// SPDX-License-Identifier: GPL-2.0 #define _GNU_SOURCE#include <errno.h>#include <linux/types.h>#include <poll.h>#include <signal.h>#include <stdbool.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <syscall.h>#include <sys/wait.h>#include <unistd.h> #include "pidfd.h"#include "kselftest.h" static bool timeout; static void handle_alarm(int sig){	timeout = true;} int main(int argc, char **argv){	struct pollfd fds;	int iter, nevents;	int nr_iterations = 10000; 	fds.events = POLLIN; 	if (argc > 2)		ksft_exit_fail_msg("Unexpected command line argument\n"); 	if (argc == 2) {		nr_iterations = atoi(argv[1]);		if (nr_iterations <= 0)			ksft_exit_fail_msg("invalid input parameter %s\n",					argv[1]);	} 	ksft_print_msg("running pidfd poll test for %d iterations\n",		nr_iterations); 	for (iter = 0; iter < nr_iterations; iter++) {		int pidfd;		int child_pid = fork(); 		if (child_pid < 0) {			if (errno == EAGAIN) {				iter--;				continue;			}			ksft_exit_fail_msg(				"%s - failed to fork a child process\n",				strerror(errno));		} 		if (child_pid == 0) {			/* Child process just sleeps for a min and exits */			sleep(60);			exit(EXIT_SUCCESS);		} 		/* Parent kills the child and waits for its death */		pidfd = sys_pidfd_open(child_pid, 0);		if (pidfd < 0)			ksft_exit_fail_msg("%s - pidfd_open failed\n",					strerror(errno)); 		/* Setup 3 sec alarm - plenty of time */		if (signal(SIGALRM, handle_alarm) == SIG_ERR)			ksft_exit_fail_msg("%s - signal failed\n",					strerror(errno));		alarm(3); 		/* Send SIGKILL to the child */		if (sys_pidfd_send_signal(pidfd, SIGKILL, NULL, 0))			ksft_exit_fail_msg("%s - pidfd_send_signal failed\n",					strerror(errno)); 		/* Wait for the death notification */		fds.fd = pidfd;		nevents = poll(&fds, 1, -1); 		/* Check for error conditions */		if (nevents < 0)			ksft_exit_fail_msg("%s - poll failed\n",					strerror(errno)); 		if (nevents != 1)			ksft_exit_fail_msg("unexpected poll result: %d\n",					nevents); 		if (!(fds.revents & POLLIN))			ksft_exit_fail_msg(				"unexpected event type received: 0x%x\n",				fds.revents); 		if (timeout)			ksft_exit_fail_msg(				"death notification wait timeout\n"); 		close(pidfd);		/* Wait for child to prevent zombies */		if (waitpid(child_pid, NULL, 0) < 0)			ksft_exit_fail_msg("%s - waitpid failed\n",					strerror(errno)); 	} 	ksft_test_result_pass("pidfd poll test: pass\n");	ksft_exit_pass();}