src/regress/sys/kern/sigsuspend/sigsuspend.c

   1 /*      $OpenBSD: sigsuspend.c,v 1.2 2010/06/20 17:57:09 phessler Exp $ */
   2 /*
   3  *      Written by Artur Grabowski <art@openbsd.org> 2005, Public domain.
   4  */
   5
   6 #include <stdlib.h>
   7 #include <signal.h>
   8 #include <string.h>
   9 #include <unistd.h>
  10 #include <err.h>
  11 #include <sys/types.h>
  12 #include <sys/wait.h>
  13
  14 sig_atomic_t gotusr1;
  15 sig_atomic_t gotusr2;
  16
  17 void
  18 usr1handler(int signo)
  19 {
  20         gotusr1 = 1;
  21 }
  22
  23 void
  24 usr2handler(int signo)
  25 {
  26         gotusr2 = 1;
  27 }
  28
  29 int
  30 main()
  31 {
  32         sigset_t set, oset;
  33         struct sigaction sa;
  34         pid_t pid, ppid;
  35         int status;
  36
  37         ppid = getpid();
  38
  39         memset(&sa, 0, sizeof(sa));
  40         sigemptyset(&sa.sa_mask);
  41         sa.sa_handler = usr1handler;
  42         if (sigaction(SIGUSR1, &sa, NULL))
  43                 err(1, "sigaction(USR1)");
  44
  45         sa.sa_handler = usr2handler;
  46         if (sigaction(SIGUSR2, &sa, NULL))
  47                 err(1, "sigaction(USR2)");
  48
  49         /*
  50          * Set the procmask to mask the early USR1 the child will send us.
  51          */
  52         sigemptyset(&set);
  53         sigaddset(&set, SIGUSR1);
  54         sigaddset(&set, SIGUSR2);
  55         if (sigprocmask(SIG_BLOCK, &set, &oset))
  56                 err(1, "sigprocmask");
  57
  58         switch((pid = fork())) {
  59         case 0:
  60                 /*
  61                  * In the child.
  62                  */
  63
  64                 kill(ppid, SIGUSR1);    /* Tell the parent we're ready. */
  65
  66                 sigemptyset(&set);
  67                 sigaddset(&set, SIGUSR2);
  68                 sigsuspend(&set);
  69
  70                 /*
  71                  * Check that sigsuspend didn't change the signal mask.
  72                  */
  73                 if (sigprocmask(SIG_SETMASK, NULL, &oset))
  74                         err(1, "sigprocmask");
  75                 if (!sigismember(&oset, SIGUSR1) ||
  76                     !sigismember(&oset, SIGUSR2))
  77                         errx(1, "sigprocmask is bad");
  78
  79                 /* Check that we got the sigusr1 that we expected. */
  80                 if (!gotusr1)
  81                         errx(1, "didn't get usr1");
  82                 if (gotusr2)
  83                         errx(1, "got incorrect usr2");
  84
  85                 sigemptyset(&set);
  86                 sigaddset(&set, SIGUSR1);
  87                 sigsuspend(&set);
  88
  89                 if (!gotusr2)
  90                         errx(1, "didn't get usr2");
  91
  92                 _exit(0);
  93         case -1:
  94                 err(1, "fork");
  95         default:
  96                 /*
  97                  * In the parent.
  98                  * Waiting for the initial USR1 that tells us the child
  99                  * is ready.
 100                  */
 101                 while (gotusr1 == 0)
 102                         sigsuspend(&oset);
 103
 104                 /*
 105                  * Check that sigsuspend didn't change the signal mask.
 106                  */
 107                 if (sigprocmask(SIG_SETMASK, NULL, &oset))
 108                         err(1, "sigprocmask");
 109                 if (!sigismember(&oset, SIGUSR1) ||
 110                     !sigismember(&oset, SIGUSR2))
 111                         errx(1, "sigprocmask is bad");
 112
 113                 /*
 114                  * Deliberately send USR2 first to confuse.
 115                  */
 116                 kill(pid, SIGUSR2);
 117                 kill(pid, SIGUSR1);
 118
 119                 if (waitpid(pid, &status, 0) != pid)
 120                         err(1, "waitpid");
 121
 122                 if (WIFEXITED(status))
 123                         exit(WEXITSTATUS(status));
 124                 exit(1);
 125         }
 126         /* NOTREACHED */
 127 }
 128
 129