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