On Fri 12-10-18 02:43:02, Nixiaoming wrote: > On Thu, Oct 11, 2018 at 6:16 PM Jan Kara <mailto:jack@xxxxxxx> wrote: > >On Thu 04-10-18 00:25:38, Amir Goldstein wrote: > >> 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> > > > >Just one question occurred to me (after discussion with a colleague about > >this feature): Ming, why do you actually need to know thread ID and > >thread-group ID is not enough? Also note that standard glibc threading > >functions are *not* going to be compatible with the ID returned from > >fanotify (e.g. it will be different from POSIX thread ID as returned by > >pthread_self()). So the feature is somewhat difficult to use from > >userspace... (at least you could use gettid() systemcall to get the ID of > >current thread but there's not glibc wrapper for it). > > > > When using fanotify to monitor system critical directories or files, > the monitor and event trigger are not the same process. > The monitoring task wants to know which task triggers the event. > If the event is triggered by multiple threads, > I hope to know which thread is triggered by the task, > can't see the pthread id here, but I can see the tid. OK, thanks for clarification. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
