tests/efault3.c

   1 /* Test that libsigsegv does not interfere with fault handling inside
   2    system calls.
   3    Copyright (C) 2009-2010  Eric Blake <ebb9@byu.net>
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software Foundation,
  17    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  18
  19 #ifndef _MSC_VER
  20 # include <config.h>
  21 #endif
  22
  23 #include "sigsegv.h"
  24
  25 #if HAVE_STACK_OVERFLOW_RECOVERY && HAVE_SIGSEGV_RECOVERY && HAVE_EFAULT_SUPPORT
  26
  27 #include <errno.h>
  28 #include <fcntl.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <unistd.h>
  32
  33 #include "altstack.h"
  34
  35 /* A NULL pointer.
  36    If we were to use a literal NULL, gcc would give a warning on glibc systems:
  37    "warning: null argument where non-null required".  */
  38 const char *null_pointer = NULL;
  39
  40 static int
  41 sigsegv_handler (void *fault_address, int serious)
  42 {
  43   /* This test is only enabled when ENABLE_EFAULT is true.  If we get here,
  44      the ENABLE_EFAULT handling in libsigsegv is incomplete.  */
  45   abort ();
  46 }
  47
  48 static void
  49 stackoverflow_handler (int emergency, stackoverflow_context_t scp)
  50 {
  51   /* This test is only enabled when ENABLE_EFAULT is true.  If we get here,
  52      the ENABLE_EFAULT handling in libsigsegv is incomplete.  */
  53   abort ();
  54 }
  55
  56 int
  57 main ()
  58 {
  59   /* Test whether the OS handles some faults by itself.  */
  60   if (open (null_pointer, O_RDONLY) != -1 || errno != EFAULT)
  61     {
  62       fprintf (stderr, "EFAULT not detected alone.\n");
  63       exit (1);
  64     }
  65
  66   /* Prepare the storage for the alternate stack.  */
  67   prepare_alternate_stack ();
  68
  69   /* Install the stack overflow handler.  */
  70   if (stackoverflow_install_handler (&stackoverflow_handler,
  71                                      mystack, SIGSTKSZ)
  72       < 0)
  73     exit (2);
  74
  75   /* Install the SIGSEGV handler.  */
  76   if (sigsegv_install_handler (&sigsegv_handler) < 0)
  77     exit (2);
  78
  79   /* Test that the library does not interfere with OS faults.  */
  80   if (open (null_pointer, O_RDONLY) != -1 || errno != EFAULT)
  81     {
  82       fprintf (stderr, "EFAULT not detected with handler.\n");
  83       exit (1);
  84     }
  85
  86   /* Validate that the alternate stack did not overflow.  */
  87   check_alternate_stack_no_overflow ();
  88
  89   /* Test passed!  */
  90   printf ("Test passed.\n");
  91   return 0;
  92 }
  93
  94 #else
  95
  96 int
  97 main ()
  98 {
  99   return 77;
 100 }
 101
 102 #endif