yocto machine class解析之st-partitions-image

stm32mp157 yocto的meta-st-stm32mp layer中提供了几个class,后续几篇文章重点分析这些class文件：
第一篇就从st-partitions-image.bbclass 开始，st所有创建image的bb文件都会引用st-partitions-image，包括bootfs userfs vendorfs等image的bb 文件。这个class会在image编译以后生成分区镜像。

ENABLE_PARTITIONS_IMAGE ?= "1"PARTITIONS_CONFIG ??= "" PARTITIONS_IMAGE ??= "" PARTITIONS_MOUNTPOINT ??= ""python __anonymous () {# We check first if it is requested to generate any partition imagesif d.getVar('ENABLE_PARTITIONS_IMAGE') != "1":bb.note('ENABLE_PARTITIONS_IMAGE not enabled')return# -----------------------------------------------------------------------------# Update the partition configuration set by user# -----------------------------------------------------------------------------partitionsconfigflags = d.getVarFlags('PARTITIONS_CONFIG')# The "doc" varflag is special, we don't want to see it herepartitionsconfigflags.pop('doc', None)partitionsconfig = (d.getVar('PARTITIONS_CONFIG') or "").split()# Init image_summary_listimage_summary_list = ''if len(partitionsconfig) > 0:for config in partitionsconfig:for f, v in partitionsconfigflags.items():if config == f:items = v.split(',')if items[0]:if len(items) > 5:raise bb.parse.SkipRecipe('Only image,label,mountpoint,size,type can be specified!')# Make sure that we're dealing with partition image and not rootfs imageif len(items) > 2 and items[2]:# Mount point available, so we're dealing with partition image# PARTITIONS_IMAGE appendingbb.debug(1, "Appending '%s' to PARTITIONS_IMAGE." % items[0])d.appendVar('PARTITIONS_IMAGE', ' ' + items[0])# PARTITIONS_MOUNTPOINT appendingbb.debug(1, "Appending '%s' to PARTITIONS_MOUNTPOINT." % items[2])d.appendVar('PARTITIONS_MOUNTPOINT', ' ' + items[2])# Update IMAGE vars for each partition imageif items[1]:bb.debug(1, "Set UBI_VOLNAME to %s for %s partition image." % (items[1], items[0]))d.setVar('UBI_VOLNAME_pn-%s' % d.expand(items[0]), items[1])if d.expand(items[1])[-2:] != 'fs':bb.debug(1, "Set IMAGE_NAME_SUFFIX to '.%sfs' for %s partition image." % (items[1], items[0]))d.setVar('IMAGE_NAME_SUFFIX_pn-%s' % d.expand(items[0]), '.' + items[1] + 'fs')else:bb.debug(1, "Set IMAGE_NAME_SUFFIX to '.%s' for %s partition image." % (items[1], items[0]))d.setVar('IMAGE_NAME_SUFFIX_pn-%s' % d.expand(items[0]), '.' + items[1])else:bb.fatal('[PARTITIONS_CONFIG] Missing label setting for %s image' % items[0])if items[2]:bb.debug(1, "Set IMAGE_PARTITION_MOUNTPOINT to %s for %s partition image." % (items[2], items[0]))d.setVar('IMAGE_PARTITION_MOUNTPOINT_pn-%s' % d.expand(items[0]), items[2])if items[3]:bb.debug(1, "Set IMAGE_ROOTFS_SIZE to %s for %s partition image." % (items[3], items[0]))d.setVar('IMAGE_ROOTFS_SIZE_pn-%s' % d.expand(items[0]), items[3])else:bb.fatal('[PARTITIONS_CONFIG] Missing size setting for %s image' % items[0])# Manage IMAGE_SUMMARY_LIST configuration according to PARTITION_CONFIG setif d.getVar('ENABLE_IMAGE_LICENSE_SUMMARY') == "1":if not items[2]:# Set '/' as default mountpoint for