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platform_system_core/libsparse/sparse_read.cpp

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/*
* Copyright (C) 2012 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.
*/
#define _FILE_OFFSET_BITS 64
#define _LARGEFILE64_SOURCE 1
#include <fcntl.h>
#include <inttypes.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <algorithm>
#include <string>
#include <sparse/sparse.h>
#include "android-base/stringprintf.h"
#include "defs.h"
#include "output_file.h"
#include "sparse_crc32.h"
#include "sparse_file.h"
#include "sparse_format.h"
#if defined(__APPLE__) && defined(__MACH__)
#define lseek64 lseek
#define off64_t off_t
#endif
#define SPARSE_HEADER_MAJOR_VER 1
#define SPARSE_HEADER_LEN (sizeof(sparse_header_t))
#define CHUNK_HEADER_LEN (sizeof(chunk_header_t))
static constexpr int64_t COPY_BUF_SIZE = 1024 * 1024;
static char* copybuf;
static std::string ErrorString(int err) {
if (err == -EOVERFLOW) return "EOF while reading file";
if (err == -EINVAL) return "Invalid sparse file format";
if (err == -ENOMEM) return "Failed allocation while reading file";
return android::base::StringPrintf("Unknown error %d", err);
}
class SparseFileSource {
public:
/* Seeks the source ahead by the given offset. */
virtual void Seek(int64_t offset) = 0;
/* Return the current offset. */
virtual int64_t GetOffset() = 0;
/* Set the current offset. Return 0 if successful. */
virtual int SetOffset(int64_t offset) = 0;
/* Adds the given length from the current offset of the source to the file at the given block.
* Return 0 if successful. */
virtual int AddToSparseFile(struct sparse_file* s, int64_t len, unsigned int block) = 0;
/* Get data of fixed size from the current offset and seek len bytes. Return 0 if successful. */
virtual int ReadValue(void* ptr, int len) = 0;
/* Find the crc32 of the next len bytes and seek ahead len bytes. Return 0 if successful. */
virtual int GetCrc32(uint32_t* crc32, int64_t len) = 0;
virtual ~SparseFileSource(){};
};
class SparseFileFdSource : public SparseFileSource {
private:
int fd;
public:
SparseFileFdSource(int fd) : fd(fd) {}
~SparseFileFdSource() override {}
void Seek(int64_t off) override { lseek64(fd, off, SEEK_CUR); }
int64_t GetOffset() override { return lseek64(fd, 0, SEEK_CUR); }
int SetOffset(int64_t offset) override {
return lseek64(fd, offset, SEEK_SET) == offset ? 0 : -errno;
}
int AddToSparseFile(struct sparse_file* s, int64_t len, unsigned int block) override {
return sparse_file_add_fd(s, fd, GetOffset(), len, block);
}
int ReadValue(void* ptr, int len) override { return read_all(fd, ptr, len); }
int GetCrc32(uint32_t* crc32, int64_t len) override {
int chunk;
int ret;
while (len) {
chunk = std::min(len, COPY_BUF_SIZE);
ret = read_all(fd, copybuf, chunk);
if (ret < 0) {
return ret;
}
*crc32 = sparse_crc32(*crc32, copybuf, chunk);
len -= chunk;
}
return 0;
}
};
class SparseFileBufSource : public SparseFileSource {
private:
char* buf;
int64_t offset;
public:
SparseFileBufSource(char* buf) : buf(buf), offset(0) {}
~SparseFileBufSource() override {}
void Seek(int64_t off) override {
buf += off;
offset += off;
}
int64_t GetOffset() override { return offset; }
int SetOffset(int64_t off) override {
buf += off - offset;
offset = off;
return 0;
}
int AddToSparseFile(struct sparse_file* s, int64_t len, unsigned int block) override {
return sparse_file_add_data(s, buf, len, block);
}
int ReadValue(void* ptr, int len) override {
memcpy(ptr, buf, len);
Seek(len);
return 0;
}
int GetCrc32(uint32_t* crc32, int64_t len) override {
*crc32 = sparse_crc32(*crc32, buf, len);
Seek(len);
return 0;
}
};
static void verbose_error(bool verbose, int err, const char* fmt, ...) {
if (!verbose) return;
std::string msg = ErrorString(err);
if (fmt) {
msg += " at ";
va_list argp;
va_start(argp, fmt);
android::base::StringAppendV(&msg, fmt, argp);
va_end(argp);
}
sparse_print_verbose("%s\n", msg.c_str());
}
static int process_raw_chunk(struct sparse_file* s, unsigned int chunk_size,
SparseFileSource* source, unsigned int blocks, unsigned int block,
uint32_t* crc32) {
int ret;
int64_t len = blocks * s->block_size;
if (chunk_size % s->block_size != 0) {
return -EINVAL;
