Refactor kernel image and initrd detection code

kernel installation is not always in a fixed location /boot, there are
multiple different style of kernel installation, and initramfs location
changes with kernel. The two files should be detected together and adapt
to different style.

To do so we use a list of known installation destinations, and a list
of possible kernel image and initrd names. Iterate the two list to
detect the installation location of the two files. If GRUB is in use,
the BOOT_IMAGE= cmdline from GRUB will also be considered. And also
prefers user specified config if given.

Previous atomic workaround is no longer needed as the new detection
method can cover that case.

Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>

dracut-early-kdump-module-setup.sh

@@ -21,18 +21,13 @@ depends() {
 }
 
 prepare_kernel_initrd() {
-    KDUMP_BOOTDIR=$(check_boot_dir "${KDUMP_BOOTDIR}")
-    if [ -z "$KDUMP_KERNELVER" ]; then
-        kdump_kver=`uname -r`
-        if [ "$kernel" != "$kdump_kver" ]; then
-            dwarn "Using current kernel version '$kdump_kver' for early kdump," \
+    prepare_kdump_bootinfo
+
+    # $kernel is a variable from dracut
+    if [ "$KDUMP_KERNELVER" != $kernel ]; then
+        dwarn "Using kernel version '$KDUMP_KERNELVER' for early kdump," \
             "but the initramfs is generated for kernel version '$kernel'"
     fi
-    else
-        kdump_kver=$KDUMP_KERNELVER
-    fi
-    KDUMP_KERNEL="${KDUMP_BOOTDIR}/${KDUMP_IMG}-${kdump_kver}${KDUMP_IMG_EXT}"
-    KDUMP_INITRD="${KDUMP_BOOTDIR}/initramfs-${kdump_kver}kdump.img"
 }
 
 install() {

kdump-lib.sh

@@ -666,24 +666,68 @@ prepare_kexec_args()
     echo $kexec_args
 }
 
-check_boot_dir()
+#
+# Detect initrd and kernel location, results are stored in global enviromental variables:
+# KDUMP_BOOTDIR, KDUMP_KERNELVER, KDUMP_KERNEL, DEFAULT_INITRD, and KDUMP_INITRD
+#
+# Expectes KDUMP_BOOTDIR, KDUMP_IMG, KDUMP_IMG_EXT, KDUMP_KERNELVER to be loaded from config already
+# and will prefer already set values so user can specify custom kernel/initramfs location
+#
+prepare_kdump_bootinfo()
 {
-    local kdump_bootdir=$1
-    #If user specify a boot dir for kdump kernel, let's use it. Otherwise
-    #check whether it's a atomic host. If yes parse the subdirectory under
-    #/boot; If not just find it under /boot.
-    if [ -n "$kdump_bootdir" ]; then
-        echo "$kdump_bootdir"
-        return
+    local boot_imglist boot_dirlist boot_initrdlist curr_kver="$(uname -r)"
+    local machine_id
+
+    if [ -z "$KDUMP_KERNELVER"]; then
+        KDUMP_KERNELVER="$(uname -r)"
     fi
 
-    if ! is_atomic || [ "$(uname -m)" = "s390x" ]; then
-        kdump_bootdir="/boot"
-    else
-        eval $(cat /proc/cmdline| grep "BOOT_IMAGE" | cut -d' ' -f1)
-        kdump_bootdir="/boot"$(dirname ${BOOT_IMAGE#*)})
+    read machine_id < /etc/machine-id
+    boot_dirlist=${KDUMP_BOOTDIR:-"/boot /boot/efi /efi /"}
+    boot_imglist="$KDUMP_IMG-$KDUMP_KERNELVER$KDUMP_IMG_EXT $machine_id/$KDUMP_KERNELVER/$KDUMP_IMG"
+
+    # Use BOOT_IMAGE as reference if possible, strip the GRUB root device prefix in (hd0,gpt1) format
+    local boot_img="$(cat /proc/cmdline | sed "s/^BOOT_IMAGE=\((\S*)\)\?\(\S*\) .*/\2/")"
+    if [ -n "$boot_img" ]; then
+        boot_imglist="$boot_img $boot_imglist"
+    fi
+
+    for dir in $boot_dirlist; do
+        for img in $boot_imglist; do
+            if [ -f "$dir/$img" ]; then
+                KDUMP_KERNEL=$(echo $dir/$img | tr -s '/')
+                break 2
+            fi
+        done
+    done
+
+    if ! [ -e "$KDUMP_KERNEL" ]; then
+        echo "Failed to detect kdump kernel location"
+        return 1
+    fi
+
+    # Set KDUMP_BOOTDIR to where kernel image is stored
+    KDUMP_BOOTDIR=$(dirname $KDUMP_KERNEL)
+
+    # Default initrd should just stay aside of kernel image, try to find it in KDUMP_BOOTDIR
+    boot_initrdlist="initramfs-$KDUMP_KERNELVER.img initrd"
+    for initrd in $boot_initrdlist; do
+        if [ -f "$KDUMP_BOOTDIR/$initrd" ]; then
+            DEFAULT_INITRD="$KDUMP_BOOTDIR/$initrd"
+            break
+        fi
+    done
+
+    # Get kdump initrd from default initrd filename
+    # initramfs-5.7.9-200.fc32.x86_64.img => initramfs-5.7.9-200.fc32.x86_64kdump.img
+    # initrd => initrdkdump
+    if [[ -z "$DEFAULT_INITRD" ]]; then
+        KDUMP_INITRD=${KDUMP_BOOTDIR}/initramfs-${KDUMP_KERNELVER}kdump.img
+    elif [[ $(basename $DEFAULT_INITRD) == *.* ]]; then
+        KDUMP_INITRD=${DEFAULT_INITRD%.*}kdump.${DEFAULT_INITRD##*.}
+    else
+        KDUMP_INITRD=${DEFAULT_INITRD}kdump
     fi
-    echo $kdump_bootdir
 }
 
