[PATCH v2 28/49] bash scripts: fix redundant exit code check

[Kairui Song]

As suggested by:
https://github.com/koalaman/shellcheck/wiki/SC2181

Signed-off-by: Kairui Song <kasong(a)redhat.com&gt;
---
 dracut-module-setup.sh |  41 ++++++---------
 kdumpctl               | 112 +++++++++++++----------------------------
 mkdumprd               |  40 ++++-----------
 3 files changed, 61 insertions(+), 132 deletions(-)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index 600bdc51..46c0087a 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -255,8 +255,7 @@ kdump_static_ip() {
             _gateway="[$_gateway]"
         else
             _prefix=$(cut -d'/' -f2 <<< "$_ipaddr")
-            _netmask=$(cal_netmask_by_prefix "$_prefix"
"$_ipv6_flag")
-            if [[ "$?" -ne 0 ]]; then
+            if ! _netmask=$(cal_netmask_by_prefix "$_prefix"
"$_ipv6_flag"); then
                 derror "Failed to calculate netmask for $_ipaddr"
                 exit 1
             fi
@@ -358,10 +357,7 @@ kdump_setup_bridge() {
         [[ -e $_dev ]] || continue
         _kdumpdev=$_dev
         if kdump_is_bond "$_dev"; then
-            $(kdump_setup_bond "$_dev"
"$(get_nmcli_connection_show_cmd_by_ifname "$_dev")")
-            if [[ $? != 0 ]]; then
-                exit 1
-            fi
+            $(kdump_setup_bond "$_dev"
"$(get_nmcli_connection_show_cmd_by_ifname "$_dev")") || exit 1
         elif kdump_is_team "$_dev"; then
             kdump_setup_team "$_dev"
         elif kdump_is_vlan "$_dev"; then
@@ -419,9 +415,7 @@ kdump_setup_team() {
     echo " team=$_netdev:${_slaves%,}" >>
"${initdir}/etc/cmdline.d/44team.conf"
     #Buggy version teamdctl outputs to stderr!
     #Try to use the latest version of teamd.
-    teamdctl "$_netdev" config dump >
"${initdir}/tmp/$$-$_netdev.conf"
-    if [[ $? -ne 0 ]]
-    then
+    if ! teamdctl "$_netdev" config dump >
"${initdir}/tmp/$$-$_netdev.conf"; then
         derror "teamdctl failed."
         exit 1
     fi
@@ -441,10 +435,7 @@ kdump_setup_vlan() {
         derror "Vlan over bridge is not supported!"
         exit 1
     elif kdump_is_bond "$_phydev"; then
-        $(kdump_setup_bond "$_phydev"
"$(get_nmcli_connection_show_cmd_by_ifname "$_phydev")")
-        if [[ $? != 0 ]]; then
-            exit 1
-        fi
+        $(kdump_setup_bond "$_phydev"
"$(get_nmcli_connection_show_cmd_by_ifname "$_phydev")") || exit 1
         echo " vlan=$(kdump_setup_ifname "$_netdev"):$_phydev" >
"${initdir}/etc/cmdline.d/43vlan.conf"
     else
         _kdumpdev="$(kdump_setup_ifname "$_phydev")"
@@ -515,8 +506,8 @@ kdump_setup_znet() {
 