rootfs in IMAGE_SUMMARY_LISTitems[2] = '/'image_summary_list += items[0] + ':' + items[2] + ';'# Manage multiubi volume list STM32MP_UBI_VOLUMEif bb.utils.contains('IMAGE_FSTYPES', 'stmultiubi', True, False, d) and d.getVar('ENABLE_MULTIVOLUME_UBI') == "1":bb.debug(1, "Appending '%s' image with %s size to STM32MP_UBI_VOLUME." % (items[0], items[3]))d.appendVar('STM32MP_UBI_VOLUME', ' ' + items[0] + ':' + items[3])else:bb.fatal('[PARTITIONS_CONFIG] Missing image setting')break# Reset IMAGE_LIST_SUMMARY with computed partition configurationif d.getVar('ENABLE_IMAGE_LICENSE_SUMMARY') == "1":bb.debug(1, "Set IMAGE_SUMMARY_LIST with configuration: %s." % image_summary_list)d.setVar('IMAGE_SUMMARY_LIST', image_summary_list)# Init partition list from PARTITIONS_IMAGEimage_partitions = (d.getVar('PARTITIONS_IMAGE') or "").split()# -----------------------------------------------------------------------------# Make sure to append the partition build to current image target# -----------------------------------------------------------------------------if len(image_partitions) > 0:# Gather all current taskstasks = filter(lambda k: d.getVarFlag(k, "task", True), d.keys())for task in tasks:# Check that we are dealing with image recipeif task == 'do_image_complete':# Init current image namecurrent_image_name = d.getVar('PN') or ""# Init RAMFS image if anyinitramfs = d.getVar('INITRAMFS_IMAGE') or ""# Init INITRD image if anyinitrd = d.getVar('INITRD_IMAGE') or ""# We need to append partition images generation only to image# that are not one of the defined partitions and not the InitRAMFS image.# Without this check we would create circular dependencyif current_image_name not in image_partitions and current_image_name != initramfs and current_image_name != initrd:for partition in image_partitions:bb.debug(1, "Appending %s image build to 'do_image_complete' depends tasks." % partition)d.appendVarFlag('do_image_complete', 'depends', ' %s:do_image_complete' % partition)bb.debug(1, "Appending 'image_rootfs_image_clean_task' to IMAGE_PREPROCESS_COMMAND.")d.appendVar('IMAGE_PREPROCESS_COMMAND', 'image_rootfs_image_clean_task;')# Manage multiubi volume build enable for current imageif bb.utils.contains('IMAGE_FSTYPES', 'stmultiubi', True, False, d) and d.getVar('ENABLE_MULTIVOLUME_UBI') == "1":bb.debug(1, "Appending 'st_multivolume_ubifs' to IMAGE_POSTPROCESS_COMMAND.")d.appendVar('IMAGE_POSTPROCESS_COMMAND', 'st_multivolume_ubifs;') }image_rootfs_image_clean_task() {bbnote "PARTITIONS_IMAGE"bbnote ">>> ${PARTITIONS_IMAGE}"bbnote "PARTITIONS_MOUNTPOINT"bbnote ">>> ${PARTITIONS_MOUNTPOINT}"unset i jfor img in ${PARTITIONS_IMAGE}; doi=$(expr $i + 1);for part in ${PARTITIONS_MOUNTPOINT}; doj=$(expr $j + 1);if [ $j -eq $i ]; thenbbnote "Expecting to clean folder:"bbnote ">>> ${IMAGE_ROOTFS}/$part"if [ -d ${IMAGE_ROOTFS}/$part ]; thenrm -rf ${IMAGE_ROOTFS}/$part/*bbnote ">>> DONE"elsebbnote ">>> NOT DONE : $part folder doesn't exist in image rootfs"fifidoneunset jdoneunset i }

