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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-16 20:47:14 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-16 20:47:14 (GMT)
commita9dce6679d736cb3d612af39bab9f31f8db66f9b (patch)
tree7a5e010464d0154fce53aea3c9e3fac2b37c2912 /arch
parentf67e3fb4891287b8248ebb3320f794b9f5e782d4 (diff)
parent575a0ae9744d571f7c6aae4487a05850baae9e1c (diff)
Merge tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull pidfd system call from Christian Brauner: "This introduces the ability to use file descriptors from /proc/<pid>/ as stable handles on struct pid. Even if a pid is recycled the handle will not change. For a start these fds can be used to send signals to the processes they refer to. With the ability to use /proc/<pid> fds as stable handles on struct pid we can fix a long-standing issue where after a process has exited its pid can be reused by another process. If a caller sends a signal to a reused pid it will end up signaling the wrong process. With this patchset we enable a variety of use cases. One obvious example is that we can now safely delegate an important part of process management - sending signals - to processes other than the parent of a given process by sending file descriptors around via scm rights and not fearing that the given process will have been recycled in the meantime. It also allows for easy testing whether a given process is still alive or not by sending signal 0 to a pidfd which is quite handy. There has been some interest in this feature e.g. from systems management (systemd, glibc) and container managers. I have requested and gotten comments from glibc to make sure that this syscall is suitable for their needs as well. In the future I expect it to take on most other pid-based signal syscalls. But such features are left for the future once they are needed. This has been sitting in linux-next for quite a while and has not caused any issues. It comes with selftests which verify basic functionality and also test that a recycled pid cannot be signaled via a pidfd. Jon has written about a prior version of this patchset. It should cover the basic functionality since not a lot has changed since then: https://lwn.net/Articles/773459/ The commit message for the syscall itself is extensively documenting the syscall, including it's functionality and extensibility" * tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: selftests: add tests for pidfd_send_signal() signal: add pidfd_send_signal() syscall
Diffstat (limited to 'arch')
2 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 8da7859..1f9607e 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -429,6 +429,7 @@
421 i386 rt_sigtimedwait_time64 sys_rt_sigtimedwait __ia32_compat_sys_rt_sigtimedwait_time64
422 i386 futex_time64 sys_futex __ia32_sys_futex
423 i386 sched_rr_get_interval_time64 sys_sched_rr_get_interval __ia32_sys_sched_rr_get_interval
+424 i386 pidfd_send_signal sys_pidfd_send_signal __ia32_sys_pidfd_send_signal
425 i386 io_uring_setup sys_io_uring_setup __ia32_sys_io_uring_setup
426 i386 io_uring_enter sys_io_uring_enter __ia32_sys_io_uring_enter
427 i386 io_uring_register sys_io_uring_register __ia32_sys_io_uring_register
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index c768447..92ee0b4 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -345,6 +345,7 @@
334 common rseq __x64_sys_rseq
# don't use numbers 387 through 423, add new calls after the last
# 'common' entry
+424 common pidfd_send_signal __x64_sys_pidfd_send_signal
425 common io_uring_setup __x64_sys_io_uring_setup
426 common io_uring_enter __x64_sys_io_uring_enter
427 common io_uring_register __x64_sys_io_uring_register

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