 kdump_get_ip_route()
 {
-    local _route=$(/sbin/ip -o route get to "$1" 2>&1)
-    if [[ $? != 0 ]]; then
+    local _route
+    if ! _route=$(/sbin/ip -o route get to "$1" 2>&1); then
         derror "Bad kdump network destination: $1"
         exit 1
     fi
@@ -560,8 +551,7 @@ kdump_install_net() {
     _znet_netdev=$(find_online_znet_device)
     if [[ -n "$_znet_netdev" ]]; then
         _nm_show_cmd_znet=$(get_nmcli_connection_show_cmd_by_ifname
"$_znet_netdev")
-        $(kdump_setup_znet "$_znet_netdev" "$_nm_show_cmd_znet")
-        if [[ $? != 0 ]]; then
+        if ! $(kdump_setup_znet "$_znet_netdev"
"$_nm_show_cmd_znet"); then
             derror "Failed to set up znet"
             exit 1
         fi
@@ -591,10 +581,7 @@ kdump_install_net() {
     if kdump_is_bridge "$_netdev"; then
         kdump_setup_bridge "$_netdev"
     elif kdump_is_bond "$_netdev"; then
-        $(kdump_setup_bond "$_netdev" "$_nm_show_cmd")
-        if [[ $? != 0 ]]; then
-            exit 1
-        fi
+        $(kdump_setup_bond "$_netdev" "$_nm_show_cmd") || exit 1
     elif kdump_is_team "$_netdev"; then
         kdump_setup_team "$_netdev"
     elif kdump_is_vlan "$_netdev"; then
@@ -836,8 +823,10 @@ kdump_setup_iscsi_device() {
     fi
 
     # Setup initator
-    initiator_str=$(kdump_get_iscsi_initiator)
-    [[ $? -ne "0" ]] && derror "Failed to get initiator name"
&& return 1
+    if ! initiator_str=$(kdump_get_iscsi_initiator); then
+        derror "Failed to get initiator name"
+        return 1
+    fi
 
     # If initiator details do not exist already, append.
     if ! grep -q "$initiator_str" "$netroot_conf"; then
@@ -877,8 +866,7 @@ get_alias() {
     for ip in $ips
     do
             # in /etc/hosts, alias can come at the 2nd column
-            entries=$(grep "$ip" /etc/hosts | awk '{ $1=""; print
$0 }')
-            if [[ $? -eq 0 ]]; then
+            if entries=$(grep "$ip" /etc/hosts | awk '{ $1="";
print $0 }'); then
                     alias_set="$alias_set $entries"
             fi
     done
@@ -1003,8 +991,7 @@ kdump_install_random_seed() {
 kdump_install_systemd_conf() {
     # Kdump turns out to require longer default systemd mount timeout
     # than 1st kernel(90s by default), we use default 300s for kdump.
-    grep -r "^[[:space:]]*DefaultTimeoutStartSec="
"${initdir}/etc/systemd/system.conf"* &>/dev/null
-    if [[ $? -ne 0 ]]; then
+    if ! grep -q -r "^[[:space:]]*DefaultTimeoutStartSec="
"${initdir}/etc/systemd/system.conf"*; then
         mkdir -p "${initdir}/etc/systemd/system.conf.d"
         echo "[Manager]" >
"${initdir}/etc/systemd/system.conf.d/kdump.conf"
         echo "DefaultTimeoutStartSec=300s" >>
"${initdir}/etc/systemd/system.conf.d/kdump.conf"
diff --git a/kdumpctl b/kdumpctl
index f65f8e3d..ecfe3d77 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -37,8 +37,7 @@ fi
 . /lib/kdump/kdump-logger.sh
 
 #initiate the kdump logger
-dlog_init
-if [[ $? -ne 0 ]]; then
+if ! dlog_init; then
 	echo "failed to initiate the kdump logger."
 	exit 1
 fi
@@ -47,8 +46,7 @@ single_instance_lock()
 {
 	local rc timeout=5
 
-	exec 9>/var/lock/kdump
-	if [[ $? -ne 0 ]]; then
+	if ! exec 9>/var/lock/kdump; then
 		derror "Create file lock failed"
 		exit 1
 	fi
@@ -80,8 +78,7 @@ save_core()
 
