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