1# 2# Copyright OpenEmbedded Contributors 3# 4# SPDX-License-Identifier: MIT 5# 6 7# Class for setting up /etc in overlayfs 8# 9# In order to have /etc directory in overlayfs a special handling at early boot stage is required 10# The idea is to supply a custom init script that mounts /etc before launching actual init program, 11# because the latter already requires /etc to be mounted 12# 13# The configuration must be machine specific. You should at least set these three variables: 14# OVERLAYFS_ETC_MOUNT_POINT ?= "/data" 15# OVERLAYFS_ETC_FSTYPE ?= "ext4" 16# OVERLAYFS_ETC_DEVICE ?= "/dev/mmcblk0p2" 17# 18# To control more mount options you should consider setting mount options: 19# OVERLAYFS_ETC_MOUNT_OPTIONS ?= "defaults" 20# 21# The class provides two options for /sbin/init generation 22# 1. Default option is to rename original /sbin/init to /sbin/init.orig and place generated init under 23# original name, i.e. /sbin/init. It has an advantage that you won't need to change any kernel 24# parameters in order to make it work, but it poses a restriction that package-management can't 25# be used, becaause updating init manager would remove generated script 26# 2. If you are would like to keep original init as is, you can set 27# OVERLAYFS_ETC_USE_ORIG_INIT_NAME = "0" 28# Then generated init will be named /sbin/preinit and you would need to extend you kernel parameters 29# manually in your bootloader configuration. 30# 31# Regardless which mode you choose, update and migration strategy of configuration files under /etc 32# overlay is out of scope of this class 33 34ROOTFS_POSTPROCESS_COMMAND += '${@bb.utils.contains("IMAGE_FEATURES", "overlayfs-etc", "create_overlayfs_etc_preinit", "", d)}' 35IMAGE_FEATURES_CONFLICTS_overlayfs-etc = "${@ 'package-management' if bb.utils.to_boolean(d.getVar('OVERLAYFS_ETC_USE_ORIG_INIT_NAME'), True) else ''}" 36 37OVERLAYFS_ETC_MOUNT_POINT ??= "" 38OVERLAYFS_ETC_FSTYPE ??= "" 39OVERLAYFS_ETC_DEVICE ??= "" 40OVERLAYFS_ETC_USE_ORIG_INIT_NAME ??= "1" 41OVERLAYFS_ETC_MOUNT_OPTIONS ??= "defaults" 42OVERLAYFS_ETC_INIT_TEMPLATE ??= "${COREBASE}/meta/files/overlayfs-etc-preinit.sh.in" 43OVERLAYFS_ETC_EXPOSE_LOWER ??= "0" 44OVERLAYFS_ETC_CREATE_MOUNT_DIRS ??= "1" 45 46python create_overlayfs_etc_preinit() { 47 overlayEtcMountPoint = d.getVar("OVERLAYFS_ETC_MOUNT_POINT") 48 overlayEtcFsType = d.getVar("OVERLAYFS_ETC_FSTYPE") 49 overlayEtcDevice = d.getVar("OVERLAYFS_ETC_DEVICE") 50 51 if not overlayEtcMountPoint: 52 bb.fatal("OVERLAYFS_ETC_MOUNT_POINT must be set in your MACHINE configuration") 53 if not overlayEtcDevice: 54 bb.fatal("OVERLAYFS_ETC_DEVICE must be set in your MACHINE configuration") 55 if not overlayEtcFsType: 56 bb.fatal("OVERLAYFS_ETC_FSTYPE should contain a valid file system type on {0}".format(overlayEtcDevice)) 57 58 with open(d.getVar("OVERLAYFS_ETC_INIT_TEMPLATE"), "r") as f: 59 PreinitTemplate = f.read() 60 61 useOrigInit = oe.types.boolean(d.getVar('OVERLAYFS_ETC_USE_ORIG_INIT_NAME')) 62 preinitPath = oe.path.join(d.getVar("IMAGE_ROOTFS"), d.getVar("base_sbindir"), "preinit") 63 initBaseName = oe.path.join(d.getVar("base_sbindir"), "init") 64 origInitNameSuffix = ".orig" 65 exposeLower = oe.types.boolean(d.getVar('OVERLAYFS_ETC_EXPOSE_LOWER')) 66 createMoundDirs = oe.types.boolean(d.getVar('OVERLAYFS_ETC_CREATE_MOUNT_DIRS')) 67 68 args = { 69 'OVERLAYFS_ETC_MOUNT_POINT': overlayEtcMountPoint, 70 'OVERLAYFS_ETC_MOUNT_OPTIONS': d.getVar('OVERLAYFS_ETC_MOUNT_OPTIONS'), 71 'OVERLAYFS_ETC_FSTYPE': overlayEtcFsType, 72 'OVERLAYFS_ETC_DEVICE': overlayEtcDevice, 73 'SBIN_INIT_NAME': initBaseName + origInitNameSuffix if useOrigInit else initBaseName, 74 'OVERLAYFS_ETC_EXPOSE_LOWER': "true" if exposeLower else "false", 75 'CREATE_MOUNT_DIRS': "true" if createMoundDirs else "false" 76 } 77 78 if useOrigInit: 79 # rename original /sbin/init 80 origInit = oe.path.join(d.getVar("IMAGE_ROOTFS"), initBaseName) 81 bb.debug(1, "rootfs path %s, init path %s, test %s" % (d.getVar('IMAGE_ROOTFS'), origInit, d.getVar("IMAGE_ROOTFS"))) 82 bb.utils.rename(origInit, origInit + origInitNameSuffix) 83 preinitPath = origInit 84 85 with open(preinitPath, 'w') as f: 86 f.write(PreinitTemplate.format(**args)) 87 os.chmod(preinitPath, 0o755) 88} 89