 	mkdir -p "$coredir"
 	ddebug "cp --sparse=always /proc/vmcore $coredir/vmcore-incomplete"
-	cp --sparse=always /proc/vmcore "$coredir/vmcore-incomplete"
-	if [[ $? == 0 ]]; then
+	if cp --sparse=always /proc/vmcore "$coredir/vmcore-incomplete"; then
 		mv "$coredir/vmcore-incomplete" "$coredir/vmcore"
 		dinfo "saved a vmcore to $coredir"
 	else
@@ -95,8 +92,7 @@ save_core()
 		ddebug "makedumpfile --dump-dmesg $coredir/vmcore $coredir/dmesg"
 		makedumpfile --dump-dmesg "$coredir/vmcore" "$coredir/dmesg"
>/dev/null 2>&1
 		ddebug "dumpoops -d $coredir/dmesg"
-		dumpoops -d "$coredir/dmesg" >/dev/null 2>&1
-		if [[ $? == 0 ]]; then
+		if dumpoops -d "$coredir/dmesg" >/dev/null 2>&1; then
 			dinfo "kernel oops has been collected by abrt tool"
 		fi
 	fi
@@ -121,8 +117,7 @@ check_earlykdump_is_enabled()
 rebuild_kdump_initrd()
 {
 	ddebug "rebuild kdump initrd: $MKDUMPRD $TARGET_INITRD $KDUMP_KERNELVER"
-	$MKDUMPRD "$TARGET_INITRD" "$KDUMP_KERNELVER"
-	if [[ $? != 0 ]]; then
+	if ! $MKDUMPRD "$TARGET_INITRD" "$KDUMP_KERNELVER"; then
 		derror "mkdumprd: failed to make kdump initrd"
 		return 1
 	fi
@@ -184,8 +179,7 @@ backup_default_initrd()
 		dinfo "Backing up $DEFAULT_INITRD before rebuild."
 		# save checksum to verify before restoring
 		sha1sum "$DEFAULT_INITRD" > "$INITRD_CHECKSUM_LOCATION"
-		cp "$DEFAULT_INITRD" "$DEFAULT_INITRD_BAK"
-		if [[ $? -ne 0 ]]; then
+		if ! cp "$DEFAULT_INITRD" "$DEFAULT_INITRD_BAK"; then
 			dwarn "WARNING: failed to backup $DEFAULT_INITRD."
 			rm -f "$DEFAULT_INITRD_BAK"
 		fi
@@ -210,8 +204,7 @@ restore_default_initrd()
 			dwarn "WARNING: checksum mismatch! Can't restore original initrd.."
 		else
 			rm -f $INITRD_CHECKSUM_LOCATION
-			mv "$DEFAULT_INITRD_BAK" "$DEFAULT_INITRD"
-			if [[ $? -eq 0 ]]; then
+			if mv "$DEFAULT_INITRD_BAK" "$DEFAULT_INITRD"; then
 				derror "Restoring original initrd as fadump mode is disabled."
 				sync
 			fi
@@ -308,8 +301,7 @@ get_pcs_cluster_modified_files()
 
 setup_initrd()
 {
-	prepare_kdump_bootinfo
-	if [[ $? -ne 0 ]]; then
+	if ! prepare_kdump_bootinfo; then
 		derror "failed to prepare for kdump bootinfo."
 		return 1
 	fi
@@ -372,8 +364,7 @@ check_files_modified()
 			files="$files /lib/modules/$KDUMP_KERNELVER/modules.dep"
 		fi
 		for _module in $EXTRA_MODULES; do
-			_module_file="$(modinfo --set-version "$KDUMP_KERNELVER" --filename
"$_module" 2>/dev/null)"
-			if [[ $? -eq 0 ]]; then
+			if _module_file="$(modinfo --set-version "$KDUMP_KERNELVER" --filename
"$_module" 2>/dev/null)"; then
 				files="$files $_module_file"
 				for _dep_modules in $(modinfo -F depends "$_module" | tr ',' '
'); do
 				    files="$files $(modinfo --set-version "$KDUMP_KERNELVER"
--filename "$_dep_modules" 2>/dev/null)"
@@ -389,8 +380,7 @@ check_files_modified()
 
