sysdeps/generic/abort.c

   1 /* Copyright (C) 1991, 1993, 1995, 1996, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <bits/libc-lock.h>
  20 #include <signal.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25
  26 /* Try to get a machine dependent instruction which will make the
  27    program crash.  This is used in case everything else fails.  */
  28 #include <abort-instr.h>
  29 #ifndef ABORT_INSTRUCTION
  30 /* No such instruction is available.  */
  31 # define ABORT_INSTRUCTION
  32 #endif
  33
  34 /* We must avoid to run in circles.  Therefore we remember how far we
  35    already got.  */
  36 static int stage;
  37
  38 /* We should be prepared for multiple threads trying to run abort.  */
  39 __libc_lock_define_initialized_recursive (static, lock);
  40
  41
  42 /* Cause an abnormal program termination with core-dump.  */
  43 void
  44 abort (void)
  45 {
  46   struct sigaction act;
  47   sigset_t sigs;
  48
  49   /* First acquire the lock.  */
  50   __libc_lock_lock_recursive (lock);
  51
  52   /* Now it's for sure we are alone.  But recursive calls are possible.  */
  53
  54   /* Unlock SIGABRT.  */
  55   if (stage == 0)
  56     {
  57       ++stage;
  58       if (__sigemptyset (&sigs) == 0 &&
  59           __sigaddset (&sigs, SIGABRT) == 0)
  60         __sigprocmask (SIG_UNBLOCK, &sigs, (sigset_t *) NULL);
  61     }
  62
  63   /* Flush all streams.  We cannot close them now because the user
  64      might have registered a handler for SIGABRT.  */
  65   if (stage == 1)
  66     {
  67       ++stage;
  68       fflush (NULL);
  69     }
  70
  71   /* Send signal which possibly calls a user handler.  */
  72   if (stage == 2)
  73     {
  74       /* This stage is special: we must allow repeated calls of
  75          `abort' when a user defined handler for SIGABRT is installed.
  76          This is risky since the `raise' implementation might also
  77          fail but I don't see another possibility.  */
  78       int save_stage = stage;
  79
  80       stage = 0;
  81       __libc_lock_unlock_recursive (lock);
  82
  83       raise (SIGABRT);
  84
  85       __libc_lock_lock_recursive (lock);
  86       stage = save_stage + 1;
  87     }
  88
  89   /* There was a handler installed.  Now remove it.  */
  90   if (stage == 3)
  91     {
  92       ++stage;
  93       memset (&act, '\0', sizeof (struct sigaction));
  94       act.sa_handler = SIG_DFL;
  95       __sigfillset (&act.sa_mask);
  96       act.sa_flags = 0;
  97       __sigaction (SIGABRT, &act, NULL);
  98     }
  99
 100   /* Now close the streams which also flushes the output the user
 101      defined handler might has produced.  */
 102   if (stage == 4)
 103     {
 104       ++stage;
 105       __fcloseall ();
 106     }
 107
 108   /* Try again.  */
 109   if (stage == 5)
 110     {
 111       ++stage;
 112       raise (SIGABRT);
 113     }
 114
 115   /* Now try to abort using the system specific command.  */
 116   if (stage == 6)
 117     {
 118       ++stage;
 119       ABORT_INSTRUCTION;
 120     }
 121
 122   /* If we can't signal ourselves and the abort instruction failed, exit.  */
 123   if (stage == 7)
 124     {
 125       ++stage;
 126       _exit (127);
 127     }
 128
 129   /* If even this fails try to use the provided instruction to crash
 130      or otherwise make sure we never return.  */
 131   while (1)
 132     /* Try for ever and ever.  */
 133     ABORT_INSTRUCTION;
 134 }