From 19dbaff8dd051688c0acf1b6605bf13a7fe019bd Mon Sep 17 00:00:00 2001 From: Alexey Gladkov <gladkov.alexey@gmail.com> Date: Fri, 9 Sep 2016 15:03:41 +0200 Subject: [PATCH] rpm2cpio.sh: refactoring to reduce extra dependencies rpm2cpio.sh was refactored to minimize the use of external tools. * after refactoring the utility requires to work: dd, printf, and unarchivers; * add check that file passed as argument is a rpm-file; * fix signatures of compressed data. Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> --- scripts/rpm2cpio.sh | 92 ++++++++++++++++++++++++++++++----------------------- 1 file changed, 52 insertions(+), 40 deletions(-) diff --git a/scripts/rpm2cpio.sh b/scripts/rpm2cpio.sh index cb93ead..f7d50fd 100755 --- a/scripts/rpm2cpio.sh +++ b/scripts/rpm2cpio.sh @@ -1,41 +1,53 @@ -#!/bin/sh - -# Prevent gawk >= 4.0.x from getting funny ideas wrt UTF in printf() -LANG=C - -pkg=$1 -if [ "$pkg" = "" -o ! -e "$pkg" ]; then - echo "no package supplied" 1>&2 - exit 1 -fi - -leadsize=96 -o=`expr $leadsize + 8` -set `od -j $o -N 8 -t u1 $pkg` -il=`expr 256 \* \( 256 \* \( 256 \* $2 + $3 \) + $4 \) + $5` -dl=`expr 256 \* \( 256 \* \( 256 \* $6 + $7 \) + $8 \) + $9` -# echo "sig il: $il dl: $dl" - -sigsize=`expr 8 + 16 \* $il + $dl` -o=`expr $o + $sigsize + \( 8 - \( $sigsize \% 8 \) \) \% 8 + 8` -set `od -j $o -N 8 -t u1 $pkg` -il=`expr 256 \* \( 256 \* \( 256 \* $2 + $3 \) + $4 \) + $5` -dl=`expr 256 \* \( 256 \* \( 256 \* $6 + $7 \) + $8 \) + $9` -# echo "hdr il: $il dl: $dl" - -hdrsize=`expr 8 + 16 \* $il + $dl` -o=`expr $o + $hdrsize` - -comp=`dd if="$pkg" ibs=$o skip=1 count=1 2>/dev/null \ - | dd bs=3 count=1 2>/dev/null` - -gz="`echo . | awk '{ printf("%c%c", 0x1f, 0x8b); }'`" -lzma="`echo . | awk '{ printf("%cLZ", 0xff); }'`" -xz="`echo . | awk '{ printf("%c7z", 0xfd); }'`" -case "$comp" in - BZh) dd if="$pkg" ibs=$o skip=1 2>/dev/null | bunzip2 ;; - "$gz"*) dd if="$pkg" ibs=$o skip=1 2>/dev/null | gunzip ;; - "$xz"*) dd if="$pkg" ibs=$o skip=1 2>/dev/null | xzcat ;; - "$lzma"*) dd if="$pkg" ibs=$o skip=1 2>/dev/null | unlzma ;; - *) echo "Unrecognized rpm file: $pkg"; exit 1 ;; +#!/bin/sh -efu + +fatal() { + echo "$*" >&2 + exit 1 +} + +pkg="$1" +[ -n "$pkg" -a -e "$pkg" ] || + fatal "No package supplied" + +_dd() { + local o="$1"; shift + dd if="$pkg" skip="$o" iflag=skip_bytes status=none $* +} + +calcsize() { + offset=$(($1 + 8)) + + local i b b0 b1 b2 b3 b4 b5 b6 b7 + + i=0 + while [ $i -lt 8 ]; do + b="$(_dd $(($offset + $i)) bs=1 count=1)" + [ -z "$b" ] && + b="0" || + b="$(exec printf '%u\n' "'$b")" + eval "b$i=\$b" + i=$(($i + 1)) + done + + rsize=$((8 + ((($b0 << 24) + ($b1 << 16) + ($b2 << 8) + $b3) << 4) + ($b4 << 24) + ($b5 << 16) + ($b6 << 8) + $b7)) + offset=$(($offset + $rsize)) +} + +case "$(_dd 0 bs=8 count=1)" in + "$(printf '\355\253\356\333')"*) ;; # '\xed\xab\xee\xdb' + *) fatal "File doesn't look like rpm: $pkg" ;; +esac + +calcsize 96 +sigsize=$rsize + +calcsize $(($offset + (8 - ($sigsize % 8)) % 8)) +hdrsize=$rsize + +case "$(_dd $offset bs=3 count=1)" in + "$(printf '\102\132')"*) _dd $offset | bunzip2 ;; # '\x42\x5a' + "$(printf '\037\213')"*) _dd $offset | gunzip ;; # '\x1f\x8b' + "$(printf '\375\067')"*) _dd $offset | xzcat ;; # '\xfd\x37' + "$(printf '\135\000')"*) _dd $offset | unlzma ;; # '\x5d\x00' + *) fatal "Unrecognized rpm file: $pkg" ;; esac -- 2.10.1