// SPDX-License-Identifier: GPL-2.0

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <limits.h>
#include <linux/types.h>
#include <sched.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syscall.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/wait.h>
#include <unistd.h>

#include "pidfd.h"
#include "kselftest.h"

static int safe_int(const char *numstr, int *converted)
{
        char *err = NULL;
        long sli;

        errno = 0;
        sli = strtol(numstr, &err, 0);
        if (errno == ERANGE && (sli == LONG_MAX || sli == LONG_MIN))
                return -ERANGE;

        if (errno != 0 && sli == 0)
                return -EINVAL;

        if (err == numstr || *err != '\0')
                return -EINVAL;

        if (sli > INT_MAX || sli < INT_MIN)
                return -ERANGE;

        *converted = (int)sli;
        return 0;
}

static int char_left_gc(const char *buffer, size_t len)
{
        size_t i;

        for (i = 0; i < len; i++) {
                if (buffer[i] == ' ' ||
                    buffer[i] == '\t')
                        continue;

                return i;
        }

        return 0;
}

static int char_right_gc(const char *buffer, size_t len)
{
        int i;

        for (i = len - 1; i >= 0; i--) {
                if (buffer[i] == ' '  ||
                    buffer[i] == '\t' ||
                    buffer[i] == '\n' ||
                    buffer[i] == '\0')
                        continue;

                return i + 1;
        }

        return 0;
}

static char *trim_whitespace_in_place(char *buffer)
{
        buffer += char_left_gc(buffer, strlen(buffer));
        buffer[char_right_gc(buffer, strlen(buffer))] = '\0';
        return buffer;
}

static pid_t get_pid_from_fdinfo_file(int pidfd, const char *key, size_t keylen)
{
        int ret;
        char path[512];
        FILE *f;
        size_t n = 0;
        pid_t result = -1;
        char *line = NULL;

        snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", pidfd);

        f = fopen(path, "re");
        if (!f)
                return -1;

        while (getline(&line, &n, f) != -1) {
                char *numstr;

                if (strncmp(line, key, keylen))
                        continue;

                numstr = trim_whitespace_in_place(line + 4);
                ret = safe_int(numstr, &result);
                if (ret < 0)
                        goto out;

                break;
        }

out:
        free(line);
        fclose(f);
        return result;
}

int main(int argc, char **argv)
{
        struct pidfd_info info = {
                .mask = PIDFD_INFO_CGROUPID,
        };
        int pidfd = -1, ret = 1;
        pid_t pid;

        ksft_set_plan(4);

        pidfd = sys_pidfd_open(-1, 0);
        if (pidfd >= 0) {
                ksft_print_msg(
                        "%s - succeeded to open pidfd for invalid pid -1\n",
                        strerror(errno));
                goto on_error;
        }
        ksft_test_result_pass("do not allow invalid pid test: passed\n");

        pidfd = sys_pidfd_open(getpid(), 1);
        if (pidfd >= 0) {
                ksft_print_msg(
                        "%s - succeeded to open pidfd with invalid flag value specified\n",
                        strerror(errno));
                goto on_error;
        }
        ksft_test_result_pass("do not allow invalid flag test: passed\n");

        pidfd = sys_pidfd_open(getpid(), 0);
        if (pidfd < 0) {
                ksft_print_msg("%s - failed to open pidfd\n", strerror(errno));
                goto on_error;
        }
        ksft_test_result_pass("open a new pidfd test: passed\n");

        pid = get_pid_from_fdinfo_file(pidfd, "Pid:", sizeof("Pid:") - 1);
        ksft_print_msg("pidfd %d refers to process with pid %d\n", pidfd, pid);

        if (ioctl(pidfd, PIDFD_GET_INFO, &info) < 0) {
                ksft_print_msg("%s - failed to get info from pidfd\n", strerror(errno));
                goto on_error;
        }
        if (info.pid != pid) {
                ksft_print_msg("pid from fdinfo file %d does not match pid from ioctl %d\n",
                               pid, info.pid);
                goto on_error;
        }
        if (info.ppid != getppid()) {
                ksft_print_msg("ppid %d does not match ppid from ioctl %d\n",
                               pid, info.pid);
                goto on_error;
        }
        if (info.ruid != getuid()) {
                ksft_print_msg("uid %d does not match uid from ioctl %d\n",
                               getuid(), info.ruid);
                goto on_error;
        }
        if (info.rgid != getgid()) {
                ksft_print_msg("gid %d does not match gid from ioctl %d\n",
                               getgid(), info.rgid);
                goto on_error;
        }
        if (info.euid != geteuid()) {
                ksft_print_msg("euid %d does not match euid from ioctl %d\n",
                               geteuid(), info.euid);
                goto on_error;
        }
        if (info.egid != getegid()) {
                ksft_print_msg("egid %d does not match egid from ioctl %d\n",
                               getegid(), info.egid);
                goto on_error;
        }
        if (info.suid != geteuid()) {
                ksft_print_msg("suid %d does not match suid from ioctl %d\n",
                               geteuid(), info.suid);
                goto on_error;
        }
        if (info.sgid != getegid()) {
                ksft_print_msg("sgid %d does not match sgid from ioctl %d\n",
                               getegid(), info.sgid);
                goto on_error;
        }
        if ((info.mask & PIDFD_INFO_CGROUPID) && info.cgroupid == 0) {
                ksft_print_msg("cgroupid should not be 0 when PIDFD_INFO_CGROUPID is set\n");
                goto on_error;
        }
        ksft_test_result_pass("get info from pidfd test: passed\n");

        ret = 0;

on_error:
        if (pidfd >= 0)
                close(pidfd);

        if (ret)
                ksft_exit_fail();
        ksft_exit_pass();
}