Add shell implementations of basename and dirname to rc.subr. They

are supposed to mimic basename(1) and dirname(1), except that they
are usable before /usr/bin is mounted.

etc/rc.subr

@@ -1,4 +1,4 @@
-# $NetBSD: rc.subr,v 1.91 2012/04/07 17:28:44 christos Exp $
+# $NetBSD: rc.subr,v 1.92 2012/12/17 18:17:27 apb Exp $
 #
 # Copyright (c) 1997-2011 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -1256,6 +1256,34 @@ collapse_backslash_newline()
 	done
 }
 
+# Shell implementations of basename and dirname, usable before
+# the /usr file system is mounted.
+#
+basename()
+{
+	local file="$1"
+	local suffix="$2"
+	local base
+
+	base="${file##*/}"		# remove up to and including last '/'
+	base="${base%${suffix}}"	# remove suffix, if any
+	command printf "%s\n" "${base}"
+}
+
+dirname()
+{
+	local file="$1"
+	local dir
+
+	case "$file" in
+	/*/*)	dir="${file%/*}" ;;	# common case: absolute path
+	/*)	dir="/" ;;		# special case: name in root dir
+	*/*)	dir="${file%/*}" ;;	# common case: relative path with '/'
+	*)	dir="." ;;		# special case: name without '/'
+	esac
+	command printf "%s\n" "${dir}"
+}
+
 # Override the normal "echo" and "printf" commands, so that
 # partial lines printed by rc.d scripts appear immediately,
 # instead of being buffered by rc(8)'s post-processor.

share/man/man8/rc.subr.8

@@ -1,4 +1,4 @@
-.\" 	$NetBSD: rc.subr.8,v 1.29 2011/08/11 22:52:46 apb Exp $
+.\" 	$NetBSD: rc.subr.8,v 1.30 2012/12/17 18:17:27 apb Exp $
 .\"
 .\" Copyright (c) 2002-2011 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -40,6 +40,8 @@
 .It
 .Ic backup_file Ar action Ar file Ar current Ar backup
 .It
+.Ic basename Ar file Op Ar suffix
+.It
 .Ic checkyesno Ar var
 .It
 .Ic check_pidfile Ar pidfile Ar procname Op Ar interpreter
@@ -48,6 +50,8 @@
 .It
 .Ic collapse_backslash_newline
 .It
+.Ic dirname Ar file
+.It
 .Ic err Ar exitval Ar message
 .It
 .Ic load_rc_config Ar command
@@ -157,6 +161,12 @@ otherwise
 is moved to
 .Ar backup .
 .El
+.Ic basename Ar file Op Ar suffix
+Just like
+.Xr basename 1 ,
+except implemented using shell built-in commands, and usable before the 
+.Pa /usr/bin
+direcory is available.
 .It Ic checkyesno Ar var
 Return 0 if
 .Ar var
@@ -214,6 +224,12 @@ is handled as per
 Copy input to output, collapsing
 .Ao backslash Ac Ns Ao newline Ac
 to nothing, but leaving other backslashes alone.
+.Ic dirname Ar file
+Just like
+.Xr dirname 1 ,
+except implemented using shell built-in commands, and usable before the 
+.Pa /usr/bin
+direcory is available.
 .It Ic err Ar exitval Ar message
 Display an error message to
 .Em stderr ,