tests/make-patch: mount disk image for test

Previously it would extract the stratum tarballs, since it was
easier than mounting the disk image.

Then when strata became chunk lists, this created the tarball, then
extracted it.

Now systems may contain files that aren't in the component strata,
this causes problems for tbdiff-deploy, since it tries to alter a
file that isn't there.

So to fix this, it mounts the disk image, like it should have from
the beginning.

1 files changed, 22 insertions, 6 deletions

diff --git a/tests.as-root/make-patch.script b/tests.as-root/make-patch.script
index b5385fc0..9a159a48 100755
--- a/tests.as-root/make-patch.script
+++ b/tests.as-root/make-patch.script
@@ -46,7 +46,6 @@ EOF
 # Build first image. Remember the stratum.
 "$SRCDIR/scripts/test-morph" build test:morphs-repo master hello-system.morph
 img1=$(find "$DATADIR/cache/artifacts" -maxdepth 1 -name '*.system.*')
-stratum1=$(find "$DATADIR/cache/artifacts" -maxdepth 1 -name '*.hello-stratum')
 
 # Modify the chunk, in a new branch.
 "$SRCDIR/scripts/run-git-in" "$DATADIR/chunk-repo" checkout --quiet farrokh
@@ -73,12 +72,28 @@ patch="$DATADIR/patch"
     test:morphs-repo master hello-system.morph \
     test:morphs-repo alfred hello-system.morph
 
-# Unpack the original stratum and run the program.
+# find out the offset of the partition in the disk image
+# udevadm settle is used to wait until devices have appeared
+loop=$(losetup -f --show "$img1")
+udevadm settle
+offset=$(sfdisk -d "$loop" |
+             sed -n '/start=/s/^.*start=\s*\([0-9]\+\)[^0-9].*$/\1/p' |
+             head -n 1)
+ssz=`cat "/sys/devices/virtual/block/$(basename "$loop")/queue/hw_sector_size"`
+losetup -d "$loop"
+udevadm settle
+
+# mount the disk
 mkdir "$DATADIR/unpacked"
+# this has to be done by losetup then mount, because busybox mount doesn't
+# accept the -o offset= option
+loop=$(losetup -o "$(expr "$offset" '*' "$ssz")" -f --show "$img1")
+udevadm settle
+trap 'losetup -d "$loop"' INT TERM EXIT
+mount -o subvol=factory-run -t btrfs "$loop" "$DATADIR/unpacked"
+trap 'umount "$DATADIR/unpacked"; losetup -d "$loop"' INT TERM EXIT
+
 cd "$DATADIR/unpacked"
-"$SRCDIR/scripts/assemble-stratum" --cachedir "$DATADIR/cache" "$stratum1" \
-                                   "$DATADIR/stratum.tar" hello-stratum
-tar -xf "$DATADIR/stratum.tar"
 echo "old version:"
 ./bin/hello
 
@@ -89,4 +104,5 @@ echo "new version:"
 
 # Done.
 echo "Done."
-
+# chdir out of mounted folder, so it can be unmounted
+cd /