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Commit 35e0f6d2 authored by Tao Bao's avatar Tao Bao
Browse files

Add misc_writer.

bootloader_message.h currently divides /misc into four segments. The
space between 2K and 16K is reserved for vendor use (e.g. bootloader
persists flags). This CL adds a vendor tool "misc_writer", to allow
writing data to the vendor space in /misc, before getting a dedicated
HAL for accessing /misc partition (b/131775112).

Targets need to explicitly include the module, then invoke the
executable to write data. For example, the following command will write
3-byte data ("0xABCDEF") to offset 4 in vendor space (i.e. 2048 + 4 in
/misc).
$ /vendor/bin/misc_writer --vendor-space-offset 4 --hex-string 0xABCDEF

Bug: 132906936
Test: Run recovery_unit_test on crosshatch.
Test: Call the command via init.hardware.rc on crosshatch. Check that
      the call finishes successfully. Then check the contents written to
      /misc (`dd bs=1 skip=2048 if=/dev/block/sda2 count=32 | xxd`).
Change-Id: I79548fc63fc79b705a0320868690569c3106949f
Merged-In: I79548fc63fc79b705a0320868690569c3106949f
(cherry picked from commit 7ae01698)
parent 9681eef5
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+21 −4
Original line number Diff line number Diff line
@@ -14,9 +14,8 @@
// limitations under the License.
//

cc_library {
    name: "libbootloader_message",
    recovery_available: true,
cc_defaults {
    name: "libbootloader_message_defaults",
    srcs: ["bootloader_message.cpp"],
    cflags: [
        "-Wall",
@@ -24,7 +23,25 @@ cc_library {
    ],
    shared_libs: [
        "libbase",
        "libfs_mgr",
    ],
    static_libs: [
        "libfstab",
    ],
    export_include_dirs: ["include"],
}

cc_library {
    name: "libbootloader_message",
    defaults: [
        "libbootloader_message_defaults",
    ],
    recovery_available: true,
}

cc_library_static {
    name: "libbootloader_message_vendor",
    defaults: [
        "libbootloader_message_defaults",
    ],
    vendor: true,
}
+42 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@
#include <string.h>

#include <string>
#include <string_view>
#include <vector>

#include <android-base/file.h>
@@ -32,7 +33,17 @@
using android::fs_mgr::Fstab;
using android::fs_mgr::ReadDefaultFstab;

static std::string g_misc_device_for_test;

// Exposed for test purpose.
void SetMiscBlockDeviceForTest(std::string_view misc_device) {
  g_misc_device_for_test = misc_device;
}

static std::string get_misc_blk_device(std::string* err) {
  if (!g_misc_device_for_test.empty()) {
    return g_misc_device_for_test;
  }
  Fstab fstab;
  if (!ReadDefaultFstab(&fstab)) {
    *err = "failed to read default fstab";
@@ -228,6 +239,37 @@ bool write_wipe_package(const std::string& package_data, std::string* err) {
                              WIPE_PACKAGE_OFFSET_IN_MISC, err);
}

static bool OffsetAndSizeInVendorSpace(size_t offset, size_t size) {
  auto total_size = WIPE_PACKAGE_OFFSET_IN_MISC - VENDOR_SPACE_OFFSET_IN_MISC;
  return size <= total_size && offset <= total_size - size;
}

bool ReadMiscPartitionVendorSpace(void* data, size_t size, size_t offset, std::string* err) {
  if (!OffsetAndSizeInVendorSpace(offset, size)) {
    *err = android::base::StringPrintf("Out of bound read (offset %zu size %zu)", offset, size);
    return false;
  }
  auto misc_blk_device = get_misc_blk_device(err);
  if (misc_blk_device.empty()) {
    return false;
  }
  return read_misc_partition(data, size, misc_blk_device, VENDOR_SPACE_OFFSET_IN_MISC + offset,
                             err);
}

bool WriteMiscPartitionVendorSpace(const void* data, size_t size, size_t offset, std::string* err) {
  if (!OffsetAndSizeInVendorSpace(offset, size)) {
    *err = android::base::StringPrintf("Out of bound write (offset %zu size %zu)", offset, size);
    return false;
  }
  auto misc_blk_device = get_misc_blk_device(err);
  if (misc_blk_device.empty()) {
    return false;
  }
  return write_misc_partition(data, size, misc_blk_device, VENDOR_SPACE_OFFSET_IN_MISC + offset,
                              err);
}

extern "C" bool write_reboot_bootloader(void) {
  std::string err;
  return write_reboot_bootloader(&err);
+11 −2
Original line number Diff line number Diff line
@@ -28,8 +28,9 @@
// 16K - 64K    Used by uncrypt and recovery to store wipe_package for A/B devices
// Note that these offsets are admitted by bootloader,recovery and uncrypt, so they
// are not configurable without changing all of them.
static const size_t BOOTLOADER_MESSAGE_OFFSET_IN_MISC = 0;
static const size_t WIPE_PACKAGE_OFFSET_IN_MISC = 16 * 1024;
constexpr size_t BOOTLOADER_MESSAGE_OFFSET_IN_MISC = 0;
constexpr size_t VENDOR_SPACE_OFFSET_IN_MISC = 2 * 1024;
constexpr size_t WIPE_PACKAGE_OFFSET_IN_MISC = 16 * 1024;

