sysrc(8): Add `key-=remove' and improve `key+=append' syntax

MFC after:	3 days
X-MFC-to:	stable/10 stable/9

2 files changed, 186 insertions, 26 deletions

diff --git a/usr.sbin/sysrc/sysrc b/usr.sbin/sysrc/sysrc
index 8a1a863..bcb2178 100644
--- a/usr.sbin/sysrc/sysrc
+++ b/usr.sbin/sysrc/sysrc
@@ -1,6 +1,6 @@
 #!/bin/sh
 #-
-# Copyright (c) 2010-2014 Devin Teske
+# Copyright (c) 2010-2015 Devin Teske
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -40,7 +40,7 @@ BSDCFG_SHARE="/usr/share/bsdconfig"
 #
 # Version information
 #
-SYSRC_VERSION="6.2 Nov-3,2014"
+SYSRC_VERSION="6.3 Mar-4,2015"
 
 #
 # Options
@@ -94,7 +94,7 @@ help()
 	local optfmt="\t%-11s%s\n"
 	local envfmt="\t%-17s%s\n"
 
-	f_err "Usage: %s [OPTIONS] name[[+]=value] ...\n" "$pgm"
+	f_err "Usage: %s [OPTIONS] name[[+|-]=value] ...\n" "$pgm"
 
 	f_err "OPTIONS:\n"
 	f_err "$optfmt" "-a" \
@@ -531,6 +531,7 @@ while [ $# -gt 0 ]; do
 
 	case "$NAME" in
 	*+) mode=APPEND NAME="${NAME%+}" ;;
+	*-) mode=REMOVE NAME="${NAME%-}" ;;
 	 *) mode=ASSIGN
 	esac
 
