【转】Android OTA 升级之一：编译升级包

Android OTA 升级之一：编译升级包

作者： 宋立新

Email ： zjujoe@yahoo.com

前言

       OTA 升级是 Android 系统提供的标准软件升级方式。 它功能强大，提供了完全升级、增量升级模式，可以通过 SD 卡升级，也可以通过网络升级。

       这里，我们先研究最简单的情况，通过 SD 卡进行完全升级。

       如何执行升级就不多说了，网上有很多资料。（比如，介绍 HTC 手机如何升级）。我们感兴趣的是它是如何实现的，作为开发者，如何修改它以符合我们的定制化需求。

       首先，我们研究一下 ota 升级包的编译过程。

Quick start

       首先编译出 android, 然后执行：

make otapackage

    即可获得： out/target/product/{product_name}/ {product_name} -ota-eng.{uid}.zip

    将该文件改名为 update.zip 放到 T 卡根目录 , 即可开始 recovery 模式下的 OTA 升级。

编译过程研究

 

主要分两步，第一步， 会准备一个包，其中包含升级需要的内容 ( 原材料 ) ，比如， system 目录。

第二步，运行 python 脚本 ./build/tools/releasetools/ota_from_target_files ，以步骤一准备的 ZIP 包作为输入，最终生成需要的升级包。

 

步骤一

编译脚本如下 :

(From: build/core/Makefile)

 

 

