So far, /squash/root.img was the only squash'ed file in the initramfs
image. But with the introduction of '--squash-input-images' option,
initramfs image can have more than one squash'ed images. Make squash
image setup flexible to leverage the new option.
For that purpose, add 'setup-sqaush-conditional.sh' script which is
same as 'setup-squash.sh' script except for a couple of changes.
One, it sources 'squash-image-conditional.sh' script. Two, it calls
setup_squash_image_conditional() function implemented in the sourced
script before mounting the squash image (/squash/root.img).
'squash-image-conditional.sh' script here has a dummy implementation
for setup_squash_image_conditional() function. Introduce a new dracut
option '--squash-image-conditional' to overwrite the stock script
(squash/squash-image-conditional.sh) with a custom script.
Usage: dracut --squash-image-conditional custom-script.sh
The 'custom-script.sh' script file is expected to be implemented in
such a way that /squash/root.img file is updated appropriately, on
calling setup_squash_image_conditional() function, for every possible
boot scenario.
Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxx>
---
dracut.sh | 26 ++++++++--
modules.d/99squash/module-setup.sh | 17 ++++++
modules.d/99squash/setup-squash-conditional.sh | 65 ++++++++++++++++++++++++
modules.d/99squash/squash-image-conditional.sh | 5 ++
4 files changed, 109 insertions(+), 4 deletions(-)
create mode 100755 modules.d/99squash/setup-squash-conditional.sh
create mode 100755 modules.d/99squash/squash-image-conditional.sh
diff --git a/dracut.sh b/dracut.sh
index 1a84a707..5fdb4104 100755
--- a/dracut.sh
+++ b/dracut.sh
@@ -90,6 +90,14 @@ Creates initial ramdisk images for preloading modules
/squash/root1.img, /squash/root2.img, etc., squash
images are created, one each for each input initramfs
image provided, in that order.
+ --squash-image-conditional [FILE]
+ Install a custom script [FILE] in place of
+ '/squash/squash-image-conditional.sh' file to override
+ setup_squash_image_conditional() function's dummy
+ implementation with the one that updates squash image
+ appropriately for every possible boot scenario on the
+ given system. (Ideally, used in combination with
+ --squash-input-images option).
-m, --modules [LIST] Specify a space-separated list of dracut modules to
call when building the initramfs. Modules are located
in /usr/lib/dracut/modules.d.
@@ -382,6 +390,7 @@ rearrange_params()
--long prefix: \
--long rebuild: \
--long squash-input-images: \
+ --long squash-image-conditional: \
--long force \
--long kernel-only \
--long no-kernel \
@@ -588,7 +597,8 @@ eval set -- "$TEMP"
while :; do
if [[ $1 != "--" ]] && [[ $1 != "--rebuild" ]]; then
- [[ $1 != "--squash-input-images" ]] && PARMS_TO_STORE+=" $1";
+ [[ $1 != "--squash-input-images" ]] \
+ && [[ $1 != "--squash-image-conditional" ]] && PARMS_TO_STORE+=" $1";
fi
case $1 in
--kver) kernel="$2"; PARMS_TO_STORE+=" '$2'"; shift;;
@@ -627,6 +637,7 @@ while :; do
shift
;;
--squash-input-images) squash_input_images_l=("$2"); shift;;
+ --squash-image-conditional) squash_image_conditional="$2"; shift;;
-f|--force) force=yes;;
--kernel-only) kernel_only="yes"; no_kernel="no";;
--no-kernel) kernel_only="no"; no_kernel="yes";;
@@ -728,7 +739,7 @@ while (($# > 0)); do
shift
done
-# error check --squash-input-images & prepare squash_input_images
+# error check squash related options & get absolute paths for the files provided.
unset squash_input_images
for _input_file in $squash_input_images_l; do
if [[ ! -e "$_input_file" ]]; then
@@ -739,6 +750,12 @@ for _input_file in $squash_input_images_l; do
squash_input_images+=("$_input_file ")
done
+if [[ -n "$squash_image_conditional" ]] && [[ ! -e "$squash_image_conditional" ]]; then
+ echo "dracut: script file '$squash_image_conditional' to setup squash image, does not exist!"
+ exit 1
+fi
+_abs_sqsh_img_cond="$(readlink -f "$squash_image_conditional")" && squash_image_conditional="$_abs_sqsh_img_cond"
+
[[ $sysroot_l ]] && dracutsysrootdir="$sysroot_l"
if [[ $regenerate_all == "yes" ]]; then
@@ -1704,7 +1721,7 @@ export initdir dracutbasedir \
systemdutildir systemdutilconfdir systemdcatalog systemdntpunits \
systemdntpunitsconfdir systemdsystemunitdir systemdsystemconfdir \
hostonly_cmdline loginstall \
- squash_input_images \
+ squash_input_images squash_image_conditional \
tmpfilesdir
mods_to_load=""
