kdumpctl: merge check_current_{kdump,fadump}_status

Both functions are almost identical. The only differences are (1) the
sysfs node the status is read from and (2) the fact the fadump version
doesn't verify if the file it's trying to read actually exists. Thus
merge the two functions and get rid of the check_current_status wrapper.

While at it rename the function to is_kernel_loaded which explains
better what the function does.

Finally, after moving FADUMP_REGISTER_SYS_NODE shellcheck can no longer
access the definition and starts complaining about it not being quoted.
Thus quote all uses of FADUMP_REGISTER_SYS_NODE.

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

dracut-early-kdump.sh

@@ -37,7 +37,7 @@ early_kdump_load()
         return 1
     fi
 
-    if check_current_kdump_status; then
+    if is_kernel_loaded "kdump"; then
         return 1
     fi
 

kdump-lib.sh

@@ -9,6 +9,7 @@ else
 fi
 
 FADUMP_ENABLED_SYS_NODE="/sys/kernel/fadump_enabled"
+FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump_registered"
 
 is_fadump_capable()
 {
@@ -494,19 +495,31 @@ check_kdump_feasibility()
 	return $?
 }
 
-check_current_kdump_status()
+is_kernel_loaded()
 {
-	if [[ ! -f /sys/kernel/kexec_crash_loaded ]]; then
+	local _sysfs _mode
-		derror "Perhaps CONFIG_CRASH_DUMP is not enabled in kernel"
+
+	_mode=$1
+
+	case "$_mode" in
+	kdump)
+		_sysfs="/sys/kernel/kexec_crash_loaded"
+		;;
+	fadump)
+		_sysfs="$FADUMP_REGISTER_SYS_NODE"
+		;;
+	*)
+		derror "Unknown dump mode '$_mode' provided"
+		return 1
+		;;
+	esac
+
+	if [[ ! -f $_sysfs ]]; then
+		derror "$_mode is not supported on this kernel"
 		return 1
 	fi
 
-	rc=$(< /sys/kernel/kexec_crash_loaded)
+	[[ $(< $_sysfs) -eq 1 ]]
-	if [[ $rc == 1 ]]; then
-		return 0
-	else
-		return 1
-	fi
 }
 
 # remove_cmdline_param <kernel cmdline> <param1> [<param2>] ... [<paramN>]

kdumpctl

@@ -14,7 +14,6 @@ DEFAULT_INITRD_BAK=""
 INITRD_CHECKSUM_LOCATION=""
 KDUMP_INITRD=""
 TARGET_INITRD=""
-FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump_registered"
 #kdump shall be the default dump mode
 DEFAULT_DUMP_MODE="kdump"
 image_time=0
@@ -837,23 +836,6 @@ show_reserved_mem()
 	dinfo "Reserved ${mem_mb}MB memory for crash kernel"
 }
 
-check_current_fadump_status()
-{
-	# Check if firmware-assisted dump has been registered.
-	rc=$(< $FADUMP_REGISTER_SYS_NODE)
-	[[ $rc -eq 1 ]] && return 0
-	return 1
-}
-
-check_current_status()
-{
-	if [[ $DEFAULT_DUMP_MODE == "fadump" ]]; then
-		check_current_fadump_status
-	else
-		check_current_kdump_status
-	fi
-}
-
 save_raw()
 {
 	local raw_target
@@ -974,8 +956,8 @@ check_dump_feasibility()
 
 start_fadump()
 {
-	echo 1 > $FADUMP_REGISTER_SYS_NODE
+	echo 1 > "$FADUMP_REGISTER_SYS_NODE"
-	if ! check_current_fadump_status; then
+	if ! is_kernel_loaded "fadump"; then
 		derror "fadump: failed to register"
 		return 1
 	fi
@@ -1040,7 +1022,7 @@ start()
 		return 1
 	fi
 
-	if [[ $DEFAULT_DUMP_MODE == "kdump" ]] && check_current_kdump_status; then
+	if [[ $DEFAULT_DUMP_MODE == "kdump" ]] && is_kernel_loaded "kdump"; then
 		dwarn "Kdump already running: [WARNING]"
 		return 0
 	fi
@@ -1065,7 +1047,7 @@ start()
 
 reload()
 {
-	if ! check_current_status; then
+	if ! is_kernel_loaded "$DEFAULT_DUMP_MODE"; then
 		dwarn "Kdump was not running: [WARNING]"
 	fi
 
@@ -1096,8 +1078,8 @@ reload()
 
 stop_fadump()
 {
-	echo 0 > $FADUMP_REGISTER_SYS_NODE
+	echo 0 > "$FADUMP_REGISTER_SYS_NODE"
-	if check_current_fadump_status; then
+	if is_kernel_loaded "fadump"; then
 		derror "fadump: failed to unregister"
 		return 1
 	fi
@@ -1126,7 +1108,7 @@ stop_kdump()
 
 reload_fadump()
 {
-	if echo 1 > $FADUMP_REGISTER_SYS_NODE; then
+	if echo 1 > "$FADUMP_REGISTER_SYS_NODE"; then
 		dinfo "fadump: re-registered successfully"
 		return 0
 	else
@@ -1739,7 +1721,7 @@ main()
 		;;
 	status)
 		EXIT_CODE=0
-		check_current_status
+		is_kernel_loaded "$DEFAULT_DUMP_MODE"
 		case "$?" in
 		0)
 			dinfo "Kdump is operational"