【轉】openwrt make menuconfig過程（提取menuconfig）

轉自：https://www.cnblogs.com/tfanalysis/p/3625430.html

 

參考網站：http://wiki.openwrt.org/doc/howto/buildroot.exigence

需要下載必要的庫文件，編譯器等。。。

 

1 首先要獲得openwrt的源碼，參考openwrt.org官方網站的內容 https://dev.openwrt.org/wiki/GetSource

其中trunk為開發版本，最新的穩定版為12.09 branch (Attitude Adjustment)。

使用git獲得：git clone git://git.openwrt.org/12.09/openwrt.git

如果要更新源碼則運行git pull即可。

使用svn獲得：svn co svn://svn.openwrt.org/openwrt/branches/attitude_adjustment

2 下載完源碼之后

獲取包列表：

./scripts/feeds update -a

將包選項加到menuconfig中去：

./scripts/feeds install -a

3 make menuconfig

在此菜單中選擇要編譯的模塊並生成依賴

3.1

我們打開openwrt根目錄下的Makefile文件，發現並沒有找到menuconfig這個目標，這個目標是在

include $(TOPDIR)/include/toplevel.mk

所指的toplevel.mk中定義的，如下圖：

它的依賴是scripts/config/mconf和prepare-tmpinfo FORCE

• scripts/config/mconf是一個已經存在的可執行文件；
• prepare-tmpinfo是本文件中的一個目標，等會再闡述；
• FORCE尚還不清楚它的作用和來源；

我們先看看menuconfig中的命令

    if [ \! -e .config -a -e $(HOME)/.openwrt/defconfig ]; then \
        cp $(HOME)/.openwrt/defconfig .config; \
    fi
    $< Config.in

這是一句shell腳本，意思是：如果不存在.config而且存在$(HOME)/.openwrt/defconfig，則拷貝$(HOME)/.openwrt/defconfig為.config

 $<是什么？The automatic variable ‘$<’ is just the first prerequisite，即是指scripts/config/mconf。
把這兩個字符串連起來看就知道什么意思啦：scripts/config/mconf Config.in

你也可以直接到openwrt目錄下去試運行一下這個指令，如下圖，正是我們運行make menuconfig時出現的畫面（下圖我已經關閉了menuconfig）：

3.2

 好！現在我們回頭去理prepare-tmpinfo的帳，並且看看能不能把Config.in這個文件搞懂是怎么回事。

prepare-tmpinfo: FORCE
    mkdir -p tmp/info
    $(_SINGLE)$(NO_TRACE_MAKE) -j1 -r -s -f include/scan.mk SCAN_TARGET="packageinfo" SCAN_DIR="package" SCAN_NAME="package" SCAN_DEPS="$(TOPDIR)/include/package*.mk $(TOPDIR)/overlay/*/*.mk" SCAN_DEPTH=5 SCAN_EXTRA=""
    $(_SINGLE)$(NO_TRACE_MAKE) -j1 -r -s -f include/scan.mk SCAN_TARGET="targetinfo" SCAN_DIR="target/linux" SCAN_NAME="target" SCAN_DEPS="profiles/*.mk $(TOPDIR)/include/kernel*.mk $(TOPDIR)/include/target.mk" SCAN_DEPTH=2 SCAN_EXTRA="" SCAN_MAKEOPTS="TARGET_BUILD=1"
    for type in package target; do \
        f=tmp/.$${type}info; t=tmp/.config-$${type}.in; \
        [ "$$t" -nt "$$f" ] || ./scripts/metadata.pl $${type}_config "$$f" > "$$t" || { rm -f "$$t"; echo "Failed to build $$t"; false; break; }; \
    done
    ./scripts/metadata.pl package_mk tmp/.packageinfo > tmp/.packagedeps || { rm -f tmp/.packagedeps; false; }
    touch $(TOPDIR)/tmp/.build

3.2.1

兩個變量

_SINGLE在頂層Makefile中定義：

_SINGLE=export MAKEFLAGS=$(space);

NO_TRACE_MAKE的-/include/verbose.mk中定義：

ifeq ($(NO_TRACE_MAKE),)
NO_TRACE_MAKE := $(MAKE) V=s$(OPENWRT_VERBOSE)
export NO_TRACE_MAKE
endif

 這里的命令先是去make V=xx -j1 -r -s -f include/scan.mk（分別Verbose，單線程，沒有內建規則，指定Makefile文件）。所以我們再打開include/scan.mk文件看看怎么回事。最終目標是：

all: $(TMP_DIR)/.$(SCAN_TARGET)