}
if (chunk_size / s->block_size != blocks) {
return -EINVAL;
}
ret = source->AddToSparseFile(s, len, block);
if (ret < 0) {
return ret;
}
if (crc32) {
ret = source->GetCrc32(crc32, len);
if (ret < 0) {
return ret;
}
} else {
source->Seek(len);
}
return 0;
}
static int process_fill_chunk(struct sparse_file* s, unsigned int chunk_size,
SparseFileSource* source, unsigned int blocks, unsigned int block,
uint32_t* crc32) {
int ret;
int chunk;
int64_t len = (int64_t)blocks * s->block_size;
uint32_t fill_val;
uint32_t* fillbuf;
unsigned int i;
if (chunk_size != sizeof(fill_val)) {
return -EINVAL;
}
ret = source->ReadValue(&fill_val, sizeof(fill_val));
if (ret < 0) {
return ret;
}
ret = sparse_file_add_fill(s, fill_val, len, block);
if (ret < 0) {
return ret;
}
if (crc32) {
/* Fill copy_buf with the fill value */
fillbuf = (uint32_t*)copybuf;
for (i = 0; i < (COPY_BUF_SIZE / sizeof(fill_val)); i++) {
fillbuf[i] = fill_val;
}
while (len) {
chunk = std::min(len, COPY_BUF_SIZE);
*crc32 = sparse_crc32(*crc32, copybuf, chunk);
len -= chunk;
}
}
return 0;
}
static int process_skip_chunk(struct sparse_file* s, unsigned int chunk_size,
SparseFileSource* source __unused, unsigned int blocks,
unsigned int block __unused, uint32_t* crc32) {
if (chunk_size != 0) {
return -EINVAL;
}
if (crc32) {
int64_t len = (int64_t)blocks * s->block_size;
memset(copybuf, 0, COPY_BUF_SIZE);
while (len) {
int chunk = std::min(len, COPY_BUF_SIZE);
*crc32 = sparse_crc32(*crc32, copybuf, chunk);
len -= chunk;
}
}
return 0;
}
static int process_crc32_chunk(SparseFileSource* source, unsigned int chunk_size, uint32_t* crc32) {
uint32_t file_crc32;
if (chunk_size != sizeof(file_crc32)) {
return -EINVAL;
}
int ret = source->ReadValue(&file_crc32, sizeof(file_crc32));
if (ret < 0) {
return ret;
}
if (crc32 != nullptr && file_crc32 != *crc32) {
return -EINVAL;
}
return 0;
}
static int process_chunk(struct sparse_file* s, SparseFileSource* source, unsigned int chunk_hdr_sz,
chunk_header_t* chunk_header, unsigned int cur_block, uint32_t* crc_ptr) {
int ret;
unsigned int chunk_data_size;
int64_t offset = source->GetOffset();
chunk_data_size = chunk_header->total_sz - chunk_hdr_sz;
switch (chunk_header->chunk_type) {
case CHUNK_TYPE_RAW:
ret =
process_raw_chunk(s, chunk_data_size, source, chunk_header->chunk_sz, cur_block, crc_ptr);
if (ret < 0) {
verbose_error(s->verbose, ret, "data block at %" PRId64, offset);
return ret;
}
return chunk_header->chunk_sz;
case CHUNK_TYPE_FILL:
ret = process_fill_chunk(s, chunk_data_size, source, chunk_header->chunk_sz, cur_block,
crc_ptr);
if (ret < 0) {
verbose_error(s->verbose, ret, "fill block at %" PRId64, offset);
return ret;
}
return chunk_header->chunk_sz;
case CHUNK_TYPE_DONT_CARE:
ret = process_skip_chunk(s, chunk_data_size, source, chunk_header->chunk_sz, cur_block,
crc_ptr);
if (chunk_data_size != 0) {
if (ret < 0) {
verbose_error(s->verbose, ret, "skip block at %" PRId64, offset);
return ret;
}
}
return chunk_header->chunk_sz;
case CHUNK_TYPE_CRC32:
ret = process_crc32_chunk(source, chunk_data_size, crc_ptr);
if (ret < 0) {
verbose_error(s->verbose, -EINVAL, "crc block at %" PRId64, offset);
return ret;
}
return 0;
default:
verbose_error(s->verbose, -EINVAL, "unknown block %04X at %" PRId64, chunk_header->chunk_type,
offset);
}
return 0;
}
static int sparse_file_read_sparse(struct sparse_file* s, SparseFileSource* source, bool crc) {
int ret;
unsigned int i;
sparse_header_t sparse_header;
chunk_header_t chunk_header;
uint32_t crc32 = 0;
uint32_t* crc_ptr = nullptr;
unsigned int cur_block = 0;
if (!copybuf) {
copybuf = (char*)malloc(COPY_BUF_SIZE);
}
if (!copybuf) {
return -ENOMEM;
}
if (crc) {
crc_ptr = &crc32;
}
ret = source->ReadValue(&sparse_header, sizeof(sparse_header));
if (ret < 0) {
return ret;
}
if (sparse_header.magic != SPARSE_HEADER_MAGIC) {
return -EINVAL;
}
if (sparse_header.major_version != SPARSE_HEADER_MAJOR_VER) {
return -EINVAL;
}
if (sparse_header.file_hdr_sz < SPARSE_HEADER_LEN) {
return -EINVAL;
}
if (sparse_header.chunk_hdr_sz < sizeof(chunk_header)) {
return -EINVAL;
}
if (sparse_header.file_hdr_sz > SPARSE_HEADER_LEN) {
/* Skip the remaining bytes in a header that is longer than
* we expected.