 #

kdumpctl

@@ -2,6 +2,7 @@
 KEXEC=/sbin/kexec
 
 KDUMP_KERNELVER=""
+KDUMP_KERNEL=""
 KDUMP_COMMANDLINE=""
 KEXEC_ARGS=""
 KDUMP_CONFIG_FILE="/etc/kdump.conf"
@@ -13,6 +14,7 @@ INITRD_CHECKSUM_LOCATION="/boot/.fadump_initrd_checksum"
 DUMP_TARGET=""
 DEFAULT_INITRD=""
 DEFAULT_INITRD_BAK=""
+KDUMP_INITRD=""
 TARGET_INITRD=""
 FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump_registered"
 #kdump shall be the default dump mode
@@ -94,7 +96,7 @@ rebuild_fadump_initrd()
 	# this file tells the initrd is fadump enabled
 	touch /tmp/fadump.initramfs
 	target_initrd_tmp="$TARGET_INITRD.tmp"
-	$MKDUMPRD $target_initrd_tmp --rebuild $DEFAULT_INITRD_BAK --kver $kdump_kver \
+	$MKDUMPRD $target_initrd_tmp --rebuild $DEFAULT_INITRD_BAK --kver $KDUMP_KERNELVER \
 		-i /tmp/fadump.initramfs /etc/fadump.initramfs
 	if [ $? != 0 ]; then
 		echo "mkdumprd: failed to rebuild initrd with fadump support" >&2
@@ -118,7 +120,7 @@ check_earlykdump_is_enabled()
 
 rebuild_kdump_initrd()
 {
-	$MKDUMPRD $TARGET_INITRD $kdump_kver
+	$MKDUMPRD $TARGET_INITRD $KDUMP_KERNELVER
 	if [ $? != 0 ]; then
 		echo "mkdumprd: failed to make kdump initrd" >&2
 		return 1
@@ -189,6 +191,10 @@ backup_default_initrd()
 
 restore_default_initrd()
 {
+	if [ ! -f "$DEFAULT_INITRD" ]; then
+		return
+	fi
+
 	# If a backup initrd exists, we must be switching back from
 	# fadump to kdump. Restore the original default initrd.
 	if [ -f $DEFAULT_INITRD_BAK ] && [ -f $INITRD_CHECKSUM_LOCATION ]; then
@@ -301,18 +307,12 @@ get_pcs_cluster_modified_files()
 
 setup_initrd()
 {
-	KDUMP_BOOTDIR=$(check_boot_dir "${KDUMP_BOOTDIR}")
-
-	if [ -z "$KDUMP_KERNELVER" ]; then
-		kdump_kver=`uname -r`
-	else
-		kdump_kver=$KDUMP_KERNELVER
+	prepare_kdump_bootinfo
+	if [ $? -ne 0 ]; then
+		return 1
 	fi
 
-	kdump_kernel="${KDUMP_BOOTDIR}/${KDUMP_IMG}-${kdump_kver}${KDUMP_IMG_EXT}"
-
-	DEFAULT_INITRD="${KDUMP_BOOTDIR}/initramfs-`uname -r`.img"
-	DEFAULT_INITRD_BAK="${KDUMP_BOOTDIR}/.initramfs-`uname -r`.img.default"
+	DEFAULT_INITRD_BAK="$KDUMP_BOOTDIR/.$(basename $DEFAULT_INITRD).default"
 	if [ $DEFAULT_DUMP_MODE == "fadump" ]; then
 		TARGET_INITRD="$DEFAULT_INITRD"
 
@@ -320,7 +320,7 @@ setup_initrd()
 		# with fadump aware initrd
 		backup_default_initrd
 	else
-		TARGET_INITRD="${KDUMP_BOOTDIR}/initramfs-${kdump_kver}kdump.img"
+		TARGET_INITRD="$KDUMP_INITRD"
 
