You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
74 lines
2.2 KiB
74 lines
2.2 KiB
#!/bin/sh |
|
# img-lib.sh: utilities for dealing with archives and filesystem images. |
|
# |
|
# TODO: identify/unpack rpm, deb, maybe others? |
|
|
|
|
|
# super-simple "file" that only identifies archives. |
|
# works with stdin if $1 is not set. |
|
det_archive() { |
|
# NOTE: echo -e works in ash and bash, but not dash |
|
local bz="BZh" xz="$(echo -e '\xfd7zXZ')" gz="$(echo -e '\x1f\x8b')" zs="$(echo -e '\x28\xB5\x2F\xFD')" |
|
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" ;; |
|
$zs*) echo "zstd" ;; |
|
07070*) echo "cpio" ;; |
|
*ustar) echo "tar" ;; |
|
esac |
|
} |
|
|
|
# determine filesystem type for a filesystem image |
|
det_fs_img() { |
|
local dev=$(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|zstd) decompr="$ft -dc" ;; |
|
cpio|tar) decompr="cat";; |
|
*) return 1 ;; |
|
esac |
|
ft="$($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)" |
|
copytree $mnt $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_archive $img)" ]; then |
|
unpack_archive "$@" || { warn "can't unpack archive file!"; return 1; } |
|
else |
|
unpack_fs "$@" || { warn "can't unpack filesystem image!"; return 1; } |
|
fi |
|
}
|
|
|