existing watch */ #define IN_ISDIR 0x40000000 /* event occurred against dir */ #define IN_ONESHOT 0x80000000 /* only send event once */ |