// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#define _GNU_SOURCE
#include <stdio.h>
#include <sched.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <test_progs.h>

/* TDIR must be in a location we can create a directory in. */
#define TDIR "/tmp/test_bpffs_testdir"

static int read_iter(char *file)
{
        /* 1024 should be enough to get contiguous 4 "iter" letters at some point */
        char buf[1024];
        int fd, len;

        fd = open(file, 0);
        if (fd < 0)
                return -1;
        while ((len = read(fd, buf, sizeof(buf))) > 0) {
                buf[sizeof(buf) - 1] = '\0';
                if (strstr(buf, "iter")) {
                        close(fd);
                        return 0;
                }
        }
        close(fd);
        return -1;
}

static int fn(void)
{
        struct stat a, b, c;
        int err, map;

        err = unshare(CLONE_NEWNS);
        if (!ASSERT_OK(err, "unshare"))
                goto out;

        err = mount("", "/", "", MS_REC | MS_PRIVATE, NULL);
        if (!ASSERT_OK(err, "mount /"))
                goto out;

        err =  mkdir(TDIR, 0777);
        /* If the directory already exists we can carry on. It may be left over
         * from a previous run.
         */
        if ((err && errno != EEXIST) && !ASSERT_OK(err, "mkdir " TDIR))
                goto out;

        err = mount("none", TDIR, "tmpfs", 0, NULL);
        if (!ASSERT_OK(err, "mount tmpfs"))
                goto out;

        err = mkdir(TDIR "/fs1", 0777);
        if (!ASSERT_OK(err, "mkdir " TDIR "/fs1"))
                goto out;
        err = mkdir(TDIR "/fs2", 0777);
        if (!ASSERT_OK(err, "mkdir " TDIR "/fs2"))
                goto out;

        err = mount("bpf", TDIR "/fs1", "bpf", 0, NULL);
        if (!ASSERT_OK(err, "mount bpffs " TDIR "/fs1"))
                goto out;
        err = mount("bpf", TDIR "/fs2", "bpf", 0, NULL);
        if (!ASSERT_OK(err, "mount bpffs " TDIR "/fs2"))
                goto out;

        err = read_iter(TDIR "/fs1/maps.debug");
        if (!ASSERT_OK(err, "reading " TDIR "/fs1/maps.debug"))
                goto out;
        err = read_iter(TDIR "/fs2/progs.debug");
        if (!ASSERT_OK(err, "reading " TDIR "/fs2/progs.debug"))
                goto out;

        err = mkdir(TDIR "/fs1/a", 0777);
        if (!ASSERT_OK(err, "creating " TDIR "/fs1/a"))
                goto out;
        err = mkdir(TDIR "/fs1/a/1", 0777);
        if (!ASSERT_OK(err, "creating " TDIR "/fs1/a/1"))
                goto out;
        err = mkdir(TDIR "/fs1/b", 0777);
        if (!ASSERT_OK(err, "creating " TDIR "/fs1/b"))
                goto out;

        map = bpf_map_create(BPF_MAP_TYPE_ARRAY, NULL, 4, 4, 1, NULL);
        if (!ASSERT_GT(map, 0, "create_map(ARRAY)"))
                goto out;
        err = bpf_obj_pin(map, TDIR "/fs1/c");
        if (!ASSERT_OK(err, "pin map"))
                goto out;
        close(map);

        /* Check that RENAME_EXCHANGE works for directories. */
        err = stat(TDIR "/fs1/a", &a);
        if (!ASSERT_OK(err, "stat(" TDIR "/fs1/a)"))
                goto out;
        err = renameat2(0, TDIR "/fs1/a", 0, TDIR "/fs1/b", RENAME_EXCHANGE);
        if (!ASSERT_OK(err, "renameat2(/fs1/a, /fs1/b, RENAME_EXCHANGE)"))
                goto out;
        err = stat(TDIR "/fs1/b", &b);
        if (!ASSERT_OK(err, "stat(" TDIR "/fs1/b)"))
                goto out;
        if (!ASSERT_EQ(a.st_ino, b.st_ino, "b should have a's inode"))
                goto out;
        err = access(TDIR "/fs1/b/1", F_OK);
        if (!ASSERT_OK(err, "access(" TDIR "/fs1/b/1)"))
                goto out;

        /* Check that RENAME_EXCHANGE works for mixed file types. */
        err = stat(TDIR "/fs1/c", &c);
        if (!ASSERT_OK(err, "stat(" TDIR "/fs1/map)"))
                goto out;
        err = renameat2(0, TDIR "/fs1/c", 0, TDIR "/fs1/b", RENAME_EXCHANGE);
        if (!ASSERT_OK(err, "renameat2(/fs1/c, /fs1/b, RENAME_EXCHANGE)"))
                goto out;
        err = stat(TDIR "/fs1/b", &b);
        if (!ASSERT_OK(err, "stat(" TDIR "/fs1/b)"))
                goto out;
        if (!ASSERT_EQ(c.st_ino, b.st_ino, "b should have c's inode"))
                goto out;
        err = access(TDIR "/fs1/c/1", F_OK);
        if (!ASSERT_OK(err, "access(" TDIR "/fs1/c/1)"))
                goto out;

        /* Check that RENAME_NOREPLACE works. */
        err = renameat2(0, TDIR "/fs1/b", 0, TDIR "/fs1/a", RENAME_NOREPLACE);
        if (!ASSERT_ERR(err, "renameat2(RENAME_NOREPLACE)")) {
                err = -EINVAL;
                goto out;
        }
        err = access(TDIR "/fs1/b", F_OK);
        if (!ASSERT_OK(err, "access(" TDIR "/fs1/b)"))
                goto out;

out:
        umount(TDIR "/fs1");
        umount(TDIR "/fs2");
        rmdir(TDIR "/fs1");
        rmdir(TDIR "/fs2");
        umount(TDIR);
        rmdir(TDIR);
        exit(err);
}

void test_test_bpffs(void)
{
        int err, duration = 0, status = 0;
        pid_t pid;

        pid = fork();
        if (CHECK(pid == -1, "clone", "clone failed %d", errno))
                return;
        if (pid == 0)
                fn();
        err = waitpid(pid, &status, 0);
        if (CHECK(err == -1 && errno != ECHILD, "waitpid", "failed %d", errno))
                return;
        if (CHECK(WEXITSTATUS(status), "bpffs test ", "failed %d", WEXITSTATUS(status)))
                return;
}