1073 # Depending on the various images guarantees that the underlying
1074 # directories are up-to-date.
1075 $(BUILT_TARGET_FILES_PACKAGE): /
1076                 $(INSTALLED_BOOTIMAGE_TARGET) /
1077                 $(INSTALLED_RADIOIMAGE_TARGET) /
1078                 $(INSTALLED_RECOVERYIMAGE_TARGET) /
1079                 $(INSTALLED_FACTORYIMAGE_TARGET) /
1080                 $(INSTALLED_SYSTEMIMAGE) /
1081                 $(INSTALLED_USERDATAIMAGE_TARGET) /
1082                 $(INSTALLED_SECROIMAGE_TARGET) /
1083                 $(INSTALLED_ANDROID_INFO_TXT_TARGET) /
1084                 $(built_ota_tools) /
1085                 $(APKCERTS_FILE) /
1086                 $(HOST_OUT_EXECUTABLES)/fs_config /
1087                 | $(ACP)
1088         @echo "Package target files: $@"
1089         $(hide) rm -rf $@ $(zip_root)
1090         $(hide) mkdir -p $(dir $@) $(zip_root)
1091         @# Components of the recovery image
1092         $(hide) mkdir -p $(zip_root)/RECOVERY
1093         $(hide) $(call package_files-copy-root, /
1094                 $(TARGET_RECOVERY_ROOT_OUT),$(zip_root)/RECOVERY/RAMDISK)
1095 ifdef INSTALLED_KERNEL_TARGET
1096         $(hide) $(ACP) $(INSTALLED_KERNEL_TARGET) $(zip_root)/RECOVERY/kernel
1097         $(hide) $(ACP) $(recovery_ramdisk) $(zip_root)/RECOVERY/ramdisk
1098 endif
1099 ifdef INSTALLED_2NDBOOTLOADER_TARGET
1100         $(hide) $(ACP) /
1101                 $(INSTALLED_2NDBOOTLOADER_TARGET) $(zip_root)/RECOVERY/second
1102 endif
1103 ifdef BOARD_KERNEL_CMDLINE
1104         $(hide) echo "$(BOARD_KERNEL_CMDLINE)"  > $(zip_root)/RECOVERY/cmdline
1105 endif
1106 ifdef BOARD_KERNEL_BASE
1107         $(hide) echo "$(BOARD_KERNEL_BASE)"  > $(zip_root)/RECOVERY/ base
1108 endif
1109         @# Components of the factory image
1110         $(hide) mkdir -p $(zip_root)/FACTORY
1111         $(hide) $(call package_files-copy-root, /
1112                 $(TARGET_FACTORY_ROOT_OUT),$(zip_root)/FACTORY/RAMDISK)
1113 ifdef INSTALLED_KERNEL_TARGET
1114         $(hide) $(ACP) $(INSTALLED_KERNEL_TARGET) $(zip_root)/FACTORY/kernel
1115 endif
1116 ifdef INSTALLED_2NDBOOTLOADER_TARGET
1117         $(hide) $(ACP) /
1118                 $(INSTALLED_2NDBOOTLOADER_TARGET) $(zip_root)/FACTORY/second
1119 endif
1120 ifdef BOARD_KERNEL_CMDLINE
1121         $(hide) echo "$(BOARD_KERNEL_CMDLINE)"  > $(zip_root)/FACTORY/cmdline
1122 endif
1123 ifdef BOARD_KERNEL_BASE
1124         $(hide) echo "$(BOARD_KERNEL_BASE)"  > $(zip_root)/FACTORY/ base
1125 endif
1126         @# Components of the boot image
1127         $(hide) mkdir -p $(zip_root)/BOOT
1128         $(hide) $(call package_files-copy-root, /
1129                 $(TARGET_ROOT_OUT),$(zip_root)/BOOT/RAMDISK)
1130 ifdef INSTALLED_KERNEL_TARGET
1131         $(hide) $(ACP) $(INSTALLED_KERNEL_TARGET) $(zip_root)/BOOT/kernel
1132         $(hide) $(ACP) $(INSTALLED_RAMDISK_TARGET) $(zip_root)/BOOT/ramdisk
1133 endif
1134 ifdef INSTALLED_2NDBOOTLOADER_TARGET
1135         $(hide) $(ACP) /
1136                 $(INSTALLED_2NDBOOTLOADER_TARGET) $(zip_root)/BOOT/second
1137 endif
1138 ifdef BOARD_KERNEL_CMDLINE
1139         $(hide) echo "$(BOARD_KERNEL_CMDLINE)"  > $(zip_root)/BOOT/cmdline
1140 endif
1141 ifdef BOARD_KERNEL_BASE
1142         $(hide) echo "$(BOARD_KERNEL_BASE)"  > $(zip_root)/BOOT/ base
1143 endif
1144         $(hide) $(foreach  t,$(INSTALLED_RADIOIMAGE_TARGET),/
1145                     mkdir -p $(zip_root)/RADIO; /
1146                     $(ACP) $(t) $(zip_root)/RADIO/$(notdir $(t));)
1147         @# Contents of the system image
1148         $(hide) $(call package_files-copy-root, /
1149                 $(SYSTEMIMAGE_SOURCE_DIR),$(zip_root)/SYSTEM)
1150         @# Contents of the data image
1151         $(hide) $(call package_files-copy-root, /
1152                 $(TARGET_OUT_DATA),$(zip_root)/DATA)
1153         @# Extra contents of the OTA package
1154         $(hide) mkdir -p $(zip_root)/OTA/bin
1155         $(hide) $(ACP) $(INSTALLED_ANDROID_INFO_TXT_TARGET) $(zip_root)/OTA/
1156         $(hide) $(ACP) $(PRIVATE_OTA_TOOLS) $(zip_root)/OTA/bin/
1157         @# Files that do  not end up  in  any images, but are necessary to
1158         @# build them.
1159         $(hide) mkdir -p $(zip_root)/META
1160         $(hide) $(ACP) $(APKCERTS_FILE) $(zip_root)/META/apkcerts.txt
1161         $(hide) echo "$(PRODUCT_OTA_PUBLIC_KEYS)"  > $(zip_root)/META/otakeys.txt
1162         $(hide) echo "$(PRIVATE_RECOVERY_API_VERSION)"  > $(zip_root)/META/recovery-api-version.txt
1163         $(hide) echo "blocksize $(BOARD_FLASH_BLOCK_SIZE)" > $(zip_root)/META/imagesizes.txt
1164         $(hide) echo "boot $(call image-size-from-data-size,$(BOARD_BOOTIMAGE_PARTITION_SIZE))"  >> $(zip_root)/META/imagesizes.txt
1165         $(hide) echo "recovery $(call image-size-from-data-size,$(BOARD_RECOVERYIMAGE_PARTITION_SIZE))"  >> $(zip_root)/META/imagesizes.txt
1166         $(hide) echo "system $(call image-size-from-data-size,$(BOARD_SYSTEMIMAGE_PARTITION_SIZE))"  >> $(zip_root)/META/imagesizes.txt
1167         $(hide) echo "secro $(call image-size-from-data-size,$(BOARD_SECROIMAGE_PARTITION_SIZE))"  >> $(zip_root)/META/imagesizes.txt
1168         $(hide) echo "userdata $(call image-size-from-data-size,$(BOARD_USERDATAIMAGE_PARTITION_SIZE))"  >> $(zip_root)/META/imagesizes.txt
1169         $(hide) echo "$(tool_extensions)"  > $(zip_root)/META/tool-extensions.txt
1170         @# Zip everything up, preserving symlinks
1171         $(hide) (cd $(zip_root) && zip -qry ../$(notdir $@) .)
1172         @# Run fs_config on all the system files in  the zip, and save the output
1173         $(hide) zipinfo -1 $@ | awk -F/ 'BEGIN { OFS="/" } /^SYSTEM/// {$$1 = "system"; print}' | $(HOST_OUT_EXECUTABLES)/fs_config > $(zip_root)/META/filesystem_config.txt
1174         $(hide) (cd $(zip_root) && zip -q ../$(notdir $@) META/filesystem_config.txt)

