memcheck/tests/x86-linux/int3-x86.c

   1
   2 #undef _GNU_SOURCE
   3 #define _GNU_SOURCE 1
   4
   5 #include <signal.h>
   6 #include <stdio.h>
   7 #include <sys/ucontext.h>
   8
   9 static char* eip_at_sig = NULL;
  10
  11 static void int_handler(int signum, siginfo_t *si, void *uc_arg)
  12 {
  13    ucontext_t *uc = (ucontext_t *)uc_arg;
  14    /* Note that uc->uc_mcontext is an embedded struct, not a pointer */
  15    mcontext_t *mc = &(uc->uc_mcontext);
  16    void *pc = (void*)mc->gregs[REG_EIP];
  17    printf("in int_handler, EIP is ...\n");
  18    eip_at_sig = pc;
  19 }
  20
  21 static void register_handler(int sig, void *handler)
  22 {
  23    struct sigaction sa;
  24    sa.sa_flags = SA_RESTART | SA_SIGINFO;
  25    sigfillset(&sa.sa_mask);
  26    sa.sa_sigaction = handler;
  27    sigaction(sig, &sa, NULL);
  28 }
  29
  30 int main(void) {
  31    char *intaddr = NULL;
  32    puts("main");
  33    register_handler(SIGTRAP, int_handler);
  34    asm volatile(
  35       "movl $zz_int, %%edx\n"
  36       "mov %%edx, %0\n"
  37       "zz_int:\n"
  38       "int $3\n"
  39       : /* no outputs */
  40       : "m" (intaddr) /* input: address of var to store target addr to */
  41       : /* clobbers */ "edx"
  42       );
  43    /* intaddr is the address of the int 3 insn.  eip_at_sig is the PC
  44       after the exception, which should be the next insn along.
  45       Hence: */
  46    if (intaddr != NULL && eip_at_sig != NULL
  47        && eip_at_sig == intaddr+1)
  48      printf("PASS\n");
  49    else
  50      printf("FAIL\n");
  51    return 0;
  52 }