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/*
* Copyright (C) 2020 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 required 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.
*/
#include "dump.h"
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parsebool.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <dirent.h>
#include <errno.h>
#include <libgen.h>
#include <openssl/sha.h>
#include <selinux/android.h>
#include <selinux/selinux.h>
#include <sys/mount.h>
#include <sys/poll.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/vfs.h>
#include <sys/xattr.h>
#include <unistd.h>
#include "linux/incrementalfs.h"
#include <chrono>
#include <fstream>
#include <iostream>
#include <iterator>
#include <optional>
#include <string_view>
using namespace std::literals;
namespace {
// stuff from the internal incfs implementation
#ifndef __packed
#define __packed __attribute__((packed))
#endif
struct mem_range {
char* data;
size_t len;
};
#define INCFS_MAX_NAME_LEN 255
#define INCFS_FORMAT_V1 1
#define INCFS_FORMAT_CURRENT_VER INCFS_FORMAT_V1
enum incfs_metadata_type {
INCFS_MD_NONE = 0,
INCFS_MD_BLOCK_MAP = 1,
INCFS_MD_FILE_ATTR = 2,
INCFS_MD_SIGNATURE = 3
};
enum incfs_file_header_flags {
INCFS_FILE_COMPLETE = 1 << 0,
};
/* Header included at the beginning of all metadata records on the disk. */
struct incfs_md_header {
uint8_t h_md_entry_type;
/*
* Size of the metadata record.
* (e.g. inode, dir entry etc) not just this struct.
*/
int16_t h_record_size;
/*
* CRC32 of the metadata record.
* (e.g. inode, dir entry etc) not just this struct.
*/
int32_t h_record_crc;
/* Offset of the next metadata entry if any */
int64_t h_next_md_offset;
/* Offset of the previous metadata entry if any */
int64_t h_prev_md_offset;
} __packed;
/* Backing file header */
struct incfs_file_header {
/* Magic number: INCFS_MAGIC_NUMBER */
int64_t fh_magic;
/* Format version: INCFS_FORMAT_CURRENT_VER */
int64_t fh_version;
/* sizeof(incfs_file_header) */
int16_t fh_header_size;
/* INCFS_DATA_FILE_BLOCK_SIZE */
int16_t fh_data_block_size;
/* File flags, from incfs_file_header_flags */
int32_t fh_file_header_flags;
/* Offset of the first metadata record */
int64_t fh_first_md_offset;
/*
* Put file specific information after this point
*/
/* Full size of the file's content */
int64_t fh_file_size;
/* File uuid */
incfs_uuid_t fh_uuid;
} __packed;
enum incfs_block_map_entry_flags {
INCFS_BLOCK_COMPRESSED_LZ4 = (1 << 0),
INCFS_BLOCK_HASH = (1 << 1),
};
/* Block map entry pointing to an actual location of the data block. */
struct incfs_blockmap_entry {
/* Offset of the actual data block. Lower 32 bits */
int32_t me_data_offset_lo;
/* Offset of the actual data block. Higher 16 bits */
int16_t me_data_offset_hi;
/* How many bytes the data actually occupies in the backing file */
int16_t me_data_size;
/* Block flags from incfs_block_map_entry_flags */
int16_t me_flags;
} __packed;
/* Metadata record for locations of file blocks. Type = INCFS_MD_BLOCK_MAP */
struct incfs_blockmap {
struct incfs_md_header m_header;
/* Base offset of the array of incfs_blockmap_entry */
int64_t m_base_offset;
/* Size of the map entry array in blocks */
int32_t m_block_count;
} __packed;
/* Metadata record for file attribute. Type = INCFS_MD_FILE_ATTR */
struct incfs_file_attr {
struct incfs_md_header fa_header;
int64_t fa_offset;
int16_t fa_size;