1073
 # Depending on the various images guarantees that the underlying
1074 # directories are up-to-date.
1075 $(BUILT_TARGET_FILES_PACKAGE): /
1076                 $(INSTALLED_BOOTIMAGE_TARGET) /
1077                 $(INSTALLED_RADIOIMAGE_TARGET) /
1078                 $(INSTALLED_RECOVERYIMAGE_TARGET) /
1079                 $(INSTALLED_FACTORYIMAGE_TARGET) /
1080                 $(INSTALLED_SYSTEMIMAGE) /
1081                 $(INSTALLED_USERDATAIMAGE_TARGET) /
1082                 $(INSTALLED_SECROIMAGE_TARGET) /
1083                 $(INSTALLED_ANDROID_INFO_TXT_TARGET) /
1084                 $(built_ota_tools) /
1085                 $(APKCERTS_FILE) /
1086                 $(HOST_OUT_EXECUTABLES)/fs_config /
1087                 | $(ACP)
1088         @echo "Package target files: $@"
1089         $(hide) rm -rf $@ $(zip_root)
1090         $(hide) mkdir -p $(dir $@) $(zip_root)
1091         @# Components of the recovery image
1092         $(hide) mkdir -p $(zip_root)/RECOVERY
1093         $(hide) $(call package_files-copy-root, /
1094
$(TARGET_RECOVERY_ROOT_OUT),$(zip_root)/RECOVERY/RAMDISK)
1095 ifdef INSTALLED_KERNEL_TARGET
1096         $(hide) $(ACP) $(INSTALLED_KERNEL_TARGET)
$(zip_root)/RECOVERY/kernel
1097         $(hide) $(ACP) $(recovery_ramdisk)
$(zip_root)/RECOVERY/ramdisk
1098 endif
1099 ifdef INSTALLED_2NDBOOTLOADER_TARGET
1100         $(hide) $(ACP) /
1101                 $(INSTALLED_2NDBOOTLOADER_TARGET)
$(zip_root)/RECOVERY/second
1102 endif
1103 ifdef BOARD_KERNEL_CMDLINE
1104         $(hide) echo "$(BOARD_KERNEL_CMDLINE)" >
$(zip_root)/RECOVERY/cmdline
1105 endif
1106 ifdef BOARD_KERNEL_BASE
1107         $(hide) echo "$(BOARD_KERNEL_BASE)" >
$(zip_root)/RECOVERY/base
1108 endif
1109         @# Components of the factory image
1110         $(hide) mkdir -p $(zip_root)/FACTORY
1111         $(hide) $(call package_files-copy-root, /
1112
$(TARGET_FACTORY_ROOT_OUT),$(zip_root)/FACTORY/RAMDISK)
1113 ifdef INSTALLED_KERNEL_TARGET
1114         $(hide) $(ACP) $(INSTALLED_KERNEL_TARGET)
$(zip_root)/FACTORY/kernel
1115 endif
1116 ifdef INSTALLED_2NDBOOTLOADER_TARGET
1117         $(hide) $(ACP) /
1118                 $(INSTALLED_2NDBOOTLOADER_TARGET)
$(zip_root)/FACTORY/second
1119 endif
1120 ifdef BOARD_KERNEL_CMDLINE
1121         $(hide) echo "$(BOARD_KERNEL_CMDLINE)" >
$(zip_root)/FACTORY/cmdline
1122 endif
1123 ifdef BOARD_KERNEL_BASE
1124         $(hide) echo "$(BOARD_KERNEL_BASE)" >
$(zip_root)/FACTORY/base
1125 endif
1126         @# Components of the boot image
1127         $(hide) mkdir -p $(zip_root)/BOOT
1128         $(hide) $(call package_files-copy-root, /
1129                 $(TARGET_ROOT_OUT),$(zip_root)/BOOT/RAMDISK)
1130 ifdef INSTALLED_KERNEL_TARGET
1131         $(hide) $(ACP) $(INSTALLED_KERNEL_TARGET)
$(zip_root)/BOOT/kernel
1132         $(hide) $(ACP) $(INSTALLED_RAMDISK_TARGET)
$(zip_root)/BOOT/ramdisk
1133 endif
1134 ifdef INSTALLED_2NDBOOTLOADER_TARGET
