/* Pseudo implementation of waitid.

   Copyright (C) 1997-2018 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

   <http://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)

{

  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;

    }

  /* 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

		     );

  if (child == -1)

    /* `waitpid' set `errno' for us.  */

    return -1;

  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.  */

      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);

    }

#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)

{

  if (SINGLE_THREAD_P)

    return do_waitid (idtype, id, infop, options);

  int oldtype = LIBC_CANCEL_ASYNC ();

  int result = do_waitid (idtype, id, infop, options);

  LIBC_CANCEL_RESET (oldtype);

  return result;

}

weak_alias (__waitid, waitid)

strong_alias (__waitid, __libc_waitid)