int32_t fa_crc;
} __packed;
/* Metadata record for file signature. Type = INCFS_MD_SIGNATURE */
struct incfs_file_signature {
struct incfs_md_header sg_header;
int32_t sg_sig_size; /* The size of the signature. */
int64_t sg_sig_offset; /* Signature's offset in the backing file */
int32_t sg_hash_tree_size; /* The size of the hash tree. */
int64_t sg_hash_tree_offset; /* Hash tree offset in the backing file */
} __packed;
typedef union {
struct incfs_md_header md_header;
struct incfs_blockmap blockmap;
struct incfs_file_attr file_attr;
struct incfs_file_signature signature;
} md_buffer;
#define INCFS_MAX_METADATA_RECORD_SIZE sizeof(md_buffer)
class Dump {
public:
Dump(std::string_view backingFile)
: mBackingFile(android::base::Basename(std::string(backingFile))), mIn(backingFile) {}
void run() {
if (!mIn) {
err() << "bad input file name " << mBackingFile;
return;
}
auto header = read<incfs_file_header>();
out() << "header: " << hex(header.fh_magic) << ", " << header.fh_version << ", "
<< hex(header.fh_data_block_size) << ", " << header.fh_header_size << ", "
<< header.fh_file_size;
if (header.fh_magic != INCFS_MAGIC_NUMBER) {
err() << "bad magic, expected: " << hex(INCFS_MAGIC_NUMBER);
}
if (header.fh_version != INCFS_FORMAT_CURRENT_VER) {
err() << "bad version, expected: " << INCFS_FORMAT_CURRENT_VER;
}
if (header.fh_data_block_size != INCFS_DATA_FILE_BLOCK_SIZE) {
err() << "bad data block size, expected: " << hex(INCFS_DATA_FILE_BLOCK_SIZE);
}
if (header.fh_header_size != sizeof(header)) {
err() << "bad header size, expected: " << sizeof(header);
}
{
auto ostream = out() << "flags: " << hex(header.fh_file_header_flags);
if (header.fh_file_header_flags & INCFS_FILE_COMPLETE) {
out() << "(file_complete)";
}
}
out() << "first metadata block offset: " << hex(header.fh_first_md_offset);
auto metadataOffset = header.fh_first_md_offset;
if (mIn.tellg() != metadataOffset) {
out() << "gap of " << metadataOffset - mIn.tellg()
<< " bytes to the first metadata record";
}
incfs_md_header prevMd = {};
do {
dumpMd(metadataOffset, prevMd);
} while (metadataOffset != 0);
out() << "finished" << (mIn ? "" : " with read errors");
}
private:
auto scopedNesting() {
++mNesting;
auto undoNesting = [this](auto) { --mNesting; };
return std::unique_ptr<Dump, decltype(undoNesting)>(this, std::move(undoNesting));
}
const char* mdType(int type) {
switch (type) {
case INCFS_MD_NONE:
return "none";
case INCFS_MD_BLOCK_MAP:
return "block map";
case INCFS_MD_FILE_ATTR:
return "file attr";
case INCFS_MD_SIGNATURE:
return "signature";
default:
return "unknown";
}
}
std::string blockFlags(int flags) {
if (!flags) {
return {};
}
std::string res = "(";
if (flags & INCFS_BLOCK_COMPRESSED_LZ4) {
res += "|compressed|";
}
if (flags & INCFS_BLOCK_HASH) {
res += "|hash|";
}
res += ")";
return res;
}
void dumpBlockmap(int64_t offset, int64_t count) {
auto nesting = scopedNesting();
mIn.seekg(offset);
for (int64_t i = 0; i != count; ++i) {
auto ostream = out() << i << " @ " << hex(mIn.tellg()) << ": [ ";
auto block = read<incfs_blockmap_entry>();
auto blockOffset =
uint64_t(block.me_data_offset_lo) | (uint64_t(block.me_data_offset_hi) << 32);
if (blockOffset) {
ostream << block.me_data_size << " @ " << hex(blockOffset);
} else {
ostream << "missing";
}
ostream << " ], flags = " << block.me_flags << blockFlags(block.me_flags);
}
}
void dumpAttr(int64_t offset, int64_t size) {