 	# HOOKS is mandatory and need to check the modification time
 	files="$files $HOOKS"
-	check_exist "$files" && check_executable "$EXTRA_BINS"
-	[[ $? -ne 0 ]] && return 2
+	check_exist "$files" && check_executable "$EXTRA_BINS" ||
return 2
 
 	for file in $files; do
 		if [[ -e "$file" ]]; then
@@ -455,7 +445,7 @@ check_drivers_modified()
 		# Skip deprecated/invalid driver name or built-in module
 		_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" ]] || [[
"$_module_filename" = *"(builtin)"* ]]; then
+		if [[ -z "$_module_name" ]] || [[ -z "$_module_filename" ]] || [[
"$_module_filename" = *"(builtin)"* ]]; then
 			continue
 		fi
 		if ! [[ " $_old_drivers " == *" $_module_name "* ]]; then
@@ -505,8 +495,7 @@ check_fs_modified()
 
 	# if --mount argument present then match old and new target, mount
 	# point and file system. If any of them mismatches then rebuild
-	echo "$_dracut_args" | grep "\-\-mount" &> /dev/null
-	if [[ $? -eq 0 ]];then
+	if echo "$_dracut_args" | grep "\-\-mount" &> /dev/null;
then
 		# shellcheck disable=SC2046
 		set -- $(echo "$_dracut_args" | awk -F "--mount '" '{print
$2}' | cut -d' ' -f1,2,3)
 		_old_dev=$1
@@ -558,11 +547,7 @@ check_rebuild()
 	local force_rebuild force_no_rebuild
 	local ret system_modified="0"
 
-	setup_initrd
-
-	if [[ $? -ne 0 ]]; then
-		return 1
-	fi
+	setup_initrd || return 1
 
 	force_no_rebuild=$(kdump_get_conf_val force_no_rebuild)
 	force_no_rebuild=${force_no_rebuild:-0}
@@ -761,8 +746,7 @@ check_and_wait_network_ready()
 
 		# if server removes the authorized_keys or, no /root/.ssh/kdump_id_rsa
 		ddebug "$errmsg"
-		echo "$errmsg" | grep -q "Permission denied\|No such file or
directory\|Host key verification failed" &> /dev/null
-		if [[ $? -eq 0 ]]; then
+		if echo "$errmsg" | grep -q "Permission denied\|No such file or
directory\|Host key verification failed" &> /dev/null; then
 			derror "Could not create $DUMP_TARGET:$SAVE_PATH, you probably need to run
\"kdumpctl propagate\""
 			return 1
 		fi
@@ -788,16 +772,11 @@ check_and_wait_network_ready()
 check_ssh_target()
 {
 	check_and_wait_network_ready
-	if [[ $? -ne 0 ]]; then
-		return 1
-	fi
-	return 0
 }
 
 propagate_ssh_key()
 {
-	check_ssh_config
-	if [[ $? -ne 0 ]]; then
+	if ! check_ssh_config; then
 		derror "No ssh config specified in $KDUMP_CONFIG_FILE.  Can't propagate"
 		exit 1
 	fi
@@ -904,8 +883,7 @@ local_fs_dump_target()
 {
 	local _target
 
-	_target=$(egrep "^ext[234]|^xfs|^btrfs|^minix" /etc/kdump.conf)
-	if [[ $? -eq 0 ]]; then
+	if _target=$(grep -E "^ext[234]|^xfs|^btrfs|^minix" /etc/kdump.conf); then
 		echo "$_target" | awk '{print $2}'
 	fi
 }
@@ -967,8 +945,7 @@ check_fence_kdump_config()
 			return 1
 		fi
 		# node can be ipaddr
-		echo "$ipaddrs " | grep "$node " > /dev/null
-		if [[ $? -eq 0 ]]; then
+		if echo "$ipaddrs " | grep "$node " > /dev/null; then
 			derror "Option fence_kdump_nodes cannot contain $node"
 			return 1
 		fi
@@ -1062,14 +1039,12 @@ check_final_action_config()
 
 start()
 {
-	check_dump_feasibility
-	if [[ $? -ne 0 ]]; then
+	if ! check_dump_feasibility; then
 		derror "Starting kdump: [FAILED]"
 		return 1
 	fi
 
-	check_config
-	if [[ $? -ne 0 ]]; then
+	if ! check_config; then
 		derror "Starting kdump: [FAILED]"
 		return 1
 	fi
@@ -1078,14 +1053,12 @@ start()
 		selinux_relabel
 	fi
 
