[PATCH v2] wic: Introduce empty plugin to create unformatted empty partitions

[PATCH v2] wic: Introduce empty plugin to create unformatted empty partitions

[Diego Sueiro]

The empty wic plugin is used to create unformatted empty partitions for wic
images.

To use it you must pass "empty" as argument for the "--source" parameter in
the wks file. For example:
    part foo --source empty --ondisk sda --size="1024" --align 1024

Also adds a selftest for this plugin where the 'Fstype' column from 'wic
ls' should be empty for the second partition as listed in
test_empty_plugin.wks.

Signed-off-by: Diego Sueiro <diego.sueiro@arm.com>
---
 meta-selftest/wic/test_empty_plugin.wks |  4 ++++
 meta/lib/oeqa/selftest/cases/wic.py     | 20 ++++++++++++++++
 scripts/lib/wic/plugins/source/empty.py | 32 +++++++++++++++++++++++++
 3 files changed, 56 insertions(+)
 create mode 100644 meta-selftest/wic/test_empty_plugin.wks
 create mode 100644 scripts/lib/wic/plugins/source/empty.py

diff --git a/meta-selftest/wic/test_empty_plugin.wks b/meta-selftest/wic/test_empty_plugin.wks
new file mode 100644
index 0000000000..4e91e04e19
--- /dev/null
+++ b/meta-selftest/wic/test_empty_plugin.wks
@@ -0,0 +1,4 @@
+# short-description: image for checking empty partition creation
+
+part / --source rootfs --fstype=ext4 --align 1024 --use-uuid
+part empty --source empty --ondisk sda --size 1024 --align 1024
diff --git a/meta/lib/oeqa/selftest/cases/wic.py b/meta/lib/oeqa/selftest/cases/wic.py
index 714637ec1e..091f0ab47c 100644
--- a/meta/lib/oeqa/selftest/cases/wic.py
+++ b/meta/lib/oeqa/selftest/cases/wic.py
@@ -990,6 +990,26 @@ class Wic2(WicTestCase):
             out = glob(self.resultdir + "%s-*direct" % wksname)
             self.assertEqual(1, len(out))
 
+    def test_empty_plugin(self):
+        """Test empty plugin"""
+        config = 'IMAGE_FSTYPES = "wic"\nWKS_FILE = "test_empty_plugin.wks"\n'
+        self.append_config(config)
+        self.assertEqual(0, bitbake('core-image-minimal').status)
+        self.remove_config(config)
+
+        bb_vars = get_bb_vars(['DEPLOY_DIR_IMAGE', 'MACHINE'])
+        deploy_dir = bb_vars['DEPLOY_DIR_IMAGE']
+        machine = bb_vars['MACHINE']
+        image_path = os.path.join(deploy_dir, 'core-image-minimal-%s.wic' % machine)
+        self.assertEqual(True, os.path.exists(image_path))
+
+        sysroot = get_bb_var('RECIPE_SYSROOT_NATIVE', 'wic-tools')
+
+        # Fstype column from 'wic ls' should be empty for the second partition
+        # as listed in test_empty_plugin.wks
+        result = runCmd("wic ls %s -n %s | awk -F ' ' '{print $1 \" \" $5}' | grep '^2' | wc -w" % (image_path, sysroot))
+        self.assertEqual('1', result.output)
+
     @only_for_arch(['i586', 'i686', 'x86_64'])
     def test_biosplusefi_plugin_qemu(self):
         """Test biosplusefi plugin in qemu"""
diff --git a/scripts/lib/wic/plugins/source/empty.py b/scripts/lib/wic/plugins/source/empty.py
new file mode 100644
index 0000000000..041617d648
--- /dev/null
+++ b/scripts/lib/wic/plugins/source/empty.py
@@ -0,0 +1,32 @@
+#
+# SPDX-License-Identifier: MIT
+#
+
+# The empty wic plugin is used to create unformatted empty partitions for wic
+# images.
+# To use it you must pass "empty" as argument for the "--source" parameter in
+# the wks file. For example:
+# part foo --source empty --ondisk sda --size="1024" --align 1024
+
+import logging
+
+from wic.pluginbase import SourcePlugin
+
+logger = logging.getLogger('wic')
+
+class EmptyPartitionPlugin(SourcePlugin):
+    """
+    Populate unformatted empty partition.
+    """
+
+    name = 'empty'
+
+    @classmethod
+    def do_prepare_partition(cls, part, source_params, cr, cr_workdir,
+                             oe_builddir, bootimg_dir, kernel_dir,
+                             rootfs_dir, native_sysroot):
+        """
+        Called to do the actual content population for a partition i.e. it
+        'prepares' the partition to be incorporated into the image.
+        """
+        return
-- 
2.17.1