debug/tst-longjmp_chk2.c

   1 /* Test case mostly written by Paolo Bonzini <pbonzini@redhat.com>.  */
   2 #include <assert.h>
   3 #include <setjmp.h>
   4 #include <signal.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <sys/types.h>
   8 #include <sys/time.h>
   9 #include <sys/resource.h>
  10
  11
  12 static jmp_buf mainloop;
  13 static sigset_t mainsigset;
  14 static int pass;
  15
  16
  17 static void
  18 stackoverflow_handler (int sig)
  19 {
  20   stack_t altstack;
  21   pass++;
  22   sigaltstack (NULL, &altstack);
  23   /* Using printf is not really kosher in signal handlers but we know
  24      it will work.  */
  25   printf ("%*sin signal handler\n", pass, "");
  26   if (altstack.ss_flags & SS_ONSTACK)
  27     printf ("%*son alternate stack\n", pass, "");
  28   siglongjmp (mainloop, pass);
  29 }
  30
  31
  32 static volatile int *
  33 recurse_1 (int n, volatile int *p)
  34 {
  35   if (n >= 0)
  36     *recurse_1 (n + 1, p) += n;
  37   return p;
  38 }
  39
  40
  41 static int
  42 recurse (int n)
  43 {
  44   int sum = 0;
  45   return *recurse_1 (n, &sum);
  46 }
  47
  48
  49 static int
  50 do_test (void)
  51 {
  52   char mystack[SIGSTKSZ];
  53   stack_t altstack;
  54   struct sigaction action;
  55   sigset_t emptyset;
  56   /* Before starting the endless recursion, try to be friendly to the user's
  57      machine.  On some Linux 2.2.x systems, there is no stack limit for user
  58      processes at all.  We don't want to kill such systems.  */
  59   struct rlimit rl;
  60   rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
  61   setrlimit (RLIMIT_STACK, &rl);
  62   /* Install the alternate stack.  */
  63   altstack.ss_sp = mystack;
  64   altstack.ss_size = sizeof (mystack);
  65   altstack.ss_flags = 0; /* no SS_DISABLE */
  66   if (sigaltstack (&altstack, NULL) < 0)
  67     {
  68       puts ("first sigaltstack failed");
  69       return 0;
  70     }
  71   /* Install the SIGSEGV handler.  */
  72   sigemptyset (&action.sa_mask);
  73   action.sa_handler = &stackoverflow_handler;
  74   action.sa_flags = SA_ONSTACK;
  75   sigaction (SIGSEGV, &action, (struct sigaction *) NULL);
  76   sigaction (SIGBUS, &action, (struct sigaction *) NULL);
  77
  78   /* Save the current signal mask.  */
  79   sigemptyset (&emptyset);
  80   sigprocmask (SIG_BLOCK, &emptyset, &mainsigset);
  81
  82   /* Provoke two stack overflows in a row.  */
  83   if (sigsetjmp (mainloop, 1) != 0)
  84     {
  85       assert (pass != 0);
  86       printf ("%*sout of signal handler\n", pass, "");
  87     }
  88   else
  89     assert (pass == 0);
  90
  91   sigaltstack (NULL, &altstack);
  92   if (altstack.ss_flags & SS_ONSTACK)
  93     printf ("%*son alternate stack\n", pass, "");
  94   else
  95     printf ("%*snot on alternate stack\n", pass, "");
  96
  97   if (pass < 2)
  98     {
  99       recurse (0);
 100       puts ("recurse call returned");
 101       return 2;
 102     }
 103
 104   altstack.ss_flags |= SS_DISABLE;
 105   if (sigaltstack (&altstack, NULL) == -1)
 106     printf ("disabling alternate stack failed\n");
 107   else
 108     printf ("disabling alternate stack succeeded \n");
 109
 110   return 0;
 111 }
 112
 113 #define TEST_FUNCTION do_test ()
 114 #include "../test-skeleton.c"