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/* $OpenBSD: earlysig.c,v 1.1 2013/06/21 06:47:20 guenther Exp $ */
/*
* Public domain. 2005, Otto Moerbeek; 2013, Philip Guenther
*
* Try to create the case where a signal is delivered to a process before
* the pthread fork() wrapper can unlock the ld.so bind lock.
*/
#include <sys/types.h>
#include <sys/time.h>
#include <sys/utsname.h>
#include <sys/wait.h>
#include <err.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
void dohup(int signo)
{
struct utsname name;
uname(&name); /* anything that'll require binding */
}
void *tmain(void *arg)
{
return (arg);
}
int
main()
{
pthread_t tid;
pid_t pid, rpid;
int r, status;
if (signal(SIGHUP, dohup) == SIG_ERR)
err(1, "signal");
/* make sure the thread library is fully active */
if ((r = pthread_create(&tid, NULL, tmain, NULL)))
errx(1, "pthread_create: %s", strerror(r));
pthread_join(tid, NULL);
/* make sure kill() and all the symbols in fork() are bound */
kill(0, 0);
if ((pid = fork()) <= 0) {
if (pid == -1)
err(1, "fork");
_exit(0);
}
if (waitpid(pid, &status, 0) == -1)
err(1, "waitpid");
switch(pid = fork()) {
case -1:
err(1, "fork");
break;
case 0:
sleep(2);
_exit(0);
default:
kill(pid, SIGHUP);
sleep(3);
if ((rpid = waitpid(pid, &status, WNOHANG)) == -1)
err(1, "waitpid");
if (rpid == 0) {
/* took too long */
kill(pid, SIGKILL);
if (waitpid(pid, &status, 0) == -1)
err(1, "waitpid");
}
if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
exit(0);
else if (WIFEXITED(status))
errx(1, "child exited with status %d",
WEXITSTATUS(status));
else if (WTERMSIG(status) == SIGKILL)
errx(1, "failed: child hung");
errx(1, "child killed by signal %d", WTERMSIG(status));
}
}
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