1135         $(hide) $(ACP) /
1136                 $(INSTALLED_2NDBOOTLOADER_TARGET)
$(zip_root)/BOOT/second
1137 endif
1138 ifdef BOARD_KERNEL_CMDLINE
1139         $(hide) echo "$(BOARD_KERNEL_CMDLINE)" >
$(zip_root)/BOOT/cmdline
1140 endif
1141 ifdef BOARD_KERNEL_BASE
1142         $(hide) echo "$(BOARD_KERNEL_BASE)" >
$(zip_root)/BOOT/base
1143 endif
1144         $(hide) $(foreach t,$(INSTALLED_RADIOIMAGE_TARGET),/
1145                     mkdir -p $(zip_root)/RADIO; /
1146                     $(ACP) $(t) $(zip_root)/RADIO/$(notdir $(t));)
1147         @# Contents of the system image
1148         $(hide) $(call package_files-copy-root, /
1149                 $(SYSTEMIMAGE_SOURCE_DIR),$(zip_root)/SYSTEM)
1150         @# Contents of the data image
1151         $(hide) $(call package_files-copy-root, /
1152                 $(TARGET_OUT_DATA),$(zip_root)/DATA)
1153         @# Extra contents of the OTA package
1154         $(hide) mkdir -p $(zip_root)/OTA/bin
1155         $(hide) $(ACP) $(INSTALLED_ANDROID_INFO_TXT_TARGET)
$(zip_root)/OTA/
1156         $(hide) $(ACP) $(PRIVATE_OTA_TOOLS) $(zip_root)/OTA/bin/
1157         @# Files that do not end up in any images, but are
necessary to
1158         @# build them.
1159         $(hide) mkdir -p $(zip_root)/META
1160         $(hide) $(ACP) $(APKCERTS_FILE)
$(zip_root)/META/apkcerts.txt
1161         $(hide) echo "$(PRODUCT_OTA_PUBLIC_KEYS)" >
$(zip_root)/META/otakeys.txt
1162         $(hide) echo "$(PRIVATE_RECOVERY_API_VERSION)" >
$(zip_root)/META/recovery-api-version.txt
1163         $(hide) echo "blocksize $(BOARD_FLASH_BLOCK_SIZE)" >
$(zip_root)/META/imagesizes.txt
1164         $(hide) echo "boot $(call
image-size-from-data-size,$(BOARD_BOOTIMAGE_PARTITION_SIZE))" >>
$(zip_root)/META/imagesizes.txt
1165         $(hide) echo "recovery $(call
image-size-from-data-size,$(BOARD_RECOVERYIMAGE_PARTITION_SIZE))"
>> $(zip_root)/META/imagesizes.txt
1166         $(hide) echo "system $(call
image-size-from-data-size,$(BOARD_SYSTEMIMAGE_PARTITION_SIZE))" >>
 $(zip_root)/META/imagesizes.txt
1167         $(hide) echo "secro $(call
image-size-from-data-size,$(BOARD_SECROIMAGE_PARTITION_SIZE))" >>
$(zip_root)/META/imagesizes.txt
1168         $(hide) echo "userdata $(call
image-size-from-data-size,$(BOARD_USERDATAIMAGE_PARTITION_SIZE))"
>> $(zip_root)/META/imagesizes.txt
1169         $(hide) echo "$(tool_extensions)" >
$(zip_root)/META/tool-extensions.txt
1170         @# Zip everything up, preserving symlinks
1171         $(hide) (cd $(zip_root) && zip -qry ../$(notdir $@)
 .)
1172         @# Run fs_config on all the system files in the zip, and
save the output
1173         $(hide) zipinfo -1 $@ | awk -F/ 'BEGIN { OFS="/" }
/^SYSTEM/// {$$1 = "system"; print}' | $(HOST_OUT_EXECUTABLES)/fs_config
 > $(zip_root)/META/filesystem_config.txt
1174         $(hide) (cd $(zip_root) && zip -q ../$(notdir $@)
META/filesystem_config.txt)