*/
source->Seek(sparse_header.file_hdr_sz - SPARSE_HEADER_LEN);
}
for (i = 0; i < sparse_header.total_chunks; i++) {
ret = source->ReadValue(&chunk_header, sizeof(chunk_header));
if (ret < 0) {
return ret;
}
if (sparse_header.chunk_hdr_sz > CHUNK_HEADER_LEN) {
/* Skip the remaining bytes in a header that is longer than
* we expected.
*/
source->Seek(sparse_header.chunk_hdr_sz - CHUNK_HEADER_LEN);
}
ret = process_chunk(s, source, sparse_header.chunk_hdr_sz, &chunk_header, cur_block, crc_ptr);
if (ret < 0) {
return ret;
}
cur_block += ret;
}
if (sparse_header.total_blks != cur_block) {
return -EINVAL;
}
return 0;
}
static int sparse_file_read_normal(struct sparse_file* s, int fd) {
int ret;
uint32_t* buf = (uint32_t*)malloc(s->block_size);
unsigned int block = 0;
int64_t remain = s->len;
int64_t offset = 0;
unsigned int to_read;
unsigned int i;
bool sparse_block;
if (!buf) {
return -ENOMEM;
}
while (remain > 0) {
to_read = std::min(remain, (int64_t)(s->block_size));
ret = read_all(fd, buf, to_read);
if (ret < 0) {
error("failed to read sparse file");
free(buf);
return ret;
}
if (to_read == s->block_size) {
sparse_block = true;
for (i = 1; i < s->block_size / sizeof(uint32_t); i++) {
if (buf[0] != buf[i]) {
sparse_block = false;
break;
}
}
} else {
sparse_block = false;
}
if (sparse_block) {
/* TODO: add flag to use skip instead of fill for buf[0] == 0 */
sparse_file_add_fill(s, buf[0], to_read, block);
} else {
sparse_file_add_fd(s, fd, offset, to_read, block);
}
remain -= to_read;
offset += to_read;
block++;
}
free(buf);
return 0;
}
int sparse_file_read(struct sparse_file* s, int fd, bool sparse, bool crc) {
if (crc && !sparse) {
return -EINVAL;
}
if (sparse) {
SparseFileFdSource source(fd);
return sparse_file_read_sparse(s, &source, crc);
} else {
return sparse_file_read_normal(s, fd);
}
}
int sparse_file_read_buf(struct sparse_file* s, char* buf, bool crc) {
SparseFileBufSource source(buf);
return sparse_file_read_sparse(s, &source, crc);
}
static struct sparse_file* sparse_file_import_source(SparseFileSource* source, bool verbose,
bool crc) {
int ret;
sparse_header_t sparse_header;
int64_t len;
struct sparse_file* s;
ret = source->ReadValue(&sparse_header, sizeof(sparse_header));
if (ret < 0) {
verbose_error(verbose, ret, "header");
return nullptr;
}
if (sparse_header.magic != SPARSE_HEADER_MAGIC) {
verbose_error(verbose, -EINVAL, "header magic");
return nullptr;
}
if (sparse_header.major_version != SPARSE_HEADER_MAJOR_VER) {
verbose_error(verbose, -EINVAL, "header major version");
return nullptr;
}
if (sparse_header.file_hdr_sz < SPARSE_HEADER_LEN) {
return nullptr;
}
if (sparse_header.chunk_hdr_sz < sizeof(chunk_header_t)) {
return nullptr;
}
len = (int64_t)sparse_header.total_blks * sparse_header.blk_sz;
s = sparse_file_new(sparse_header.blk_sz, len);
if (!s) {
verbose_error(verbose, -EINVAL, nullptr);
return nullptr;
}
ret = source->SetOffset(0);
if (ret < 0) {
verbose_error(verbose, ret, "seeking");
sparse_file_destroy(s);
return nullptr;
}
s->verbose = verbose;
ret = sparse_file_read_sparse(s, source, crc);
if (ret < 0) {
sparse_file_destroy(s);
return nullptr;
}
return s;
}
struct sparse_file* sparse_file_import(int fd, bool verbose, bool crc) {
SparseFileFdSource source(fd);
return sparse_file_import_source(&source, verbose, crc);
}
struct sparse_file* sparse_file_import_buf(char* buf, bool verbose, bool crc) {
SparseFileBufSource source(buf);
return sparse_file_import_source(&source, verbose, crc);
}
struct sparse_file* sparse_file_import_auto(int fd, bool crc, bool verbose) {
struct sparse_file* s;
int64_t len;
int ret;
s = sparse_file_import(fd, verbose, crc);
if (s) {
return s;
}
len = lseek64(fd, 0, SEEK_END);
if (len < 0) {
return nullptr;
}
lseek64(fd, 0, SEEK_SET);
s = sparse_file_new(4096, len);
if (!s) {
return nullptr;
}
ret = sparse_file_read_normal(s, fd);
if (ret < 0) {
sparse_file_destroy(s);
return nullptr;
}
return s;
}
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