sysdeps/posix/waitid.c

   1 /* Pseudo implementation of waitid.
   2    Copyright (C) 1997, 1998, 2002 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 static int
  32 do_waitid (idtype_t idtype, id_t id, siginfo_t *infop, int options)
  33 {
  34   pid_t pid, child;
  35   int status;
  36
  37   switch (idtype)
  38     {
  39     case P_PID:
  40       if(id <= 0)
  41         goto invalid;
  42       pid = (pid_t) id;
  43       break;
  44     case P_PGID:
  45       if (id < 0 || id == 1)
  46         goto invalid;
  47       pid = (pid_t) -id;
  48       break;
  49     case P_ALL:
  50       pid = -1;
  51       break;
  52     default:
  53     invalid:
  54       __set_errno (EINVAL);
  55       return -1;
  56     }
  57
  58   /* Technically we're supposed to return EFAULT if infop is bogus,
  59      but that would involve mucking with signals, which is
  60      too much hassle.  User will have to deal with SIGSEGV/SIGBUS.
  61      We just check for a null pointer. */
  62
  63   if (infop == NULL)
  64     {
  65       __set_errno (EFAULT);
  66       return -1;
  67     }
  68
  69   child = __waitpid (pid, &status, options);
  70
  71   if (child == -1)
  72     /* `waitpid' set `errno' for us.  */
  73     return -1;
  74
  75   if (child == 0)
  76     {
  77       /* The WHOHANG bit in OPTIONS is set and there are children available
  78          but none has a status for us.  The XPG docs do not mention this
  79          case so we clear the `siginfo_t' struct and return successfully.  */
  80       infop->si_signo = 0;
  81       infop->si_code = 0;
  82       return 0;
  83     }
  84
  85   /* Decode the status field and set infop members... */
  86   infop->si_signo = SIGCHLD;
  87   infop->si_pid = child;
  88   infop->si_errno = 0;
  89
  90   if (WIFEXITED (status))
  91     {
  92       infop->si_code = CLD_EXITED;
  93       infop->si_status = WEXITSTATUS (status);
  94     }
  95   else if (WIFSIGNALED (status))
  96     {
  97       infop->si_code = WCOREDUMP (status) ? CLD_DUMPED : CLD_KILLED;
  98       infop->si_status = WTERMSIG (status);
  99     }
 100   else if (WIFSTOPPED (status))
 101     {
 102       infop->si_code = CLD_STOPPED;
 103       infop->si_status = WSTOPSIG (status);
 104     }
 105 #ifdef WIFCONTINUED
 106   else if (WIFCONTINUED (status))
 107     {
 108       infop->si_code = CLD_CONTINUED;
 109       infop->si_status = SIGCONT;
 110     }
 111 #endif
 112   else
 113     /* Can't happen. */
 114     assert (! "What?");
 115
 116   return 0;
 117 }
 118
 119
 120 int
 121 __waitid (idtype, id, infop, options)
 122      idtype_t idtype;
 123      id_t id;
 124      siginfo_t *infop;
 125      int options;
 126 {
 127   if (SINGLE_THREAD_P)
 128     return do_waitid (idtype, id, infop, options);
 129
 130   int oldtype = LIBC_CANCEL_ASYNC ();
 131
 132   int result = do_waitid (idtype, id, infop, options);
 133
 134   LIBC_CANCEL_RESET (oldtype);
 135
 136   return result;
 137 }
 138 weak_alias (__waitid, waitid)
 139 strong_alias (__waitid, __libc_waitid)