From 6437fecca30deb88e5901ab03168cb7b40c7e0a7 Mon Sep 17 00:00:00 2001
From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Tue, 19 Nov 2019 18:34:19 -0300
Subject: [PATCH] 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)
---
 sysdeps/{posix => mach/hurd}/waitid.c | 70 +++++------------------------------
 1 file changed, 9 insertions(+), 61 deletions(-)
 rename sysdeps/{posix => mach/hurd}/waitid.c (65%)

diff --git a/sysdeps/posix/waitid.c b/sysdeps/mach/hurd/waitid.c
similarity index 65%
rename from sysdeps/posix/waitid.c
rename to sysdeps/mach/hurd/waitid.c
index f752076..dce7233 100644
--- a/sysdeps/posix/waitid.c
+++ b/sysdeps/mach/hurd/waitid.c
@@ -17,25 +17,11 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <assert.h>
 #include <errno.h>
-#include <signal.h>
-#define __need_NULL
-#include <stddef.h>
 #include <sys/wait.h>
-#include <sys/types.h>
-#include <sysdep-cancel.h>
 
-
-#ifdef DO_WAITID
-# define OUR_WAITID DO_WAITID
-#elif !defined NO_DO_WAITID
-# define OUR_WAITID do_waitid
-#endif
-
-#ifdef OUR_WAITID
-static int
-OUR_WAITID (idtype_t idtype, id_t id, siginfo_t *infop, int options)
+int
+__waitid (idtype_t idtype, id_t id, siginfo_t *infop, int options)
 {
   pid_t pid, child;
   int status;
@@ -43,7 +29,7 @@ OUR_WAITID (idtype_t idtype, id_t id, siginfo_t *infop, int options)
   switch (idtype)
     {
     case P_PID:
-      if(id <= 0)
+      if (id <= 0)
 	goto invalid;
       pid = (pid_t) id;
       break;
@@ -72,31 +58,10 @@ OUR_WAITID (idtype_t idtype, id_t id, siginfo_t *infop, int options)
       return -1;
     }
 
-  /* This emulation using waitpid cannot support the waitid modes in which
-     we do not reap the child, or match only stopped and not dead children.  */
-  if (0
-#ifdef WNOWAIT
-      || (options & WNOWAIT)
-#endif
-#ifdef WEXITED
-      || ((options & (WEXITED|WSTOPPED|WCONTINUED))
-	  != (WEXITED | (options & WSTOPPED)))
-#endif
-      )
-    {
-      __set_errno (ENOTSUP);
-      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
-#ifdef WEXITED
-		     &~ WEXITED
-#endif
-		     );
+  child = __waitpid (pid, &status, options);
 
   if (child == -1)
     /* `waitpid' set `errno' for us.  */
@@ -104,9 +69,11 @@ OUR_WAITID (idtype_t idtype, id_t id, siginfo_t *infop, int options)
 
   if (child == 0)
     {
-      /* The WHOHANG bit in OPTIONS is set and there are children available
-	 but none has a status for us.  The XPG docs do not mention this
-	 case so we clear the `siginfo_t' struct and return successfully.  */
+      /* 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;
@@ -132,27 +99,8 @@ OUR_WAITID (idtype_t idtype, id_t id, siginfo_t *infop, int options)
       infop->si_code = CLD_STOPPED;
       infop->si_status = WSTOPSIG (status);
     }
-#ifdef WIFCONTINUED
-  else if (WIFCONTINUED (status))
-    {
-      infop->si_code = CLD_CONTINUED;
-      infop->si_status = SIGCONT;
-    }
-#endif
-  else
-    /* Can't happen. */
-    assert (! "What?");
 
   return 0;
 }
-#endif
-
-
-int
-__waitid (idtype_t idtype, id_t id, siginfo_t *infop, int options)
-{
-  /* __waitpid should be a cancellation point.  */
-  return do_waitid (idtype, id, infop, options);
-}
 weak_alias (__waitid, waitid)
 strong_alias (__waitid, __libc_waitid)
-- 
2.7.4