 		# check if a backup of default initrd exists. If yes,
 		# it signifies a switch from fadump mode. So, restore
@@ -360,25 +360,25 @@ check_files_modified()
 	EXTRA_BINS="$EXTRA_BINS $CHECK_FILES"
 	CHECK_FILES=`grep ^extra_bins $KDUMP_CONFIG_FILE | cut -d\  -f2-`
 	EXTRA_BINS="$EXTRA_BINS $CHECK_FILES"
-	files="$KDUMP_CONFIG_FILE $kdump_kernel $EXTRA_BINS $CORE_COLLECTOR"
+	files="$KDUMP_CONFIG_FILE $KDUMP_KERNEL $EXTRA_BINS $CORE_COLLECTOR"
 	[[ -e /etc/fstab ]] && files="$files /etc/fstab"
 
 	# Check for any updated extra module
 	EXTRA_MODULES="$(grep ^extra_modules $KDUMP_CONFIG_FILE | sed 's/^extra_modules\s*//')"
 	if [ -n "$EXTRA_MODULES" ]; then
-		if [ -e /lib/modules/$kdump_kver/modules.dep ]; then
-			files="$files /lib/modules/$kdump_kver/modules.dep"
+		if [ -e /lib/modules/$KDUMP_KERNELVER/modules.dep ]; then
+			files="$files /lib/modules/$KDUMP_KERNELVER/modules.dep"
 		fi
 		for _module in $EXTRA_MODULES; do
-			_module_file="$(modinfo --set-version "$kdump_kver" --filename "$_module" 2>/dev/null)"
+			_module_file="$(modinfo --set-version "$KDUMP_KERNELVER" --filename "$_module" 2>/dev/null)"
 			if [[ $? -eq 0 ]]; then
 				files="$files $_module_file"
 				for _dep_modules in $(modinfo -F depends $_module | tr ',' ' '); do
-				    files="$files $(modinfo --set-version "$kdump_kver" --filename $_dep_modules 2>/dev/null)"
+				    files="$files $(modinfo --set-version "$KDUMP_KERNELVER" --filename $_dep_modules 2>/dev/null)"
 				done
 			else
 				# If it's not a module nor builtin, give an error
-				if ! ( modprobe --set-version "$kdump_kver" --dry-run "$_module" &>/dev/null ); then
+				if ! ( modprobe --set-version "$KDUMP_KERNELVER" --dry-run "$_module" &>/dev/null ); then
 					echo "Module $_module not found"
 				fi
 			fi
@@ -472,8 +472,8 @@ check_dump_fs_modified()
 	check_block_and_slaves_all _record_block_drivers "$(get_maj_min "$_target")"
 	for _driver in $_target_drivers; do
 		# Skip deprecated/invalid driver name or built-in module
-		_module_name=$(modinfo --set-version "$kdump_kver" -F name $_driver 2>/dev/null)
-		_module_filename=$(modinfo --set-version "$kdump_kver" -n $_driver 2>/dev/null)
+		_module_name=$(modinfo --set-version "$KDUMP_KERNELVER" -F name $_driver 2>/dev/null)
+		_module_filename=$(modinfo --set-version "$KDUMP_KERNELVER" -n $_driver 2>/dev/null)
 		if [ $? -ne 0 ] || [ -z "$_module_name" ] || [[ "$_module_filename" = *"(builtin)"* ]]; then
 			continue
 		fi
@@ -540,7 +540,7 @@ check_wdt_modified()
 		# modalias. Currently load all of them.
 		# TODO: Need to find a way to avoid any unwanted module
 		# represented by modalias
-		_wdtdrv=$(modprobe --set-version "$kdump_kver" -R $_wdtdrv 2>/dev/null)
+		_wdtdrv=$(modprobe --set-version "$KDUMP_KERNELVER" -R $_wdtdrv 2>/dev/null)
 		if [[ $_wdtdrv ]]; then
 			for i in $_wdtdrv; do
 				_drivers[$i]=1
@@ -555,7 +555,7 @@ check_wdt_modified()
 			[[ -f "$_wdtppath/modalias" ]] || continue
 
 			_wdtdrv=$(< "$_wdtppath/modalias")
-			_wdtdrv=$(modprobe --set-version "$kdump_kver" -R $_wdtdrv 2>/dev/null)
+			_wdtdrv=$(modprobe --set-version "$KDUMP_KERNELVER" -R $_wdtdrv 2>/dev/null)
 			if [[ $_wdtdrv ]]; then
 				for i in $_wdtdrv; do
 					_drivers[$i]=1
@@ -700,7 +700,7 @@ load_kdump()
 
 	$KEXEC $KEXEC_ARGS $standard_kexec_args \
 		--command-line="$KDUMP_COMMANDLINE" \
-		--initrd=$TARGET_INITRD $kdump_kernel
+		--initrd=$TARGET_INITRD $KDUMP_KERNEL
 	if [ $? == 0 ]; then
 		echo "kexec: loaded kdump kernel"
 		return 0