From 87f4900826bd4387a098fdb9a003e66a0ca057c8 Mon Sep 17 00:00:00 2001 From: Thierry Bultel Date: Mon, 15 Aug 2022 13:17:08 +0200 Subject: [PATCH] package/dracut: new host package Dracut is the tool used by desktop distributions to build initrds. In the embedded world, it can be very useful, too, for instance when wanting to create an initramfs for a system recovery mode. Whereas it is definitively possible to achieve this with buildroot, the process is to have a dedicated buildroot configuration for that, and perform a full build. Instead of doing that, dracut can pick the needed binaries/shared libraries, configuration files, or kernel modules from the 'target' directory. The advantage is to save build time, and also to have a consistency between the packages versions taken for the recovery and the production filesystem. The principle of dracut is based on the so-called 'dracut modules'. The modules determine what will be included in the initramfs. For example, one of dracut's modules checks the kernel modules that are included and also includes the corresponding firmware blobs. On the host, they are on host/lib/dracut/modules.d Each directory as a prefix number for the order of execution, and at least a "module-setup.sh" script. Dracut sources all of them, and typically calls the "check()" function, which is the placeholder for required binaries (that are aimed to be polulated in the initrd), then the "depends()" function, that lists other modules to depend on, and the "install()" function, that makes the actual work. Dracut was initially thought to work with systems using systemd, but it can also work without it. Do to so, every "systemd-xxx" module must be disabled in the dracut configuration file. For convenience, the 05busybox-init module is provided, to support busybox init system. Note that this module should *not* be enabled when using systemd init. It is therefore only installed if busybox init is selected. Musl and uClibc make assumptions about the existence of some symlinks that are not discoverable with readelf. Therefore, another module 05libc-links is provided that creates those links. The module is installed regardless of which libc is used - the script itself discovers if the links need to be installed based on which libc is found. Signed-off-by: Thierry Bultel [arnout@mind.be: many changes] Signed-off-by: Arnout Vandecappelle (Essensium/Mind) Cc: Adam Duskett [yann.morin.1998@free.fr: some additional fixups] Signed-off-by: Yann E. MORIN --- DEVELOPERS | 2 + package/Config.in.host | 1 + ...001-dracut.sh-don-t-unset-LD_PRELOAD.patch | 31 ++++++++++ package/dracut/Config.in.host | 9 +++ package/dracut/busybox-init-module-setup.sh | 59 +++++++++++++++++++ package/dracut/dracut.hash | 3 + package/dracut/dracut.mk | 48 +++++++++++++++ package/dracut/dracut_wrapper | 38 ++++++++++++ package/dracut/libc-links-module-setup.sh | 27 +++++++++ 9 files changed, 218 insertions(+) create mode 100644 package/dracut/0001-dracut.sh-don-t-unset-LD_PRELOAD.patch create mode 100644 package/dracut/Config.in.host create mode 100644 package/dracut/busybox-init-module-setup.sh create mode 100644 package/dracut/dracut.hash create mode 100644 package/dracut/dracut.mk create mode 100644 package/dracut/dracut_wrapper create mode 100755 package/dracut/libc-links-module-setup.sh diff --git a/DEVELOPERS b/DEVELOPERS index d2bd0d809a..4287fd9cf7 100644 --- a/DEVELOPERS +++ b/DEVELOPERS @@ -225,6 +225,7 @@ F: package/espeak/ N: Arnout Vandecappelle F: package/arp-scan/ F: package/dehydrated/ +F: package/dracut/ F: package/freescale-imx/firmware-imx/ F: package/freescale-imx/imx-lib/ F: package/libpagekite/ @@ -2796,6 +2797,7 @@ F: configs/beagleboardx15_defconfig F: package/pugixml/ N: Thierry Bultel +F: package/dracut/ F: package/mpd-mpc/ N: Thijs Vermeir diff --git a/package/Config.in.host b/package/Config.in.host index 99edeafece..f437ef680c 100644 --- a/package/Config.in.host +++ b/package/Config.in.host @@ -19,6 +19,7 @@ menu "Host utilities" source "package/dos2unix/Config.in.host" source "package/dosfstools/Config.in.host" source "package/doxygen/Config.in.host" + source "package/dracut/Config.in.host" source "package/dtc/Config.in.host" source "package/e2fsprogs/Config.in.host" source "package/e2tools/Config.in.host" diff --git a/package/dracut/0001-dracut.sh-don-t-unset-LD_PRELOAD.patch b/package/dracut/0001-dracut.sh-don-t-unset-LD_PRELOAD.patch new file mode 100644 index 0000000000..394917eeb0 --- /dev/null +++ b/package/dracut/0001-dracut.sh-don-t-unset-LD_PRELOAD.patch @@ -0,0 +1,31 @@ +From bb12f15856911d8532b569116da7dab4cbf107be Mon Sep 17 00:00:00 2001 +From: Thierry Bultel +Date: Mon, 10 Jan 2022 09:09:43 +0100 +Subject: [PATCH] dracut.sh: don't unset LD_PRELOAD + +LD_PRELOAD and LD_LIBRARY_PATH are needed to run under fakeroot. + +Signed-off-by: Thierry Bultel +Signed-off-by: Arnout Vandecappelle (Essensium/Mind) +[yann.morin.1998@free.fr: commit log also mentions LD_LIBRARY_PATH] +Signed-off-by: Yann E. MORIN +--- + dracut.sh | 2 -- + 1 file changed, 2 deletions(-) + +diff --git a/dracut.sh b/dracut.sh +index 60ac46f4..37f25b38 100755 +--- a/dracut.sh ++++ b/dracut.sh +@@ -868,8 +868,6 @@ export LC_ALL=C + export LANG=C + unset LC_MESSAGES + unset LC_CTYPE +-unset LD_LIBRARY_PATH +-unset LD_PRELOAD + unset GREP_OPTIONS + + export DRACUT_LOG_LEVEL=warning +-- +2.37.1 + diff --git a/package/dracut/Config.in.host b/package/dracut/Config.in.host new file mode 100644 index 0000000000..18f562b310 --- /dev/null +++ b/package/dracut/Config.in.host @@ -0,0 +1,9 @@ +config BR2_PACKAGE_HOST_DRACUT + bool + select BR2_PACKAGE_HOST_KMOD + help + dracut is used to create an initramfs image by + copying tools and files from an installed system + and combining it with the dracut framework. + + https://dracut.wiki.kernel.org diff --git a/package/dracut/busybox-init-module-setup.sh b/package/dracut/busybox-init-module-setup.sh new file mode 100644 index 0000000000..d6ea94350f --- /dev/null +++ b/package/dracut/busybox-init-module-setup.sh @@ -0,0 +1,59 @@ +#!/bin/bash + +check() { + require_binaries busybox || return 1 + return 0 +} + +depends() { + return 0 +} + +install_busybox_links() { + dir="${1}" + linkname="${2}" + + (cd "${dracutsysrootdir?}${dir}" && + for x in *; do + if [ "$(readlink "${x}")" = "${linkname}" ]; then + ln -sf "${linkname}" "${initdir?}/${dir}/${x}" + fi + done + ) +} + +install() { + inst_multiple /bin/busybox + + # wrapper script for early console; will launch /sbin/init + # after having mounted devtmpfs + inst_multiple /init + + if [ -e "${dracutsysrootdir?}/lib64" ]; then + ln -sf lib "${initdir?}/lib64" + ln -sf lib "${initdir?}/usr/lib64" + fi + + if [ -e "${dracutsysrootdir?}/lib32" ]; then + ln -sf lib "${initdir?}/lib32" + ln -sf lib "${initdir?}/usr/lib32" + fi + + install_busybox_links "/bin" "busybox" + install_busybox_links "/sbin" "../bin/busybox" + if [ ! -L "${dracutsysrootdir?}/bin" ]; then + install_busybox_links "/usr/bin" "../../bin/busybox" + install_busybox_links "/usr/sbin" "../../bin/busybox" + fi + + inst_multiple \ + /etc/inittab \ + /etc/init.d/rcS \ + /etc/init.d/rcK \ + /etc/issue \ + /etc/fstab \ + /etc/group \ + /etc/passwd \ + /etc/shadow \ + /etc/hostname +} diff --git a/package/dracut/dracut.hash b/package/dracut/dracut.hash new file mode 100644 index 0000000000..3cda736856 --- /dev/null +++ b/package/dracut/dracut.hash @@ -0,0 +1,3 @@ +# Locally computed +sha256 4baa08206cceeb124dbf1075a0daf774b5a8f144ce2e01d82a144af3020fd65b dracut-055.tar.xz +sha256 8177f97513213526df2cf6184d8ff986c675afb514d4e68a404010521b880643 COPYING diff --git a/package/dracut/dracut.mk b/package/dracut/dracut.mk new file mode 100644 index 0000000000..2b6a144aac --- /dev/null +++ b/package/dracut/dracut.mk @@ -0,0 +1,48 @@ +################################################################################ +# +# dracut +# +################################################################################ + +DRACUT_VERSION = 055 +DRACUT_SOURCE = dracut-$(DRACUT_VERSION).tar.xz +DRACUT_SITE = $(BR2_KERNEL_MIRROR)/linux/utils/boot/dracut +DRACUT_LICENSE = GPL-2.0 +DRACUT_LICENSE_FILES = COPYING + +HOST_DRACUT_DEPENDENCIES = host-pkgconf host-kmod host-prelink-cross + +define HOST_DRACUT_POST_INSTALL_WRAPPER_SCRIPT + mv $(HOST_DIR)/bin/dracut $(HOST_DIR)/bin/dracut.real + install -D -m 0755 $(HOST_DRACUT_PKGDIR)/dracut_wrapper \ + $(HOST_DIR)/bin/dracut +endef +HOST_DRACUT_POST_INSTALL_HOOKS += HOST_DRACUT_POST_INSTALL_WRAPPER_SCRIPT + +# When using uClibc or musl, there must be "ld-uClibc.so.1" or +# "ld-musl-x.so" symlinks, respectively - else the init process cannot +# start +define HOST_DRACUT_POST_INSTALL_LIBC_LINKS_MODULE + $(INSTALL) -D -m 0755 package/dracut/libc-links-module-setup.sh \ + $(HOST_DIR)/lib/dracut/modules.d/05libc-links/module-setup.sh +endef +HOST_DRACUT_POST_INSTALL_HOOKS += HOST_DRACUT_POST_INSTALL_LIBC_LINKS_MODULE + +ifeq ($(BR2_INIT_BUSYBOX),y) +# Dracut does not support busybox init (systemd init is assumed to work +# out of the box, though). It provides a busybox module, that does not +# use the same paths as buildroot, and is not meant to be used as an init +# system. +# So it is simpler for users to disable the standard 'busybox' module in +# the configuration file, and enable the "busybox-init' module instead. +# Note that setting the script as executable (0755) is not mandatory, +# but this is what dracut does on all its modules, so lets just conform +# to it. +define HOST_DRACUT_POST_INSTALL_BUSYBOX_INIT_MODULE + $(INSTALL) -D -m 0755 package/dracut/busybox-init-module-setup.sh \ + $(HOST_DIR)/lib/dracut/modules.d/05busybox-init/module-setup.sh +endef +HOST_DRACUT_POST_INSTALL_HOOKS += HOST_DRACUT_POST_INSTALL_BUSYBOX_INIT_MODULE +endif + +$(eval $(host-autotools-package)) diff --git a/package/dracut/dracut_wrapper b/package/dracut/dracut_wrapper new file mode 100644 index 0000000000..0464db17fe --- /dev/null +++ b/package/dracut/dracut_wrapper @@ -0,0 +1,38 @@ +#!/bin/bash +set -e + +# Find the --sysroot argument +sysroot= +next_arg=false +for arg; do + if ${next_arg}; then + next_arg=false + sysroot="${arg}" + continue # not break, in case there are more than one + fi + case "${arg}" in + (--sysroot|-r) + next_arg=true + continue + ;; + (--sysroot=*) + sysroot="${arg#*=}" + continue # not break, in case there are more than one + ;; + (-r?*) + sysroot="${arg#-r}" + continue # not break, in case there are more than one + ;; + esac +done +if [ -z "${sysroot}" ]; then + echo "${0}: --sysroot argument must be given." 1>&2 + exit 1 +fi + +topdir="$(dirname "$(realpath "$(dirname "${0}")")")" +export DRACUT_LDD="${topdir}/sbin/prelink-rtld --root='${sysroot}'" +export DRACUT_INSTALL="${topdir}/lib/dracut/dracut-install" +export DRACUT_LDCONFIG=/bin/true +export dracutbasedir="${topdir}/lib/dracut" +exec "${topdir}/bin/dracut.real" "${@}" diff --git a/package/dracut/libc-links-module-setup.sh b/package/dracut/libc-links-module-setup.sh new file mode 100755 index 0000000000..26ebc5bc84 --- /dev/null +++ b/package/dracut/libc-links-module-setup.sh @@ -0,0 +1,27 @@ +#!/bin/bash + +# Adds the missing links for uClibc or musl, if needed + +check() { + return 0 +} + +depends() { + return 0 +} + +install() { + # Despite of the fact that the listed dependency (reported by readelf -d) + # is purely /lib/libc.so, the musl symlink is needed anyway. + musl_link="$(find "${dracutsysrootdir?}/lib/" -name "ld-musl-*.so*")" + if [ -n "${musl_link}" ] ; then + ln -s libc.so "${initdir?}/lib/${musl_link##*/}" + fi + + # Same for uClibc, the listed dependency + # is ld-uClibc.so.1, the loader needs the ld-uClibc.so.0, too + uclibc_link="$(find "${dracutsysrootdir?}/lib/" -name "ld-uClibc-*.so*")" + if [ -n "$uclibc_link" ] ; then + ln -s ld-uClibc.so.1 "${initdir?}/lib/ld-uClibc.so.0" + fi +}