| /* |
| * Copyright 2006 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 "SysUtil.h" |
| |
| #include <assert.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <limits.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/mman.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| #include <algorithm> |
| #include <string> |
| #include <vector> |
| |
| #include <android-base/file.h> |
| #include <android-base/logging.h> |
| #include <android-base/strings.h> |
| #include <android-base/unique_fd.h> |
| |
| static bool sysMapFD(int fd, MemMapping* pMap) { |
| CHECK(pMap != nullptr); |
| |
| struct stat sb; |
| if (fstat(fd, &sb) == -1) { |
| PLOG(ERROR) << "fstat(" << fd << ") failed"; |
| return false; |
| } |
| |
| void* memPtr = mmap(nullptr, sb.st_size, PROT_READ, MAP_PRIVATE, fd, 0); |
| if (memPtr == MAP_FAILED) { |
| PLOG(ERROR) << "mmap(" << sb.st_size << ", R, PRIVATE, " << fd << ", 0) failed"; |
| return false; |
| } |
| |
| pMap->addr = static_cast<unsigned char*>(memPtr); |
| pMap->length = sb.st_size; |
| pMap->ranges.push_back({ memPtr, static_cast<size_t>(sb.st_size) }); |
| |
| return true; |
| } |
| |
| // A "block map" which looks like this (from uncrypt/uncrypt.cpp): |
| // |
| // /dev/block/platform/msm_sdcc.1/by-name/userdata # block device |
| // 49652 4096 # file size in bytes, block size |
| // 3 # count of block ranges |
| // 1000 1008 # block range 0 |
| // 2100 2102 # ... block range 1 |
| // 30 33 # ... block range 2 |
| // |
| // Each block range represents a half-open interval; the line "30 33" |
| // reprents the blocks [30, 31, 32]. |
| static int sysMapBlockFile(const char* filename, MemMapping* pMap) { |
| CHECK(pMap != nullptr); |
| |
| std::string content; |
| if (!android::base::ReadFileToString(filename, &content)) { |
| PLOG(ERROR) << "Failed to read " << filename; |
| return -1; |
| } |
| |
| std::vector<std::string> lines = android::base::Split(android::base::Trim(content), "\n"); |
| if (lines.size() < 4) { |
| LOG(ERROR) << "Block map file is too short: " << lines.size(); |
| return -1; |
| } |
| |
| size_t size; |
| unsigned int blksize; |
| if (sscanf(lines[1].c_str(), "%zu %u", &size, &blksize) != 2) { |
| LOG(ERROR) << "Failed to parse file size and block size: " << lines[1]; |
| return -1; |
| } |
| |
| size_t range_count; |
| if (sscanf(lines[2].c_str(), "%zu", &range_count) != 1) { |
| LOG(ERROR) << "Failed to parse block map header: " << lines[2]; |
| return -1; |
| } |
| |
| size_t blocks; |
| if (blksize != 0) { |
| blocks = ((size - 1) / blksize) + 1; |
| } |
| if (size == 0 || blksize == 0 || blocks > SIZE_MAX / blksize || range_count == 0 || |
| lines.size() != 3 + range_count) { |
| LOG(ERROR) << "Invalid data in block map file: size " << size << ", blksize " << blksize |
| << ", range_count " << range_count << ", lines " << lines.size(); |
| return -1; |
| } |
| |
| // Reserve enough contiguous address space for the whole file. |
| void* reserve = mmap64(nullptr, blocks * blksize, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0); |
| if (reserve == MAP_FAILED) { |
| PLOG(ERROR) << "failed to reserve address space"; |
| return -1; |
| } |
| |
| const std::string& block_dev = lines[0]; |
| android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(block_dev.c_str(), O_RDONLY))); |
| if (fd == -1) { |
| PLOG(ERROR) << "failed to open block device " << block_dev; |
| munmap(reserve, blocks * blksize); |
| return -1; |
| } |
| |
| pMap->ranges.resize(range_count); |
| |
| unsigned char* next = static_cast<unsigned char*>(reserve); |
| size_t remaining_size = blocks * blksize; |
| bool success = true; |
| for (size_t i = 0; i < range_count; ++i) { |
| const std::string& line = lines[i + 3]; |
| |
| size_t start, end; |
| if (sscanf(line.c_str(), "%zu %zu\n", &start, &end) != 2) { |
| LOG(ERROR) << "failed to parse range " << i << " in block map: " << line; |
| success = false; |
| break; |
| } |
| size_t length = (end - start) * blksize; |
| if (end <= start || (end - start) > SIZE_MAX / blksize || length > remaining_size) { |
| LOG(ERROR) << "unexpected range in block map: " << start << " " << end; |
| success = false; |
| break; |
| } |
| |
| void* addr = mmap64(next, length, PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, |
| static_cast<off64_t>(start) * blksize); |
| if (addr == MAP_FAILED) { |
| PLOG(ERROR) << "failed to map block " << i; |
| success = false; |
| break; |
| } |
| pMap->ranges[i].addr = addr; |
| pMap->ranges[i].length = length; |
| |
| next += length; |
| remaining_size -= length; |
| } |
| if (success && remaining_size != 0) { |
| LOG(ERROR) << "ranges in block map are invalid: remaining_size = " << remaining_size; |
| success = false; |
| } |
| if (!success) { |
| munmap(reserve, blocks * blksize); |
| return -1; |
| } |
| |
| pMap->addr = static_cast<unsigned char*>(reserve); |
| pMap->length = size; |
| |
| LOG(INFO) << "mmapped " << range_count << " ranges"; |
| |
| return 0; |
| } |
| |
| int sysMapFile(const char* fn, MemMapping* pMap) { |
| if (fn == nullptr || pMap == nullptr) { |
| LOG(ERROR) << "Invalid argument(s)"; |
| return -1; |
| } |
| |
| *pMap = {}; |
| |
| if (fn[0] == '@') { |
| if (sysMapBlockFile(fn + 1, pMap) != 0) { |
| LOG(ERROR) << "Map of '" << fn << "' failed"; |
| return -1; |
| } |
| } else { |
| // This is a regular file. |
| android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(fn, O_RDONLY))); |
| if (fd == -1) { |
| PLOG(ERROR) << "Unable to open '" << fn << "'"; |
| return -1; |
| } |
| |
| if (!sysMapFD(fd, pMap)) { |
| LOG(ERROR) << "Map of '" << fn << "' failed"; |
| return -1; |
| } |
| } |
| return 0; |
| } |
| |
| /* |
| * Release a memory mapping. |
| */ |
| void sysReleaseMap(MemMapping* pMap) { |
| std::for_each(pMap->ranges.cbegin(), pMap->ranges.cend(), [](const MappedRange& range) { |
| if (munmap(range.addr, range.length) == -1) { |
| PLOG(ERROR) << "munmap(" << range.addr << ", " << range.length << ") failed"; |
| } |
| }); |
| pMap->ranges.clear(); |
| } |