3.2.2

這時scan.mk先定義了一個叫做PackageDir的“函數”（命令序列，后面將會使用）：

define PackageDir
  $(TMP_DIR)/.$(SCAN_TARGET): $(TMP_DIR)/info/.$(SCAN_TARGET)-$(1)
  $(TMP_DIR)/info/.$(SCAN_TARGET)-$(1): $(SCAN_DIR)/$(2)/Makefile $(SCAN_STAMP) $(foreach DEP,$(DEPS_$(SCAN_DIR)/$(1)/Makefile) $(SCAN_DEPS),$(wildcard $(if $(filter /%,$(DEP)),$(DEP),$(SCAN_DIR)/$(1)/$(DEP))))
    { \
        $$(call progress,Collecting $(SCAN_NAME) info: $(SCAN_DIR)/$(2)) \
        echo Source-Makefile: $(SCAN_DIR)/$(2)/Makefile; \
        $(NO_TRACE_MAKE) --no-print-dir -r DUMP=1 -C $(SCAN_DIR)/$(2) $(SCAN_MAKEOPTS) 2>/dev/null || { \
            mkdir -p "$(TOPDIR)/logs/$(SCAN_DIR)/$(2)"; \
            $(NO_TRACE_MAKE) --no-print-dir -r DUMP=1 -C $(SCAN_DIR)/$(2) $(SCAN_MAKEOPTS) > $(TOPDIR)/logs/$(SCAN_DIR)/$(2)/dump.txt 2>&1; \
            $$(call progress,ERROR: please fix $(SCAN_DIR)/$(2)/Makefile - see logs/$(SCAN_DIR)/$(2)/dump.txt for details\n) \
            rm -f $$@; \
        }; \
        echo; \
    } > $$@ || true
endef

3.2.3

這個命令系列的用法可以看下面的$(call progress, Colleting....)，progress也正是scan.mk文件中定義的一個命令序列：

$(TMP_DIR)/.$(SCAN_TARGET): $(TARGET_STAMP) $(SCAN_STAMP)
    $(call progress,Collecting $(SCAN_NAME) info: merging...)
    -cat $(FILELIST) | awk '{gsub(/\//, "_", $$0);print "$(TMP_DIR)/info/.$(SCAN_TARGET)-" $$0}' | xargs cat > $@ 2>/dev/null
    $(call progress,Collecting $(SCAN_NAME) info: done)
    echo

 具體progress的定義是這樣的：

ifeq ($(IS_TTY),1)
  define progress
    printf "\033[M\r$(1)" >&2;
  endef
else
  define progress
    :;
  endef
endif

所以，調用它之后會輸出“<[M Collecting package info : merging... ”"....info: done"類似這樣的信息（重定義到2，標准錯誤輸出），$(1)表示第一個參數的意思

中間則輸出awk信息，來研究下這個語句

-cat $(FILELIST) | awk '{gsub(/\//, "_", $$0);print "$(TMP_DIR)/info/.$(SCAN_TARGET)-" $$0}' | xargs cat > $@ 2>/dev/null

 處理過程：

1. -cat $(FILELIST)，-cat最頭的-表示如果出錯也不提示如意思；
2. cat得的數據輸出通過awk的解析

   awk '{gsub(/\//, "_", $$0);print "$(TMP_DIR)/info/.$(SCAN_TARGET)-" $$0}'

3. awk得的數據輸出通過xargs cat（分小段輸出給@，也就是@，也就是(TMP_DIR)/.$(SCAN_TARGET)自己！），而錯誤輸出的定義到null

看上面的過程，這部分主要問題是要搞清楚$(FILELIST)和awk的用法：

先上$(FILELIST)

$(FILELIST):
    rm -f $(TMP_DIR)/info/.files-$(SCAN_TARGET)-*
    $(call FIND_L, $(SCAN_DIR)) $(SCAN_EXTRA) -mindepth 1 $(if $(SCAN_DEPTH),-maxdepth $(SCAN_DEPTH)) -name Makefile | xargs grep -HE 'call (Build/DefaultTargets|Build(Package|Target)|.+Package)' | sed -e 's#^$(SCAN_DIR)/##' -e 's#/Makefile:.*##' | uniq > $@

這兒的FIND_L命令序列實在x/tmp/.host.mk中定義的（該mk文件由x/include/host.mk生成）

FIND_L=/usr/bin/find -L $(1)

因而這個命令就演變成了系統指令find/xarg&grep/sed/uniq的用法了。

1 find查找$(SCAN_DIR)中的叫做Makefile的文件（搜索深度1~5）；

2 xargs grep會展開各個Makefile文件，-H為顯示時makefile名字，-E為啟用后面跟着的正則表達式；

這兒call (Build/DefaultTargets|Build(Package|Target)|.+Package)會匹配到call Build/DefaultTargets或者BuildPackage或BuildTarget或者_任意多個字符_Package等三種情況的字符串（以行為結束）；

