In order to identify which thread triggered the event in a
multi-threaded program, add the FAN_EVENT_INFO_TID flag in fanotify_init
to opt-in for reporting the event creator's thread id information.
Signed-off-by: nixiaoming <nixiaoming@xxxxxxxxxx>
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/notify/fanotify/fanotify.c | 9 ++++++---
fs/notify/fanotify/fanotify.h | 2 +-
fs/notify/fanotify/fanotify_user.c | 4 ++--
include/linux/fanotify.h | 3 +++
include/uapi/linux/fanotify.h | 3 +++
5 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 361e3a0a445c..2c57186caa2e 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -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_EVENT_INFO_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));
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 88a8290a61cb..ea05b8a401e7 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -19,7 +19,7 @@ struct fanotify_event_info {
* during this object's lifetime
*/
struct path path;
- struct pid *tgid;
+ struct pid *pid;
};
/*
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 14594e491d2b..e03be5071362 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -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,
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index afddd7e0d5a1..05b696b4856b 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -18,7 +18,10 @@
#define FANOTIFY_CLASS_BITS (FAN_CLASS_NOTIF | FAN_CLASS_CONTENT | \
FAN_CLASS_PRE_CONTENT)
+#define FANOTIFY_EVENT_INFO_FLAGS (FAN_EVENT_INFO_TID)
+
#define FANOTIFY_INIT_FLAGS (FANOTIFY_CLASS_BITS | \
+ FANOTIFY_EVENT_INFO_FLAGS | \
FAN_CLOEXEC | FAN_NONBLOCK | \
FAN_UNLIMITED_QUEUE | FAN_UNLIMITED_MARKS)
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index d0c05de670ef..00b2304ed124 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -40,6 +40,9 @@
#define FAN_UNLIMITED_MARKS 0x00000020
#define FAN_ENABLE_AUDIT 0x00000040
+/* Flags to determine fanotify event format */
+#define FAN_EVENT_INFO_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 |\
--
2.17.1
