Add and use sparse-gunzip in loopback-rootfs

This reduces the space required from the full size of the compressed
disk image, which meant that tests could not be run on systems where
TMPDIR is a smallish tmpfs.

2 files changed, 8 insertions, 2 deletions

diff --git a/scripts/sparse-gunzip b/scripts/sparse-gunzip
new file mode 100755
index 00000000..b6e1aa16
--- /dev/null
+++ b/scripts/sparse-gunzip
@@ -0,0 +1,6 @@
+#!/usr/bin/python
+from morphlib.util import copyfileobj
+import gzip, sys
+infh = gzip.GzipFile(fileobj=sys.stdin)
+copyfileobj(infh, sys.stdout)
+infh.close()
diff --git a/tests.as-root/lib b/tests.as-root/lib
index 6818abde..2492bb53 100644
--- a/tests.as-root/lib
+++ b/tests.as-root/lib
@@ -21,8 +21,8 @@ loopback_rootfs() {
     # Find offset partition offset in a rootfs and mount it
     ROOTFS="$1"
 
-    mv "$ROOTFS" "$ROOTFS-unzipped.gz"
-    gunzip "$ROOTFS-unzipped.gz"
+    PYTHONPATH="$SRCDIR" "$SRCDIR/scripts/sparse-gunzip" \
+                         <"$ROOTFS" >"$ROOTFS-unzipped"
 
     OFFSET=$(sfdisk -d "$ROOTFS-unzipped" | \
         grep -m 1 -o 'start=\s\+\([0-9]\+\)' | awk '{ print $2 }')