kdumpctl: refractor check_rebuild

check_rebuild uses a bunch of local variables to store the result of the
different checks performed. At the end of the function it then evaluates
which check failed to print an appropriate info and trigger a rebuild if
needed. This not only makes the function hard to read but also requires
all checks to be executed even if an earlier one already determined that
the initrd needs to be rebuild. Thus refractor check_rebuild such that
it only checks whether the initrd needs to rebuild and trigger the
rebuild by the caller (if needed). While at it rename the function to
need_initrd_rebuild.

Furthermore also move setup_initrd to the caller so it is more consisted
with the other users of the function.

Signed-off-by: Philipp Rudo <prudo@redhat.com>
Reviewed-by: Coiby Xu <coxu@redhat.com>

kdumpctl

@@ -560,72 +560,58 @@ check_system_modified()
 	return 0
 }
 
-check_rebuild()
+# need_initrd_rebuild - check whether the initrd needs to be rebuild
+# Returns:
+#	0	if does not need to be rebuild
+#	1	if it needs to be rebuild
+#	2	if an error occurred
+need_initrd_rebuild()
 {
-	local capture_capable_initrd="1"
 	local force_rebuild force_no_rebuild
-	local ret system_modified="0"
 
-	setup_initrd || return 1
+	force_no_rebuild=${OPT[force_no_rebuild]:-0}
-
-	force_no_rebuild=${OPT[force_no_rebuild]}
-	force_no_rebuild=${force_no_rebuild:-0}
 	if [[ $force_no_rebuild != "0" ]] && [[ $force_no_rebuild != "1" ]]; then
 		derror "Error: force_no_rebuild value is invalid"
-		return 1
+		return 2
 	fi
 
-	force_rebuild=${OPT[force_rebuild]}
+	force_rebuild=${OPT[force_rebuild]:-0}
-	force_rebuild=${force_rebuild:-0}
 	if [[ $force_rebuild != "0" ]] && [[ $force_rebuild != "1" ]]; then
 		derror "Error: force_rebuild value is invalid"
-		return 1
+		return 2
 	fi
 
 	if [[ $force_no_rebuild == "1" && $force_rebuild == "1" ]]; then
 		derror "Error: force_rebuild and force_no_rebuild are enabled simultaneously in kdump.conf"
-		return 1
+		return 2
 	fi
 
-	# Will not rebuild kdump initrd
 	if [[ $force_no_rebuild == "1" ]]; then
 		return 0
 	fi
 
-	#check to see if dependent files has been modified
+	if [[ $force_rebuild == "1" ]]; then
-	#since last build of the image file
-	if [[ -f $TARGET_INITRD ]]; then
-		image_time=$(stat -c "%Y" "$TARGET_INITRD" 2> /dev/null)
-
-		#in case of fadump mode, check whether the default/target
-		#initrd is already built with dump capture capability
-		if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
-			capture_capable_initrd=$(lsinitrd -f $DRACUT_MODULES_FILE "$TARGET_INITRD" | grep -c -e ^kdumpbase$ -e ^zz-fadumpinit$)
-		fi
-	fi
-
-	check_system_modified
-	ret=$?
-	if [[ $ret -eq 2 ]]; then
-		return 1
-	elif [[ $ret -eq 1 ]]; then
-		system_modified="1"
-	fi
-
-	if [[ $image_time -eq 0 ]]; then
-		dinfo "No kdump initial ramdisk found."
-	elif [[ $capture_capable_initrd == "0" ]]; then
-		dinfo "Rebuild $TARGET_INITRD with dump capture support"
-	elif [[ $force_rebuild != "0" ]]; then
 		dinfo "Force rebuild $TARGET_INITRD"
-	elif [[ $system_modified != "0" ]]; then
+		return 1
-		:
-	else
-		return 0
 	fi
 
-	dinfo "Rebuilding $TARGET_INITRD"
+	if [[ ! -f $TARGET_INITRD ]]; then
-	rebuild_initrd
+		dinfo "No kdump initial ramdisk found."
+		return 1
+	fi
+
+	# in case of fadump mode, check whether the default/target initrd is
+	# already built with dump capture capability
+	if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
+		if ! lsinitrd -f $DRACUT_MODULES_FILE "$TARGET_INITRD" | grep -q -e ^kdumpbase$ -e ^zz-fadumpinit$; then
+			dinfo "Rebuild $TARGET_INITRD with dump capture support"
+			return 1
+		fi
+	fi
+
+	image_time=$(stat -c "%Y" "$TARGET_INITRD" 2> /dev/null)
+	check_system_modified
+
 }
 
 # On ppc64le LPARs, the keys trusted by firmware do not end up in
@@ -1001,7 +987,20 @@ start()
 	fi
 
 	check_and_wait_network_ready || return
-	check_rebuild || return
+	setup_initrd || return
+	need_initrd_rebuild
+	case "$?" in
+		0)
+			# Nothing to do
+			;;
+		1)
+			dinfo "Rebuilding $TARGET_INITRD"
+			rebuild_initrd || return
+			;;
+		*)
+			return
+			;;
+	esac
 	start_dump || return
 
 	dinfo "Starting kdump: [OK]"