From eda1092cc58a57ac753c1c35550b5572737cb170 Mon Sep 17 00:00:00 2001
From: framp <framp@linux-tips-and-tricks.de>
Date: Wed, 14 Feb 2018 20:05:03 +0100
Subject: [PATCH 1/3] Added cleanup function trap

---
 pishrink.sh | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/pishrink.sh b/pishrink.sh
index 9e57e6b..fe6c2ee 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -1,5 +1,9 @@
 #!/bin/bash
 
+function cleanup() {
+  losetup -d "$loopback" || true
+}
+
 usage() { echo "Usage: $0 [-s] imagefile.img [newimagefile.img]"; exit -1; }
 
 should_skip_autoexpand=false
@@ -50,6 +54,9 @@ if [ -n "$2" ]; then
   img="$2"
 fi
 
+# cleanup at script exit
+trap cleanup ERR EXIT
+
 #Gather info
 beforesize=$(ls -lh "$img" | cut -d ' ' -f 5)
 parted_output=$(parted -ms "$img" unit B print | tail -n 1)
@@ -166,7 +173,6 @@ fi
 sleep 1
 
 #Shrink partition
-losetup -d "$loopback"
 partnewsize=$(($minsize * $blocksize))
 newpartend=$(($partstart + $partnewsize))
 parted -s -a minimal "$img" rm $partnum >/dev/null

From 67add2e6135978e9e599b888d41cadc1e58bbf5c Mon Sep 17 00:00:00 2001
From: framp <framp@linux-tips-and-tricks.de>
Date: Wed, 14 Feb 2018 20:05:03 +0100
Subject: [PATCH 2/3] Added cleanup function trap

---
 pishrink.sh | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/pishrink.sh b/pishrink.sh
index 9e57e6b..4cbc518 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -1,5 +1,9 @@
 #!/bin/bash
 
+function cleanup() {
+  [[ -n $loopback ]] && losetup -d "$loopback"
+}
+
 usage() { echo "Usage: $0 [-s] imagefile.img [newimagefile.img]"; exit -1; }
 
 should_skip_autoexpand=false
@@ -50,6 +54,9 @@ if [ -n "$2" ]; then
   img="$2"
 fi
 
+# cleanup at script exit
+trap cleanup ERR EXIT
+
 #Gather info
 beforesize=$(ls -lh "$img" | cut -d ' ' -f 5)
 parted_output=$(parted -ms "$img" unit B print | tail -n 1)
@@ -166,7 +173,6 @@ fi
 sleep 1
 
 #Shrink partition
-losetup -d "$loopback"
 partnewsize=$(($minsize * $blocksize))
 newpartend=$(($partstart + $partnewsize))
 parted -s -a minimal "$img" rm $partnum >/dev/null

From 8aae06a4b20b1638237e4a5442a26ebb3fe6a3b1 Mon Sep 17 00:00:00 2001
From: framp <framp@linux-tips-and-tricks.de>
Date: Sat, 24 Mar 2018 12:01:59 +0100
Subject: [PATCH 3/3] Modified cleanup

---
 pishrink.sh | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/pishrink.sh b/pishrink.sh
index 4cbc518..1d68900 100755
--- a/pishrink.sh
+++ b/pishrink.sh
@@ -1,7 +1,9 @@
 #!/bin/bash
 
 function cleanup() {
-  [[ -n $loopback ]] && losetup -d "$loopback"
+  if losetup $loopback &>/dev/null; then
+	losetup -d "$loopback"
+  fi
 }
 
 usage() { echo "Usage: $0 [-s] imagefile.img [newimagefile.img]"; exit -1; }