1// SPDX-License-Identifier: GPL-2.0
  2
  3#define _GNU_SOURCE
  4#include <errno.h>
  5#include <linux/types.h>
  6#include <linux/wait.h>
  7#include <poll.h>
  8#include <signal.h>
  9#include <stdbool.h>
 10#include <stdio.h>
 11#include <stdlib.h>
 12#include <string.h>
 13#include <syscall.h>
 14#include <sys/wait.h>
 15#include <unistd.h>
 16
 17#include "pidfd.h"
 18#include "../kselftest.h"
 19
 20static bool timeout;
 21
 22static void handle_alarm(int sig)
 23{
 24	timeout = true;
 25}
 26
 27int main(int argc, char **argv)
 28{
 29	struct pollfd fds;
 30	int iter, nevents;
 31	int nr_iterations = 10000;
 32
 33	fds.events = POLLIN;
 34
 35	if (argc > 2)
 36		ksft_exit_fail_msg("Unexpected command line argument\n");
 37
 38	if (argc == 2) {
 39		nr_iterations = atoi(argv[1]);
 40		if (nr_iterations <= 0)
 41			ksft_exit_fail_msg("invalid input parameter %s\n",
 42					argv[1]);
 43	}
 44
 45	ksft_print_msg("running pidfd poll test for %d iterations\n",
 46		nr_iterations);
 47
 48	for (iter = 0; iter < nr_iterations; iter++) {
 49		int pidfd;
 50		int child_pid = fork();
 51
 52		if (child_pid < 0) {
 53			if (errno == EAGAIN) {
 54				iter--;
 55				continue;
 56			}
 57			ksft_exit_fail_msg(
 58				"%s - failed to fork a child process\n",
 59				strerror(errno));
 60		}
 61
 62		if (child_pid == 0) {
 63			/* Child process just sleeps for a min and exits */
 64			sleep(60);
 65			exit(EXIT_SUCCESS);
 66		}
 67
 68		/* Parent kills the child and waits for its death */
 69		pidfd = sys_pidfd_open(child_pid, 0);
 70		if (pidfd < 0)
 71			ksft_exit_fail_msg("%s - pidfd_open failed\n",
 72					strerror(errno));
 73
 74		/* Setup 3 sec alarm - plenty of time */
 75		if (signal(SIGALRM, handle_alarm) == SIG_ERR)
 76			ksft_exit_fail_msg("%s - signal failed\n",
 77					strerror(errno));
 78		alarm(3);
 79
 80		/* Send SIGKILL to the child */
 81		if (sys_pidfd_send_signal(pidfd, SIGKILL, NULL, 0))
 82			ksft_exit_fail_msg("%s - pidfd_send_signal failed\n",
 83					strerror(errno));
 84
 85		/* Wait for the death notification */
 86		fds.fd = pidfd;
 87		nevents = poll(&fds, 1, -1);
 88
 89		/* Check for error conditions */
 90		if (nevents < 0)
 91			ksft_exit_fail_msg("%s - poll failed\n",
 92					strerror(errno));
 93
 94		if (nevents != 1)
 95			ksft_exit_fail_msg("unexpected poll result: %d\n",
 96					nevents);
 97
 98		if (!(fds.revents & POLLIN))
 99			ksft_exit_fail_msg(
100				"unexpected event type received: 0x%x\n",
101				fds.revents);
102
103		if (timeout)
104			ksft_exit_fail_msg(
105				"death notification wait timeout\n");
106
107		close(pidfd);
108		/* Wait for child to prevent zombies */
109		if (waitpid(child_pid, NULL, 0) < 0)
110			ksft_exit_fail_msg("%s - waitpid failed\n",
111					strerror(errno));
112
113	}
114
115	ksft_test_result_pass("pidfd poll test: pass\n");
116	return ksft_exit_pass();
117}