// 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;
}