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authorNick Piggin <npiggin@suse.de>2007-02-12 00:51:59 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-12 09:48:28 -0800
commitf9e4acf3befd3b2903e01b3ef1bd344f03299826 (patch)
tree26eb1f9e71adfd4bd5678861c8f13fd655adfa60 /fs/inotify_user.c
parentd003fb70fd356d0684ee0cd37a785e058c8678de (diff)
[PATCH] inotify: read return val fix
Fix for inotify read bug (bugzilla.kernel.org #6999) Problem Description: When reading from an inotify device with an insufficient sized buffer, read(2) will return 0 with no errno set. This is because of an logically incorrect action from the user program thus should return an more logical value. My suggestion is return -EINVAL as for bind(2). This patch is based on the proposal from Ryan <wolf0403@hotmail.com>, and feedback from John McCutchan <john@johnmccutchan.com>. Return -EINVAL if we have not passed in enough buffer space to read a single inotify event, rather than 0 which indicates that there is nothing to read. Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: "John McCutchan" <john@johnmccutchan.com> Cc: Ryan <wolf0403@hotmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/inotify_user.c')
-rw-r--r--fs/inotify_user.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/fs/inotify_user.c b/fs/inotify_user.c
index 55f6da55b7c..9f2224f65a1 100644
--- a/fs/inotify_user.c
+++ b/fs/inotify_user.c
@@ -455,8 +455,16 @@ static ssize_t inotify_read(struct file *file, char __user *buf,
break;
kevent = inotify_dev_get_event(dev);
- if (event_size + kevent->event.len > count)
+ 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;