#!/bin/sh
# Copyright 1997, 1998 Patrick Volkerding, Moorhead, MN USA
# Copyright 2002 Slackware Linux, Inc., Concord, CA USA
# All rights reserved.
#
# Redistribution and use of this script, with or without modification, is
# permitted provided that the following conditions are met:
#
# 1. Redistributions of this script must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
#  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
#  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
#  EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
#  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
#  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
#  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
#  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
#  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

argv0=${0##*/}

usage=false
stdout=false
verbose=false
strip=false
files=false
msg=""
for opt; do
	case ${opt} in
		-h|--help)       usage=true;;
		-O|--stdout)     stdout=true;;
		-v|--verbose)    verbose=true;;
		-S|--strip-path) strip=true;;
		--)              break;;
		-*)              usage=true msg="unknown option '${opt}'";;
		*)               files=true;;
	esac
done

if ! ${files} || ${usage} ; then
	cat <<-EOF
	${argv0}: Converts RPM archives to tar archives

	Usage: ${argv0} [options] <rpms>

	Options:
	  -h, --help       This help screen (imagine that)
	  -O, --stdout     Write tarball to stdout
	  -S, --strip-path Strip package name from tarball
	  -v, --verbose    Verbose output
	EOF

	if [ -n "${msg}" ] ; then
		echo "Error: ${msg}" 1>&2
		exit 1
	else
		exit 0
	fi
fi

compress="cat"
case ${argv0} in
	rpm2tar)                      suffix=".tar";;
	rpm2tarbz2)  compress="bzip2" suffix=".tar.bz2";;
	rpm2tbz2)    compress="bzip2" suffix=".tbz2";;
	rpm2tarlzma) compress="lzma"  suffix=".tarlzma";;
	rpm2tgz)     compress="gzip"  suffix=".tgz";;
	rpm2targz|*) compress="gzip"  suffix=".tar.gz";;
esac

# try to get a temp dir using progressively older/crappier methods
WORKDIR=""
trap 'rm -rf "${WORKDIR}"' 0

WORKDIR=$(mktemp -d --tmpdir ${argv0}.XXXXXX 2>/dev/null)
if [ -z "${WORKDIR}" ] ; then
	WORKDIR=$(mktemp -d -t ${argv0}.XXXXXX 2>/dev/null)
	if [ -z "${WORKDIR}" ] ; then
		[ -z "${TMPDIR}" ] && TMPDIR="/tmp"
		WORKDIR=$(mcookie 2>/dev/null)
		if [ -n "${WORKDIR}" ] ; then
			WORKDIR="${TMPDIR}/${WORKDIR}"
		else
			WORKDIR="${TMPDIR}/$$"
		fi

		worked=false
		if rm -rf "${WORKDIR}" ; then
			if mkdir -m 700 -p "${WORKDIR}" ; then
				worked=true
			elif mkdir -p "${WORKDIR}" ; then
				if chmod 700 "${WORKDIR}" ; then
					worked=true
				fi
			fi
		fi
		if ! ${worked} ; then
			echo "${argv0}: ${WORKDIR}: unable to create a temp directory"
			exit 1
		fi
	fi
fi

ret=0
dashdash=false
for file; do
	if ! ${dashdash} ; then
		case ${file} in
			-v|--verbose) continue;;
			-O|--stdout) continue;;
			-S|--strip-path) continue;;
			--) dashdash=true; continue;;
		esac
	fi

	${verbose} && printf "Processing file: ${file} ... "

	outfile=${file##*/}
	outfile=${outfile%.rpm}
	${strip} && base="" || base=${outfile%.src}
	DEST="${WORKDIR}/${base}"
	rm -rf "${DEST}"
	if ! mkdir "${DEST}" ; then
		echo "${argv0}: ${file}: ${DEST}: unable to create working directory"
		rm -rf "${WORKDIR}"
		exit 1
	fi

	# extract the CPIO from the RPM and unpack it
	(
		decompressor=""
		if command -v rpm2cpio 2>/dev/null 1>&2 ; then
			decompressor="rpm2cpio"
			rpm2cpio "${file}"
		else
			# do it by hand :/
			offset=$(rpmoffset < "${file}")
			magic=`(dd ibs=${offset} skip=1 if="${file}" count=1 | dd bs=10 count=1 | od -b) 2>/dev/null`
			case ${magic} in
				"0000000 102 132 150 "*)   decompressor="bzip2";;
				"0000000 037 213 010 "*|*) decompressor="gzip";;
			esac
			dd ibs=${offset} skip=1 if="${file}" 2>/dev/null | ${decompressor} -dc
		fi
		[ $? -ne 0 ] && echo "${argv0}: ${file}: failed to extract cpio via ${decompressor} (not actually an RPM?)" 1>&2
	) | (
		cd "${DEST}"
		# filter stupid blocks info from cpio
		cpio -i -m -d 2>/dev/null
	)

	if [ $? -ne 0 ] ; then
		ret=1

		${verbose} && echo "FAIL"
	else
		# repack the files into the appropriate tar file
		(
			cd "${WORKDIR}"
			tar cf - "./${base}"
		) | ${compress} | (
			if ${stdout} ; then
				cat
			else
				cat > "${outfile}${suffix}"
			fi
		)

		${verbose} && echo "OK"
	fi

	rm -rf "${DEST}"
done

rm -rf "${WORKDIR}"

exit ${ret}