 

 

可见往里面添加了很多内容。

L1089-1090 , 造一个目录。

L1091-1108 ，填充 RECOVERY 子目录的内容。用于生成recovery.img 。包括：kernel 的image, recovery 根文件系统的 image, recovery 根文件系统的内容：

RECOVERY$ tree -L 2

├── kernel

├── ramdisk

└── RAMDISK

    ├── advanced_meta_init.rc

    ├── data

    ├── default.prop

    ├── dev

    ├── etc

    ├── init

    ├── init.factory.rc

    ├── init.goldfish.rc

    ├── init.mt6516.rc

    ├── init.rc

    ├── meta_init.rc

    ├── proc

    ├── res

    ├── sbin

    ├── sys

    ├── system

    └── tmp

L1109-1125, 填充 FACTORY 子目录的内容， 没有用到，包括：kernel 的image

L1126-1143, 填充 BOOT 子目录的内容，用于生成boot.img 。和 RECOVERY 目录类似，包括：kernel 的image, 根文件系统的image, 根文件系统的内容：

BOOT$ tree -L 2

.

├── kernel

├── ramdisk

└── RAMDISK

    ├── advanced_meta_init.rc

    ├── data

    ├── default.prop

    ├── dev

    ├── init

    ├── init.factory.rc

    ├── init.goldfish.rc

    ├── init.mt6516.rc

    ├── init.rc

    ├── meta_init.rc

    ├── proc

    ├── res -> /system/res

    ├── sbin

    ├── sys

    └── system

L1144-1146, 填充 RADIO 子目录的内容， 没有用到。

L1147-1149, 填充 SYSTEM 子目录的内容。 这是升级的主要内容。

L1150-1152, 填充 DATA 子目录的内容。缺省没有用到。

L1153-1156, 填充 OTA/bin 子目录的内容, 这是OTA 升级自己使用的程序。后面会遇到。

OTA/bin$ tree

.

├── applypatch

├── applypatch_static

├── check_prereq

└── updater

L1159-1169, 填充 META 子目录的内容, 这里包含了OTA 脚本需要的一些附加信息。

L1170-1171, 将所有内容打包。供下一阶段使用。

L1173-1174, 生成 META/filesystem_config.txt 并将其加入到 zip 包中。该文件保存了 system 目录下各目录、文件的权限及owner.

