commit d5e15641fd19eeb8d984a99e4202ac25983447a8
Author: Rob Pearce <rpearce@squiz.net>
Date:   Sun Jul 11 10:20:48 2021 +1000

    Initial checkin.

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..b54ee20
--- /dev/null
+++ b/README.md
@@ -0,0 +1,72 @@
+# Overview
+
+Script to manage custom./etc/services entries.
+
+# Usage
+    # Show usage
+    rpearce@crom:serv$ ./serv.sh -h
+    usage:  ./serv.sh [OPTIONS] command [command_args]
+
+    Manage custom /etc/services entries.
+
+      Valid commands are:   diff sync init add del query cat
+
+       -f   Force removal of service even if multiple match.
+       -w   Update system services file (/etc/services)
+       -y   Same as -w
+
+    # Create working area in ~/.serv/
+    rpearce@crom:serv$ ./serv.sh  init
+    Initialisation of /Users/rpearce/.serv complete.
+
+    # Add a custom service
+    rpearce@crom:serv$ ./serv.sh add myservice 34777/udp
+    Added 'myservice' (34777/udp) to custom services file.
+
+    NOTE: /etc/services not touched - use -w to update it.
+    The following changes were NOT made:
+       13921a13922,13924
+       >
+       > # custom services from serv.sh
+       > myservice       34777/udp
+
+    # Look up a custom service
+    rpearce@crom:serv$ ./serv.sh query myservice
+    Found in custom services file:
+       myservice       34777/udp
+
+    # Update system /etc/services with custom services
+    rpearce@crom:serv$ ./serv.sh -w sync
+
+    (using sudo - you may be prompted for your password)
+    Password:
+    /etc/services updated:
+       13921a13922,13924
+       >
+       > # custom services from serv.sh
+       > myservice       34777/udp
+
+    rpearce@crom:serv$ tail -5 /etc/services
+    #               48557-49150 Unassigned
+    #               49151       IANA Reserved
+
+    # custom services from serv.sh
+    myservice       34777/udp
+    rpearce@crom:serv$
+
+    # Remove a custom service, and also update /etc/services
+    rpearce@crom:serv$ ./serv.sh -w rm myservice
+    Removed 'myservice' from custom services file (1 line).
+
+    (using sudo - you may be prompted for your password)
+    /etc/services updated:
+       13924d13923
+       < myservice       34777/udp
+
+    rpearce@crom:serv$ tail -5 /etc/services
+    com-bardac-dw   48556/udp    # com-bardac-dw
+    com-bardac-dw   48556/tcp    # com-bardac-dw
+    #                           Nicholas J Howes <nick@ghostwood.org>
+    #               48557-49150 Unassigned
+    #               49151       IANA Reserved
+    rpearce@crom:serv$
diff --git a/serv.sh b/serv.sh
new file mode 100755
index 0000000..e2a0e98
--- /dev/null
+++ b/serv.sh
@@ -0,0 +1,320 @@
+#!/bin/bash
+
+function lookup() {  # lookup where_var res_var what to lookup ...
+	local all what found rv localres where_var res_var
+	where_var="$1" ; shift
+	res_var="$1" ; shift
+	all="${*}"
+	what=${all// /|}
+	found=""
+	localres=$(egrep -i "$what" $SRVFILE_CUSTOM)
+	if [[ ! -z $localres ]]; then
+		found="custom"
+        else
+		localres=$(egrep -i "$what" $SRVFILE_BASE)
+		[[ ! -z $localres ]] && found="system"
+	fi
+	eval "$where_var=${found}"
+	eval "$res_var='${localres}'"
+	if [[ -z $found ]]; then
+		rv=1
+	else
+		rv=0
+	fi
+	return $rv
+	echo "$found"
+}
+
+function usage() {
+	echo "usage:  $0 [OPTIONS] command [command_args]"
+	echo
+	echo "Manage custom /etc/services entries."
+	echo
+	echo "  Valid commands are:   $VALIDMODES"
+	echo
+	echo "   -f   Force removal of service even if multiple match."
