/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless requied by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
/*
* These file system recovery tests ensure the ability to recover from
* filesystem crashes in key blocks (e.g. superblock).
*/
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <fs_mgr.h>
#include <gtest/gtest.h>
#include <logwrap/logwrap.h>
#include <sys/types.h>
#include <unistd.h>
#include "cutils/properties.h"
#include <ext4_utils/ext4.h>
#include <ext4_utils/ext4_utils.h>
#define LOG_TAG "fsRecoveryTest"
#include <utils/Log.h>
#include <testUtil.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
#define SB_OFFSET 1024
static char UMOUNT_BIN[] = "/system/bin/umount";
static char VDC_BIN[] = "/system/bin/vdc";
enum Fs_Type { FS_UNKNOWN, FS_EXT4, FS_F2FS };
namespace android {
class DataFileVerifier {
public:
explicit DataFileVerifier(const char* file_name) {
strncpy(test_file_, file_name, FILENAME_MAX);
}
void verify_write() {
int write_fd = open(test_file_, O_CREAT | O_WRONLY, 0666);
ASSERT_TRUE(write_fd);
ASSERT_EQ(write(write_fd, "TEST", 4), 4);
close(write_fd);
}
void verify_read() {
char read_buff[4];
int read_fd = open(test_file_, O_RDONLY);
ASSERT_TRUE(read_fd);
ASSERT_EQ(read(read_fd, read_buff, sizeof(read_buff)), 4);
ASSERT_FALSE(strncmp(read_buff, "TEST", 4));
close(read_fd);
}
~DataFileVerifier() {
unlink(test_file_);
}
private:
char test_file_[FILENAME_MAX];
};
namespace ext4 {
bool getSuperBlock(const int blk_fd, struct ext4_super_block* sb) {
if (lseek(blk_fd, SB_OFFSET, SEEK_SET) == -1) {
testPrintE("Cannot lseek to ext4 superblock to read");
return false;
}
if (read(blk_fd, sb, sizeof(*sb)) != sizeof(*sb)) {
testPrintE("Cannot read ext4 superblock");
return false;
}
if (sb->s_magic != 0xEF53) {
testPrintE("Invalid ext4 superblock magic");
return false;
}
return true;
}
bool setSbErrorBit(const int blk_fd) {
// Read super block.
struct ext4_super_block sb;
if (!getSuperBlock(blk_fd, &sb)) {
return false;
}
// Check that the detected errors bit is not set.
if (sb.s_state & 0x2) {
testPrintE("Ext4 superblock already corrupted");
return false;
}
// Set the detected errors bit.
sb.s_state |= 0x2;
// Write superblock.
if (lseek(blk_fd, SB_OFFSET, SEEK_SET) == -1) {
testPrintE("Cannot lseek to superblock to write\n");
return false;
}
if (write(blk_fd, &sb, sizeof(sb)) != sizeof(sb)) {
testPrintE("Cannot write superblock\n");
return false;
}
return true;
}
bool corruptGdtFreeBlock(const int blk_fd) {
// Read super block.
struct ext4_super_block sb;
if (!getSuperBlock(blk_fd, &sb)) {
return false;
}
// Make sure the block size is 2K or 4K.
if ((sb.s_log_block_size != 1) && (sb.s_log_block_size != 2)) {
testPrintE("Ext4 block size not 2K or 4K\n");
return false;
}
int block_size = 1 << (10 + sb.s_log_block_size);
int num_bgs = DIV_ROUND_UP(sb.s_blocks_count_lo, sb.s_blocks_per_group);
if (sb.s_desc_size != sizeof(struct ext2_group_desc)) {
testPrintE("Can't handle ext4 block group descriptor size of %d",
sb.s_desc_size);
return false;
}
// Read first block group descriptor, decrement free block count, and
// write it back out.
if (lseek(blk_fd, block_size, SEEK_SET) == -1) {
testPrintE("Cannot lseek to ext4 block group descriptor table to read");
return false;
}
// Read in block group descriptors till we read one that has at least one free
// block.
