【转】Android OTA 升级之一：编译升级包

原文地址： http://blog.csdn.net/zjujoe/archive/2011/02/24/6206010.aspx
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 underlying1074 # 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 image1092 $(hide) mkdir -p $(zip_root)/RECOVERY1093 $(hide) $(call package_files-copy-root, /1094 $(TARGET_RECOVERY_ROOT_OUT),$(zip_root)/RECOVERY/RAMDISK)1095 ifdef INSTALLED_KERNEL_TARGET1096 $(hide) $(ACP) $(INSTALLED_KERNEL_TARGET) $(zip_root)/RECOVERY/kernel1097 $(hide) $(ACP) $(recovery_ramdisk) $(zip_root)/RECOVERY/ramdisk1098 endif1099 ifdef INSTALLED_2NDBOOTLOADER_TARGET1100 $(hide) $(ACP) /1101 $(INSTALLED_2NDBOOTLOADER_TARGET) $(zip_root)/RECOVERY/second1102 endif1103 ifdef BOARD_KERNEL_CMDLINE1104 $(hide) echo "$(BOARD_KERNEL_CMDLINE)"
> $(zip_root)/RECOVERY/cmdline1105 endif1106 ifdef BOARD_KERNEL_BASE1107 $(hide) echo "$(BOARD_KERNEL_BASE)"
> $(zip_root)/RECOVERY/
base1108 endif1109 @# Components of the factory image1110 $(hide) mkdir -p $(zip_root)/FACTORY1111 $(hide) $(call package_files-copy-root, /1112 $(TARGET_FACTORY_ROOT_OUT),$(zip_root)/FACTORY/RAMDISK)1113 ifdef INSTALLED_KERNEL_TARGET1114 $(hide) $(ACP) $(INSTALLED_KERNEL_TARGET) $(zip_root)/FACTORY/kernel1115 endif1116 ifdef INSTALLED_2NDBOOTLOADER_TARGET1117 $(hide) $(ACP) /1118 $(INSTALLED_2NDBOOTLOADER_TARGET) $(zip_root)/FACTORY/second1119 endif1120 ifdef BOARD_KERNEL_CMDLINE1121 $(hide) echo "$(BOARD_KERNEL_CMDLINE)"
> $(zip_root)/FACTORY/cmdline1122 endif1123 ifdef BOARD_KERNEL_BASE1124 $(hide) echo "$(BOARD_KERNEL_BASE)"
> $(zip_root)/FACTORY/
base1125 endif1126 @# Components of the boot image1127 $(hide) mkdir -p $(zip_root)/BOOT1128 $(hide) $(call package_files-copy-root, /1129 $(TARGET_ROOT_OUT),$(zip_root)/BOOT/RAMDISK)1130 ifdef INSTALLED_KERNEL_TARGET1131 $(hide) $(ACP) $(INSTALLED_KERNEL_TARGET) $(zip_root)/BOOT/kernel1132 $(hide) $(ACP) $(INSTALLED_RAMDISK_TARGET) $(zip_root)/BOOT/ramdisk1133 endif1134 ifdef INSTALLED_2NDBOOTLOADER_TARGET1135 $(hide) $(ACP) /1136 $(INSTALLED_2NDBOOTLOADER_TARGET) $(zip_root)/BOOT/second1137 endif1138 ifdef BOARD_KERNEL_CMDLINE1139 $(hide) echo "$(BOARD_KERNEL_CMDLINE)"
> $(zip_root)/BOOT/cmdline1140 endif1141 ifdef BOARD_KERNEL_BASE1142 $(hide) echo "$(BOARD_KERNEL_BASE)"
> $(zip_root)/BOOT/
base1143 endif1144 $(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 image1148 $(hide) $(call package_files-copy-root, /1149 $(SYSTEMIMAGE_SOURCE_DIR),$(zip_root)/SYSTEM)1150 @# Contents of the data image1151 $(hide) $(call package_files-copy-root, /1152 $(TARGET_OUT_DATA),$(zip_root)/DATA)1153 @# Extra contents of the OTA package1154 $(hide) mkdir -p $(zip_root)/OTA/bin1155 $(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 to1158 @# build them.1159 $(hide) mkdir -p $(zip_root)/META1160 $(hide) $(ACP) $(APKCERTS_FILE) $(zip_root)/META/apkcerts.txt1161 $(hide) echo "$(PRODUCT_OTA_PUBLIC_KEYS)"
> $(zip_root)/META/otakeys.txt1162 $(hide) echo "$(PRIVATE_RECOVERY_API_VERSION)"
> $(zip_root)/META/recovery-api-version.txt1163 $(hide) echo "blocksize $(BOARD_FLASH_BLOCK_SIZE)"
> $(zip_root)/META/imagesizes.txt1164 $(hide) echo "boot $(call image-size-from-data-size,$(BOARD_BOOTIMAGE_PARTITION_SIZE))"
>> $(zip_root)/META/imagesizes.txt1165 $(hide) echo "recovery $(call image-size-from-data-size,$(BOARD_RECOVERYIMAGE_PARTITION_SIZE))"
>> $(zip_root)/META/imagesizes.txt1166 $(hide) echo "system $(call image-size-from-data-size,$(BOARD_SYSTEMIMAGE_PARTITION_SIZE))"
>> $(zip_root)/META/imagesizes.txt1167 $(hide) echo "secro $(call image-size-from-data-size,$(BOARD_SECROIMAGE_PARTITION_SIZE))"
>> $(zip_root)/META/imagesizes.txt1168 $(hide) echo "userdata $(call image-size-from-data-size,$(BOARD_USERDATAIMAGE_PARTITION_SIZE))"
>> $(zip_root)/META/imagesizes.txt1169 $(hide) echo "$(tool_extensions)"
> $(zip_root)/META/tool-extensions.txt1170 @# Zip everything up, preserving symlinks1171 $(hide) (cd $(zip_root) && zip -qry ../$(notdir $@) .)1172 @# Run fs_config on all the system files in
the zip, and save the output1173 $(hide) zipinfo -1 $@ | awk -F/ 'BEGIN { OFS="/" } /^SYSTEM/// {$$1 = "system"; print}'
| $(HOST_OUT_EXECUTABLES)/fs_config > $(zip_root)/META/filesystem_config.txt1174 $(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)_debug1189 endif1190 name := $(name)-ota-$(FILE_NAME_TAG)11911192 INTERNAL_OTA_PACKAGE_TARGET := $(PRODUCT_OUT)/$(name).zip11931194 $(INTERNAL_OTA_PACKAGE_TARGET): KEY_CERT_PAIR := $(DEFAULT_KEY_CERT_PAIR)11951196 ifeq ($(TARGET_OTA_SCRIPT_MODE),)1197 # default
to
"auto"1198 $(INTERNAL_OTA_PACKAGE_TARGET): scriptmode := auto1199 else1200 $(INTERNAL_OTA_PACKAGE_TARGET): scriptmode := $(TARGET_OTA_SCRIPT_MODE)1201 endif12021203 $(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。