blob: 1cfd8bbf306320b017ea583c42aa8da78f035791 [file] [log] [blame]
// Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "update_engine/extent_mapper.h"
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <linux/fs.h>
#include "update_engine/graph_types.h"
#include "update_engine/graph_utils.h"
#include "update_engine/utils.h"
using std::string;
using std::vector;
namespace chromeos_update_engine {
namespace extent_mapper {
namespace {
const int kBlockSize = 4096;
}
bool ExtentsForFileChunkFibmap(const std::string& path,
off_t chunk_offset,
off_t chunk_size,
std::vector<Extent>* out) {
CHECK(out);
CHECK_EQ(0, chunk_offset % kBlockSize);
CHECK(chunk_size == -1 || chunk_size >= 0);
struct stat stbuf;
int rc = stat(path.c_str(), &stbuf);
TEST_AND_RETURN_FALSE_ERRNO(rc == 0);
TEST_AND_RETURN_FALSE(S_ISREG(stbuf.st_mode));
int fd = open(path.c_str(), O_RDONLY, 0);
TEST_AND_RETURN_FALSE_ERRNO(fd >= 0);
ScopedFdCloser fd_closer(&fd);
// Get file size in blocks
rc = fstat(fd, &stbuf);
if (rc < 0) {
perror("fstat");
return false;
}
CHECK_LE(chunk_offset, stbuf.st_size);
off_t size = stbuf.st_size - chunk_offset;
if (chunk_size != -1) {
size = std::min(size, chunk_size);
}
const int block_count = (size + kBlockSize - 1) / kBlockSize;
const int start_block = chunk_offset / kBlockSize;
Extent current;
current.set_start_block(0);
current.set_num_blocks(0);
for (int i = start_block; i < start_block + block_count; i++) {
unsigned int block32 = i;
rc = ioctl(fd, FIBMAP, &block32);
TEST_AND_RETURN_FALSE_ERRNO(rc == 0);
const uint64_t block = (block32 == 0 ? kSparseHole : block32);
graph_utils::AppendBlockToExtents(out, block);
}
return true;
}
bool ExtentsForFileFibmap(const std::string& path, std::vector<Extent>* out) {
return ExtentsForFileChunkFibmap(path, 0, -1, out);
}
bool GetFilesystemBlockSize(const std::string& path, uint32_t* out_blocksize) {
int fd = open(path.c_str(), O_RDONLY, 0);
TEST_AND_RETURN_FALSE_ERRNO(fd >= 0);
ScopedFdCloser fd_closer(&fd);
int rc = ioctl(fd, FIGETBSZ, out_blocksize);
TEST_AND_RETURN_FALSE_ERRNO(rc != -1);
return true;
}
} // namespace extent_mapper
} // namespace chromeos_update_engine