img-lib handles identifying and unpacking archives (uncompressed or
compressed) and filesystem images.
Currently tar and gzip are required; cpio and xz are optional, and bzip2
is supported but unused.
Signed-off-by: Will Woods <wwoods@xxxxxxxxxx>
---
modules.d/99img-lib/img-lib.sh | 72 +++++++++++++++++++++++++++++++++++
modules.d/99img-lib/module-setup.sh | 23 +++++++++++
2 files changed, 95 insertions(+), 0 deletions(-)
create mode 100755 modules.d/99img-lib/img-lib.sh
create mode 100755 modules.d/99img-lib/module-setup.sh
diff --git a/modules.d/99img-lib/img-lib.sh b/modules.d/99img-lib/img-lib.sh
new file mode 100755
index 0000000..582b416
--- /dev/null
+++ b/modules.d/99img-lib/img-lib.sh
@@ -0,0 +1,72 @@
+#!/bin/bash
+# img-lib.sh: utilities for dealing with archives and filesystem images.
+#
+# TODO: identify/unpack rpm, deb?
+
+
+# super-simple "file" that only identifies archives.
+# works with stdin if $1 is not set.
+det_archive() {
+ local bz="BZh" xz="$(echo -e '\xfd7zXZ')" gz="$(echo -e '\x1f\x8b')"
+ local headerblock="$(dd ${1:+if=$1} bs=262 count=1 2>/dev/null)"
+ case "$headerblock" in
+ $xz*) echo "xz" ;;
+ $gz*) echo "gzip" ;;
+ $bz*) echo "bzip2" ;;
+ 07070*) echo "cpio" ;;
+ *ustar) echo "tar" ;;
+ esac
+}
+
+# determine filesystem type for a filesystem image
+det_fs_img() {
+ local dev=$(losetup --find --show "$1") rv=""
+ det_fs $dev; rv=$?
+ losetup -d $dev
+ return $rv
+}
+
+# unpack_archive ARCHIVE OUTDIR
+# unpack a (possibly compressed) cpio/tar archive
+unpack_archive() {
+ local img="$1" outdir="$2" archiver="" decompr=""
+ local ft="$(det_archive $img)"
+ case "$ft" in
+ xz|gzip|bzip2) decompr="$decompr -dc" ;;
+ cpio|tar) decompr="cat";;
+ *) return 1 ;;
+ esac
+ ft="$($decompr $img | det_archive)"
+ case "$ft" in
+ cpio) archiver="cpio -iumd" ;;
+ tar) archiver="tar -xf -" ;;
+ *) return 2 ;;
+ esac
+ mkdir -p $outdir
+ ( cd $outdir; $decompr | $archiver 2>/dev/null ) < $img
+}
+
+# unpack_fs FSIMAGE OUTDIR
+# unpack a filesystem image
+unpack_fs() {
+ local img="$1" outdir="$2" mnt="$(mkuniqdir /tmp unpack_fs.)"
+ mount -o loop $img $mnt || { rmdir $mnt; return 1; }
+ mkdir -p $outdir; outdir="$(cd $outdir; pwd)"
+ ( cd $mnt; cp -a -t $outdir . )
+ umount $mnt
+ rmdir $mnt
+}
+
+# unpack an image file - compressed/uncompressed cpio/tar, filesystem, whatever
+# unpack_img IMAGEFILE OUTDIR
+unpack_img() {
+ local img="$1" outdir="$2"
+ [ -r "$img" ] || { warn "can't read img!"; return 1; }
+ [ -n "$outdir" ] || { warn "unpack_img: no output dir given"; return 1; }
+
+ if [ "$(det_img $img)" ]; then
+ unpack_archive "$@" || { warn "can't unpack archive file!"; return 1; }
+ else
+ unpack_fs "$@" || { warn "can't unpack filesystem image!"; return 1; }
+ fi
+}
diff --git a/modules.d/99img-lib/module-setup.sh b/modules.d/99img-lib/module-setup.sh
new file mode 100755
index 0000000..eead2ab
--- /dev/null
+++ b/modules.d/99img-lib/module-setup.sh
@@ -0,0 +1,23 @@
+#!/bin/bash
+# module-setup for img-lib
+
+check() {
+ for cmd in tar gzip dd; do
+ command -v $cmd >/dev/null || return 1
+ done
+ return 255
+}
+
+depends() {
+ return 0
+}
+
+install() {
+ # NOTE/TODO: we require bash, but I don't know how to specify that..
+ dracut_install tar gzip dd
+ dracut_install -o cpio xz
+ # TODO: make this conditional on a cmdline flag / config option
+ # dracut_install -o bzip2
+ inst "$moddir/img-lib.sh" "/lib/img-lib.sh"
+}
+
--
1.7.7.6
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