@@ -594,29 +595,70 @@ while [ $# -gt 0 ]; do
 		fi
 
 		#
-		# If `-N' is passed, simplify the output
+		# Determine both `before' value and appropriate `new' value
 		#
-		if [ ! "$SHOW_VALUE" ]; then
-			echo "$NAME"
-			case "$mode" in
-			APPEND)
-				before=$( f_sysrc_get "$NAME" )
-				f_sysrc_set "$NAME" "$before${1#*=}"
-				;;
-			*)
-				f_sysrc_set "$NAME" "${1#*=}"
+		case "$mode" in
+		APPEND)
+			before=$( f_sysrc_get "$NAME" )
+			add="${1#*=}"
+			delim="${add%"${add#?}"}" # first character
+			oldIFS="$IFS"
+			case "$delim" in
+			""|[$IFS]|[a-zA-Z0-9]) delim=" " ;;
+			*) IFS="$delim"
 			esac
-		else
+			new="$before"
+			for a in $add; do
+				[ "$a" ] || continue
+				skip=
+				for b in $before; do
+					[ "$b" = "$a" ] && skip=1 break
+				done
+				[ "$skip" ] || new="$new$delim$a"
+			done
+			new="${new#"$delim"}" IFS="$oldIFS"
+			unset add delim oldIFS a skip b
+			[ "$SHOW_FILE" ] && before=$( f_sysrc_find "$NAME" )
+			;;
+		REMOVE)
+			before=$( f_sysrc_get "$NAME" )
+			remove="${1#*=}"
+			delim="${remove%"${remove#?}"}" # first character
+			oldIFS="$IFS"
+			case "$delim" in
+			""|[$IFS]|[a-zA-Z0-9]) delim=" " ;;
+			*) IFS="$delim"
+			esac
+			new=
+			for b in $before; do
+				[ "$b" ] || continue
+				add=1
+				for r in $remove; do
+					[ "$r" = "$b" ] && add= break
+				done
+				[ "$add" ] && new="$new$delim$b"
+			done
+			new="${new#"$delim"}" IFS="$oldIFS"
+			unset remove delim oldIFS b add r
+			[ "$SHOW_FILE" ] && before=$( f_sysrc_find "$NAME" )
+			;;
+		*)
 			if [ "$SHOW_FILE" ]; then
 				before=$( f_sysrc_find "$NAME" )
 			else
 				before=$( f_sysrc_get "$NAME" )
 			fi
-			if case "$mode" in
-				APPEND) f_sysrc_set "$NAME" "$before${1#*=}" ;;
-				     *) f_sysrc_set "$NAME" "${1#*=}"
-				esac
-			then
+			new="${1#*=}"
+		esac
+
+		#
+		# If `-N' is passed, simplify the output
+		#
+		if [ ! "$SHOW_VALUE" ]; then
+			echo "$NAME"
+			f_sysrc_set "$NAME" "$new"
+		else
+			if f_sysrc_set "$NAME" "$new"; then
 				if [ "$SHOW_FILE" ]; then
 					after=$( f_sysrc_find "$NAME" )
 				else
diff --git a/usr.sbin/sysrc/sysrc.8 b/usr.sbin/sysrc/sysrc.8
index cba481f..1bd761a 100644
--- a/usr.sbin/sysrc/sysrc.8
+++ b/usr.sbin/sysrc/sysrc.8
@@ -1,4 +1,4 @@
-.\" Copyright (c) 2011-2014 Devin Teske
+.\" Copyright (c) 2011-2015 Devin Teske
 .\" All rights reserved.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 4, 2014
+.Dd March 4, 2015
 .Dt SYSRC 8
 .Os
 .Sh NAME
@@ -35,7 +35,7 @@
 .Op Fl cdDeFhinNqvx
 .Op Fl f Ar file
 .Op Fl j Ar jail | Fl R Ar dir
-.Ar name Ns Op Ns Oo + Oc Ns = Ns Ar value
+.Ar name Ns Op Ns Oo +|- Oc Ns = Ns Ar value
 .Ar ...
 .Nm
 .Op Fl cdDeFhinNqvx
@@ -136,9 +136,14 @@ and also has the same
 .Ql name[=value]
 syntax for making queries/assignments.
 In addition
-.Pq unlike Xr sysctl 8 ,
+.Pq but unlike Xr sysctl 8 ,
 .Ql name+=value
-is supported for appending values.
+is supported for adding items to values
+.Pq see APPENDING VALUES
+and
+.Ql name-=value
+is supported for removing items from values
+.Pq see SUBTRACTING VALUES .
 .Pp
 However, while
 .Xr sysctl 8
@@ -187,6 +192,115 @@ modifying these integral files (yet taking care not to allow the file to
 grow unwieldy should
 .Nm
 be called repeatedly).
+.Sh APPENDING VALUES
+When using the
+.Ql key+=value
+syntax to add items to existing values,
+the first character of the value is taken as the delimiter separating items
+.Pq usually Qo \  Qc or Qo , Qc .
+For example, in the following statement:
+.Bl -tag -width indent+
+.It \ 
+.Nm
+cloned_interfaces+=" gif0"
+.El
+.Pp
+the first character is a space, informing
+.Nm
+that existing values are to be considered separated by whitespace.
+If
+.Ql gif0
+is not found in the existing value for
+.Va cloned_interfaces ,
+it is added
+.Pq with delimiter only if existing value is non-NULL .
+.Pp
+For convenience, if the first character is alpha-numeric
+.Pq letters A-Z, a-z, or numbers 0-9 ,
+.Nm
+uses the default setting of whitespace as separator.
+For example, the above and below statements are equivalent since
+.Dq gif0
+starts with an alpha-numeric character
+.Pq the letter Li g :
+.Pp
+.Bl -tag -width indent+
+.It \ 
+.Nm
+cloned_interfaces+=gif0
+.El
+.Pp
+Take the following sequence for example:
+.Bl -tag -width indent+
+.It \ 
+.Nm
+cloned_interfaces= # start with NULL
+.It \ 
+.Nm
+cloned_interfaces+=gif0
+.Dl # NULL -> `gif0' Pq NB: no preceding delimiter
+.It \ 
+.Nm
+cloned_interfaces+=gif0 # no change
+.It \ 
+.Nm
+cloned_interfaces+="tun0 gif0"
+.Dl # `gif0' -> `gif0 tun0' Pq NB: no duplication
+.El
+.Pp
+.Nm
+prevents the same value from being added if already there.
+.Sh SUBTRACTING VALUES
+When using the
+.Ql key-=value
+syntax to remove items from existing values,
+the first character of the value is taken as the delimiter separating items
+.Pq usually Qo \  Qc or Qo , Qc .
+For example, in the following statement:
+.Pp
+.Dl Nm cloned_interfaces-=" gif0"
+.Pp
+the first character is a space, informing
+.Nm
+that existing values are to be considered separated by whitespace.
+If
+.Ql gif0
+is found in the existing value for
+.Va cloned_interfaces ,
+it is removed
+.Pq extra delimiters removed .
+.Pp
+For convenience, if the first character is alpha-numeric
+.Pq letters A-Z, a-z, or numbers 0-9 ,
+.Nm
+uses the default setting of whitespace as separator.
+For example, the above and below statements are equivalent since
+.Dq gif0
+starts with an alpha-numeric character
+.Pq the letter Li g :
+.Pp
+.Bl -tag -width indent+
+.It \ 
+.Nm
+cloned_interfaces-=gif0
+.El
+.Pp
+Take the following sequence for example:
+.Bl -tag -width indent+
+.It \ 
+.Nm
+foo="bar baz" # start
+.It \ 
+.Nm
+foo-=bar # `bar baz' -> `baz'
+.It \ 
+.Nm
+foo-=baz # `baz' -> NULL
+.El
+.Pp
+.Nm
+removes all occurrences of all items provided
+and collapses extra delimiters between items.
 .Sh ENVIRONMENT
 The following environment variables are referenced by
 .Nm :
@@ -250,8 +364,12 @@ Working on other files, such as
 Appending to existing values:
 .Pp
 .Nm
-\&cloned_interfaces+=" gif0"
-.Dl appends Qo \ gif0 Qc to $cloned_interfaces .
+\&cloned_interfaces+=gif0
+.Dl appends Qo gif0 Qc to $cloned_interfaces Pq see APPENDING VALUES .
+.Pp
+.Nm
+\&cloned_interfaces-=gif0
+.Dl removes Qo gif0 Qc from $cloned_interfaces Pq see SUBTRACTING VALUES .
 .Pp
 In addition to the above syntax,
 .Nm