lkml.org 
[lkml]   [2005]   [Dec]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subject[patch] add two inotify_add_watch flags
    From
    Date
    Yo,

    The below patch lets user space 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>
    Index: linux-2.6.14-rc5/fs/inotify.c
    ===================================================================
    --- linux-2.6.14-rc5.orig/fs/inotify.c 2005-10-20 02:23:05.000000000 -0400
    +++ linux-2.6.14-rc5/fs/inotify.c 2005-12-06 19:01:22.000000000 -0500
    @@ -363,11 +363,18 @@
    /*
    * 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,
    + int only_dir, int dont_follow_symlink)
    {
    int error;
    + unsigned flags = 0;

    - error = __user_walk(dirname, LOOKUP_FOLLOW, nd);
    + if (!dont_follow_symlink)
    + flags |= LOOKUP_FOLLOW;
    + if (only_dir)
    + flags |= LOOKUP_DIRECTORY;
    +
    + error = __user_walk(dirname, flags, nd);
    if (error)
    return error;
    /* you can only watch an inode if you have read permissions on it */
    @@ -943,7 +950,7 @@
    goto fput_and_out;
    }

    - ret = find_inode(path, &nd);
    + ret = find_inode(path, &nd, mask & IN_ONLYDIR, mask & IN_DONT_FOLLOW);
    if (unlikely(ret))
    goto fput_and_out;

    Index: linux-2.6.14-rc5/include/linux/inotify.h
    ===================================================================
    --- linux-2.6.14-rc5.orig/include/linux/inotify.h 2005-10-20 02:23:05.000000000 -0400
    +++ linux-2.6.14-rc5/include/linux/inotify.h 2005-12-06 18:57:11.000000000 -0500
    @@ -47,6 +47,8 @@
    #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 */
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-12-07 05:34    [W:0.025 / U:3.828 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site