jehanne/qa/lib/newlib/205-signals.c

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2017-05-29 01:53:37 +02:00
#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
}
}