-	save_raw
-	if [[ $? -ne 0 ]]; then
+	if ! save_raw; then
 		derror "Starting kdump: [FAILED]"
 		return 1
 	fi
 
-	check_current_status
-	if [[ $? == 0 ]]; then
+	if check_current_status; then
 		dwarn "Kdump already running: [WARNING]"
 		return 0
 	fi
@@ -1097,14 +1070,12 @@ start()
 		fi
 	fi
 
-	check_rebuild
-	if [[ $? != 0 ]]; then
+	if ! check_rebuild; then
 		derror "Starting kdump: [FAILED]"
 		return 1
 	fi
 
-	start_dump
-	if [[ $? != 0 ]]; then
+	if ! start_dump; then
 		derror "Starting kdump: [FAILED]"
 		return 1
 	fi
@@ -1114,8 +1085,7 @@ start()
 
 reload()
 {
-	check_current_status
-	if [[ $? -ne 0 ]]; then
+	if ! check_current_status; then
 		dwarn "Kdump was not running: [WARNING]"
 	fi
 
@@ -1123,24 +1093,20 @@ reload()
 		reload_fadump
 		return $?
 	else
-		stop_kdump
-	fi
-
-	if [[ $? -ne 0 ]]; then
-		derror "Stopping kdump: [FAILED]"
-		return 1
+		if ! stop_kdump; then
+			derror "Stopping kdump: [FAILED]"
+			return 1
+		fi
 	fi
 
 	dinfo "Stopping kdump: [OK]"
 
-	setup_initrd
-	if [[ $? -ne 0 ]]; then
+	if ! setup_initrd; then
 		derror "Starting kdump: [FAILED]"
 		return 1
 	fi
 
-	start_dump
-	if [[ $? -ne 0 ]]; then
+	if ! start_dump; then
 		derror "Starting kdump: [FAILED]"
 		return 1
 	fi
@@ -1168,6 +1134,7 @@ stop_kdump()
 		$KEXEC -p -u
 	fi
 
+	# shellcheck disable=SC2181
 	if [[ $? != 0 ]]; then
 		derror "kexec: failed to unload kdump kernel"
 		return 1
@@ -1179,16 +1146,14 @@ stop_kdump()
 
 reload_fadump()
 {
-	echo 1 > $FADUMP_REGISTER_SYS_NODE
-	if [[ $? == 0 ]]; then
+	if echo 1 > $FADUMP_REGISTER_SYS_NODE; then
 		dinfo "fadump: re-registered successfully"
 		return 0
 	else
 		# FADump could fail on older kernel where re-register
 		# support is not enabled. Try stop/start from userspace
 		# to handle such scenario.
-		stop_fadump
-		if [[ $? == 0 ]]; then
+		if stop_fadump; then
 			start_fadump
 			return $?
 		fi
@@ -1205,6 +1170,7 @@ stop()
 		stop_kdump
 	fi
 
+	# shellcheck disable=SC2181
 	if [[ $? != 0 ]]; then
 		derror "Stopping kdump: [FAILED]"
 		return 1
@@ -1215,10 +1181,7 @@ stop()
 }
 
 rebuild() {
-	check_config
-	if [[ $? -ne 0 ]]; then
-		return 1
-	fi
+	check_config || return 1
 
 	if check_ssh_config; then
 		if ! check_ssh_target; then
@@ -1226,10 +1189,7 @@ rebuild() {
 		fi
 	fi
 
-	setup_initrd
-	if [[ $? -ne 0 ]]; then
-		return 1
-	fi
+	setup_initrd || return 1
 
 	dinfo "Rebuilding $TARGET_INITRD"
 	rebuild_initrd
diff --git a/mkdumprd b/mkdumprd
index 9800934e..a2c6ed29 100644
--- a/mkdumprd
+++ b/mkdumprd
@@ -17,8 +17,7 @@ fi
 export IN_KDUMP=1
 