/* Bootloader Message (2-KiB)
 *
@@ -228,6 +229,14 @@ bool read_wipe_package(std::string* package_data, size_t size, std::string* err)
// Write the wipe package into BCB (to offset WIPE_PACKAGE_OFFSET_IN_MISC).
bool write_wipe_package(const std::string& package_data, std::string* err);

// Reads data from the vendor space in /misc partition, with the given offset and size. Note that
// offset is in relative to the start of vendor space.
bool ReadMiscPartitionVendorSpace(void* data, size_t size, size_t offset, std::string* err);

// Writes the given data to the vendor space in /misc partition, at the given offset. Note that
// offset is in relative to the start of the vendor space.
bool WriteMiscPartitionVendorSpace(const void* data, size_t size, size_t offset, std::string* err);

#else

#include <stdbool.h>

misc_writer/Android.bp

0 → 100644
+40 −0
Original line number Diff line number Diff line
//
// Copyright (C) 2019 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.
//

cc_binary {
    name: "misc_writer",
    vendor: true,

    srcs: [
        "misc_writer.cpp",
    ],

    cpp_std: "experimental",

    cflags: [
        "-Wall",
        "-Werror",
    ],

    shared_libs: [
        "libbase",
    ],

    static_libs: [
        "libbootloader_message_vendor",
        "libfstab",
    ],
}
+106 −0
Original line number Diff line number Diff line
/*
 * Copyright (C) 2019 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 <errno.h>
#include <getopt.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>

#include <iostream>
#include <string>
#include <string_view>
#include <vector>

#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <bootloader_message/bootloader_message.h>

using namespace std::string_literals;

static std::vector<uint8_t> ParseHexString(std::string_view hex_string) {
  auto length = hex_string.size();
  if (length % 2 != 0 || length == 0) {
    return {};
  }

  std::vector<uint8_t> result(length / 2);
  for (size_t i = 0; i < length / 2; i++) {
    auto sub = "0x" + std::string(hex_string.substr(i * 2, 2));
    if (!android::base::ParseUint(sub, &result[i])) {
      return {};
    }
  }
  return result;
}

static int Usage(std::string_view name) {
  std::cerr << name << " usage:\n";
  std::cerr << name << " [--vendor-space-offset <offset>] --hex-string 0xABCDEF\n";
  std::cerr << "Writes the given hex string to the specified offset in vendor space in /misc "
               "partition. Offset defaults to 0 if unspecified.\n";
  return EXIT_FAILURE;
}

// misc_writer is a vendor tool that writes data to the vendor space in /misc.
int main(int argc, char** argv) {
  constexpr struct option OPTIONS[] = {
    { "vendor-space-offset", required_argument, nullptr, 0 },
    { "hex-string", required_argument, nullptr, 0 },
    { nullptr, 0, nullptr, 0 },
  };

  // Offset defaults to 0 if unspecified.
  size_t offset = 0;
  std::string_view hex_string;

  int arg;
  int option_index;
  while ((arg = getopt_long(argc, argv, "", OPTIONS, &option_index)) != -1) {
    if (arg != 0) {
      LOG(ERROR) << "Invalid command argument";
      return Usage(argv[0]);
    }
    auto option_name = OPTIONS[option_index].name;
    if (option_name == "vendor-space-offset"s) {
      if (!android::base::ParseUint(optarg, &offset)) {
        LOG(ERROR) << "Failed to parse the offset: " << optarg;
        return Usage(argv[0]);
      }
    } else if (option_name == "hex-string"s) {
      hex_string = optarg;
    }
  }

  if (hex_string.starts_with("0x") || hex_string.starts_with("0X")) {
    hex_string = hex_string.substr(2);
  }
  if (hex_string.empty()) {
    LOG(ERROR) << "Invalid input hex string: " << hex_string;
    return Usage(argv[0]);
  }

  auto data = ParseHexString(hex_string);
  if (data.empty()) {
    LOG(ERROR) << "Failed to parse the input hex string: " << hex_string;
    return EXIT_FAILURE;
  }
  if (std::string err; !WriteMiscPartitionVendorSpace(data.data(), data.size(), offset, &err)) {
    LOG(ERROR) << "Failed to write to misc partition: " << err;
    return EXIT_FAILURE;
  }
  return EXIT_SUCCESS;
}
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