Android source build/envsetup.sh 及lunch 過程

1，source build/envsetup.sh

        source 是用來運行 shell 腳本的命令  功能和 "."  和相同，因此 也可以寫作： . build/envsetup.sh

運行效果結果如下：

xxx@xxx:~/xxx/kitkat$ . build/envsetup.sh

including device/generic/armv7-a-neon/vendorsetup.sh

including device/generic/x86/vendorsetup.sh

including device/generic/mips/vendorsetup.sh

including sdk/bash_completion/adb.bash

buddy@RD3-199:~/C_BQ_T628VX_01/kitkat-mstar-master$

那麼上面的結果是如何產生的呢？運行envsetup.sh的發生了什麼呢？我們自己添加的客戶分支是如何加入到 lunch 的選項中去的呢？

a，關於envsetup

envsetup 爲我們提供了很多的shell腳本函數，例如 envsetup 開頭的第一個函數 hmm，

function hmm() {

cat <<EOF

Invoke ". build/envsetup.sh" from your shell to add the following functions to your environment:

- lunch: lunch <product_name>-<build_variant>

- tapas: tapas [<App1> <App2> ...] [arm|x86|mips|armv5] [eng|userdebug|user]

- croot: Changes directory to the top of the tree.

- m: Makes from the top of the tree.

- mm: Builds all of the modules in the current directory, but not their dependencies.

- mmm: Builds all of the modules in the supplied directories, but not their dependencies.

- mma: Builds all of the modules in the current directory, and their dependencies.

- mmma: Builds all of the modules in the supplied directories, and their dependencies.

- cgrep: Greps on all local C/C++ files.

- jgrep: Greps on all local Java files.

- resgrep: Greps on all local res/*.xml files.

- godir: Go to the directory containing a file.

 

Look at the source to view more functions. The complete list is:

EOF

T=$(gettop)    #gettop也是envsetup.sh 中定義的一個 函數，有興趣的童鞋可以看一下具體實現

local A

A=""

for i in `cat $T/build/envsetup.sh | sed -n "/^function /s/function \([a-z_]*\).*/\1/p" | sort`; do

A="$A $i"

done

echo $A

}

在運行envsetup .sh以後 就可以使用 hmm命令了，此時終端會輸出命令幫助提示。

簡單來說，envsetup.sh  給我們提供了一組自定義的 shell命令，而lunch 就是這些自定義命令中的一個。

2，lunch 命令

我們依然來看  envsetup.sh，在envsetup.sh 中可以找到 lunch 定義

function lunch()

{

local answer

 

if [ "$1" ] ; then #lunch可以接受一個輸入參數，例如 lunch xxx-userdebug 此時直接選擇了xxx。

answer=$1

else # 如果沒有輸入參數，則打印選擇菜單，並等待選擇輸入

print_lunch_menu

echo -n "Which would you like? [aosp_arm-eng] "

read answer

fi

 

local selection=

 

if [ -z "$answer" ] #如果answer爲空

then

selection=aosp_arm-eng #默認選擇aosp_arm-eng

elif (echo -n $answer | grep -q -e "^[0-9][0-9]*$")

then

if [ $answer -le ${#LUNCH_MENU_CHOICES[@]} ]

then

selection=${LUNCH_MENU_CHOICES[$(($answer-1))]}

fi

elif (echo -n $answer | grep -q -e "^[^\-][^\-]*-[^\-][^\-]*$") #不以 ‘-’ 開頭和結束

then

selection=$answer

fi

 

if [ -z "$selection" ]

then

echo

echo "Invalid lunch combo: $answer"

return 1

fi

#導出編譯使用的環境變量 

export TARGET_BUILD_APPS=

#提取"-"位置以前的字符串 這裏是“xxx” 

local product=$(echo -n $selection | sed -e "s/-.*$//")

check_product $product

if [ $? -ne 0 ]

then

echo

echo "** Don't have a product spec for: '$product'"

echo "** Do you have the right repo manifest?"

product=

fi

#提取"-"位置以後的字符串“ userdebug ” 

local variant=$(echo -n $selection | sed -e "s/^[^\-]*-//")

check_variant $variant

if [ $? -ne 0 ]

then

echo

echo "** Invalid variant: '$variant'"

echo "** Must be one of ${VARIANT_CHOICES[@]}"

variant=

fi

 

if [ -z "$product" -o -z "$variant" ] #如果爲空則返回

then

echo

return 1

fi

 

#導出編譯使用的環境變量

export TARGET_PRODUCT=$product

export TARGET_BUILD_VARIANT=$variant

export TARGET_BUILD_TYPE=release

 

echo

 

set_stuff_for_environment

printconfig

}

看一看其中調用的幾個函數

print_lunch_menu

function print_lunch_menu()

{

local uname=$(uname)

echo

echo "You're building on" $uname

echo

echo "Lunch menu... pick a combo:"

