// SPDX-License-Identifier: GPL-2.0
/* Test triggering of loading of firmware from different mount
 * namespaces. Expect firmware to be always loaded from the mount
 * namespace of PID 1. */
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <sched.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

static char *fw_path = NULL;

static void die(char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        vfprintf(stderr, fmt, ap);
        va_end(ap);
        if (fw_path)
                unlink(fw_path);
        umount("/lib/firmware");
        exit(EXIT_FAILURE);
}

static void trigger_fw(const char *fw_name, const char *sys_path)
{
        int fd;

        fd = open(sys_path, O_WRONLY);
        if (fd < 0)
                die("open failed: %s\n",
                    strerror(errno));
        if (write(fd, fw_name, strlen(fw_name)) != strlen(fw_name))
                exit(EXIT_FAILURE);
        close(fd);
}

static void setup_fw(const char *fw_path)
{
        int fd;
        const char fw[] = "ABCD0123";

        fd = open(fw_path, O_WRONLY | O_CREAT, 0600);
        if (fd < 0)
                die("open failed: %s\n",
                    strerror(errno));
        if (write(fd, fw, sizeof(fw) -1) != sizeof(fw) -1)
                die("write failed: %s\n",
                    strerror(errno));
        close(fd);
}

static bool test_fw_in_ns(const char *fw_name, const char *sys_path, bool block_fw_in_parent_ns)
{
        pid_t child;

        if (block_fw_in_parent_ns)
                if (mount("test", "/lib/firmware", "tmpfs", MS_RDONLY, NULL) == -1)
                        die("blocking firmware in parent ns failed\n");

        child = fork();
        if (child == -1) {
                die("fork failed: %s\n",
                        strerror(errno));
        }
        if (child != 0) { /* parent */
                pid_t pid;
                int status;

                pid = waitpid(child, &status, 0);
                if (pid == -1) {
                        die("waitpid failed: %s\n",
                                strerror(errno));
                }
                if (pid != child) {
                        die("waited for %d got %d\n",
                                child, pid);
                }
                if (!WIFEXITED(status)) {
                        die("child did not terminate cleanly\n");
                }
                if (block_fw_in_parent_ns)
                        umount("/lib/firmware");
                return WEXITSTATUS(status) == EXIT_SUCCESS;
        }

        if (unshare(CLONE_NEWNS) != 0) {
                die("unshare(CLONE_NEWNS) failed: %s\n",
                        strerror(errno));
        }
        if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) == -1)
                die("remount root in child ns failed\n");

        if (!block_fw_in_parent_ns) {
                if (mount("test", "/lib/firmware", "tmpfs", MS_RDONLY, NULL) == -1)
                        die("blocking firmware in child ns failed\n");
        } else
                umount("/lib/firmware");

        trigger_fw(fw_name, sys_path);

        exit(EXIT_SUCCESS);
}

int main(int argc, char **argv)
{
        const char *fw_name = "test-firmware.bin";
        char *sys_path;
        if (argc != 2)
                die("usage: %s sys_path\n", argv[0]);

        /* Mount tmpfs to /lib/firmware so we don't have to assume
           that it is writable for us.*/
        if (mount("test", "/lib/firmware", "tmpfs", 0, NULL) == -1)
                die("mounting tmpfs to /lib/firmware failed\n");

        sys_path = argv[1];
        if (asprintf(&fw_path, "/lib/firmware/%s", fw_name) < 0)
                die("error: failed to build full fw_path\n");

        setup_fw(fw_path);

        setvbuf(stdout, NULL, _IONBF, 0);
        /* Positive case: firmware in PID1 mount namespace */
        printf("Testing with firmware in parent namespace (assumed to be same file system as PID1)\n");
        if (!test_fw_in_ns(fw_name, sys_path, false))
                die("error: failed to access firmware\n");

        /* Negative case: firmware in child mount namespace, expected to fail */
        printf("Testing with firmware in child namespace\n");
        if (test_fw_in_ns(fw_name, sys_path, true))
                die("error: firmware access did not fail\n");

        unlink(fw_path);
        free(fw_path);
        umount("/lib/firmware");
        exit(EXIT_SUCCESS);
}