$ head META/filesystem_config.txt

system 0 0 755

system/usr 0 0 755

system/usr/srec 0 0 755

system/usr/srec/config 0 0 755

system/usr/srec/config/en.us 0 0 755

system/usr/srec/config/en.us/grammars 0 0 755

system/usr/srec/config/en.us/grammars/phone_type_choice.g2g 0 0 644

system/usr/srec/config/en.us/grammars/VoiceDialer.g2g 0 0 644

system/usr/srec/config/en.us/grammars/boolean.g2g 0 0 644

system/usr/srec/config/en.us/g2p 0 0 755

这里，目录由 zipinfo –l 提供， 而权限则由 fs_config 设定。此程序的源码位于：build/tools/fs_config, 其中fs_config包含了一个头文件：

54 #include " private/android_filesystem_config.h "

这个文件(system/core/include/private/android_filesystem_config.h ) 以hardcoding 的方式设定了 system 下各目录、文件的权限、属主。比如：

152      { 00440, AID_ROOT ,      AID_SHELL ,     "system/etc/init.goldfish.rc" },

153      { 00550, AID_ROOT ,      AID_SHELL ,     "system/etc/init.goldfish.sh" },

154      { 00440, AID_ROOT ,      AID_SHELL ,     "system/etc/init.trout.rc" },

155      { 00550, AID_ROOT ,      AID_SHELL ,     "system/etc/init.ril" },

如果需要升级其它内容，比如 bootloader, 则可以在这里加入。

步骤二

编译脚本如下 :

(From: build/core/Makefile)

 

1186 name := $(TARGET_PRODUCT)
1187 ifeq ($(TARGET_BUILD_TYPE),debug)
1188   name := $(name)_debug
1189 endif
1190 name := $(name)-ota-$(FILE_NAME_TAG)
1191
1192 INTERNAL_OTA_PACKAGE_TARGET := $(PRODUCT_OUT)/$(name).zip
1193
1194 $(INTERNAL_OTA_PACKAGE_TARGET): KEY_CERT_PAIR := $(DEFAULT_KEY_CERT_PAIR)
1195
1196 ifeq ($(TARGET_OTA_SCRIPT_MODE),)
1197 # default  to  "auto"
1198 $(INTERNAL_OTA_PACKAGE_TARGET): scriptmode := auto
1199 else
1200 $(INTERNAL_OTA_PACKAGE_TARGET): scriptmode := $(TARGET_OTA_SCRIPT_MODE)
1201 endif
1202
1203 $(INTERNAL_OTA_PACKAGE_TARGET): $(BUILT_TARGET_FILES_PACKAGE) $(OTATOOLS)
1204         @echo "Package OTA: $@"
1205         $(hide) ./build/tools/releasetools/ota_from_target_files /
1206            -m $(scriptmode) /
1207            -p $(HOST_OUT) /
1208            -k $(KEY_CERT_PAIR) /
1209            $(BUILT_TARGET_FILES_PACKAGE) $@

1186 name := $(TARGET_PRODUCT)
1187 ifeq ($(TARGET_BUILD_TYPE),debug)
1188   name := $(name)_debug
1189 endif
1190 name := $(name)-ota-$(FILE_NAME_TAG)
1191
1192 INTERNAL_OTA_PACKAGE_TARGET := $(PRODUCT_OUT)/$(name).zip
1193
1194 $(INTERNAL_OTA_PACKAGE_TARGET): KEY_CERT_PAIR := $(DEFAULT_KEY_CERT_PAIR)
1195
1196 ifeq ($(TARGET_OTA_SCRIPT_MODE),)
1197 # default to "auto"
1198 $(INTERNAL_OTA_PACKAGE_TARGET): scriptmode := auto
1199 else
1200 $(INTERNAL_OTA_PACKAGE_TARGET): scriptmode := $(TARGET_OTA_SCRIPT_MODE)
1201 endif
1202
1203 $(INTERNAL_OTA_PACKAGE_TARGET): $(BUILT_TARGET_FILES_PACKAGE) $(OTATOOLS)
1204         @echo "Package OTA: $@"
1205         $(hide) ./build/tools/releasetools/ota_from_target_files /
1206            -m $(scriptmode) /
1207            -p $(HOST_OUT) /
1208            -k $(KEY_CERT_PAIR) /
1209            $(BUILT_TARGET_FILES_PACKAGE) $@

 

 

核心是一个python 脚本: ota_from_target_files, 它以前一步骤生成的ZIP 包作为输入，生成可用于OTA 升级的zip 包。 具体内容我们后文继续分析。