[DTrace-devel] [oracle/dtrace-utils] 2120a7: proc: use pidfd_open(..., PIDFD_THREAD) if available

[Nick Alcock]

  Branch: refs/heads/nix/2.0/pidfds
  Home:   https://github.com/oracle/dtrace-utils
  Commit: 2120a703ead38ce1e074e97becf87968d8b836ba
      https://github.com/oracle/dtrace-utils/commit/2120a703ead38ce1e074e97becf87968d8b836ba
  Author: Nick Alcock <nick.alcock at oracle.com>
  Date:   2022-12-14 (Wed, 14 Dec 2022)

  Changed paths:
    M Makeconfig
    M include/port.h
    M libdtrace/dt_proc.c
    M libport/Build
    A libport/pid_fd.c

  Log Message:
  -----------
  proc: use pidfd_open(..., PIDFD_THREAD) if available

With luck this approach might possibly perhaps go upstream!

We still fall back to waitfd if using PIDFD_THREAD doesn't work.
Complicated somewhat by having to use SYS_syscall() if a glibc too old
to support pidfd_open() isn't available (i.e. all released ones: it'll
be in 2.36), and by the likelihood that PIDFD_THREAD isn't in the
header even if the header is present, but otherwise fairly trivial.

Signed-off-by: Nick Alcock <nick.alcock at oracle.com>