3 files changed, 404 insertions, 0 deletions

diff --git a/bootloader_message/Android.mk b/bootloader_message/Android.mk
new file mode 100644
index 000000000..815ac67d7
--- /dev/null
+++ b/bootloader_message/Android.mk
@@ -0,0 +1,24 @@
+# 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.
+
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+LOCAL_CLANG := true
+LOCAL_SRC_FILES := bootloader_message.cpp
+LOCAL_MODULE := libbootloader_message
+LOCAL_STATIC_LIBRARIES := libbase libfs_mgr
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
+include $(BUILD_STATIC_LIBRARY)
diff --git a/bootloader_message/bootloader_message.cpp b/bootloader_message/bootloader_message.cpp
new file mode 100644
index 000000000..e7195ae9d
--- /dev/null
+++ b/bootloader_message/bootloader_message.cpp
@@ -0,0 +1,181 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <bootloader_message/bootloader_message.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/system_properties.h>
+
+#include <string>
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
+#include <fs_mgr.h>
+
+static struct fstab* read_fstab(std::string* err) {
+  // The fstab path is always "/fstab.${ro.hardware}".
+  std::string fstab_path = "/fstab.";
+  char value[PROP_VALUE_MAX];
+  if (__system_property_get("ro.hardware", value) == 0) {
+    *err = "failed to get ro.hardware";
+    return nullptr;
+  }
+  fstab_path += value;
+  struct fstab* fstab = fs_mgr_read_fstab(fstab_path.c_str());
+  if (fstab == nullptr) {
+    *err = "failed to read " + fstab_path;
+  }
+  return fstab;
+}
+
+static std::string get_misc_blk_device(std::string* err) {
+  struct fstab* fstab = read_fstab(err);
+  if (fstab == nullptr) {
+    return "";
+  }
+  fstab_rec* record = fs_mgr_get_entry_for_mount_point(fstab, "/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, size_t offset, std::string* err) {
+  std::string misc_blk_device = get_misc_blk_device(err);
+  if (misc_blk_device.empty()) {
+    return false;
+  }
+  if (!wait_for_device(misc_blk_device, err)) {
+    return false;
+  }
+  android::base::unique_fd fd(open(misc_blk_device.c_str(), O_WRONLY | O_SYNC));
+  if (fd.get() == -1) {
+    *err = android::base::StringPrintf("failed to open %s: %s", misc_blk_device.c_str(),
+                                       strerror(errno));
+    return false;
+  }
+  if (lseek(fd.get(), 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.get(), 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, size_t offset, std::string* err) {
+  std::string misc_blk_device = get_misc_blk_device(err);
+  if (misc_blk_device.empty()) {
+    return false;
+  }
+  android::base::unique_fd fd(open(misc_blk_device.c_str(), O_WRONLY | O_SYNC));
+  if (fd.get() == -1) {
+    *err = android::base::StringPrintf("failed to open %s: %s", misc_blk_device.c_str(),
+                                       strerror(errno));
+    return false;
+  }
+  if (lseek(fd.get(), 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.get(), p, size)) {
+    *err = android::base::StringPrintf("failed to write %s: %s", misc_blk_device.c_str(),
+                                       strerror(errno));
+    return false;
+  }
+
+  // TODO: O_SYNC and fsync duplicates each other?
+  if (fsync(fd.get()) == -1) {
+    *err = android::base::StringPrintf("failed to fsync %s: %s", misc_blk_device.c_str(),
+                                       strerror(errno));
+    return false;
+  }
+  return true;
+}
+
+bool read_bootloader_message(bootloader_message* boot, std::string* err) {
+  return read_misc_partition(boot, sizeof(*boot), BOOTLOADER_MESSAGE_OFFSET_IN_MISC, err);
+}
+
+bool write_bootloader_message(const bootloader_message& boot, std::string* err) {
+  return write_misc_partition(&boot, sizeof(boot), BOOTLOADER_MESSAGE_OFFSET_IN_MISC, 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 = {};
+  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 write_bootloader_message(boot, err);
+}
+
+bool read_wipe_package(std::string* package_data, size_t size, std::string* err) {
+  package_data->resize(size);
+  return read_misc_partition(&(*package_data)[0], size, WIPE_PACKAGE_OFFSET_IN_MISC, err);
+}
+
+bool write_wipe_package(const std::string& package_data, std::string* err) {
+  return write_misc_partition(package_data.data(), package_data.size(),
+                              WIPE_PACKAGE_OFFSET_IN_MISC, err);
+}
+
+extern "C" bool write_bootloader_message(const char* options) {
+  std::string err;
+  return write_bootloader_message({options}, &err);
+}
diff --git a/bootloader_message/include/bootloader_message/bootloader_message.h b/bootloader_message/include/bootloader_message/bootloader_message.h
new file mode 100644
index 000000000..f343c64ac
--- /dev/null
+++ b/bootloader_message/include/bootloader_message/bootloader_message.h
@@ -0,0 +1,199 @@
+/*
+ * 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 is written by the bootloader after the
+ * completion of an "update-radio" or "update-hboot" command.
+ *
+ * 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.
+ */
+struct bootloader_message_ab {
+    struct bootloader_message message;
+    char slot_suffix[32];
+
+    // Round up the entire struct to 4096-byte.
+    char reserved[2016];
+};
+
+/**
+ * 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>
+
+bool read_bootloader_message(bootloader_message* boot, std::string* err);
+bool write_bootloader_message(const bootloader_message& boot, std::string* err);
+bool write_bootloader_message(const std::vector<std::string>& options, std::string* err);
+bool clear_bootloader_message(std::string* err);
+
+bool read_wipe_package(std::string* package_data, size_t size, std::string* err);
+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);
+
+#endif  // ifdef __cplusplus
+
+#endif  // _BOOTLOADER_MESSAGE_H