bootcontrol: Add initial support
This patch adds the basic Boot Control HAL implementation that allows
to operate A/B metadata on 'misc' partition. The HAL is based on
Android reference implementation [1] and provides basic functionality
for all interface methods.
This module should be enabled by adding lines to the .mk-file, like:
PRODUCT_PACKAGES += bootctrl.am57x
Also, A/B system updates has to be enabled according to [2] (including
on bootloader side).
Test: run 'bootctl' on target device
[1] bootable/recovery/boot_control
[2] https://source.android.com/devices/tech/ota/ab/ab_implement
Change-Id: I19852920834eeb3e98e7d6acf06a554e2beaa736
Signed-off-by: Ruslan Trofymenko <ruslan.trofymenko@linaro.org>
diff --git a/bootctrl/bootloader_message.h b/bootctrl/bootloader_message.h
new file mode 100644
index 0000000..e5b9489
--- /dev/null
+++ b/bootctrl/bootloader_message.h
@@ -0,0 +1,249 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+
+#ifndef _BOOTLOADER_MESSAGE_H
+#define _BOOTLOADER_MESSAGE_H
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+
+// Spaces used by misc partition are as below:
+// 0 - 2K For bootloader_message
+// 2K - 16K Used by Vendor's bootloader (the 2K - 4K range may be optionally used
+// as bootloader_message_ab struct)
+// 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;
+
+/* Bootloader Message (2-KiB)
+ *
+ * This structure describes the content of a block in flash
+ * that is used for recovery and the bootloader to talk to
+ * each other.
+ *
+ * The command field is updated by linux when it wants to
+ * reboot into recovery or to update radio or bootloader firmware.
+ * It is also updated by the bootloader when firmware update
+ * is complete (to boot into recovery for any final cleanup)
+ *
+ * The status field was used by the bootloader after the completion
+ * of an "update-radio" or "update-hboot" command, which has been
+ * deprecated since Froyo.
+ *
+ * The recovery field is only written by linux and used
+ * for the system to send a message to recovery or the
+ * other way around.
+ *
+ * The stage field is written by packages which restart themselves
+ * multiple times, so that the UI can reflect which invocation of the
+ * package it is. If the value is of the format "#/#" (eg, "1/3"),
+ * the UI will add a simple indicator of that status.
+ *
+ * We used to have slot_suffix field for A/B boot control metadata in
+ * this struct, which gets unintentionally cleared by recovery or
+ * uncrypt. Move it into struct bootloader_message_ab to avoid the
+ * issue.
+ */
+struct bootloader_message {
+ char command[32];
+ char status[32];
+ char recovery[768];
+
+ // The 'recovery' field used to be 1024 bytes. It has only ever
+ // been used to store the recovery command line, so 768 bytes
+ // should be plenty. We carve off the last 256 bytes to store the
+ // stage string (for multistage packages) and possible future
+ // expansion.
+ char stage[32];
+
+ // The 'reserved' field used to be 224 bytes when it was initially
+ // carved off from the 1024-byte recovery field. Bump it up to
+ // 1184-byte so that the entire bootloader_message struct rounds up
+ // to 2048-byte.
+ char reserved[1184];
+};
+
+/**
+ * We must be cautious when changing the bootloader_message struct size,
+ * because A/B-specific fields may end up with different offsets.
+ */
+#if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
+static_assert(sizeof(struct bootloader_message) == 2048,
+ "struct bootloader_message size changes, which may break A/B devices");
+#endif
+
+/**
+ * The A/B-specific bootloader message structure (4-KiB).
+ *
+ * We separate A/B boot control metadata from the regular bootloader
+ * message struct and keep it here. Everything that's A/B-specific
+ * stays after struct bootloader_message, which should be managed by
+ * the A/B-bootloader or boot control HAL.
+ *
+ * The slot_suffix field is used for A/B implementations where the
+ * bootloader does not set the androidboot.ro.boot.slot_suffix kernel
+ * commandline parameter. This is used by fs_mgr to mount /system and
+ * other partitions with the slotselect flag set in fstab. A/B
+ * implementations are free to use all 32 bytes and may store private
+ * data past the first NUL-byte in this field. It is encouraged, but
+ * not mandatory, to use 'struct bootloader_control' described below.
+ *
+ * The update_channel field is used to store the Omaha update channel
+ * if update_engine is compiled with Omaha support.
+ */
+struct bootloader_message_ab {
+ struct bootloader_message message;
+ char slot_suffix[32];
+ char update_channel[128];
+
+ // Round up the entire struct to 4096-byte.
+ char reserved[1888];
+};
+
+/**
+ * Be cautious about the struct size change, in case we put anything post
+ * bootloader_message_ab struct (b/29159185).
