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Add misc_writer.

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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
This commit is contained in:
Tao Bao 2019-05-16 14:42:42 -07:00
parent e7a0262c14
commit 7ae0169842
6 changed files with 259 additions and 14 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
bootloader_message/Android.bp
View file

@ -14,10 +14,8 @@
// limitations under the License.
//
cc_library {
name: "libbootloader_message",
recovery_available: true,
host_supported: true,
cc_defaults {
name: "libbootloader_message_defaults",
srcs: ["bootloader_message.cpp"],
cflags: [
"-Wall",
@ -26,24 +24,36 @@ cc_library {
shared_libs: [
"libbase",
],
static_libs: [
"libfstab",
],
export_include_dirs: ["include"],
}
cc_library {
name: "libbootloader_message",
defaults: [
"libbootloader_message_defaults",
],
recovery_available: true,
host_supported: true,
target: {
android: {
shared_libs: [
"libfs_mgr",
],
},
host: {
shared_libs: [
"libcutils", // for strlcpy
],
static_libs: [
"libfstab",
],
},
darwin: {
enabled: false,
},
}
}
cc_library_static {
name: "libbootloader_message_vendor",
defaults: [
"libbootloader_message_defaults",
],
vendor: true,
}

42
bootloader_message/bootloader_message.cpp
View file

@ -21,6 +21,7 @@
#include <string.h>
#include <string>
#include <string_view>
#include <vector>
#include <android-base/file.h>
@ -36,7 +37,17 @@
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";
@ -242,6 +253,37 @@ 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);

13
bootloader_message/include/bootloader_message/bootloader_message.h
View file

@ -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)
*
@ -233,6 +234,14 @@ 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>

40
misc_writer/Android.bp Normal file
View file

@ -0,0 +1,40 @@
//
// 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
misc_writer/misc_writer.cpp Normal file
View file

@ -0,0 +1,106 @@
/*
* 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;
}

38
tests/unit/bootloader_message_test.cpp
View file

@ -15,6 +15,7 @@
*/
#include <string>
#include <string_view>
#include <vector>
#include <android-base/file.h>
@ -22,6 +23,10 @@
#include <bootloader_message/bootloader_message.h>
#include <gtest/gtest.h>
using namespace std::string_literals;
extern void SetMiscBlockDeviceForTest(std::string_view misc_device);
TEST(BootloaderMessageTest, read_and_write_bootloader_message) {
TemporaryFile temp_misc;
@ -114,3 +119,36 @@ TEST(BootloaderMessageTest, update_bootloader_message_recovery_options_long) {
std::string(boot.reserved, sizeof(boot.reserved)));
}
TEST(BootloaderMessageTest, WriteMiscPartitionVendorSpace) {
TemporaryFile temp_misc;
ASSERT_TRUE(android::base::WriteStringToFile(std::string(4096, '\x00'), temp_misc.path));
SetMiscBlockDeviceForTest(temp_misc.path);
constexpr std::string_view kTestMessage = "kTestMessage";
std::string err;
ASSERT_TRUE(WriteMiscPartitionVendorSpace(kTestMessage.data(), kTestMessage.size(), 0, &err));
std::string message;
message.resize(kTestMessage.size());
ASSERT_TRUE(ReadMiscPartitionVendorSpace(message.data(), message.size(), 0, &err));
ASSERT_EQ(kTestMessage, message);
// Write with an offset.
ASSERT_TRUE(WriteMiscPartitionVendorSpace("\x00\x00", 2, 5, &err));
ASSERT_TRUE(ReadMiscPartitionVendorSpace(message.data(), message.size(), 0, &err));
ASSERT_EQ("kTest\x00\x00ssage"s, message);
// Write with the right size.
auto start_offset =
WIPE_PACKAGE_OFFSET_IN_MISC - VENDOR_SPACE_OFFSET_IN_MISC - kTestMessage.size();
ASSERT_TRUE(
WriteMiscPartitionVendorSpace(kTestMessage.data(), kTestMessage.size(), start_offset, &err));
// Out-of-bound write.
ASSERT_FALSE(WriteMiscPartitionVendorSpace(kTestMessage.data(), kTestMessage.size(),
start_offset + 1, &err));
// Message won't fit.
std::string long_message(WIPE_PACKAGE_OFFSET_IN_MISC - VENDOR_SPACE_OFFSET_IN_MISC + 1, 'a');
ASSERT_FALSE(WriteMiscPartitionVendorSpace(long_message.data(), long_message.size(), 0, &err));
}