unmkinitramfs: Rewrite command syntax

I'm not comfortable with unmkinitramfs passing through everything to
cpio, considering what a sharp tool cpio is.  Instead of that,
recognise and pass through the few specific options that are
important.

Always pass --preserve-modification-time --no-absolute-filenames
--quiet.

Take the initramfs filename as a mandatory argument rather than
expecting a file on stdin, to be more consistent lsinitramfs and
mkinitramfs do.

Take an output directory as a mandatory argument (except when
listing), rather than extracting to the current directory.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

1 files changed, 3 insertions, 3 deletions

diff --git a/lsinitramfs b/lsinitramfs
index 14705ad..a96308d 100755
--- a/lsinitramfs
+++ b/lsinitramfs
@@ -12,7 +12,7 @@ if [ "$#" -eq 0 ] ; then
 	exit 1
 fi
 
-cpio_args="--quiet --list"
+umi_opts="--list"
 
 OPTIONS=`getopt -o hl --long help,long -n "$0" -- "$@"`
 # Check for non-GNU getopt
@@ -27,7 +27,7 @@ while true; do
 		exit 0
 	;;
 	-l|--long)
-		cpio_args="${cpio_args:+${cpio_args} --verbose}"
+		umi_opts="${umi_opts:+${umi_opts} --verbose}"
 		shift
 	;;
 	--)
@@ -41,5 +41,5 @@ while true; do
 done
 
 for initramfs in "$@" ; do
-	unmkinitramfs $cpio_args < "$initramfs"
+	unmkinitramfs $umi_opts -- "$initramfs"
 done