3 sed

4 uniq

最后獲得的文件寫到了FILELIST := $(TMP_DIR)/info/.files-$(SCAN_TARGET)-$(SCAN_COOKIE)中；

spidev_test
hostapd
opkg
fuse
hotplug2
ppp
...
feeds/xwrt/webif-iw-lua-openssl
feeds/xwrt/webif-netsukuku
feeds/xwrt/webif-mesh
feeds/xwrt/webif-fonheartbeat
robocfg
comgt
rssileds
madwifi
grub
libjson-c
odhcp6c
rotary-gpio-custom
ead
rtc-rv5c386a
sierra-directip
button-hotplug
grub2
kexec-tools
linux-atm
util-linux
xfsprogs
pjsip
ltq-tapidemo
owsip
fbtest
gpioctl
uboot-omap4
i2c-gpio-custom
ltq-tapi
ltq-vmmc
uboot-lantiq
swconfig
uhttpd
trelay
iptables
switch
owipcalc
ltq-kpi2udp

 3.2.4

(TMPDIR)/.(TMPDIR)/.(SCAN_TARGET)的信賴，條件

• $(TARGET_STAMP)

 

• $(SCAN_STAMP)

 

4 編譯得的bin文件在bin目錄中。

 

使用make menuconfig --debug -w --just-print命令，不執行操作僅調試，結果為：

 1 GNU Make 3.81
 2 Copyright (C) 2006  Free Software Foundation, Inc.
 3 This is free software; see the source for copying conditions.
 4 There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
 5 PARTICULAR PURPOSE.
 6 
 7 This program built for x86_64-pc-linux-gnu
 8 Reading makefiles...
 9 Updating goal targets....
10  File `menuconfig' does not exist.
11     Target `scripts/config/mconf_check' is double-colon and has no prerequisites.
12     Must remake target `scripts/config/mconf_check'.
13 make: Entering directory `/home/tf/projects/openwrt'
14 { [ -f "scripts/config/mconf_check.1" ] && mv "scripts/config/mconf_check.1"; /home/tf/projects/openwrt/scripts/timestamp.pl -x "*/.svn*" -x ".*" -x "*:*" -x "*\!*" -x "* *" -x "*\#*" -x "*/.*_check" -x "*/.*.swp"  -n scripts/config/mconf scripts/config && {  touch -r "scripts/config/mconf" "scripts/config/mconf_check"; } } || {  touch "scripts/config/mconf_check"; }
15     Successfully remade target file `scripts/config/mconf_check'.
16    Prerequisite `scripts/config/mconf_check' is newer than target `scripts/config/mconf'.
17   Must remake target `scripts/config/mconf'.
18 export MAKEFLAGS= ;umask 022; cmd() { >/dev/null 2>&1 make -s $* < /dev/null || { echo "make $*: build failed. Please re-run make with V=s to see what's going on"; false; } } 8>&1 9>&2; cmd -s -C scripts/config all CC="gcc"
19   Successfully remade target file `scripts/config/mconf'.
20    File `prepare-tmpinfo' does not exist.
21      File `FORCE' does not exist.
22     Must remake target `FORCE'.
23     Successfully remade target file `FORCE'.
24   Must remake target `prepare-tmpinfo'.
25 mkdir -p tmp/info
26 export MAKEFLAGS= ;make V=s -j1 -r -s -f include/scan.mk SCAN_TARGET="packageinfo" SCAN_DIR="package" SCAN_NAME="package" SCAN_DEPS="/home/tf/projects/openwrt/include/package*.mk /home/tf/projects/openwrt/overlay/*/*.mk" SCAN_DEPTH=5 SCAN_EXTRA=""
27 export MAKEFLAGS= ;make V=s -j1 -r -s -f include/scan.mk SCAN_TARGET="targetinfo" SCAN_DIR="target/linux" SCAN_NAME="target" SCAN_DEPS="profiles/*.mk /home/tf/projects/openwrt/include/kernel*.mk /home/tf/projects/openwrt/include/target.mk" SCAN_DEPTH=2 SCAN_EXTRA="" SCAN_MAKEOPTS="TARGET_BUILD=1"
28 for type in package target; do \
29         f=tmp/.${type}info; t=tmp/.config-${type}.in; \
30         [ "$t" -nt "$f" ] || ./scripts/metadata.pl ${type}_config "$f" > "$t" || { rm -f "$t"; echo "Failed to build $t"; false; break; }; \
31     done
32 ./scripts/metadata.pl package_mk tmp/.packageinfo > tmp/.packagedeps || { rm -f tmp/.packagedeps; false; }
33 touch /home/tf/projects/openwrt/tmp/.build
34   Successfully remade target file `prepare-tmpinfo'.
35 Must remake target `menuconfig'.
36 if [ \! -e .config -a -e /home/tf/.openwrt/defconfig ]; then \
37         cp /home/tf/.openwrt/defconfig .config; \
38     fi
39 scripts/config/mconf Config.in
40 Successfully remade target file `menuconfig'.
41 make: Leaving directory `/home/tf/projects/openwrt'