diff options
Diffstat (limited to 'bootctrl/bootloader_message.cpp')
-rw-r--r-- | bootctrl/bootloader_message.cpp | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/bootctrl/bootloader_message.cpp b/bootctrl/bootloader_message.cpp new file mode 100644 index 0000000..a4634ed --- /dev/null +++ b/bootctrl/bootloader_message.cpp @@ -0,0 +1,249 @@ +/* + * Copyright (C) 2016 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 "bootloader_message.h" + +#include <errno.h> +#include <fcntl.h> +#include <string.h> + +#include <string> +#include <vector> + +#include <android-base/file.h> +#include <android-base/properties.h> +#include <android-base/stringprintf.h> +#include <android-base/unique_fd.h> +#include <fstab/fstab.h> + +constexpr off_t kBootloaderControlOffset = offsetof(bootloader_message_ab, slot_suffix); + +static std::string get_misc_blk_device(std::string* err) { + std::unique_ptr<fstab, decltype(&fs_mgr_free_fstab)> fstab(fs_mgr_read_fstab_default(), + fs_mgr_free_fstab); + if (!fstab) { + *err = "failed to read default fstab"; + return ""; + } + fstab_rec* record = fs_mgr_get_entry_for_mount_point(fstab.get(), "/misc"); + if (record == nullptr) { + *err = "failed to find /misc partition"; + return ""; + } + return record->blk_device; +} + +// In recovery mode, recovery can get started and try to access the misc +// device before the kernel has actually created it. +static bool wait_for_device(const std::string& blk_device, std::string* err) { + int tries = 0; + int ret; + err->clear(); + do { + ++tries; + struct stat buf; + ret = stat(blk_device.c_str(), &buf); + if (ret == -1) { + *err += android::base::StringPrintf("failed to stat %s try %d: %s\n", + blk_device.c_str(), tries, strerror(errno)); + sleep(1); + } + } while (ret && tries < 10); + + if (ret) { + *err += android::base::StringPrintf("failed to stat %s\n", blk_device.c_str()); + } + return ret == 0; +} + +static bool read_misc_partition(void* p, size_t size, const std::string& misc_blk_device, + size_t offset, std::string* err) { + if (!wait_for_device(misc_blk_device, err)) { + return false; + } + android::base::unique_fd fd(open(misc_blk_device.c_str(), O_RDONLY)); + if (fd == -1) { + *err = android::base::StringPrintf("failed to open %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + if (lseek(fd, static_cast<off_t>(offset), SEEK_SET) != static_cast<off_t>(offset)) { + *err = android::base::StringPrintf("failed to lseek %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + if (!android::base::ReadFully(fd, p, size)) { + *err = android::base::StringPrintf("failed to read %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + return true; +} + +static bool write_misc_partition(const void* p, size_t size, const std::string& misc_blk_device, + size_t offset, std::string* err) { + android::base::unique_fd fd(open(misc_blk_device.c_str(), O_WRONLY)); + if (fd == -1) { + *err = android::base::StringPrintf("failed to open %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + if (lseek(fd, static_cast<off_t>(offset), SEEK_SET) != static_cast<off_t>(offset)) { + *err = android::base::StringPrintf("failed to lseek %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + if (!android::base::WriteFully(fd, p, size)) { + *err = android::base::StringPrintf("failed to write %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + if (fsync(fd) == -1) { + *err = android::base::StringPrintf("failed to fsync %s: %s", misc_blk_device.c_str(), + strerror(errno)); + return false; + } + return true; +} + +std::string get_bootloader_message_blk_device(std::string* err) { + std::string misc_blk_device = get_misc_blk_device(err); + if (misc_blk_device.empty()) return ""; + if (!wait_for_device(misc_blk_device, err)) return ""; + return misc_blk_device; +} + +bool read_bootloader_message_from(bootloader_message* boot, const std::string& misc_blk_device, + std::string* err) { + return