cross-fix-root: add some usage text

Be nice to users instead of exiting all the time with no output.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

1 files changed, 41 insertions, 23 deletions

diff --git a/wrappers/cross-fix-root b/wrappers/cross-fix-root
index 663db9f..234f2bb 100755
--- a/wrappers/cross-fix-root
+++ b/wrappers/cross-fix-root
@@ -1,16 +1,25 @@
 #!/bin/sh
-# Copyright 2008-2009 Gentoo Foundation
+# Copyright 2008-2010 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
-#
-# fix library perms, mung paths in pkg-config files, libtool linker scripts,
-# and random -config scripts to point to our build directory, and cross-compile
-# symlinks for the -config scripts as autotool packages will search for
-# prefixed -config scripts when cross-compiling.  note: the ugly ln/mv is to
-# work around a possible race condition if multiple make jobs are generating
-# the same symlink at the same time.  a `mv` is "atomic" (it uses rename())
-# while a `ln` is actually unlink();symlink();.
-#
+usage() {
+	cat <<-EOF
+	Usage: cross-fix-root <sysroot> <cross-bindir> <cross-prefix>
+	       cross-fix-root <cross-prefix>
+	       cross-fix-root # takes settings from env
+
+	Environment variables:
+	  CROSS_COMPILE=<cross-prefix>
+	  (SYSROOT|ROOT|STAGEDIR)=<sysroot>
+
+	Description:
+	  Fix library perms and mung paths in libtool linker scripts & random -config
+	  scripts to point to our SYSROOT directory.  Add symlinks for the -config
+	  with cross-compiler prefixes as autotool packages will search for them first
+	  when cross-compiling.
+	EOF
+	exit 1
+}
 
 LIBDIR="usr/lib"
 SYSROOT=${SYSROOT:-${ROOT:-${STAGEDIR}}}
@@ -20,19 +29,24 @@ if [ -n "${ROOTDIR}" ] ; then
 	CROSS_BINDIR="${ROOTDIR}/tools"
 fi
 CROSS_PREFIX=${CROSS_COMPILE}
-if [ -n "$3" ] ; then
-	SYSROOT="$1"
-	CROSS_BINDIR="$2"
-	CROSS_PREFIX="$3"
-elif [ -n "$1" ] ; then
-	if [ -e "/usr/$1" ] ; then
-		SYSROOT="/usr/$1"
-		CROSS_BINDIR="/usr/bin"
-		CROSS_PREFIX="$1-"
-	else
-		exit 1
-	fi
-fi
+case $# in
+	3)
+		SYSROOT="$1"
+		CROSS_BINDIR="$2"
+		CROSS_PREFIX="$3"
+		;;
+	1)
+		if [ -e "/usr/${1:-..........}" ] ; then
+			SYSROOT="/usr/$1"
+			CROSS_BINDIR="/usr/bin"
+			CROSS_PREFIX="$1-"
+		else
+			usage
+		fi
+		;;
+	0) [ -z "${SYSROOT}" ] && usage ;;
+	*) usage ;;
+esac
 
 cd "${SYSROOT}" || exit 0
 
@@ -61,6 +75,10 @@ if [ -d usr/bin ] ; then
 	if [ -n "${CROSS_BINDIR}" ] && [ -d "${CROSS_BINDIR}" ] && [ -n "${CROSS_PREFIX}" ] ; then
 		cd usr/bin || exit 1
 		for config in *-config ; do
+			# work around a possible race condition if multiple make jobs
+			# are generating the same symlink at the same time.  a `mv`
+			# is "atomic" (it uses rename())  while a `ln` is actually
+			# unlink() followed by a symlink().
 			ln -s "${SYSROOT}/usr/bin/${config}" "${CROSS_BINDIR}/${CROSS_PREFIX}${config}.$$"
 			mv "${CROSS_BINDIR}/${CROSS_PREFIX}${config}.$$" "${CROSS_BINDIR}/${CROSS_PREFIX}${config}"
 		done