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