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/*
* Check tracing of looping threads.
*
* Copyright (c) 2009-2019 The strace developers.
* All rights reserved.
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "tests.h"
#include <assert.h>
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
static void *
thread(void *arg)
{
for (;;)
getuid();
return arg;
}
int
main(int ac, const char *av[])
{
assert(ac == 3);
int timeout = atoi(av[1]);
assert(timeout > 0);
int num_threads = atoi(av[2]);
assert(num_threads > 0);
/*
* Unblock all signals.
*/
static sigset_t mask;
if (sigprocmask(SIG_SETMASK, &mask, NULL))
perror_msg_and_fail("sigprocmask");
/*
* Reset SIGALRM and SIGHUP signal handlers.
*/
static const struct sigaction sa_def = { .sa_handler = SIG_DFL };
if (sigaction(SIGHUP, &sa_def, NULL))
perror_msg_and_fail("sigaction SIGHUP");
if (sigaction(SIGALRM, &sa_def, NULL))
perror_msg_and_fail("sigaction SIGALRM");
/*
* Create a new process group.
*/
if (setpgid(0, 0))
perror_msg_and_fail("setpgid");
/*
* Set an alarm clock.
*/
alarm(timeout);
/*
* When the main process terminates, the process group becomes orphaned.
* If any member of the orphaned process group is stopped, then
* a SIGHUP signal followed by a SIGCONT signal is sent to each process
* in the orphaned process group.
* Create a process in a stopped state to activate this behaviour.
*/
const pid_t stopped = fork();
if (stopped < 0)
perror_msg_and_fail("fork");
if (!stopped) {
raise(SIGSTOP);
_exit(0);
}
/*
* Wait for the process to stop.
*/
int status;
if (waitpid(stopped, &status, WUNTRACED) != stopped)
perror_msg_and_fail("waitpid WUNTRACED");
if (!WIFSTOPPED(status) || WSTOPSIG(status) != SIGSTOP)
error_msg_and_fail("waitpid WUNTRACED: "
"unexpected wait status %d", status);
/*
* Create all threads in a subprocess, this guarantees that
* their tracer will not be their parent.
*/
pid_t pid = fork();
if (pid < 0)
perror_msg_and_fail("fork");
if (!pid) {
for (int i = 0; i < num_threads; i++) {
pthread_t t;
if ((errno = pthread_create(&t, NULL, thread, NULL))) {
if (EAGAIN == errno)
break;
perror_msg_and_fail("pthread_create #%d", i);
}
}
/* This terminates all threads created above. */
_exit(0);
}
if (waitpid(pid, &status, 0) != pid)
perror_msg_and_fail("waitpid");
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
error_msg_and_fail("waitpid: unexpected wait status %d",
status);
/*
* Make the process group orphaned.
*/
return 0;
}
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