posix: Remove posix waitid

The POSIX waitid implementation is problematic in some ways:

  - It emulates using waitpid, which default implementation calls
    wait4 and wait4 returns ENOSYS as default.

  - Also by using waitpid it does not allod support the WNOWAIT,
    WEXITED, WSTOPPED, or WCONTINUED flag.  With current POSIX
    specification the flags are no longer marked as optional.

Also due BZ#23091 Hurd still uses the implementation, so it is moved
to as a Hurd arch-specific folder (with some minor cleanups).

Checked against a i686-gnu (run-built-tests=no)

1 files changed, 106 insertions, 0 deletions

diff --git a/sysdeps/mach/hurd/waitid.c b/sysdeps/mach/hurd/waitid.c
new file mode 100644
index 0000000000..dce72339dd
--- /dev/null
+++ b/sysdeps/mach/hurd/waitid.c
@@ -0,0 +1,106 @@
+/* Pseudo implementation of waitid.
+   Copyright (C) 1997-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1997.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <sys/wait.h>
+
+int
+__waitid (idtype_t idtype, id_t id, siginfo_t *infop, int options)
+{
+  pid_t pid, child;
+  int status;
+
+  switch (idtype)
+    {
+    case P_PID:
+      if (id <= 0)
+	goto invalid;
+      pid = (pid_t) id;
+      break;
+    case P_PGID:
+      if (id < 0 || id == 1)
+	goto invalid;
+      pid = (pid_t) -id;
+      break;
+    case P_ALL:
+      pid = -1;
+      break;
+    default:
+    invalid:
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  /* Technically we're supposed to return EFAULT if infop is bogus,
+     but that would involve mucking with signals, which is
+     too much hassle.  User will have to deal with SIGSEGV/SIGBUS.
+     We just check for a null pointer. */
+
+  if (infop == NULL)
+    {
+      __set_errno (EFAULT);
+      return -1;
+    }
+
+  /* Note the waitid() is a cancellation point.  But since we call
+     waitpid() which itself is a cancellation point we do not have
+     to do anything here.  */
+  child = __waitpid (pid, &status, options);
+
+  if (child == -1)
+    /* `waitpid' set `errno' for us.  */
+    return -1;
+
+  if (child == 0)
+    {
+      /* POSIX.1-2008, Technical Corrigendum 1 XSH/TC1-2008/0713 [153] states
+	 that if waitid returns because WNOHANG was specified and status is
+	 not available for any process specified by idtype and id, then the
+	 si_signo and si_pid members of the structure pointed to by infop
+	 shall be set to zero.  */
+      infop->si_signo = 0;
+      infop->si_code = 0;
+      return 0;
+    }
+
+  /* Decode the status field and set infop members... */
+  infop->si_signo = SIGCHLD;
+  infop->si_pid = child;
+  infop->si_errno = 0;
+
+  if (WIFEXITED (status))
+    {
+      infop->si_code = CLD_EXITED;
+      infop->si_status = WEXITSTATUS (status);
+    }
+  else if (WIFSIGNALED (status))
+    {
+      infop->si_code = WCOREDUMP (status) ? CLD_DUMPED : CLD_KILLED;
+      infop->si_status = WTERMSIG (status);
+    }
+  else if (WIFSTOPPED (status))
+    {
+      infop->si_code = CLD_STOPPED;
+      infop->si_status = WSTOPSIG (status);
+    }
+
+  return 0;
+}
+weak_alias (__waitid, waitid)
+strong_alias (__waitid, __libc_waitid)