+	echo "   -w   Update system services file ($SRVFILE_ACTIVE)" 
+	echo "   -y   Same as -w"
+	echo
+}
+
+function getalt() {
+	local newmode
+	newmode="$1"
+	case $1 in
+		a)
+			newmode="add";
+			;;
+		q)
+			newmode="query";
+			;;
+		rm)
+			newmode="del";
+			;;
+	esac
+	echo "$newmode"
+
+}
+
+function makeboth() {
+	local n p both
+	n="$1"
+	p="$2"
+	both="$n"
+	if [[ ! -z $p ]]; then
+		if [[ ! -z $n ]]; then
+			both="$both ("
+		fi
+		both="$both$p"
+		if [[ ! -z $n ]]; then
+			both="$both)"
+		fi
+	fi
+	echo "$both"
+}
+
+function stageforsync() {
+	cp -fp "$SRVFILE_BASE" "$SRVFILE_STAGE"
+	echo >> "$SRVFILE_STAGE"
+	echo "# custom services from serv.sh" >> "$SRVFILE_STAGE"
+	cat "$SRVFILE_CUSTOM" >> "$SRVFILE_STAGE"
+}
+
+function synctoactive() {
+	local perm dres 
+
+	stageforsync
+	dres=$(diff "$SRVFILE_ACTIVE" "$SRVFILE_STAGE")
+
+	echo
+	if [[ $DOIT -eq 1 ]]; then
+		perm=$(stat -f "%p" "$SRVFILE_ACTIVE")
+		if [[ $UID -ne 0 && $EUID -ne 0 ]]; then
+			echo "(using sudo - you may be prompted for your password)"
+			sudo cp -fp "$SRVFILE_ACTIVE" "$SRVFILE_ACTIVE.orig"
+			sudo cp -fp "$SRVFILE_STAGE" "$SRVFILE_ACTIVE"
+			sudo chmod $perm "$SRVFILE_ACTIVE"
+		else
+			cp -fp "$SRVFILE_ACTIVE" "$SRVFILE_ACTIVE.orig"
+			cp -fp "$SRVFILE_STAGE" "$SRVFILE_ACTIVE"
+			chmod $perm "$SRVFILE_ACTIVE"
+		fi
+
+		if [[ -z $dres ]]; then
+			echo "No changes required to $SRVFILE_ACTIVE."
+		else
+			echo "$SRVFILE_ACTIVE updated:"
+			echo "$dres" | sed -e 's/^/   /'
+		fi
+	else
+		echo "NOTE: $SRVFILE_ACTIVE not touched - use -w to update it."
+		echo "The following changes were NOT made:"
+		if [[ -z $dres ]]; then
+			echo "   (none)"
+		else
+			echo "$dres" | sed -e 's/^/   /'
+		fi
+	fi
+}
+
+# Handle args
+VALIDPROTOS="tcp udp"
+VALIDMODES="diff sync init add del query cat"
+MODE=""
+SRVFILE_ACTIVE="/etc/services"
+SRVDIR="${HOME}/.serv"
+SRVFILE_BASE="${SRVDIR}/base"
+SRVFILE_CUSTOM="${SRVDIR}/custom"
+SRVFILE_STAGE="${SRVDIR}/stage"
+PROTOFILE=/etc/protocols
+FORCE=0
+DOIT=0
+
+ARGS="fhwy"
+while getopts "$ARGS" i; do
+	case "$i" in
+		f)
+			FORCE=1
+			;;
+		h)
+			usage;
+                        exit 1
+			;;
+		w)
+			DOIT=1;
+			;;
+		y)
+			DOIT=1;
+			;;
+		*)
+			echo "ERROR: invalid argument:  $i";
+			usage;
+			;;
+	esac
+done
+shift $((OPTIND - 1))
+
+if [[ $# -eq 0 ]]; then
+	echo "Error - no mode provided."
+	usage
+	exit 1
+fi
+
+MODE="$1"
+shift 1
+MODE=$(getalt $MODE)
+
+if [[ $VALIDMODES != *$MODE* ]]; then
+	echo "Error - invalid mode '$MODE'"
+	echo "Valid modes are:   $VALIDMODES"
+	exit 1
+fi
+
+
+if [[ $MODE == "cat" ]]; then
+	echo "Current custom services (from $SRVFILE_CUSTOM):"
+	cat "$SRVFILE_CUSTOM" | sed -e 's/^/   /'
+	exit 0
+elif [[ $MODE == "diff" ]]; then
+	stageforsync
+	dres=$(diff "$SRVFILE_ACTIVE" "$SRVFILE_STAGE")
+	echo "Changes to be synced into $SRVFILE_ACTIVE:"
+	if [[ -z $dres ]]; then
+		echo "   (none)"
+	else
+		echo "$dres" | sed -e 's/^/   /'
+	fi
+	exit 0
+elif [[ $MODE == "sync" ]]; then
+	# just update /etc/services
+	synctoactive
+	exit 0
+elif [[ $MODE == "init" ]]; then
+	wantargs=0
+elif [[ $MODE == "add" ]]; then
+	wantargs=2
+else
+	wantargs=1
+fi
+
+if [[ $# -lt $wantargs ]]; then
+	echo "Bad arguments - want $wantargs, got $#"
+	echo
+	usage
+	exit 1
+fi
+
+name="$1"
+protoport="$2"
+if [[ -z $protoport ]]; then
+	proto=""
+	port=""
+else
+	if [[ $protoport != */* ]]; then
+		echo "Error - bad service specification '$protoport'"
+		echo "Must use the format:   port/protocol"
+		exit 1
+	fi
+	proto="${protoport#*/}"
+	port="${protoport%/*}"
+	re='^[0-9]+$'
+	if [[ ! $port =~ $re ]]; then
+		echo "Error - port '$port' is not a number."
