// SPDX-License-Identifier: GPL-2.0#define _GNU_SOURCE #include <stdio.h>#include <stdlib.h>#include <signal.h>#include <limits.h>#include <unistd.h>#include <errno.h>#include <string.h>#include <fcntl.h>#include <linux/unistd.h>#include <linux/kcmp.h> #include <sys/syscall.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/wait.h>#include <sys/epoll.h> #include "kselftest.h" static long sys_kcmp(int pid1, int pid2, int type, unsigned long fd1, unsigned long fd2){	return syscall(__NR_kcmp, pid1, pid2, type, fd1, fd2);} static const unsigned int duped_num = 64; int main(int argc, char **argv){	const char kpath[] = "kcmp-test-file";	struct kcmp_epoll_slot epoll_slot;	struct epoll_event ev;	int pid1, pid2;	int pipefd[2];	int fd1, fd2;	int epollfd;	int status;	int fddup; 	fd1 = open(kpath, O_RDWR | O_CREAT | O_TRUNC, 0644);	pid1 = getpid(); 	if (fd1 < 0) {		perror("Can't create file");		ksft_exit_fail();	} 	if (pipe(pipefd)) {		perror("Can't create pipe");		ksft_exit_fail();	} 	epollfd = epoll_create1(0);	if (epollfd < 0) {		perror("epoll_create1 failed");		ksft_exit_fail();	} 	memset(&ev, 0xff, sizeof(ev));	ev.events = EPOLLIN | EPOLLOUT; 	if (epoll_ctl(epollfd, EPOLL_CTL_ADD, pipefd[0], &ev)) {		perror("epoll_ctl failed");		ksft_exit_fail();	} 	fddup = dup2(pipefd[1], duped_num);	if (fddup < 0) {		perror("dup2 failed");		ksft_exit_fail();	} 	if (epoll_ctl(epollfd, EPOLL_CTL_ADD, fddup, &ev)) {		perror("epoll_ctl failed");		ksft_exit_fail();	}	close(fddup); 	pid2 = fork();	if (pid2 < 0) {		perror("fork failed");		ksft_exit_fail();	} 	if (!pid2) {		int pid2 = getpid();		int ret; 		ksft_print_header();		ksft_set_plan(3); 		fd2 = open(kpath, O_RDWR);		if (fd2 < 0) {			perror("Can't open file");			ksft_exit_fail();		} 		/* An example of output and arguments */		printf("pid1: %6d pid2: %6d FD: %2ld FILES: %2ld VM: %2ld "		       "FS: %2ld SIGHAND: %2ld IO: %2ld SYSVSEM: %2ld "		       "INV: %2ld\n",		       pid1, pid2,		       sys_kcmp(pid1, pid2, KCMP_FILE,		fd1, fd2),		       sys_kcmp(pid1, pid2, KCMP_FILES,		0, 0),		       sys_kcmp(pid1, pid2, KCMP_VM,		0, 0),		       sys_kcmp(pid1, pid2, KCMP_FS,		0, 0),		       sys_kcmp(pid1, pid2, KCMP_SIGHAND,	0, 0),		       sys_kcmp(pid1, pid2, KCMP_IO,		0, 0),		       sys_kcmp(pid1, pid2, KCMP_SYSVSEM,	0, 0), 			/* This one should fail */		       sys_kcmp(pid1, pid2, KCMP_TYPES + 1,	0, 0)); 		/* This one should return same fd */		ret = sys_kcmp(pid1, pid2, KCMP_FILE, fd1, fd1);		if (ret) {			printf("FAIL: 0 expected but %d returned (%s)\n",				ret, strerror(errno));			ksft_inc_fail_cnt();			ret = -1;		} else {			printf("PASS: 0 returned as expected\n");			ksft_inc_pass_cnt();		} 		/* Compare with self */		ret = sys_kcmp(pid1, pid1, KCMP_VM, 0, 0);		if (ret) {			printf("FAIL: 0 expected but %d returned (%s)\n",				ret, strerror(errno));			ksft_inc_fail_cnt();			ret = -1;		} else {			printf("PASS: 0 returned as expected\n");			ksft_inc_pass_cnt();		} 		/* Compare epoll target */		epoll_slot = (struct kcmp_epoll_slot) {			.efd	= epollfd,			.tfd	= duped_num,			.toff	= 0,		};		ret = sys_kcmp(pid1, pid1, KCMP_EPOLL_TFD, pipefd[1],			       (unsigned long)(void *)&epoll_slot);		if (ret) {			printf("FAIL: 0 expected but %d returned (%s)\n",				ret, strerror(errno));			ksft_inc_fail_cnt();			ret = -1;		} else {			printf("PASS: 0 returned as expected\n");			ksft_inc_pass_cnt();		}  		if (ret)			ksft_exit_fail();		else			ksft_exit_pass();	} 	waitpid(pid2, &status, P_ALL); 	return 0;}