st-partitions-image.bbclass 整个文件看起来比较长，其实里面大部分都是调试日志。 总共有几部分组成：

重要的三个变量
ENABLE_PARTITIONS_IMAGE:用来控制是否使能生成分区镜像，在镜像bb文件中可以覆盖此变量控制该class的功能
PARTITIONS_CONFIG：设置的分区配置
PARTITIONS_IMAGE：分区镜像的名字
PARTITIONS_MOUNTPOINT：分区镜像的挂载点

一个匿名函数
以PARTITIONS_CONFIG 为输入，PARTITIONS_IMAGE 和PARTITIONS_MOUNTPOINT 为输出
通过bitbake -e fs-mp1a-qt可以先看一下最终的变量值：

PARTITIONS_CONFIG=" bootfs vendorfs rootfs userfs" //PARTITIONS_CONFIG[xxxfs] 字段含义 // "${STM32MP_XXFS_IMAGE},${STM32MP_XXFS_LABEL},${STM32MP_XXFS_MOUNTPOINT},${XXFS_PARTITION_SIZE},System"PARTITIONS_CONFIG[bootfs] ?= "st-image-bootfs,boot,/boot,65536,System" PARTITIONS_CONFIG[vendorfs] ?= "st-image-vendorfs,vendorfs,/vendor,16384,FileSystem" PARTITIONS_CONFIG[rootfs] ?= "fs-mp1a-qt-openstlinux-eglfs,rootfs,1253376,FileSystem" PARTITIONS_CONFIG[userfs] ?= "st-image-userfs,userfs,/usr/local,131072,FileSystem"PARTITIONS_IMAGE=" st-image-bootfs st-image-vendorfs st-image-userfs" PARTITIONS_MOUNTPOINT=" /boot /vendor /usr/local"

下面详细分析python __anonymous是怎么处理的：
输入变量PARTITIONS_CONFIG：
PARTITIONS_CONFIG=" bootfs vendorfs rootfs userfs"
PARTITIONS_CONFIG[bootfs] ?= “st-image-bootfs,boot,/boot,65536,System”
PARTITIONS_CONFIG[vendorfs] ?= “st-image-vendorfs,vendorfs,/vendor,16384,FileSystem”
PARTITIONS_CONFIG[rootfs] ?= “fs-mp1a-qt-openstlinux-eglfs,rootfs,1253376,FileSystem”
PARTITIONS_CONFIG[userfs] ?= “st-image-userfs,userfs,/usr/local,131072,FileSystem”

partitionsconfigflags：
bootfs “st-image-bootfs,boot,/boot,65536,System”
vendorfs “st-image-vendorfs,vendorfs,/vendor,16384,FileSystem”
rootfs “fs-mp1a-qt-openstlinux-eglfs,rootfs,1253376,FileSystem”
userfs “st-image-userfs,userfs,/usr/local,131072,FileSystem”

partitionsconfig：
bootfs vendorfs rootfs userfs

for config in partitionsconfig:for f, v in partitionsconfigflags.items():if config == f:items = v.split(',')

上面这段判断可以知道(以第一个bootfs为例) items= {st-image-bootfs boot /boot 65536 System }

if len(items) > 2 and items[2]:# Mount point available, so we're dealing with partition image# PARTITIONS_IMAGE appendingbb.debug(1, "Appending '%s' to PARTITIONS_IMAGE." % items[0])d.appendVar('PARTITIONS_IMAGE', ' ' + items[0])# PARTITIONS_MOUNTPOINT appendingbb.debug(1, "Appending '%s' to PARTITIONS_MOUNTPOINT." % items[2])d.appendVar('PARTITIONS_MOUNTPOINT', ' ' + items[2])

如果items大于2且items[2]存在，则
PARTITIONS_IMAGE += items[0] //items[0] = st-image-bootfs
PARTITIONS_MOUNTPOINT += items[2] //items[2] = /boot

如此循环下来：
PARTITIONS_IMAGE =" st-image-bootfs st-image-vendorfs fs-mp1a-qt-openstlinux-eglfs st-image-userfs"
PARTITIONS_MOUNTPOINT=" /boot /vendor rootfs /usr/local"