+ */
+#if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
+static_assert(sizeof(struct bootloader_message_ab) == 4096,
+ "struct bootloader_message_ab size changes");
+#endif
+
+#define BOOT_CTRL_MAGIC 0x42414342 /* Bootloader Control AB */
+#define BOOT_CTRL_VERSION 1
+
+struct slot_metadata {
+ // Slot priority with 15 meaning highest priority, 1 lowest
+ // priority and 0 the slot is unbootable.
+ uint8_t priority : 4;
+ // Number of times left attempting to boot this slot.
+ uint8_t tries_remaining : 3;
+ // 1 if this slot has booted successfully, 0 otherwise.
+ uint8_t successful_boot : 1;
+ // 1 if this slot is corrupted from a dm-verity corruption, 0
+ // otherwise.
+ uint8_t verity_corrupted : 1;
+ // Reserved for further use.
+ uint8_t reserved : 7;
+} __attribute__((packed));
+
+/* Bootloader Control AB
+ *
+ * This struct can be used to manage A/B metadata. It is designed to
+ * be put in the 'slot_suffix' field of the 'bootloader_message'
+ * structure described above. It is encouraged to use the
+ * 'bootloader_control' structure to store the A/B metadata, but not
+ * mandatory.
+ */
+struct bootloader_control {
+ // NUL terminated active slot suffix.
+ char slot_suffix[4];
+ // Bootloader Control AB magic number (see BOOT_CTRL_MAGIC).
+ uint32_t magic;
+ // Version of struct being used (see BOOT_CTRL_VERSION).
+ uint8_t version;
+ // Number of slots being managed.
+ uint8_t nb_slot : 3;
+ // Number of times left attempting to boot recovery.
+ uint8_t recovery_tries_remaining : 3;
+ // Ensure 4-bytes alignment for slot_info field.
+ uint8_t reserved0[2];
+ // Per-slot information. Up to 4 slots.
+ struct slot_metadata slot_info[4];
+ // Reserved for further use.
+ uint8_t reserved1[8];
+ // CRC32 of all 28 bytes preceding this field (little endian
+ // format).
+ uint32_t crc32_le;
+} __attribute__((packed));
+
+#if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus)
+static_assert(sizeof(struct bootloader_control) ==
+ sizeof(((struct bootloader_message_ab *)0)->slot_suffix),
+ "struct bootloader_control has wrong size");
+#endif
+
+#ifdef __cplusplus
+
+#include <string>
+#include <vector>
+
+// Return the block device name for the bootloader message partition and waits
+// for the device for up to 10 seconds. In case of error returns the empty
+// string.
+std::string get_bootloader_message_blk_device(std::string* err);
+
+// Read bootloader message into boot. Error message will be set in err.
+bool read_bootloader_message(bootloader_message* boot, std::string* err);
+
+// Read bootloader message from the specified misc device into boot.
+bool read_bootloader_message_from(bootloader_message* boot, const std::string& misc_blk_device,
+ std::string* err);
+
+// Read bootloader control block from the specified misc device into boot_ctrl.
+bool read_bootloader_control_from(bootloader_control* boot_ctrl, const std::string& misc_blk_device,
+ std::string* err);
+
+// Write bootloader message to BCB.
+bool write_bootloader_message(const bootloader_message& boot, std::string* err);
+
+// Write bootloader message to the specified BCB device.
+bool write_bootloader_message_to(const bootloader_message& boot,
+ const std::string& misc_blk_device, std::string* err);
+
+// Write bootloader message (boots into recovery with the options) to BCB. Will
+// set the command and recovery fields, and reset the rest.
+bool write_bootloader_message(const std::vector<std::string>& options, std::string* err);
+
+// Write bootloader control block to the specified BCB device.
+bool write_bootloader_control_to(const bootloader_control* boot_ctrl, const std::string& misc_blk_device,
+ std::string* err);
+
+// Update bootloader message (boots into recovery with the options) to BCB. Will
+// only update the command and recovery fields.
+bool update_bootloader_message(const std::vector<std::string>& options, std::string* err);
+
+// Update bootloader message (boots into recovery with the |options|) in |boot|. Will only update
+// the command and recovery fields.
+bool update_bootloader_message_in_struct(bootloader_message* boot,
+ const std::vector<std::string>& options);
+
+// Clear BCB.
+bool clear_bootloader_message(std::string* err);
+
+// Writes the reboot-bootloader reboot reason to the bootloader_message.
+bool write_reboot_bootloader(std::string* err);
+
+// Read the wipe package from BCB (from offset WIPE_PACKAGE_OFFSET_IN_MISC).
+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);
+
+#else
+
+#include <stdbool.h>
+
+// C Interface.
+bool write_bootloader_message(const char* options);
+bool write_reboot_bootloader(void);
+
+#endif // ifdef __cplusplus
+
+#endif // _BOOTLOADER_MESSAGE_H