struct ext2_group_desc gd;
for (int i = 0; i < num_bgs; i++) {
if (read(blk_fd, &gd, sizeof(gd)) != sizeof(gd)) {
testPrintE("Cannot read ext4 group descriptor %d", i);
return false;
}
if (gd.bg_free_blocks_count) {
break;
}
}
gd.bg_free_blocks_count--;
if (lseek(blk_fd, -sizeof(gd), SEEK_CUR) == -1) {
testPrintE("Cannot lseek to ext4 block group descriptor table to write");
return false;
}
if (write(blk_fd, &gd, sizeof(gd)) != sizeof(gd)) {
testPrintE("Cannot write modified ext4 group descriptor");
return false;
}
return true;
}
} // namespace ext4
class FsRecoveryTest : public ::testing::Test {
protected:
FsRecoveryTest() : fs_type(FS_UNKNOWN), blk_fd_(-1) {}
bool setCacheInfoFromFstab() {
fs_type = FS_UNKNOWN;
struct fstab *fstab = fs_mgr_read_fstab_default();
if (!fstab) {
testPrintE("failed to open default fstab\n");
} else {
// Loop through entries looking for cache.
for (int i = 0; i < fstab->num_entries; ++i) {
if (!strcmp(fstab->recs[i].mount_point, "/cache")) {
strcpy(blk_path_, fstab->recs[i].blk_device);
if (!strcmp(fstab->recs[i].fs_type, "ext4")) {
fs_type = FS_EXT4;
break;
} else if (!strcmp(fstab->recs[i].fs_type, "f2fs")) {
fs_type = FS_F2FS;
break;
}
}
}
fs_mgr_free_fstab(fstab);
}
return fs_type != FS_UNKNOWN;
}
bool unmountCache() {
char cache_str[] = "/cache";
char *umount_argv[] = {
UMOUNT_BIN,
cache_str,
};
int status;
return android_fork_execvp_ext(ARRAY_SIZE(umount_argv), umount_argv,
NULL, true, LOG_KLOG, false, NULL,
NULL, 0) >= 0;
}
bool mountAll() {
char storage_str[] = "storage";
char mountall_str[] = "mountall";
char *mountall_argv[] = {
VDC_BIN,
storage_str,
mountall_str,
};
int status;
return android_fork_execvp_ext(ARRAY_SIZE(mountall_argv), mountall_argv,
NULL, true, LOG_KLOG, false, NULL,
NULL, 0) >= 0;
}
int getCacheBlkFd() {
if (blk_fd_ == -1) {
blk_fd_ = open(blk_path_, O_RDWR);
}
return blk_fd_;
}
void closeCacheBlkFd() {
if (blk_fd_ > -1) {
close(blk_fd_);
}
blk_fd_ = -1;
}
void assertCacheHealthy() {
const char* test_file = "/cache/FsRecoveryTestGarbage.txt";
DataFileVerifier file_verify(test_file);
file_verify.verify_write();
file_verify.verify_read();
}
virtual void SetUp() {
assertCacheHealthy();
ASSERT_TRUE(setCacheInfoFromFstab());
}
virtual void TearDown() {
// Ensure /cache partition is accessible, mounted and healthy for other
// tests.
closeCacheBlkFd();
ASSERT_TRUE(mountAll());
assertCacheHealthy();
}
Fs_Type fs_type;
private:
char blk_path_[FILENAME_MAX];
int blk_fd_;
};
TEST_F(FsRecoveryTest, EXT4_CorruptGdt) {
if (fs_type != FS_EXT4) {
return;
}
// Setup test file in /cache.
const char* test_file = "/cache/CorruptGdtGarbage.txt";
DataFileVerifier file_verify(test_file);
file_verify.verify_write();
// Unmount and corrupt /cache gdt.
ASSERT_TRUE(unmountCache());
ASSERT_TRUE(ext4::corruptGdtFreeBlock(getCacheBlkFd()));
closeCacheBlkFd();
ASSERT_TRUE(mountAll());
// Verify results.
file_verify.verify_read();
}
TEST_F(FsRecoveryTest, EXT4_SetErrorBit) {
if (fs_type != FS_EXT4) {
return;
}
// Setup test file in /cache.
const char* test_file = "/cache/ErrorBitGarbagetxt";
DataFileVerifier file_verify(test_file);
file_verify.verify_write();
// Unmount and set /cache super block error bit.
ASSERT_TRUE(unmountCache());
ASSERT_TRUE(ext4::setSbErrorBit(getCacheBlkFd()));
closeCacheBlkFd();
ASSERT_TRUE(mountAll());
// Verify results.
file_verify.verify_read();
struct ext4_super_block sb;
ASSERT_TRUE(ext4::getSuperBlock(getCacheBlkFd(), &sb));
// Verify e2fsck has recovered the error bit of sb.
ASSERT_FALSE(sb.s_state & 0x2);
}
} // namespace android