From 0d0c8e54f4d7f81732675aff14c11508452b6171 Mon Sep 17 00:00:00 2001
From: Artem Smirnov <urpylka@gmail.com>
Date: Wed, 30 May 2018 23:38:42 +0300
Subject: [PATCH] image_builder: add image-shrinker

---
 image_builder/autosizer.sh | 93 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100755 image_builder/autosizer.sh

diff --git a/image_builder/autosizer.sh b/image_builder/autosizer.sh
new file mode 100755
index 00000000..d8769e0e
--- /dev/null
+++ b/image_builder/autosizer.sh
@@ -0,0 +1,93 @@
+#!/bin/bash
+
+set -e
+
+if [ $(whoami) != "root" ]; then
+  echo \
+  && echo "********************************************************************" \
+  && echo "******************** This should be run as root ********************" \
+  && echo "********************************************************************" \
+  && echo \
+  && exit 1
+fi
+
+if [[ -z $1 ]]; then
+  echo "================================================================================"
+  echo -e "\033[0;31m\033[1mAutomatic Image file resizer\033[0m\033[0m"
+  echo -e "\033[0;31m\033[1mDescription:\033[0m\033[0m This script shrink your image to 100MB free space"
+  echo -e "\033[0;31m\033[1mAuthors:\033[0m\033[0m Artem Smirnov @urpylka, SirLagz"
+  echo
+  echo -e "\033[0;31m\033[1mUsage:\033[0m\033[0m ./autosizer.sh PATH_TO_IMAGE"
+  echo
+  echo -e "\033[0;31m\033[1mRequirements:\033[0m\033[0m parted, losetup, e2fsck, resize2fs, bc, truncate"
+  echo "================================================================================"
+  exit 0
+fi
+
+echo "================================================================================"
+strImgFile=$1
+echo -e "\033[0;31m\033[1mPath to image: $strImgFile\033[0m\033[0m"
+echo "================================================================================"
+
+if [[ ! -e $strImgFile ]]; then
+  echo -e "\033[0;31m\033[1mError: File doesn't exist\033[0m\033[0m"
+  echo
+  exit 1
+fi
+
+echo "================================================================================"
+partinfo=`parted -m $strImgFile unit B print`
+echo -e "\033[0;31m\033[1mPartition information:\033[0m\033[0m\n$partinfo"
+echo "================================================================================"
+
+partnumber=`echo "$partinfo" | grep ext4 | awk -F: '{ print $1 }'`
+echo -e "\033[0;31m\033[1mPartition number: $partnumber\033[0m\033[0m"
+echo "================================================================================"
+
+partstart=`echo "$partinfo" | grep ext4 | awk -F: '{ print substr($2,0,length($2)-1) }'`
+echo -e "\033[0;31m\033[1mPartition start: $partstart (bytes)\033[0m\033[0m"
+echo "================================================================================"
+
+loopback=`losetup -f --show -o $partstart $strImgFile`
+echo -e "\033[0;31m\033[1mLoopback device: $loopback\033[0m\033[0m"
+echo "================================================================================"
+
+set +e
+e2fsck -fvy $loopback
+set -e
+
+echo "================================================================================"
+minsize=`resize2fs -P $loopback | awk -F': ' '{ print $2 }'`
+#minsize=`resize2fs -P $loopback 2> /dev/null | awk -F': ' '{ print $2 }'`
+echo -e "\033[0;31m\033[1mMinsize: $minsize (4k)\033[0m\033[0m"
+echo "================================================================================"
+
+# Add 100MB free space to image 4096 (bytes) * 25000 = 102,400,000
+minsize=`echo "$minsize+25000" | bc`
+echo -e "\033[0;31m\033[1mMinsize + 25000 (4k): $minsize (4k)\033[0m\033[0m"
+echo "================================================================================"
+
+resize2fs -p $loopback $minsize
+sleep 1
+losetup -d $loopback
+
+echo "================================================================================"
+partnewsize=`echo "$minsize * 4096" | bc`
+echo -e "\033[0;31m\033[1mNew size of part: $minsize (4k) = $partnewsize (bytes)\033[0m\033[0m"
+echo "================================================================================"
+
+newpartend=`echo "$partstart + $partnewsize" | bc`
+echo -e "\033[0;31m\033[1mNew end of part (Part start + part new size):\033[0m\033[0m"
+echo -e "\033[0;31m\033[1m$partstart (bytes) + $partnewsize (bytes) = $newpartend (bytes)\033[0m\033[0m"
+echo "================================================================================"
+
+part1=`parted $strImgFile rm 2`
+echo "================================================================================"
+part2=`parted $strImgFile unit B mkpart primary $partstart $newpartend`
+
+echo "================================================================================"
+endresult=`parted -m $strImgFile unit B print free | tail -1 | awk -F: '{ print substr($2,0,length($2)-1) }'`
+echo -e "\033[0;31m\033[1mSize of result image: $endresult (bytes)\033[0m\033[0m"
+echo "================================================================================"
+
+truncate -s $endresult $strImgFile