sysdeps/posix/waitid.c

   1 /* Pseudo implementation of waitid.
   2    Copyright (C) 1997, 1998, 2002, 2003, 2004 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1997.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <assert.h>
  22 #include <errno.h>
  23 #include <signal.h>
  24 #define __need_NULL
  25 #include <stddef.h>
  26 #include <sys/wait.h>
  27 #include <sys/types.h>
  28 #include <sysdep-cancel.h>
  29
  30
  31 #ifdef DO_WAITID
  32 # define OUR_WAITID DO_WAITID
  33 #elif !defined NO_DO_WAITID
  34 # define OUR_WAITID do_waitid
  35 #endif
  36
  37 #ifdef OUR_WAITID
  38 static int
  39 OUR_WAITID (idtype_t idtype, id_t id, siginfo_t *infop, int options)
  40 {
  41   pid_t pid, child;
  42   int status;
  43
  44   switch (idtype)
  45     {
  46     case P_PID:
  47       if(id <= 0)
  48         goto invalid;
  49       pid = (pid_t) id;
  50       break;
  51     case P_PGID:
  52       if (id < 0 || id == 1)
  53         goto invalid;
  54       pid = (pid_t) -id;
  55       break;
  56     case P_ALL:
  57       pid = -1;
  58       break;
  59     default:
  60     invalid:
  61       __set_errno (EINVAL);
  62       return -1;
  63     }
  64
  65   /* Technically we're supposed to return EFAULT if infop is bogus,
  66      but that would involve mucking with signals, which is
  67      too much hassle.  User will have to deal with SIGSEGV/SIGBUS.
  68      We just check for a null pointer. */
  69
  70   if (infop == NULL)
  71     {
  72       __set_errno (EFAULT);
  73       return -1;
  74     }
  75
  76   /* This emulation using waitpid cannot support the waitid modes in which
  77      we do not reap the child, or match only stopped and not dead children.  */
  78   if (0
  79 #ifdef WNOWAIT
  80       || (options & WNOWAIT)
  81 #endif
  82 #ifdef WEXITED
  83       || ((options & (WEXITED|WSTOPPED|WCONTINUED))
  84           != (WEXITED | (options & WUNTRACED)))
  85 #endif
  86       )
  87     {
  88       __set_errno (ENOTSUP);
  89       return -1;
  90     }
  91
  92   /* Note the waitid() is a cancellation point.  But since we call
  93      waitpid() which itself is a cancellation point we do not have
  94      to do anything here.  */
  95   child = __waitpid (pid, &status,
  96                      options
  97 #ifdef WEXITED
  98                      &~ WEXITED
  99 #endif
 100                      );
 101
 102   if (child == -1)
 103     /* `waitpid' set `errno' for us.  */
 104     return -1;
 105
 106   if (child == 0)
 107     {
 108       /* The WHOHANG bit in OPTIONS is set and there are children available
 109          but none has a status for us.  The XPG docs do not mention this
 110          case so we clear the `siginfo_t' struct and return successfully.  */
 111       infop->si_signo = 0;
 112       infop->si_code = 0;
 113       return 0;
 114     }
 115
 116   /* Decode the status field and set infop members... */
 117   infop->si_signo = SIGCHLD;
 118   infop->si_pid = child;
 119   infop->si_errno = 0;
 120
 121   if (WIFEXITED (status))
 122     {
 123       infop->si_code = CLD_EXITED;
 124       infop->si_status = WEXITSTATUS (status);
 125     }
 126   else if (WIFSIGNALED (status))
 127     {
 128       infop->si_code = WCOREDUMP (status) ? CLD_DUMPED : CLD_KILLED;
 129       infop->si_status = WTERMSIG (status);
 130     }
 131   else if (WIFSTOPPED (status))
 132     {
 133       infop->si_code = CLD_STOPPED;
 134       infop->si_status = WSTOPSIG (status);
 135     }
 136 #ifdef WIFCONTINUED
 137   else if (WIFCONTINUED (status))
 138     {
 139       infop->si_code = CLD_CONTINUED;
 140       infop->si_status = SIGCONT;
 141     }
 142 #endif
 143   else
 144     /* Can't happen. */
 145     assert (! "What?");
 146
 147   return 0;
 148 }
 149 #endif
 150
 151
 152 int
 153 __waitid (idtype, id, infop, options)
 154      idtype_t idtype;
 155      id_t id;
 156      siginfo_t *infop;
 157      int options;
 158 {
 159   if (SINGLE_THREAD_P)
 160     return do_waitid (idtype, id, infop, options);
 161
 162   int oldtype = LIBC_CANCEL_ASYNC ();
 163
 164   int result = do_waitid (idtype, id, infop, options);
 165
 166   LIBC_CANCEL_RESET (oldtype);
 167
 168   return result;
 169 }
 170 weak_alias (__waitid, waitid)
 171 strong_alias (__waitid, __libc_waitid)