这个目标用来检索package和target，再tmp下面生成索引和配置信息。

include/toplevel.mk

定义SCAN_COOKIE：SCAN_COOKIE?=$(shell echo $$$$)。

首先它通过下面两个recipe来扫描所有的package和target：

make -f include/scan.mk SCAN_TARGET="packageinfo" SCAN_DIR="package" SCAN_NAME="package" SCAN_DEPTH=5 SCAN_EXTRA=""

make -f include/scan.mk SCAN_TARGET="targetinfo" SCAN_DIR="target/linux" SCAN_NAME="target" SCAN_DEPTH=2 SCAN_EXTRA="" SCAN_MAKEOPTS="TARGET_BUILD=1"

生成package的配置

scripts/package-metadata.pl config tmp/.packageinfo > tmp/.config-package.in

生成target的配置

scripts/target-metadata.pl config tmp/.targetinfo > tmp/.config-target.in

生成

scripts/feeds feed_config > tmp/.config-feeds.in

生成

scripts/package-metadata.pl mk tmp/.packageinfo > tmp/.packagedeps

scripts/package-metadata.pl pkgaux tmp/.packageinfo > tmp/.packageauxvars

scripts/package-metadata.pl usergroup tmp/.packageinfo > tmp/.packageusergroup

最后

touch tmp/.build

include/scan.mk

生成并包含 tmp/info/.files-packageinfo.mk，这个文件依赖Makefile列表文件：

tmp/info/.overrides-packageinfo-625049

tmp/info/.files-packageinfo-625049

路径后面的数字是SCAN_COOKIE的值。在SCAN_DIR里面，使用find命令，查找最大SCAN_DEPTH深度的Makefile，如果其内容包含GREP_STRING，就认为是要找的Makefile，将查找结果输出到.files-packageinfo-625049。对于target，GREP_STRING是BuildTarget，对于package是Build/DefaultTargets | BuildPackage | KernelPackage。

.files-packageinfo-625049的内容：

base-files

boot/arm-trusted-firmware-mediatek

boot/arm-trusted-firmware-mvebu

boot/arm-trusted-firmware-rockchip

boot/arm-trusted-firmware-sunxi

boot/arm-trusted-firmware-tools

boot/at91bootstrap

。。。

生成的 tmp/info/.files-packageinfo.mk 内容：

DEPS_package/firmware/linux-firmware/Makefile=*.mk

DEPS_package/kernel/linux/Makefile=modules/*.mk $(TOPDIR)/target/linux/*/modules.mk $(TOPDIR)/include/netfilter.mk

$(eval $(call PackageDir,base-files,base-files,))

$(eval $(call PackageDir,boot_arm-trusted-firmware-mediatek,boot/arm-trusted-firmware-mediatek,))

$(eval $(call PackageDir,boot_arm-trusted-firmware-mvebu,boot/arm-trusted-firmware-mvebu,))

$(eval $(call PackageDir,boot_arm-trusted-firmware-rockchip,boot/arm-trusted-firmware-rockchip,))

$(eval $(call PackageDir,boot_arm-trusted-firmware-sunxi,boot/arm-trusted-firmware-sunxi,))

$(eval $(call PackageDir,boot_arm-trusted-firmware-tools,boot/arm-trusted-firmware-tools,))

。。。

一个包的Makefile可能依赖其它Makefile，在Makefile中使用SCAN_DEPS变量定义，比如package/firmware/linux-firmware/Makefile就有这个定义：SCAN_DEPS = *.mk，在生成的tmp/info/.files-packageinfo.mk中会定义一个DEPS_<package path>的变量等于SCAN_DEPS。

tmp/info/.files-packageinfo.mk就是DEPS_XXX的定义，表示那个包依赖哪些Makefile。还有就是所有的包的生成信息的语句：$(eval $(call PackageDir, ... ）。PackageDir定义在scan.mk

define PackageDir

$(TMP_DIR)/.$(SCAN_TARGET): $(TMP_DIR)/info/.$(SCAN_TARGET)-$(1)

$(TMP_DIR)/info/.$(SCAN_TARGET)-$(1): $(SCAN_DIR)/$(2)/Makefile $(foreach DEP,$(DEPS_$(SCAN_DIR)/$(2)/Makefile) $(SCAN_DEPS),$(wildcard $(if $(filter /%,$(DEP)),$(DEP),$(SCAN_DIR)/$(2)/$(DEP))))

{ \

$$(call progress,Collecting $(SCAN_NAME) info: $(SCAN_DIR)/$(2)) \

echo Source-Makefile: $(SCAN_DIR)/$(2)/Makefile; \

$(if $(3),echo Override: $(3),true); \

$(NO_TRACE_MAKE) --no-print-dir -r DUMP=1 FEED="$(call feedname,$(2))" -C $(SCAN_DIR)/$(2) $(SCAN_MAKEOPTS) 2>/dev/null || { \

mkdir -p "$(TOPDIR)/logs/$(SCAN_DIR)/$(2)"; \

$(NO_TRACE_MAKE) --no-print-dir -r DUMP=1 FEED="$(call feedname,$(2))" -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; \

} > $$@.tmp

mv $$@.tmp $$@

endef

它定义了一些依赖，以及如何生成tmp/info/.packageinfo-xxx

tmp/.packageinfo: tmp/info/.packageinfo-boot_arm-trusted-firmware-rockchip

tmp/info/.packageinfo-boot_arm-trusted-firmware-rockchip：

make V=ss --no-print-dir -r DUMP=1 FEED="" -C package/boot/arm-trusted-firmware-rockchip

.packageinfo是通过重定向下面命令的输出到.packageinfo文件得到的：

make V=ss --no-print-dir -r DUMP=1 FEED="" -C package/base-files/

其实我们可以单独执行查看.packageinfo信息，只要加上TOPDIR环境变量即可了。

TOPDIR=/work/openwrt make V=ss --no-print-dir -r DUMP=1 FEED="" -C package/base-files/

对于target，也可以类似的得到.targetinfo，但是多了个参数TARGET_BUILD=1，这个参数是toplevel.mk通过SCAN_MAKEOPTS传入的，比如：

TOPDIR=/work/openwrt make V=ss --no-print-dir -r DUMP=1 FEED="" -C target/linux/ramips TARGET_BUILD=1

生成的一个包的.packageinfo内容如下：

Source-Makefile: package/base-files/Makefile

Build-Depends: usign/host ucert/host

Package: base-files

Version: 0-r16087+1-1d412235a5

Depends: +libc +USE_GLIBC:librt +USE_GLIBC:libpthread +netifd +jsonfilter +SIGNED_PACKAGES:usign +SIGNED_PACKAGES:openwrt-keyring +NAND_SUPPORT:ubi-utils +fstools +fwtool

Conflicts:

Menu-Depends:

Provides:

Section: base

Category: Base system

Title: Base filesystem for OpenWrt

Maintainer:

Source:

License: GPL-2.0

Type: ipkg

Description: This package contains a base filesystem and system scripts for OpenWrt.

http://openwrt.org/

@@

最终目标是tmp/.packageinfo，PackageDir中，tmp/.packageinfo依赖于每个包的.packageinfo文件，并依赖于STMP文件tmp/info/.files-packageinfo.stamp，所以先生成所有包的.packageinfo文件，然后根据列表文件生成stamp和校验文件：tmp/info/.files-packageinfo.stamp.9f3effc0f07721f7b26eca3d95cc2f4c。最后，将所有的包的.packageinfo合并成tmp/.packageinfo。