auto nesting = scopedNesting();
out() << "attr " << offset << " " << size;
}
void dumpTree(int64_t offset, int64_t size) {
auto nesting = scopedNesting();
out() << "tree " << offset << " " << size;
}
void dumpMd(int64_t& offset, incfs_md_header& prevMd) {
md_buffer mdBuf = {};
auto& md = mdBuf.md_header;
md = readAt<incfs_md_header>(offset);
out() << "metadata: " << mdType(md.h_md_entry_type) << "(" << int(md.h_md_entry_type)
<< ")";
auto nesting = scopedNesting();
out() << "record size: " << md.h_record_size;
out() << "record crc: " << hex(md.h_record_crc);
out() << "next md offset: " << hex(md.h_next_md_offset);
out() << "prev md offset: " << hex(md.h_prev_md_offset);
{
switch (md.h_md_entry_type) {
case INCFS_MD_NONE:
out() << "nothing here";
break;
case INCFS_MD_BLOCK_MAP: {
auto& bm = mdBuf.blockmap;
bm = readAt<decltype(bm)>(offset);
out() << "offset: " << hex(bm.m_base_offset);
out() << "block count: " << bm.m_block_count;
dumpBlockmap(bm.m_base_offset, bm.m_block_count);
break;
}
case INCFS_MD_FILE_ATTR: {
auto& attr = mdBuf.file_attr;
attr = readAt<decltype(attr)>(offset);
out() << "offset: " << hex(attr.fa_offset);
out() << "size: " << attr.fa_size;
out() << "crc: " << hex(attr.fa_crc);
dumpAttr(attr.fa_offset, attr.fa_size);
break;
}
case INCFS_MD_SIGNATURE: {
auto& sig = mdBuf.signature;
sig = readAt<decltype(sig)>(offset);
out() << "signature size: " << sig.sg_sig_size;
out() << "signature offset: " << hex(sig.sg_sig_offset);
out() << "hash tree size: " << sig.sg_hash_tree_size;
out() << "hash tree offset: " << hex(sig.sg_hash_tree_offset);
dumpTree(sig.sg_hash_tree_offset, sig.sg_hash_tree_size);
break;
}
default:
out() << "don't know how to handle it";
break;
}
}
updateMaxPos();
prevMd = md;
offset = md.h_next_md_offset;
}
struct OstreamWrapper {
explicit OstreamWrapper(std::ostream& wrapped) : mWrapped(&wrapped) {}
OstreamWrapper(OstreamWrapper&& other) : mWrapped(std::exchange(other.mWrapped, nullptr)) {}
~OstreamWrapper() {
if (mWrapped) {
*mWrapped << '\n';
}
}
template <class T>
OstreamWrapper& operator<<(const T& t) & {
*mWrapped << t;
return *this;
}
template <class T>
OstreamWrapper&& operator<<(const T& t) && {
*this << t;
return std::move(*this);
}
private:
std::ostream* mWrapped;
};
std::string hex(uint64_t t) {
char buf[32] = {};
snprintf(buf, std::size(buf) - 1, "0x%llx", (unsigned long long)t);
return buf;
}
OstreamWrapper out() const {
nesting(std::cout);
std::cout << "[" << mBackingFile << "] ";
return OstreamWrapper(std::cout);
}
OstreamWrapper err() const {
nesting(std::cerr);
std::cerr << "[" << mBackingFile << "] ";
return OstreamWrapper(std::cerr);
}
void nesting(std::ostream& out) const {
for (int i = 0; i < mNesting; ++i) {
out << " ";
}
}
template <class T>
std::remove_reference_t<T> read() {
std::remove_reference_t<T> res;
mIn.read((char*)&res, sizeof(res));
return res;
}
template <class T>
std::remove_reference_t<T> readAt(int64_t pos) {
mIn.seekg(pos);
return read<T>();
}
void skip(int64_t count) { mIn.seekg(count, std::ios_base::cur); }
void updateMaxPos() { mMaxDumpedPos = std::max<int64_t>(mMaxDumpedPos, mIn.tellg()); }
std::string mBackingFile;
std::ifstream mIn;
int mNesting = 0;
int64_t mMaxDumpedPos = 0;
};
} // namespace
namespace android::incfs {
void dump(std::string_view backingFile) {
Dump(backingFile).run();
}
} // namespace android::incfs