read_misc_partition(boot, sizeof(*boot), misc_blk_device, + BOOTLOADER_MESSAGE_OFFSET_IN_MISC, err); +} + +bool read_bootloader_message(bootloader_message* boot, std::string* err) { + std::string misc_blk_device = get_misc_blk_device(err); + if (misc_blk_device.empty()) { + return false; + } + return read_bootloader_message_from(boot, misc_blk_device, err); +} + +bool read_bootloader_control_from(bootloader_control* boot_ctrl, const std::string& misc_blk_device, + std::string* err) { + return read_misc_partition(boot_ctrl, sizeof(bootloader_control), misc_blk_device, + kBootloaderControlOffset, err); +} + +bool write_bootloader_message_to(const bootloader_message& boot, const std::string& misc_blk_device, + std::string* err) { + return write_misc_partition(&boot, sizeof(boot), misc_blk_device, + BOOTLOADER_MESSAGE_OFFSET_IN_MISC, err); +} + +bool write_bootloader_message(const bootloader_message& boot, std::string* err) { + std::string misc_blk_device = get_misc_blk_device(err); + if (misc_blk_device.empty()) { + return false; + } + return write_bootloader_message_to(boot, misc_blk_device, err); +} + +bool write_bootloader_control_to(const bootloader_control* boot_ctrl, const std::string& misc_blk_device, + std::string* err) { + return write_misc_partition(boot_ctrl, sizeof(bootloader_control), misc_blk_device, + kBootloaderControlOffset, err); +} + +bool clear_bootloader_message(std::string* err) { + bootloader_message boot = {}; + return write_bootloader_message(boot, err); +} + +bool write_bootloader_message(const std::vector<std::string>& options, std::string* err) { + bootloader_message boot = {}; + update_bootloader_message_in_struct(&boot, options); + + return write_bootloader_message(boot, err); +} + +bool update_bootloader_message(const std::vector<std::string>& options, std::string* err) { + bootloader_message boot; + if (!read_bootloader_message(&boot, err)) { + return false; + } + update_bootloader_message_in_struct(&boot, options); + + return write_bootloader_message(boot, err); +} + +bool update_bootloader_message_in_struct(bootloader_message* boot, + const std::vector<std::string>& options) { + if (!boot) return false; + // Replace the command & recovery fields. + memset(boot->command, 0, sizeof(boot->command)); + memset(boot->recovery, 0, sizeof(boot->recovery)); + + strlcpy(boot->command, "boot-recovery", sizeof(boot->command)); + strlcpy(boot->recovery, "recovery\n", sizeof(boot->recovery)); + for (const auto& s : options) { + strlcat(boot->recovery, s.c_str(), sizeof(boot->recovery)); + if (s.back() != '\n') { + strlcat(boot->recovery, "\n", sizeof(boot->recovery)); + } + } + return true; +} + +bool write_reboot_bootloader(std::string* err) { + bootloader_message boot; + if (!read_bootloader_message(&boot, err)) { + return false; + } + if (boot.command[0] != '\0') { + *err = "Bootloader command pending."; + return false; + } + strlcpy(boot.command, "bootonce-bootloader", sizeof(boot.command)); + return write_bootloader_message(boot, err); +} + +bool read_wipe_package(std::string* package_data, size_t size, std::string* err) { + std::string misc_blk_device = get_misc_blk_device(err); + if (misc_blk_device.empty()) { + return false; + } + package_data->resize(size); + return read_misc_partition(&(*package_data)[0], size, misc_blk_device, + WIPE_PACKAGE_OFFSET_IN_MISC, err); +} + +bool write_wipe_package(const std::string& package_data, std::string* err) { + std::string misc_blk_device = get_misc_blk_device(err); + if (misc_blk_device.empty()) { + return false; + } + return write_misc_partition(package_data.data(), package_data.size(), misc_blk_device, + WIPE_PACKAGE_OFFSET_IN_MISC, err); +} + +extern "C" bool write_reboot_bootloader(void) { + std::string err; + return write_reboot_bootloader(&err); +} + +extern "C" bool write_bootloader_message(const char* options) { + std::string err; + return write_bootloader_message({options}, &err); +} |