这里PARTITIONS_MOUNTPOINT 和我们通过实际bitbake -e看到的环境变量对不上，我们接着往下分析

# Update IMAGE vars for each partition imageif items[1]:bb.debug(1, "Set UBI_VOLNAME to %s for %s partition image." % (items[1], items[0]))d.setVar('UBI_VOLNAME_pn-%s' % d.expand(items[0]), items[1])if d.expand(items[1])[-2:] != 'fs':bb.debug(1, "Set IMAGE_NAME_SUFFIX to '.%sfs' for %s partition image." % (items[1], items[0]))d.setVar('IMAGE_NAME_SUFFIX_pn-%s' % d.expand(items[0]), '.' + items[1] + 'fs')else:bb.debug(1, "Set IMAGE_NAME_SUFFIX to '.%s' for %s partition image." % (items[1], items[0]))d.setVar('IMAGE_NAME_SUFFIX_pn-%s' % d.expand(items[0]), '.' + items[1])else:bb.fatal('[PARTITIONS_CONFIG] Missing label setting for %s image' % items[0])if items[2]:bb.debug(1, "Set IMAGE_PARTITION_MOUNTPOINT to %s for %s partition image." % (items[2], items[0]))d.setVar('IMAGE_PARTITION_MOUNTPOINT_pn-%s' % d.expand(items[0]), items[2])if items[3]:bb.debug(1, "Set IMAGE_ROOTFS_SIZE to %s for %s partition image." % (items[3], items[0]))d.setVar('IMAGE_ROOTFS_SIZE_pn-%s' % d.expand(items[0]), items[3])else:bb.fatal('[PARTITIONS_CONFIG] Missing size setting for %s image' % items[0])

• 如果items[1]存在（以第一个bootfs为例）
  UBI_VOLNAME_pn-st-image-bootfs=/boot
• 如果items[1]的最后2位不是fs结尾则手动添加fs结尾以后设置IMAGE_NAME_SUFFIX_pn变量
  IMAGE_NAME_SUFFIX_pn-st-image-bootfs=.boot
• 如果items[2]存在
  IMAGE_PARTITION_MOUNTPOINT_pn-st-image-bootfs=/boot
• 如果items[3]存在
  IMAGE_ROOTFS_SIZE_pn-st-image-bootfs=65536

# Manage IMAGE_SUMMARY_LIST configuration according to PARTITION_CONFIG setif d.getVar('ENABLE_IMAGE_LICENSE_SUMMARY') == "1":if not items[2]:# Set '/' as default mountpoint for rootfs in IMAGE_SUMMARY_LISTitems[2] = '/'image_summary_list += items[0] + ':' + items[2] + ';'# Manage multiubi volume list STM32MP_UBI_VOLUMEif bb.utils.contains('IMAGE_FSTYPES', 'stmultiubi', True, False, d) and d.getVar('ENABLE_MULTIVOLUME_UBI') == "1":bb.debug(1, "Appending '%s' image with %s size to STM32MP_UBI_VOLUME." % (items[0], items[3]))d.appendVar('STM32MP_UBI_VOLUME', ' ' + items[0] + ':' + items[3])# Reset IMAGE_LIST_SUMMARY with computed partition configurationif d.getVar('ENABLE_IMAGE_LICENSE_SUMMARY') == "1":bb.debug(1, "Set IMAGE_SUMMARY_LIST with configuration: %s." % image_summary_list)d.setVar('IMAGE_SUMMARY_LIST', image_summary_list)

• 如果环境变量ENABLE_IMAGE_LICENSE_SUMMARY被设置
  image_summary_list += st-image-bootfs:/boot;
  循环下来image_summary_list=“st-image-bootfs:/boot;st-image-vendorfs:/vendor;fs-mp1a-qt-openstlinux-eglfs:rootfs;st-image-userfs:/usr/local;”
  IMAGE_SUMMARY_LIST = image_summary_list

• 如果IMAGE_FSTYPES 中包含stmultiubi类型且ENABLE_MULTIVOLUME_UBI变量被设置
  STM32MP_UBI_VOLUME +=" st-image-bootfs:65536"
  循环下来STM32MP_UBI_VOLUME=" st-image-bootfs:65536 st-image-vendorfs:16384 fs-mp1a-qt-openstlinux-eglfs:1253376 st-image-userfs:131072"

这里循环结束，总结一下设置了哪些变量：
PARTITIONS_IMAGE =" st-image-bootfs st-image-vendorfs fs-mp1a-qt-openstlinux-eglfs st-image-userfs"
PARTITIONS_MOUNTPOINT=" /boot /vendor rootfs /usr/local"

UBI_VOLNAME_pn-st-image-bootfs=/boot IMAGE_NAME_SUFFIX_pn-st-image-bootfs=.boot IMAGE_PARTITION_MOUNTPOINT_pn-st-image-bootfs=/boot IMAGE_ROOTFS_SIZE_pn-st-image-bootfs=65536

