support: Allow compression of sdcard.img

In image files, generated by genimage.sh, there are tens of megabytes most of which might be filled with zeros as partitions are made a bit larger than needed for minimalictic rootfs (which allows users to add more libs and aps later on without messign with partition sizes).

So adding an option for genimage.sh script, setting which we gzip image file and greatly reduce it size.

Signed-off-by Evgeniy Didin <[email protected]>

Cc Alexey Brodkin <[email protected]>

Cc arc-buildroot at synopsys.com

Cc Thomas Petazzoni <[email protected]>

---
 support/scripts/genimage.sh | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

support/scripts/genimage.sh +11 -2

index 039b3fef1d..fa00e12855 100755
@@ -1,16 +1,17 @@
 #!/usr/bin/env bash
+# -g option gzips IMAGE_FILE to reduce it size
 
 die() {
   cat <<EOF >&2
 Error: $@
 
-Usage: ${0} -c GENIMAGE_CONFIG_FILE
+Usage: ${0} -c GENIMAGE_CONFIG_FILE -g IMAGE_FILE
 EOF
   exit 1
 }
 
 # Parse arguments and put into argument list of the script
-opts="$(getopt -n "${0##*/}" -o c: -- "$@")" || exit $?
+opts="$(getopt -n "${0##*/}" -o c:g: -- "$@")" || exit $?
 eval set -- "$opts"
 
 GENIMAGE_TMP="${BUILD_DIR}/genimage.tmp"

@@ -23,6 +24,9 @@ while true ; do
 	--) # Discard all non-option parameters
 	  shift 1;
 	  break ;;
+        -g)
+	  GENIMAGE_NAME="${2}";
+          shift 2;;
 	*)
 	  die "unknown option '${1}'" ;;
 	esac

@@ -38,3 +42,8 @@ genimage \
 	--inputpath "${BINARIES_DIR}"  \
 	--outputpath "${BINARIES_DIR}" \
 	--config "${GENIMAGE_CFG}"
+if [ ${GENIMAGE_NAME} ]
+then
+echo ${GENIMAGE_NAME}
+gzip < ${BINARIES_DIR}/${GENIMAGE_NAME} > ${BINARIES_DIR}/${GENIMAGE_NAME}.gz
+fi

Signature · 6 lines

2.11.0

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Evgeniy, All,

On 2017-12-18 16:51 +0300, Evgeniy Didin spake thusly:

Quoted 9 lines

In image files, generated by genimage.sh, there are tens of megabytes most of which might be filled with zeros as partitions are made a bit larger than needed for minimalictic rootfs (which allows users to add more libs and aps later on without messign with partition sizes).

So adding an option for genimage.sh script, setting which we gzip image file and greatly reduce it size.

Sorry, I am not in favour if this.

Today you're adding gzip compression (and by the way, -g is really unusual for a compresion option, it usually is called -z), but tomorrow someone will want xz compression, then another one will want lzo or lzip or whatever...

And then someone will want to add gpg signature and encryption or whatnot...

So, in such situation, I would argue that one should provide their post-image script, that does whatever last-minute tweaks on the generated image(s).

And by the way, this patch compreses the image, but does not remove the original, so this is actually a loss of space.

So I am not in favour of this patch, sorry.