1 #include <stdio.h>
2 #include <unistd.h>
3 #include <signal.h>
4 #include <errno.h>
5 #include <sys/wait.h>
6 #include <string.h>
7
8 /* Make sure that a blocking syscall restarts if hit by a signal,
9 and SA_RESTART is set */
10
handler(int s)11 static void handler(int s)
12 {
13 }
14
main()15 int main()
16 {
17 int pid;
18 int fds[2];
19
20 if (pipe(fds) == -1) {
21 perror("FAIL: pipe\n");
22 return 1;
23 }
24
25 pid = fork();
26
27 if (pid == -1) {
28 perror("fork failed");
29 return 1;
30 }
31
32 if (pid == 0) {
33 char ch = '?';
34 int ret;
35 struct sigaction sa;
36
37 sa.sa_handler = handler;
38 sigfillset(&sa.sa_mask);
39 sa.sa_flags = SA_RESTART;
40
41 sigaction(SIGUSR1, &sa, NULL);
42
43 close(fds[1]);
44 ret = read(fds[0], &ch, 1);
45
46 if (ret != 1 || ch != 'x')
47 fprintf(stderr, "FAIL: expected 1 byte, not %d/%s/%c\n",
48 ret, strerror(errno), ch);
49 } else {
50 signal(SIGPIPE, SIG_IGN);
51
52 close(fds[0]);
53 sleep(1);
54 kill(pid, SIGUSR1);
55 sleep(1);
56 write(fds[1], "x", 1);
57
58 waitpid(pid, NULL, 0);
59 }
60
61 return 0;
62 }
63