+		echo "Must use the format:   port/protocol"
+		exit 1
+	fi
+	if [[ $port -lt 0 || $port -gt 65535 ]]; then
+		echo "Error - port '$port' must be in the range 0-65535."
+		exit 1
+	fi
+	if [[ $VALIDPROTOS != *$proto* ]]; then
+		echo "Error - invalid protocol '$proto'."
+		echo "Valid protocols are:  $VALIDPROTOS"
+		exit 1
+	fi
+	shift 2
+	comment="$*"
+fi
+both=$(makeboth $name $protoport)
+
+if [[ $MODE == "init" ]]; then
+	if [[ -d $SRVDIR ]]; then
+		echo "error -i $SRVDIR already exists."
+		exit 1
+	fi
+	mkdir -p "$SRVDIR"
+	cp -p "$SRVFILE_ACTIVE" "$SRVFILE_BASE"
+	cp /dev/null "$SRVFILE_CUSTOM"
+	echo "Initialisation of $SRVDIR complete."
+	exit 0
+elif [[ ! -d $SRVDIR ]]; then
+	echo "Error - $SRVDIR is missing."
+	echo "Use -i to initialise it."
+	exit 1
+fi
+
+
+if [[ $MODE == "query" ]]; then
+	lookup whichfile res $name $protoport
+	if [[ ! -z $whichfile ]]; then
+		echo "Found in $whichfile services file:"
+		echo "$res" | sed -e 's/^/   /'
+		exit 0
+	else
+		echo "'$both' not found."
+		exit 1
+	fi
+elif [[ $MODE == "add" ]]; then
+	lookup whichfile res $name $protoport
+	if [[ ! -z $whichfile ]]; then
+		echo "Error - this already exists in $whichfile services file:"
+		echo "$res" | sed -e 's/^/   /'
+		exit 1
+	fi
+	if [[ ${#name} -gt 15 ]]; then
+		echo "Error - service name '$name' exceeds 15 characters."
+		exit 1
+	fi
+	if [[ -z $comment ]]; then
+		printf "%-16s%s\n" "$name" "$protoport" >> $SRVFILE_CUSTOM 
+	else
+		printf "%-16s%s # %s\n" "$name" "$protoport" "$comment" >> $SRVFILE_CUSTOM 
+	fi
+	echo "Added '$name' ($protoport) to custom services file."
+	synctoactive
+elif [[ $MODE == "del" ]]; then
+	lookup whichfile res $name $protoport
+	if [[ $whichfile != "custom"  ]]; then
+		echo "Error - can't find service '$both' in custom file."
+		exit 1
+	fi
+	re="$name"
+	if [[ ! -z $protoport ]]; then
+		if [[ ! -z $re ]]; then
+			re="$re|"
+		fi
+		re="$re${protoport}"
+	fi
+	re="${re/\//\\\/}" # escape the slash
+	count=$(egrep -c "$re" $SRVFILE_CUSTOM)
+	[[ $count -eq 1 ]] && ess="" || ess="s"
+	if [[ $count -gt 1 && $FORCE -ne 1 ]]; then
+		echo "Error:  '$both' matches multiple lines for removal, use -f to confirm:"
+		echo "$res" | sed -e 's/^/   /'
+		exit 1
+	fi
+	sed -ibak "/$re/d" $SRVFILE_CUSTOM
+	sedrv=$?
+	if [[ $sedrv -eq 0 ]]; then
+		echo "Removed '$both' from custom services file ($count line$ess)."
+		rv=0
+	else
+		echo "Error failed to remove '$both' from custom services file using sed."
+		rv=1
+	fi
+	synctoactive
+	exit $rv
+fi
+
+	# TODO: sync to real serviceafile
+exit 0