 

local i=1

local choice

for choice in ${LUNCH_MENU_CHOICES[@]} #這裏輸出的就是我們看到的 lunch 命令的輸出結果

do

echo " $i. $choice"

i=$(($i+1))

done

 

echo

}

那麼 LUNCH_MENU_CHOICES 變量的數據又是從何而來呢？

# Clear this variable. It will be built up again when the vendorsetup.sh

# files are included at the end of this file.

unset LUNCH_MENU_CHOICES

#這函數就是向lunch命令添加選擇項 客戶分支裏 vendorsetup.sh 裏的那一行代碼的用途就是添加lunch選擇項

function add_lunch_combo()

{

local new_combo=$1

local c

for c in ${LUNCH_MENU_CHOICES[@]} ; do

if [ "$new_combo" = "$c" ] ; then

return

fi

done

LUNCH_MENU_CHOICES=(${LUNCH_MENU_CHOICES[@]} $new_combo)

}

 

# add the default one here

add_lunch_combo aosp_arm-eng

add_lunch_combo aosp_x86-eng

add_lunch_combo aosp_mips-eng

add_lunch_combo vbox_x86-eng

我們來看看 check_product 的作用

# check to see if the supplied product is one we can build

function check_product()

{

T=$(gettop)

if [ ! "$T" ]; then

echo "Couldn't locate the top of the tree. Try setting TOP." >&2

return

fi

#設置環境變量

CALLED_FROM_SETUP=true BUILD_SYSTEM=build/core \

TARGET_PRODUCT=$1 \

TARGET_BUILD_VARIANT= \

TARGET_BUILD_TYPE= \

TARGET_BUILD_APPS= \

get_build_var TARGET_DEVICE > /dev/null #get_build_var

# hide successful answers, but allow the errors to show

}

# Get the exact value of a build variable.

function get_build_var()

{

T=$(gettop)

if [ ! "$T" ]; then

echo "Couldn't locate the top of the tree. Try setting TOP." >&2

return

fi

    #執行config.mk配置相關的內容，

    #進一步依次執行envsetup.mk，到product_config.mk，

    #最終獲得TARGET_DEVICE變量的內容。

CALLED_FROM_SETUP=true BUILD_SYSTEM=build/core \

make --no-print-directory -C "$T" -f build/core/config.mk dumpvar-$1

}

check_variant 函數

#三種模式 user userdebug eng

VARIANT_CHOICES=(user userdebug eng)

# check to see if the supplied variant is valid

function check_variant()

{

for v in ${VARIANT_CHOICES[@]}

do

if [ "$v" = "$1" ]

then

return 0

fi

done

return 1

}

以下內容待驗證

#1.eng，那麼其編譯進去的內容包括：

· Intended for platform-level debugging

· Installs modules tagged with: eng, debug, user, and/or development

· Installs non-APK modules that have no tags specified

· Installs APKs according to the product definition files, in addition to tagged APKs

· Sets ro.secure=1

· Sets ro.debuggable=0

· Sets ro.kernel.android.checkjni=1

· adbd is enabled by default

 

#2.user,那麼其編譯進去的內容包括：

· Intended to be the final release

· Installs modules tagged as user

· Installs non-APK modules that have no tags specified

· Installs APKs according to the product definition files (tags are ignored for APK modules)

· Sets ro.secure=1

· Sets ro.debuggable=0

· adbd is disabled by default

 

#3.userdebug,那麼其編譯進去的內容包括：

the same as user, except:

· Intended for limited debugging

· Installs modules tagged with debug

· Sets ro.debuggable=1

· adbd is enabled by default

set_stuff_for_environment函數，主要設備編譯相關的環境

function set_stuff_for_environment()

{

settitle

set_java_home

setpaths

set_sequence_number

# MStar Android Patch Begin

set_ota

# MStar Android Patch End

 

export ANDROID_BUILD_TOP=$(gettop)

}

關於lunch 命令的過程已經基本清晰，那麼系統是如何找到客戶分支下的 vendorsetup.sh 呢？

3，掃描系統中的vendorsetup.sh 文件

# Execute the contents of any vendorsetup.sh files we can find.

# 檢測 device 目錄和vendor 目錄是否存在 ，並且找到 目錄下的vendorsetup.sh .最多目錄層次四層

for f in `test -d device && find device -maxdepth 4 -name 'vendorsetup.sh' 2> /dev/null` \

`test -d vendor && find vendor -maxdepth 4 -name 'vendorsetup.sh' 2> /dev/null`

do

echo "including $f"

. $f # 找到vendorsetup.sh 並執行，

done

unset f

 

addcompletions

function addcompletions()

{

local T dir f

 

# Keep us from trying to run in something that isn't bash.

if [ -z "${BASH_VERSION}" ]; then

return

fi

 

# Keep us from trying to run in bash that's too old.

if [ ${BASH_VERSINFO[0]} -lt 3 ]; then

return

fi

 

dir="sdk/bash_completion"

if [ -d ${dir} ]; then

# 掃描 /sdk/bash_completion 目錄並允許 .bash 文件

for f in `/bin/ls ${dir}/[a-z]*.bash 2> /dev/null`; do

echo "including $f"

. $f #運行bash文件

done

fi

}

source ./build/envsetup.sh

lunch

命令的基本過程大致如上所說。主要初始化編譯所需要的系統變量