signlk: remove bashisms

The script can now work with bash and POSIX shell (dash).

Signed-off-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>

signlk.sh

+#!/bin/sh
 ################################################################################
 # Copyright (c) 2016, The Linux Foundation. All rights reserved.               #
 #                                                                              #
@@ -75,7 +76,7 @@ case $i in
 esac
 done
 
-if [ "$INFILE" == "" ]; then
+if [ "$INFILE" = "" ]; then
    echo "signlk -i=input_file_name [-o=output_file_name]"
 	exit 2
 fi
@@ -83,7 +84,7 @@ fi
 INFILE_filename=$(echo $INFILE | rev | cut -f 2- -d '.' | rev)
 INFILE_extension=$(echo $INFILE | rev | cut -f 1 -d '.' | rev)
 
-if [ "$INFILE_extension" == "" ]; then
+if [ "$INFILE_extension" = "" ]; then
    echo "input file must be an elf or mbn file"
    exit 3      
 fi
@@ -93,7 +94,7 @@ if [ "$INFILE_extension" != "elf" ] &&  [ "$INFILE_extension" != "mbn" ] && [ "$
    exit 4
 fi
 
-if [ "$OUTFILE" == "" ]; then
+if [ "$OUTFILE" = "" ]; then
         OUTFILE=$INFILE_filename"_signed.mbn"
         
 fi
@@ -159,25 +160,26 @@ openssl x509 -in $tmpdir/atte_cert.PEM -inform PEM -outform DER -out $ATT 2>/dev
 openssl pkeyutl -sign -inkey $tmpdir/atte_key.PEM -in $CODE -out $SIG 2>/dev/null
 
 
-data_file_size=$( cut -d ' ' -f 1 <<< $(du -b $DATA | tr '[:blank:]' ' '))
-code_file_size=$( cut -d ' ' -f 1 <<< $(du -b $CODE | tr '[:blank:]' ' ') )
-sig_file_size=$( cut -d ' ' -f 1 <<< $(du -b $SIG | tr '[:blank:]' ' ') )
-atte_file_size=$( cut -d ' ' -f 1 <<< $(du -b $ATT | tr '[:blank:]' ' ') )
-root_file_size=$( cut -d ' ' -f 1 <<< $(du -b $ROOT | tr '[:blank:]' ' ') )
-hash_seg_file_size=$( cut -d ' ' -f 1 <<< $(du -b $tmpdir/hashSeg | tr '[:blank:]' ' ') )
+data_file_size=$(du -b $DATA | tr '[:blank:]' ' ' | cut -d ' ' -f 1)
+code_file_size=$(du -b $CODE | tr '[:blank:]' ' ' | cut -d ' ' -f 1)
+sig_file_size=$(du -b $SIG | tr '[:blank:]' ' ' | cut -d ' ' -f 1)
+atte_file_size=$(du -b $ATT | tr '[:blank:]' ' ' | cut -d ' ' -f 1)
+root_file_size=$(du -b $ROOT | tr '[:blank:]' ' ' | cut -d ' ' -f 1)
+hash_seg_file_size=$(du -b $tmpdir/hashSeg | tr '[:blank:]' ' ' | cut -d ' ' -f 1)
 hash_seg_offset=4096
 mi_hdr_size=40
 
 dd if=$TMPOUTFILE of=$OUTFILE  2>/dev/null
-dd if=$DATA of=$OUTFILE bs=1 count=$data_file_size  seek=$[hash_seg_offset+$mi_hdr_size] 2>/dev/null
-dd if=$SIG of=$OUTFILE count=$sig_file_size bs=1 seek=$[$hash_seg_offset+$mi_hdr_size+$data_file_size] 2>/dev/null
-dd if=$ATT of=$OUTFILE count=$atte_file_size bs=1 seek=$[$hash_seg_offset+$mi_hdr_size+$data_file_size+$sig_file_size] 2>/dev/null
-dd if=$ROOT of=$OUTFILE count=$root_file_size bs=1 seek=$[$hash_seg_offset+$mi_hdr_size+$data_file_size+$sig_file_size+$atte_file_size] 2>/dev/null
-dd if=$tmpdir/hashSeg of=$OUTFILE bs=1 skip=$[$mi_hdr_size+$data_file_size+$sig_file_size+$atte_file_size+$root_file_size] seek=$[$hash_seg_offset+$mi_hdr_size+$data_file_size+$sig_file_size+$atte_file_size+$root_file_size] 2>/dev/null
-dd if=$TMPOUTFILE of=$OUTFILE bs=1 skip=$[$hash_seg_offset+$hash_seg_file_size] seek=$[$hash_seg_offset+$hash_seg_file_size] 2>/dev/null
-
-if ! [[ $- =~ x ]]; then
-  rm -rf $tmpdir
+dd if=$DATA of=$OUTFILE bs=1 count=$data_file_size  seek=$((hash_seg_offset+$mi_hdr_size)) 2>/dev/null
+dd if=$SIG of=$OUTFILE count=$sig_file_size bs=1 seek=$(($hash_seg_offset+$mi_hdr_size+$data_file_size)) 2>/dev/null
+dd if=$ATT of=$OUTFILE count=$atte_file_size bs=1 seek=$(($hash_seg_offset+$mi_hdr_size+$data_file_size+$sig_file_size)) 2>/dev/null
+dd if=$ROOT of=$OUTFILE count=$root_file_size bs=1 seek=$(($hash_seg_offset+$mi_hdr_size+$data_file_size+$sig_file_size+$atte_file_size)) 2>/dev/null
+dd if=$tmpdir/hashSeg of=$OUTFILE bs=1 skip=$(($mi_hdr_size+$data_file_size+$sig_file_size+$atte_file_size+$root_file_size)) seek=$(($hash_seg_offset+$mi_hdr_size+$data_file_size+$sig_file_size+$atte_file_size+$root_file_size)) 2>/dev/null
+dd if=$TMPOUTFILE of=$OUTFILE bs=1 skip=$(($hash_seg_offset+$hash_seg_file_size)) seek=$(($hash_seg_offset+$hash_seg_file_size)) 2>/dev/null
+
+# no cleanup in debug mode
+if ! echo "$-" | grep -q 'x'; then
+   rm -rf $tmpdir
 fi
 
 echo done