granicus.if.org Git - strace/blob - test/sigkill_rain.c

   1 #include <stdlib.h>
   2 #include <stddef.h>
   3 #include <unistd.h>
   4 #include <signal.h>
   5 #include <sys/types.h>
   6 #include <sys/socket.h>
   7 #include <stdio.h>
   8 #include <sys/wait.h>
   9
  10 static const struct sockaddr sa;
  11
  12 int main(int argc, char *argv[])
  13 {
  14         int loops;
  15         int pid;
  16         sigset_t set;
  17
  18         printf(
  19 "Please run me under 'strace -f -oLOG', and examine LOG file for incorrect\n"
  20 "decoding of interrupted syscalls: grep for 'sendto', '??" /* anti-trigraph gap */ "?', 'unavailable'.\n"
  21 "Pass number of iterations in argv[1] (default: 999).\n"
  22         );
  23         fflush(NULL);
  24
  25         sigemptyset(&set);
  26         sigaddset(&set, SIGCHLD);
  27         sigprocmask(SIG_BLOCK, &set, NULL);
  28
  29         loops = 999;
  30         if (argv[1])
  31                 loops = atoi(argv[1]);
  32
  33         while (--loops >= 0) {
  34                 pid = fork();
  35
  36                 if (pid < 0)
  37                         exit(1);
  38
  39                 if (!pid) {
  40                         /* child */
  41                         int child = getpid();
  42
  43                         loops = 99;
  44                         while (--loops) {
  45                                 pid = fork();
  46
  47                                 if (pid < 0)
  48                                         exit(1);
  49
  50                                 if (!pid) {
  51                                         /* grandchild: kill child */
  52                                         kill(child, SIGKILL);
  53                                         exit(0);
  54                                 }
  55
  56                                 /* Add various syscalls you want to test here.
  57                                  * strace will decode them and suddenly find
  58                                  * process disappearing.
  59                                  * But leave at least one case "empty", so that
  60                                  * "kill grandchild" happens quicker.
  61                                  * This produces cases when strace can't even
  62                                  * decode syscall number before process dies.
  63                                  */
  64                                 switch (loops & 1) {
  65                                 case 0:
  66                                         break; /* intentionally empty */
  67                                 case 1:
  68                                         sendto(-1, "Hello cruel world", 17, 0, &sa, sizeof(sa));
  69                                         break;
  70                                 }
  71
  72                                 /* kill grandchild */
  73                                 kill(pid, SIGKILL);
  74                         }
  75
  76                         exit(0);
  77                 }
  78
  79                 /* parent */
  80                 wait(NULL);
  81         }
  82
  83         return 0;
  84 }