80 lines
1.3 KiB
C
80 lines
1.3 KiB
C
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <signal.h>
|
||
|
|
#include <sys/wait.h>
|
||
|
|
|
||
|
|
int child, cstatus;
|
||
|
|
|
||
|
|
void sigquit() {
|
||
|
|
printf("CHILD: got SIGQUIT\n");
|
||
|
|
exit(0);
|
||
|
|
}
|
||
|
|
|
||
|
|
void sigchld() {
|
||
|
|
printf("PARENT: got SIGCHLD\n");
|
||
|
|
#ifdef WITH_SIGCHLD
|
||
|
|
child = wait(&cstatus);
|
||
|
|
if(cstatus == 0)
|
||
|
|
exit(0);
|
||
|
|
else
|
||
|
|
{
|
||
|
|
printf("PARENT: child exited with status %d\n", cstatus);
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
main() {
|
||
|
|
int pid, p[2];
|
||
|
|
char dummy[1];
|
||
|
|
|
||
|
|
/* get child process */
|
||
|
|
|
||
|
|
if(pipe(p)){
|
||
|
|
perror("pipe");
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
if ((pid = fork()) < 0) {
|
||
|
|
perror("fork");
|
||
|
|
exit(2);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (pid == 0) {
|
||
|
|
printf("%d is the new child!\n", getpid());
|
||
|
|
signal(SIGHUP, SIG_IGN);
|
||
|
|
signal(SIGQUIT, sigquit);
|
||
|
|
|
||
|
|
printf("Child wait in blocking syscall...\n");
|
||
|
|
read(p[0], &dummy, 1);
|
||
|
|
/* reached only if the ignored SIGHUP interrupts the read */
|
||
|
|
printf("Child interrupted by ignored signal\n");
|
||
|
|
exit(5);
|
||
|
|
}
|
||
|
|
else /* parent */
|
||
|
|
{
|
||
|
|
signal(SIGCHLD,sigchld);
|
||
|
|
sleep(3);
|
||
|
|
printf("PARENT: sending SIGHUP\n");
|
||
|
|
kill(pid,SIGHUP);
|
||
|
|
sleep(3); /* pause for 3 secs */
|
||
|
|
printf("PARENT: sending SIGQUIT\n");
|
||
|
|
kill(pid,SIGQUIT);
|
||
|
|
|
||
|
|
#ifdef WITH_SIGCHLD
|
||
|
|
sleep(10000);
|
||
|
|
exit(1);
|
||
|
|
#else
|
||
|
|
child = wait(&cstatus);
|
||
|
|
if(child == pid && cstatus == 0)
|
||
|
|
exit(0);
|
||
|
|
else
|
||
|
|
{
|
||
|
|
printf("PARENT: child exited with status %d\n", cstatus);
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
}
|