IMAGE_SUMMARY_LIST=“st-image-bootfs:/boot;st-image-vendorfs:/vendor;fs-mp1a-qt-openstlinux-eglfs:rootfs;st-image-userfs:/usr/local;”
STM32MP_UBI_VOLUME=" st-image-bootfs:65536 st-image-vendorfs:16384 fs-mp1a-qt-openstlinux-eglfs:1253376 st-image-userfs:131072"

继续分析

image_partitions = (d.getVar('PARTITIONS_IMAGE') or "").split()if len(image_partitions) > 0:# Gather all current taskstasks = filter(lambda k: d.getVarFlag(k, "task", True), d.keys())for task in tasks:# Check that we are dealing with image recipeif task == 'do_image_complete':# Init current image namecurrent_image_name = d.getVar('PN') or ""# Init RAMFS image if anyinitramfs = d.getVar('INITRAMFS_IMAGE') or ""# Init INITRD image if anyinitrd = d.getVar('INITRD_IMAGE') or ""# We need to append partition images generation only to image# that are not one of the defined partitions and not the InitRAMFS image.# Without this check we would create circular dependencyif current_image_name not in image_partitions and current_image_name != initramfs and current_image_name != initrd:for partition in image_partitions:bb.debug(1, "Appending %s image build to 'do_image_complete' depends tasks." % partition)d.appendVarFlag('do_image_complete', 'depends', ' %s:do_image_complete' % partition)bb.debug(1, "Appending 'image_rootfs_image_clean_task' to IMAGE_PREPROCESS_COMMAND.")d.appendVar('IMAGE_PREPROCESS_COMMAND', 'image_rootfs_image_clean_task;')# Manage multiubi volume build enable for current imageif bb.utils.contains('IMAGE_FSTYPES', 'stmultiubi', True, False, d) and d.getVar('ENABLE_MULTIVOLUME_UBI') == "1":bb.debug(1, "Appending 'st_multivolume_ubifs' to IMAGE_POSTPROCESS_COMMAND.")d.appendVar('IMAGE_POSTPROCESS_COMMAND', 'st_multivolume_ubifs;')

image_partitions = [“st-image-bootfs”, “st-image-vendorfs”, “fs-mp1a-qt-openstlinux-eglfs”, “st-image-userfs” ]
找到所有非initramfs 、initrd和 image_partitions中包含的image 的 do_image_complete的task，设置他们的依赖：
do_image_complete[depends] = st-image-bootfs:do_image_complete
do_image_complete[depends] = st-image-vendorfs:do_image_complete
do_image_complete[depends] = fs-mp1a-qt-openstlinux-eglfs:do_image_complete
do_image_complete[depends] = st-image-userfs:do_image_complete
IMAGE_POSTPROCESS_COMMAND+=st_multivolume_ubifs
到这里，可以看到所有的iamge 菜谱生成进行必须先等image_partitions 中的镜像生成以后才可以生成。

这部分分析结束，还有个疑问：bitbake中的变量里面没有rootfs相关的设置，但是分析下来是有的，这里等后续image生成流程都分析完了在回头看看是不是那里过滤掉了。
PARTITIONS_IMAGE=" st-image-bootfs st-image-vendorfs st-image-userfs"
PARTITIONS_MOUNTPOINT=" /boot /vendor /usr/local"

PARTITIONS_IMAGE =" st-image-bootfs st-image-vendorfs fs-mp1a-qt-openstlinux-eglfs st-image-userfs"
PARTITIONS_MOUNTPOINT=" /boot /vendor rootfs /usr/local"

一个 task
image_rootfs_image_clean_task

最后还生名了一个task，里面比较简单：

for img in ${PARTITIONS_IMAGE}; doi=$(expr $i + 1);for part in ${PARTITIONS_MOUNTPOINT}; doj=$(expr $j + 1);if [ $j -eq $i ]; thenbbnote "Expecting to clean folder:"bbnote ">>> ${IMAGE_ROOTFS}/$part"if [ -d ${IMAGE_ROOTFS}/$part ]; thenrm -rf ${IMAGE_ROOTFS}/$part/*bbnote ">>> DONE"elsebbnote ">>> NOT DONE : $part folder doesn't exist in image rootfs"fifidoneunset jdone

最终效果就是把tmp-glibc/work/fsmp1a-ostl-linux-gnueabi/fs-mp1a-qt/1.0-r0/rootfs/boot/*删除（以bootfs为例）

DONE

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