dracut/0017-feat-squash-move-mksquashfs-to-99squash-modules-setu.patch

From bbb64f449a4f3cd76ea63d73ebc1043a3dd14118 Mon Sep 17 00:00:00 2001
From: Philipp Rudo <prudo@redhat.com>
Date: Mon, 22 Jul 2024 16:30:50 +0200
Subject: [PATCH 17/24] feat(squash): move mksquashfs to 99squash/modules-setup

When using 99squash dracut actually builds two separat initrds. The
"normal" one, that gets squashed into a squashfs image, and a
"minimalistic" one, whose only task is to mount and switch_root to the
squashfs image.

For that 99squash currently requires a lot of special handling in
dracut.sh. Move most of this special handling into 99squash itself. This
requires a new approach when building the "minimalistic" initrd. The new
approach works the following way

1. During the installation phase install the "normal" initrd into
   $initdir and the "minimalistic" initrd into $squashdir.
2. Strip the binaries in $initdir.
3. Trigger a special postinstall hook in 99squash that squashes the
   content of $initdir (excluding $squashdir) into the squashfs image,
   removes the content of $intidir (excluding $suqashdir) and, moves the
   content of $squashdir into $initdir.

Signed-off-by: Philipp Rudo <prudo@redhat.com>

(cherry picked from commit 7a4dd89ca732329893628b886fe8e78337d896e8)

Related: RHEL-43460
---
 dracut.sh                          | 35 ++++--------------
 modules.d/99squash/module-setup.sh | 58 +++++++++++++++++++++---------
 2 files changed, 49 insertions(+), 44 deletions(-)

diff --git a/dracut.sh b/dracut.sh
index cc6d6f28..68bdf33b 100755
--- a/dracut.sh
+++ b/dracut.sh
@@ -1277,6 +1277,7 @@ trap '
 trap 'exit 1;' SIGINT
 
 readonly initdir="${DRACUT_TMPDIR}/initramfs"
+readonly squashdir="$initdir/squash_root"
 mkdir -p "$initdir"
 
 if [[ $early_microcode == yes ]] || { [[ $acpi_override == yes ]] && [[ -d $acpi_table_dir ]]; }; then
@@ -1804,7 +1805,8 @@ export initdir dracutbasedir \
     host_fs_types host_devs swap_devs sshkey add_fstab \
     DRACUT_VERSION \
     prefix filesystems drivers \
-    hostonly_cmdline loginstall
+    hostonly_cmdline loginstall \
+    squashdir squash_compress
 
 mods_to_load=""
 # check all our modules to see if they should be sourced.
@@ -1909,6 +1911,8 @@ if [[ $kernel_only != yes ]]; then
     fi
 fi
 
+dracut_module_included "squash" && mkdir -p "$squashdir"
+
 _isize=0 #initramfs size
 modules_loaded=" "
 # source our modules.
@@ -2255,14 +2259,6 @@ if [[ $kernel_only != yes ]]; then
     build_ld_cache
 fi
 
-if dracut_module_included "squash"; then
-    readonly squash_dir="$initdir/squash/root"
-    readonly squash_img="$initdir/squash-root.img"
-    mkdir -p "$squash_dir"
-    dinfo "*** Install squash loader ***"
-    DRACUT_SQUASH_POST_INST=1 module_install "squash"
-fi
-
 if [[ $do_strip == yes ]] && ! [[ $DRACUT_FIPS_MODE ]]; then
     # stripping files negates (dedup) benefits of using reflink
     [[ -n $enhanced_cpio ]] && ddebug "strip is enabled alongside cpio reflink"
@@ -2282,25 +2278,8 @@ fi
 
