Commit 7e5ad817 authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Daniel Borkmann
Browse files

selftests/bpf: Test RENAME_EXCHANGE and RENAME_NOREPLACE on bpffs 



Add tests to exercise the behaviour of RENAME_EXCHANGE and RENAME_NOREPLACE
on bpffs. The former checks that after an exchange the inode of two
directories has changed. The latter checks that the source still exists
after a failed rename. Generally, having support for renameat2(RENAME_EXCHANGE)
in bpffs fixes atomic upgrades of our sk_lookup control plane.

Signed-off-by: default avatarLorenz Bauer <lmb@cloudflare.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20211028094724.59043-5-lmb@cloudflare.com
parent 9fc23c22

tools/testing/selftests/bpf/prog_tests/test_bpffs.c

+64 −1
Original line number Diff line number Diff line 
// 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>
@@ -29,7 +30,8 @@ static int read_iter(char *file) 


static int fn(void)

{

	int err;

	struct stat a, b, c;

	int err, map;



	err = unshare(CLONE_NEWNS);

	if (!ASSERT_OK(err, "unshare"))
@@ -67,6 +69,67 @@ static int fn(void) 
	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_create_map(BPF_MAP_TYPE_ARRAY, 4, 4, 1, 0);

	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");