@@ -2133,6 +2150,9 @@ if dracut_module_included "squash"; then
# We have moved them inside the squashed image, but they need to be
# accessible before mounting the image.
inst_multiple "echo" "sh" "mount" "modprobe" "mkdir"
+ if [[ -n "$squash_input_images" ]] || [[ -f "$squash_image_conditional" ]]; then
+ inst_multiple "mv" "rm"
+ fi
hostonly="" instmods "loop" "squashfs" "overlay"
# Only keep systemctl outsite if we need switch root
if [[ ! -f "$initdir/lib/dracut/no-switch-root" ]]; then
diff --git a/modules.d/99squash/module-setup.sh b/modules.d/99squash/module-setup.sh
index 9f973bda..a5d356ba 100644
--- a/modules.d/99squash/module-setup.sh
+++ b/modules.d/99squash/module-setup.sh
@@ -10,6 +10,11 @@ check() {
fi
done
+ # Include if '--squash-input-images' or '--squash-image-conditional' is used.
+ if [[ -n "$squash_input_images" ]] || [[ -f "$squash_image_conditional" ]]; then
+ return 0
+ fi
+
return 255
}
@@ -24,7 +29,17 @@ installkernel() {
install() {
inst_multiple kmod modprobe mount mkdir ln echo
- inst "$moddir"/setup-squash.sh /squash/setup-squash.sh
+ if [[ -n "$squash_input_images" ]] || [[ -f "$squash_image_conditional" ]]; then
+ inst $moddir/setup-squash-conditional.sh /squash/setup-squash.sh
+ if [[ -f "$squash_image_conditional" ]]; then
+ inst "$squash_image_conditional" /squash/squash-image-conditional.sh
+ chmod 0755 "$initdir/squash/squash-image-conditional.sh"
+ else
+ inst $moddir/squash-image-conditional.sh /squash/squash-image-conditional.sh
+ fi
+ else
+ inst $moddir/setup-squash.sh /squash/setup-squash.sh
+ fi
inst "$moddir"/clear-squash.sh /squash/clear-squash.sh
inst "$moddir"/init.sh /squash/init.sh
diff --git a/modules.d/99squash/setup-squash-conditional.sh b/modules.d/99squash/setup-squash-conditional.sh
new file mode 100755
index 00000000..41616756
--- /dev/null
+++ b/modules.d/99squash/setup-squash-conditional.sh
@@ -0,0 +1,65 @@
+#!/bin/bash
+PATH=/bin:/sbin
+
+SQUASH_IMG=/squash/root.img
+SQUASH_MNT=/squash/root
+SQUASH_MNT_REC=/squash/mounts
+
+. /squash/squash-image-conditional.sh
+
+echo $SQUASH_MNT > $SQUASH_MNT_REC
+
+# Following mount points are neccessary for mounting a squash image
+
+[ ! -d /proc/self ] && \
+ mount -t proc -o nosuid,noexec,nodev proc /proc
+
+[ ! -d /sys/kernel ] && \
+ mount -t sysfs -o nosuid,noexec,nodev sysfs /sys
+
+[ ! -e /dev/loop-control ] && \
+ mount -t devtmpfs -o mode=0755,noexec,nosuid,strictatime devtmpfs /dev
+
+# Need a loop device backend, overlayfs, and squashfs module
+modprobe loop
+if [ $? != 0 ]; then
+ echo "Unable to setup loop module"
+fi
+
+modprobe squashfs
+if [ $? != 0 ]; then
+ echo "Unable to setup squashfs module"
+fi
+
+modprobe overlay
+if [ $? != 0 ]; then
+ echo "Unable to setup overlay module"
+fi
+
+setup_squash_image_conditional
+
+[ ! -d "$SQUASH_MNT" ] && \
+ mkdir -m 0755 -p $SQUASH_MNT
+
+# Mount the squashfs image
+mount -t squashfs -o ro,loop $SQUASH_IMG $SQUASH_MNT
+
+if [ $? != 0 ]; then
+ echo "Unable to mount squashed initramfs image"
+fi
+
+for file in $SQUASH_MNT/*; do
+ file=${file#$SQUASH_MNT/}
+ lowerdir=$SQUASH_MNT/$file
+ workdir=/squash/overlay-work/$file
+ upperdir=/$file
+ mntdir=/$file
+
+ mkdir -m 0755 -p $workdir
+ mkdir -m 0755 -p $mntdir
+
+ mount -t overlay overlay -o\
+ lowerdir=$lowerdir,upperdir=$upperdir,workdir=$workdir $mntdir
+
+ echo $mntdir >> $SQUASH_MNT_REC
+done
diff --git a/modules.d/99squash/squash-image-conditional.sh b/modules.d/99squash/squash-image-conditional.sh
new file mode 100755
index 00000000..2097b767
--- /dev/null
+++ b/modules.d/99squash/squash-image-conditional.sh
@@ -0,0 +1,5 @@
+#!/bin/bash
+
+setup_squash_image_conditional() {
+ return 0
+}