 if dracut_module_included "squash"; then
     dinfo "*** Squashing the files inside the initramfs ***"
-    declare squash_compress_arg
-    # shellcheck disable=SC2086
-    if [[ $squash_compress ]]; then
-        if ! mksquashfs /dev/null "$DRACUT_TMPDIR"/.squash-test.img -no-progress -comp $squash_compress &> /dev/null; then
-            dwarn "mksquashfs doesn't support compressor '$squash_compress', failing back to default compressor."
-        else
-            squash_compress_arg="$squash_compress"
-        fi
-    fi
-
-    # shellcheck disable=SC2086
-    if ! mksquashfs "$squash_dir" "$squash_img" \
-        -no-xattrs -no-exports -noappend -no-recovery -always-use-fragments \
-        -no-progress ${squash_compress_arg:+-comp $squash_compress_arg} 1> /dev/null; then
-        dfatal "Failed making squash image"
-        exit 1
-    fi
-
-    rm -rf "$squash_dir"
+    DRACUT_SQUASH_POST_INST=1 module_install "squash"
+    rm -rf "$squashdir"
     dinfo "*** Squashing the files inside the initramfs done ***"
 
     # Skip initramfs compress
diff --git a/modules.d/99squash/module-setup.sh b/modules.d/99squash/module-setup.sh
index dc2e0a20..96d097af 100755
--- a/modules.d/99squash/module-setup.sh
+++ b/modules.d/99squash/module-setup.sh
@@ -12,26 +12,13 @@ depends() {
     return 0
 }
 
-installpost() {
+squash_install() {
     local _busybox
     _busybox=$(find_binary busybox)
 
-    # Move everything under $initdir except $squash_dir
-    # itself into squash image
-    for i in "$initdir"/*; do
-        [[ $squash_dir == "$i"/* ]] || mv "$i" "$squash_dir"/
-    done
-
     # Create mount points for squash loader
     mkdir -p "$initdir"/squash/
-    mkdir -p "$squash_dir"/squash/
-
-    # Copy dracut spec files out side of the squash image
-    # so dracut rebuild and lsinitrd can work
-    for file in "$squash_dir"/usr/lib/dracut/*; do
-        [[ -f $file ]] || continue
-        DRACUT_RESOLVE_DEPS=1 dracutsysrootdir="$squash_dir" inst "${file#"$squash_dir"}"
-    done
+    mkdir -p "$squashdir"/squash/
 
     # Install required modules and binaries for the squash image init script.
     if [[ $_busybox ]]; then
@@ -61,8 +48,47 @@ installpost() {
     build_ld_cache
 }
 
+squash_installpost() {
+    local _img="$squashdir"/squash-root.img
+    local _comp _file
+
+    # shellcheck disable=SC2086
+    if [[ $squash_compress ]]; then
+        if ! mksquashfs /dev/null "$DRACUT_TMPDIR"/.squash-test.img -no-progress -comp $squash_compress &> /dev/null; then
+            dwarn "mksquashfs doesn't support compressor '$squash_compress', failing back to default compressor."
+        else
+            _comp="$squash_compress"
+        fi
+    fi
+
+    # shellcheck disable=SC2086
+    if ! mksquashfs "$initdir" "$_img" \
+        -no-xattrs -no-exports -noappend -no-recovery -always-use-fragments \
+        -no-progress ${_comp:+-comp $_comp} \
+        -e "$squashdir" 1> /dev/null; then
+        dfatal "Failed making squash image"
+        exit 1
+    fi
+
+    # Rescue the dracut spec files so dracut rebuild and lsinitrd can work
+    for _file in "$initdir"/usr/lib/dracut/*; do
+        [[ -f $_file ]] || continue
+        DRACUT_RESOLVE_DEPS=1 dstdir=$squashdir inst "$_file" "${_file#"$initdir"}"
+    done
+
+    # Remove everything that got squashed into the image
+    for _file in "$initdir"/*; do
+        [[ $_file == "$squashdir" ]] && continue
+        rm -rf "$_file"
+    done
+    mv "$squashdir"/* "$initdir"
+}
+
 install() {
+
     if [[ $DRACUT_SQUASH_POST_INST ]]; then
-        installpost
+        squash_installpost
+    else
+        dstdir="$squashdir" squash_install
     fi
 }
-- 
2.42.0