wic: add --extra-partition-space option to set unused space

By default, the content of the partition is filled by the filesystem
without leaving any unused free space. The --extra-space flag adds
extra space to the filesystem size, not to the partition.

Unused free space after the filesystem can be useful for some cases,
such as encrypting a partition at runtime.
With --extra-partition-space 32M, we ensure that the last 32M of the
partition is unused: this space does not contain filesystem data and
can store the LUKS2 header.

The implementation sets a difference between the partition and
filesystem size:
  - With --fixed-size, the extra part space is removed from the
    filesystem size.
  - Otherwise (with or without --size flag), the extra part space is
    added to the partition size.

(From OE-Core rev: 22fd1702aedf40257aa53963b62b5ef1bbd2818a)

Signed-off-by: Pierre-Loup GOSSE <pierre-loup.gosse@smile.fr>

CC: Alexander Kanavin <alex.kanavin@gmail.com>
CC: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 47 insertions, 2 deletions

diff --git a/meta/lib/oeqa/selftest/cases/wic.py b/meta/lib/oeqa/selftest/cases/wic.py
index 44442e402d..c244c9f188 100644
--- a/meta/lib/oeqa/selftest/cases/wic.py
+++ b/meta/lib/oeqa/selftest/cases/wic.py
@@ -1166,7 +1166,7 @@ run_wic_cmd() {
 
         return wkspath
 
-    def _get_wic_partitions(self, wkspath, native_sysroot=None, ignore_status=False):
+    def _get_wic(self, wkspath, ignore_status=False):
         p = runCmd("wic create %s -e core-image-minimal -o %s" % (wkspath, self.resultdir),
                    ignore_status=ignore_status)
 
@@ -1180,7 +1180,13 @@ run_wic_cmd() {
         if not wicout:
             return (p, None)
 
-        wicimg = wicout[0]
+        return (p, wicout[0])
+
+    def _get_wic_partitions(self, wkspath, native_sysroot=None, ignore_status=False):
+        p, wicimg = self._get_wic(wkspath, ignore_status)
+
+        if wicimg is None:
+            return (p, None)
 
         if not native_sysroot:
             native_sysroot = get_bb_var("RECIPE_SYSROOT_NATIVE", "wic-tools")
@@ -1320,6 +1326,45 @@ run_wic_cmd() {
             size = int(size[:-3])
             self.assertGreaterEqual(size, 204800)
 
+    def test_extra_partition_space(self):
+        native_sysroot = get_bb_var("RECIPE_SYSROOT_NATIVE", "wic-tools")
+
+        with NamedTemporaryFile("w", suffix=".wks") as tempf:
+            tempf.write("bootloader --ptable gpt\n" \
+                        "part                 --ondisk hda --size 10M        --extra-partition-space 10M --fstype=ext4\n" \
+                        "part                 --ondisk hda --fixed-size 20M  --extra-partition-space 10M --fstype=ext4\n" \
+                        "part --source rootfs --ondisk hda                   --extra-partition-space 10M --fstype=ext4\n" \
+                        "part --source rootfs --ondisk hda --fixed-size 200M --extra-partition-space 10M --fstype=ext4\n")
+            tempf.flush()
+
+            _, wicimg = self._get_wic(tempf.name)
+
+            res = runCmd("parted -m %s unit b p" % wicimg,
+                            native_sysroot=native_sysroot, stderr=subprocess.PIPE)
+
+            # parse parted output which looks like this:
+            # BYT;\n
+            # /var/tmp/wic/build/tmpfwvjjkf_-201611101222-hda.direct:200MiB:file:512:512:msdos::;\n
+            # 1:0.00MiB:200MiB:200MiB:ext4::;\n
+            partlns = res.output.splitlines()[2:]
+
+            self.assertEqual(4, len(partlns))
+
+            # Test for each partitions that the extra part space exists
+            for part in range(0, len(partlns)):
+                part_file = os.path.join(self.resultdir, "selftest_img.part%d" % (part + 1))
+                partln = partlns[part].split(":")
+                self.assertEqual(7, len(partln))
+                self.assertRegex(partln[3], r'^[0-9]+B$')
+                part_size = int(partln[3].rstrip("B"))
+                start = int(partln[1].rstrip("B")) / 512
+                length = part_size / 512
+                runCmd("dd if=%s of=%s skip=%d count=%d" %
+                                            (wicimg, part_file, start, length))
+                res = runCmd("dumpe2fs %s -h | grep \"^Block count\"" % part_file)
+                fs_size = int(res.output.split(":")[1].strip()) * 1024
+                self.assertLessEqual(fs_size + 10485760, part_size, "part file: %s" % part_file)
+
     # TODO this test could also work on aarch64
     @skipIfNotArch(['i586', 'i686', 'x86_64'])
     @OETestTag("runqemu")