#!/bin/sh
# exploderpm
# VERSION 0.2
# Copyright 2009-2010 Gilbert Ashley <amigo@ibiblio.org>
# The code for explode_rpm was originally written by Jeff Johnson
# and modified by Lasse Collin <lasse.collin@tukaani.org>
# Copyright (C) 2005, 2006 Lasse Collin <lasse.collin@tukaani.org>

# code for handling debian archives taken from disrpm
# released under the Gnu General Public License (GPL)
# (c) bjdouma@xs4all.nl VER="v1.5, october 2004"


OPT="$1"
FILE="$2"
[[ $OPT = '-lv' ]] && VERBOSE='v' OPT='-l'
[[ $OPT = '-xv' ]] && VERBOSE='v' OPT='-x'

explode() {
  case "$1" in
    *.rpm)  explode_rpm "$FILE" ;;
    *.deb)  explode_deb "$FILE" ;;
  esac
  return $?
}


gzip_sieve()
{
	# gzip-magic: 0x1F,0x8B
	sed -ne '/1[fF]/{;N;/8[bB]$/{;s/1[fF]//g;s/^0*//g;P;};}'
}

bzip2_sieve()
{
	# bzip2-magic: 0x42,0x5A,0x68
	sed -ne '/42/{;N;/5[aA]$/{;N;/68$/{s/42//g;s/5[aA]//g;s/^0*//g;P;};};}'
}

probe()
{
	dd if=$FILE ibs=$O skip=1 2>/dev/null \
	| $2 -dc - 2>/dev/null \
	| cpio "$1" 2>/dev/null
}

explode_deb() {

PASS1="probe -t$VERBOSE"
case $OPT in
	'-l'|'-v') PASS2=":" ;;
	'-x') PASS2="probe -idm" ;;
esac

for AR in gzip bzip2 ; do
	e=1
	HEADER_SIZE=256000
	AR_OFFSETS=$(od -A d -N $HEADER_SIZE -v -t x1 -w1 $FILE | ${AR}_sieve)
	for O in $AR_OFFSETS ; do
		$PASS1 $AR 2>/dev/null && $PASS2 $AR && e=0
	done
	[ $e -eq 0 ] && return $e
done
}


explode_rpm() {
  local pkg o sigsize gz
  pkg=$1
  o=104
  set -- $(od -j $o -N 8 -t u1 -- "$pkg")
  sigsize=$((8 + 16 *
      (256 * (256 * (256 * $2 + $3) + $4) + $5) +
      (256 * (256 * (256 * $6 + $7) + $8) + $9)))
  o=$((o + sigsize + (8 - (sigsize % 8)) % 8 + 8))
  set -- $(od -j $o -N 8 -t u1 -- "$pkg")
  o=$((o + 8 + 16 *
      (256 * (256 * (256 * $2 + $3) + $4) + $5) +
      (256 * (256 * (256 * $6 + $7) + $8) + $9)))
  comp=$(dd if="$pkg" ibs=$o skip=1 count=1 2>/dev/null \
      | dd bs=3 count=1 2> /dev/null)
  gz="$(echo -en '\037\0213')"
  #xz="$(echo -en '\0fd\037\07a\058\05a\000')"
  case $OPT in
	'-x')
		case "$comp" in
			BZh)      dd if="$pkg" ibs=$o skip=1 2>/dev/null | bunzip2 | cpio --quiet -ivdm ;;
			"$gz"*)   dd if="$pkg" ibs=$o skip=1 2>/dev/null | gunzip | cpio --quiet -ivdm ;;
			"]"*)     dd if="$pkg" ibs=$o skip=1 2>/dev/null | unxz | cpio --quiet -ivdm ;;
			*)        echo "Unrecognized rpm file: $pkg"; return 1 ;;
		esac
	;;
	'-l')
		case "$comp" in
			BZh)      dd if="$pkg" ibs=$o skip=1 2>/dev/null | bunzip2 | cpio --quiet -t$VERBOSE ;;
			"$gz"*)   dd if="$pkg" ibs=$o skip=1 2>/dev/null | gunzip | cpio --quiet -t$VERBOSE ;;
			"]"*)     dd if="$pkg" ibs=$o skip=1 2>/dev/null | unxz | cpio --quiet -t$VERBOSE ;;
			*)        echo "Unrecognized rpm file: $pkg"; return 1 ;;
		esac
	;;
  esac
  [ $? != 0 ] && return 1
  # The directories that are not listed in the RPM file are always created
  # "chmod 0700" by cpio. We will reset those directories to "chmod 0755".
  # Unfortunately we cannot detect without extra help from cpio if the
  # package had some directories that shouldn't be world readable.
  find . -type d -perm 700 -exec chmod 755 {} \;
  return 0
}

# End of functions.explode.sh

explode "$FILE"