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Commit d0a6a87e authored by Amir Goldstein's avatar Amir Goldstein Committed by Jan Kara
Browse files

fanotify: support reporting thread id instead of process id 



In order to identify which thread triggered the event in a
multi-threaded program, add the FAN_REPORT_TID flag in fanotify_init to
opt-in for reporting the event creator's thread id information.

Signed-off-by: default avatarnixiaoming <nixiaoming@huawei.com>
Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent bdd5a46f

fs/notify/fanotify/fanotify.c

+6 −3
Original line number Diff line number Diff line
@@ -25,7 +25,7 @@ static bool should_merge(struct fsnotify_event *old_fsn, 
	old = FANOTIFY_E(old_fsn);

	new = FANOTIFY_E(new_fsn);



	if (old_fsn->inode == new_fsn->inode && old->tgid == new->tgid &&

	if (old_fsn->inode == new_fsn->inode && old->pid == new->pid &&

	    old->path.mnt == new->path.mnt &&

	    old->path.dentry == new->path.dentry)

		return true;
@@ -171,7 +171,10 @@ struct fanotify_event_info *fanotify_alloc_event(struct fsnotify_group *group, 
		goto out;

init: __maybe_unused

	fsnotify_init_event(&event->fse, inode, mask);

	event->tgid = get_pid(task_tgid(current));

	if (FAN_GROUP_FLAG(group, FAN_REPORT_TID))

		event->pid = get_pid(task_pid(current));

	else

		event->pid = get_pid(task_tgid(current));

	if (path) {

		event->path = *path;

		path_get(&event->path);
@@ -270,7 +273,7 @@ static void fanotify_free_event(struct fsnotify_event *fsn_event) 


	event = FANOTIFY_E(fsn_event);

	path_put(&event->path);

	put_pid(event->tgid);

	put_pid(event->pid);

	if (fanotify_is_perm_event(fsn_event->mask)) {

		kmem_cache_free(fanotify_perm_event_cachep,

				FANOTIFY_PE(fsn_event));

fs/notify/fanotify/fanotify.h

+1 −1
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ struct fanotify_event_info { 
	 * during this object's lifetime

	 */

	struct path path;

	struct pid *tgid;

	struct pid *pid;

};



/*

fs/notify/fanotify/fanotify_user.c

+2 −2
Original line number Diff line number Diff line
@@ -132,7 +132,7 @@ static int fill_event_metadata(struct fsnotify_group *group, 
	metadata->vers = FANOTIFY_METADATA_VERSION;

	metadata->reserved = 0;

	metadata->mask = fsn_event->mask & FANOTIFY_OUTGOING_EVENTS;

	metadata->pid = pid_vnr(event->tgid);

	metadata->pid = pid_vnr(event->pid);

	if (unlikely(fsn_event->mask & FAN_Q_OVERFLOW))

		metadata->fd = FAN_NOFD;

	else {
@@ -944,7 +944,7 @@ COMPAT_SYSCALL_DEFINE6(fanotify_mark, 
 */

static int __init fanotify_user_setup(void)

{

	BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 6);

	BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 7);

	BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9);



	fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,

include/linux/fanotify.h

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
				 FAN_CLASS_PRE_CONTENT)



#define FANOTIFY_INIT_FLAGS	(FANOTIFY_CLASS_BITS | \

				 FAN_REPORT_TID | \

				 FAN_CLOEXEC | FAN_NONBLOCK | \

				 FAN_UNLIMITED_QUEUE | FAN_UNLIMITED_MARKS)

include/uapi/linux/fanotify.h

+3 −0
Original line number Diff line number Diff line
@@ -40,6 +40,9 @@ 
#define FAN_UNLIMITED_MARKS	0x00000020

#define FAN_ENABLE_AUDIT	0x00000040



/* Flags to determine fanotify event format */

#define FAN_REPORT_TID		0x00000100	/* event->pid is thread id */



/* Deprecated - do not use this in programs and do not add new flags here! */

#define FAN_ALL_INIT_FLAGS	(FAN_CLOEXEC | FAN_NONBLOCK | \

				 FAN_ALL_CLASS_BITS | FAN_UNLIMITED_QUEUE |\