 #initiate the kdump logger
-dlog_init
-if [[ $? -ne 0 ]]; then
+if ! dlog_init; then
 	echo "failed to initiate the kdump logger."
 	exit 1
 fi
@@ -114,18 +113,12 @@ mkdir_save_path_ssh()
 {
     local _opt _dir
     _opt=(-i "$SSH_KEY_LOCATION" -o BatchMode=yes -o
StrictHostKeyChecking=yes)
-    ssh -qn "${_opt[@]}" "$1" mkdir -p "$SAVE_PATH"
2>&1 > /dev/null
-    _ret=$?
-    if [[ $_ret -ne 0 ]]; then
+    ssh -qn "${_opt[@]}" "$1" mkdir -p "$SAVE_PATH"
&>/dev/null || \
         perror_exit "mkdir failed on $1:$SAVE_PATH"
-    fi
 
-    #check whether user has write permission on $1:$SAVE_PATH
-    _dir=$(ssh -qn "${_opt[@]}" "$1" mktemp -dqp
"$SAVE_PATH" 2>/dev/null)
-    _ret=$?
-    if [[ $_ret -ne 0 ]]; then
+    # check whether user has write permission on $1:$SAVE_PATH
+    _dir=$(ssh -qn "${_opt[@]}" "$1" mktemp -dqp
"$SAVE_PATH" 2>/dev/null) || \
         perror_exit "Could not create temporary directory on $1:$SAVE_PATH. Make
sure user has write permission on destination"
-    fi
     ssh -qn "${_opt[@]}" "$1" rmdir "$_dir"
 
     return 0
@@ -162,11 +155,7 @@ check_size() {
             ;;
         *)
             return
-    esac
-
-    if [[ $? -ne 0 ]]; then
-            perror_exit "Check dump target size failed"
-    fi
+    esac || perror_exit "Check dump target size failed"
 
     if [[ "$avail" -lt "$memtotal" ]]; then
         dwarn "Warning: There might not be enough space to save a vmcore."
@@ -227,8 +216,7 @@ check_user_configured_target()
     if [[ -n "$_mnt" ]]; then
         if ! is_mounted "$_mnt"; then
             if [[ $_opt  = *",noauto"* ]]; then
-                mount "$_mnt"
-                [[ $? -ne 0 ]] && mount_failure "$_target"
"$_mnt" "$_fstype"
+                mount "$_mnt" || mount_failure "$_target"
"$_mnt" "$_fstype"
                 _mounted=$_mnt
             else
                 perror_exit "Dump target \"$_target\" is neither mounted
nor configured as \"noauto\""
@@ -237,8 +225,7 @@ check_user_configured_target()
     else
         _mnt=$MKDUMPRD_TMPMNT
         mkdir -p "$_mnt"
-        mount "$_target" "$_mnt" -t "$_fstype" -o defaults
-        [[ $? -ne 0 ]] && mount_failure "$_target" ""
"$_fstype"
+        mount "$_target" "$_mnt" -t "$_fstype" -o defaults
|| mount_failure "$_target" "" "$_fstype"
         _mounted=$_mnt
     fi
 
@@ -283,11 +270,9 @@ verify_core_collector() {
 }
 
 add_mount() {
-    local _mnt=$(to_mount "$@")
+    local _mnt
 
-    if [[ $? -ne 0 ]]; then
-        exit 1
-    fi
+    _mnt=$(to_mount "$@") || exit 1
 
     add_dracut_mount "$_mnt"
 }
@@ -349,15 +334,12 @@ is_unresettable()
 #return true if resettable
 check_resettable()
 {
-    local _ret _target _override_resettable
+    local _target _override_resettable
 
     _override_resettable=$(kdump_get_conf_val override_resettable)
     OVERRIDE_RESETTABLE=${_override_resettable:-$OVERRIDE_RESETTABLE}
 
-    for_each_block_target is_unresettable
-    _ret=$?
-
-    [[ $_ret -eq 0 ]] && return
+    for_each_block_target is_unresettable && return
 
     return 1
 }
-- 
2.31.1