upload android base code part3

android/bootable/recovery/otautil/SysUtil.cpp

@@ -0,0 +1,202 @@
+/*
+ * 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 <fcntl.h>
+#include <stdint.h>  // SIZE_MAX
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#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>
+
+bool MemMapping::MapFD(int fd) {
+  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;
+  }
+
+  addr = static_cast<unsigned char*>(memPtr);
+  length = sb.st_size;
+  ranges_.clear();
+  ranges_.emplace_back(MappedRange{ 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].
+bool MemMapping::MapBlockFile(const std::string& filename) {
+  std::string content;
+  if (!android::base::ReadFileToString(filename, &content)) {
+    PLOG(ERROR) << "Failed to read " << filename;
+    return false;
+  }
+
+  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 false;
+  }
+
+  size_t size;
+  size_t blksize;
+  if (sscanf(lines[1].c_str(), "%zu %zu", &size, &blksize) != 2) {
+    LOG(ERROR) << "Failed to parse file size and block size: " << lines[1];
+    return false;
+  }
+
+  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 false;
+  }
+
+  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 false;
+  }
+
+  // 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 false;
+  }
+
+  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 false;
+  }
+
+  ranges_.clear();
+
+  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 << ": " << line;
+      success = false;
+      break;
+    }
+    size_t range_size = (end - start) * blksize;
+    if (end <= start || (end - start) > SIZE_MAX / blksize || range_size > remaining_size) {
+      LOG(ERROR) << "Invalid range: " << start << " " << end;
+      success = false;
+      break;
+    }
+
+    void* range_start = mmap64(next, range_size, PROT_READ, MAP_PRIVATE | MAP_FIXED, fd,
+                               static_cast<off64_t>(start) * blksize);
+    if (range_start == MAP_FAILED) {
+      PLOG(ERROR) << "failed to map range " << i << ": " << line;
+      success = false;
+      break;
+    }
+    ranges_.emplace_back(MappedRange{ range_start, range_size });
+
+    next += range_size;
+    remaining_size -= range_size;
+  }
+  if (success && remaining_size != 0) {
+    LOG(ERROR) << "Invalid ranges: remaining_size " << remaining_size;
+    success = false;
+  }
+  if (!success) {
+    munmap(reserve, blocks * blksize);
+    return false;
+  }
+
+  addr = static_cast<unsigned char*>(reserve);
+  length = size;
+
+  LOG(INFO) << "mmapped " << range_count << " ranges";
+
+  return true;
+}
+
+bool MemMapping::MapFile(const std::string& fn) {
+  if (fn.empty()) {
+    LOG(ERROR) << "Empty filename";
+    return false;
+  }
+
+  if (fn[0] == '@') {
+    // Block map file "@/cache/recovery/block.map".
+    if (!MapBlockFile(fn.substr(1))) {
+      LOG(ERROR) << "Map of '" << fn << "' failed";
+      return false;
+    }
+  } else {
+    // This is a regular file.
+    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(fn.c_str(), O_RDONLY)));
+    if (fd == -1) {
+      PLOG(ERROR) << "Unable to open '" << fn << "'";
+      return false;
+    }
+
+    if (!MapFD(fd)) {
+      LOG(ERROR) << "Map of '" << fn << "' failed";
+      return false;
+    }
+  }
+  return true;
+}
+
+MemMapping::~MemMapping() {
+  for (const auto& range : ranges_) {
+    if (munmap(range.addr, range.length) == -1) {
+      PLOG(ERROR) << "Failed to munmap(" << range.addr << ", " << range.length << ")";
+    }
+  };
+  ranges_.clear();
+}