debug/tst-longjmp_chk.c

   1 #include <errno.h>
   2 #include <fcntl.h>
   3 #include <paths.h>
   4 #include <setjmp.h>
   5 #include <signal.h>
   6 #include <stdbool.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <unistd.h>
  10
  11 static jmp_buf b;
  12
  13
  14 static void
  15 __attribute__ ((noinline))
  16 f (void)
  17 {
  18   char buf[1000];
  19   asm volatile ("" : "=m" (buf));
  20
  21   if (setjmp (b) != 0)
  22     {
  23       puts ("second longjmp succeeded");
  24       exit (1);
  25     }
  26 }
  27
  28
  29 static bool expected_to_fail;
  30
  31
  32 static void
  33 handler (int sig)
  34 {
  35   if (expected_to_fail)
  36     _exit (0);
  37   else
  38     {
  39       static const char msg[] = "unexpected longjmp failure\n";
  40       TEMP_FAILURE_RETRY (write (STDOUT_FILENO, msg, sizeof (msg) - 1));
  41       _exit (1);
  42     }
  43 }
  44
  45
  46 int
  47 main (void)
  48 {
  49   struct sigaction sa;
  50   sa.sa_handler = handler;
  51   sa.sa_flags = 0;
  52   sigemptyset (&sa.sa_mask);
  53
  54   sigaction (SIGABRT, &sa, NULL);
  55
  56   /* Avoid all the buffer overflow messages on stderr.  */
  57   int fd = open (_PATH_DEVNULL, O_WRONLY);
  58   if (fd == -1)
  59     close (STDERR_FILENO);
  60   else
  61     {
  62       dup2 (fd, STDERR_FILENO);
  63       close (fd);
  64     }
  65   setenv ("LIBC_FATAL_STDERR_", "1", 1);
  66
  67
  68   expected_to_fail = false;
  69
  70   if (setjmp (b) == 0)
  71     {
  72       longjmp (b, 1);
  73       /* NOTREACHED */
  74       printf ("first longjmp returned\n");
  75       return 1;
  76     }
  77
  78
  79   expected_to_fail = true;
  80
  81   f ();
  82   longjmp (b, 1);
  83
  84   puts ("second longjmp returned");
  85   return 1;
  86 }