On Thu, Oct 17, 2024 at 10:05:49PM GMT, Lorenzo Stoakes wrote: > The means by which a pid is determined from a pidfd is duplicated, with > some callers holding a reference to the (pid)fd, and others explicitly > pinning the pid. > > Introduce __pidfd_get_pid() which narrows this to one approach of pinning > the pid, with an optional output parameters for file->f_flags to avoid the > need to hold onto a file to retrieve this. > > Additionally, allow the ability to open a pidfd by opening a /proc/<pid> > directory, utilised by the pidfd_send_signal() system call, providing a > pidfd_get_pid_proc() helper function to do so. > > Doing this allows us to eliminate open-coded pidfd pid lookup and to > consistently handle this in one place. > > This lays the groundwork for a subsequent patch which adds a new sentinel > pidfd to explicitly reference the current process (i.e. thread group > leader) without the need for a pidfd. > > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> Reviewed-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
