linux/include/uapi
Lorenzo Stoakes f08d0c3a71
pidfd: add PIDFD_SELF* sentinels to refer to own thread/process
It is useful to be able to utilise the pidfd mechanism to reference the
current thread or process (from a userland point of view - thread group
leader from the kernel's point of view).

Therefore introduce PIDFD_SELF_THREAD to refer to the current thread, and
PIDFD_SELF_THREAD_GROUP to refer to the current thread group leader.

For convenience and to avoid confusion from userland's perspective we alias
these:

* PIDFD_SELF is an alias for PIDFD_SELF_THREAD - This is nearly always what
  the user will want to use, as they would find it surprising if for
  instance fd's were unshared()'d and they wanted to invoke pidfd_getfd()
  and that failed.

* PIDFD_SELF_PROCESS is an alias for PIDFD_SELF_THREAD_GROUP - Most users
  have no concept of thread groups or what a thread group leader is, and
  from userland's perspective and nomenclature this is what userland
  considers to be a process.

We adjust pidfd_get_task() and the pidfd_send_signal() system call with
specific handling for this, implementing this functionality for
process_madvise(), process_mrelease() (albeit, using it here wouldn't
really make sense) and pidfd_send_signal().

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Link: https://lore.kernel.org/r/24315a16a3d01a548dd45c7515f7d51c767e954e.1738268370.git.lorenzo.stoakes@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-05 15:14:37 +01:00
..
asm-generic \n 2025-01-23 13:36:06 -08:00
drm Merge tag 'drm-msm-next-2025-01-07' of gitlab.freedesktop.org:drm/msm into drm-next 2025-01-13 11:14:07 +10:00
linux pidfd: add PIDFD_SELF* sentinels to refer to own thread/process 2025-02-05 15:14:37 +01:00
misc Revert "misc: fastrpc: Restrict untrusted app to attach to privileged PD" 2024-08-15 16:59:14 +02:00
mtd ubi: Expose interface for detailed erase counters 2025-01-18 15:32:32 +01:00
rdma RDMA/nldev: Add IB device and net device rename events 2024-11-04 06:57:21 -05:00
regulator
scsi scsi: mpi3mr: Add ioctl support for HDB 2024-06-26 23:30:09 -04:00
sound ASoC: Updates for v6.14 2025-01-20 16:15:07 +01:00
video
xen xen/privcmd: Add new syscall to get gsi from dev 2024-09-25 09:54:55 +02:00
Kbuild