test/test57.c

   1
   2 /* This test tests whether registers are correctly restored after a
   3  * signal handler is executed. The assembly file (test57loop.S) puts
   4  * 'random' values in the registers, and the C code checks whether
   5  * these values are the same, before and after the signal handler.
   6  */
   7
   8 #define _POSIX_SOURCE 1
   9
  10 #include <stdio.h>
  11 #include <signal.h>
  12 #include <err.h>
  13 #include <stdlib.h>
  14 #include <unistd.h>
  15
  16 #include <sys/types.h>
  17 #include <sys/wait.h>
  18
  19 #define SIGNAL SIGUSR1
  20
  21 volatile int remaining_invocations = 2, handler_level = 0;
  22
  23 void check_context_loop(void);
  24
  25 #define REGS 8  /* how many registers pusha and popa save. */
  26
  27 #define ESP 3   /* where is esp saved? */
  28
  29 unsigned long newstate[REGS], origstate[REGS];
  30
  31 void handler(int signal)
  32 {
  33         int st;
  34         sigset_t set, oset;
  35         handler_level++;
  36         remaining_invocations--;
  37         if(remaining_invocations < 1)
  38                 return;
  39         sigemptyset(&set);
  40         sigaddset(&set, SIGNAL);
  41         sigprocmask(SIG_UNBLOCK, &set,  &oset);
  42         wait(&st);
  43         handler_level--;
  44 }
  45
  46 int main(int argc, char *argv[])
  47 {
  48         pid_t child_pid;
  49
  50         printf("Test 57 ");
  51
  52         if(signal(SIGNAL, handler) == SIG_ERR)
  53                 err(1, "signal");
  54
  55         fflush(NULL);
  56
  57         if((child_pid=fork()) < 0)
  58                 err(1, "fork");
  59
  60         if(child_pid == 0) {
  61                 pid_t ppid = 0;
  62
  63                 /* Keep signaling the parent until
  64                  * it disappears.
  65                  */
  66                 while((ppid = getppid()) > 1) {
  67                         if(kill(ppid, SIGNAL) < 0)
  68                                 err(1, "kill");
  69                         sleep(1);
  70                 }
  71
  72                 exit(0);
  73         } else {
  74                 int i;
  75                 int err = 0;
  76
  77                 check_context_loop();
  78
  79                 /* correct 2nd esp for 'pusha' difference. */
  80                 newstate[ESP] += REGS*4;
  81
  82                 for(i = 0; i < REGS; i++) {
  83 #if 0
  84                         printf("%d %08lx %08lx diff  ",
  85                                 i, newstate[i], origstate[i]);
  86 #endif
  87                         if(newstate[i] != origstate[i]) {
  88                                 fprintf(stderr, "reg %d changed; "
  89                                         "found 0x%lx, expected 0x%lx\n",
  90                                         i, newstate[i], origstate[i]);
  91                                 err = 1;
  92                         }
  93                 }
  94
  95                 if(!err) printf("ok\n");
  96
  97                 exit(err);
  98         }
  99
 100         return 0;
 101 }
 102