[PATCH v2 2/5] wic: rawcopy: Add support for packed images

[Stefan Herbrechtsmeier <stefan.herbrechtsmeier-oss@weidmueller.com>]

From: Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>

Add support for packed images to wic rawcopy handler do minimize disk
usage in deploy directory and reuse of packed images between wic and
swupdate. Add `unpack` to sourceparams to unpack an bz2, gz and xz
archives.

Example:
part / --source rawcopy --sourceparams="file=core-image-minimal-qemu.ext4.gz,unpack"

Signed-off-by: Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>

---

Changes in v2:
- Reword WicError message and add compressor filename extension

 scripts/lib/wic/plugins/source/rawcopy.py | 29 ++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/scripts/lib/wic/plugins/source/rawcopy.py b/scripts/lib/wic/plugins/source/rawcopy.py
index fa7b1eb8ac..7c90cd3cf8 100644
--- a/scripts/lib/wic/plugins/source/rawcopy.py
+++ b/scripts/lib/wic/plugins/source/rawcopy.py
@@ -4,6 +4,8 @@
 
 import logging
 import os
+import signal
+import subprocess
 
 from wic import WicError
 from wic.pluginbase import SourcePlugin
@@ -38,6 +40,25 @@ class RawCopyPlugin(SourcePlugin):
 
         exec_cmd(cmd)
 
+    @staticmethod
+    def do_image_uncompression(src, dst, workdir):
+        def subprocess_setup():
+            # Python installs a SIGPIPE handler by default. This is usually not what
+            # non-Python subprocesses expect.
+            # SIGPIPE errors are known issues with gzip/bash
+            signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+
+        extension = os.path.splitext(src)[1]
+        decompressor = {
+            ".bz2": "bzip2",
+            ".gz": "gzip",
+            ".xz": "xz"
+        }.get(extension)
+        if not decompressor:
+            raise WicError("Not supported compressor filename extension: %s" % extension)
+        cmd = "%s -dc %s > %s" % (decompressor, src, dst)
+        subprocess.call(cmd, preexec_fn=subprocess_setup, shell=True, cwd=workdir)
+
     @classmethod
     def do_prepare_partition(cls, part, source_params, cr, cr_workdir,
                              oe_builddir, bootimg_dir, kernel_dir,
@@ -56,7 +77,13 @@ class RawCopyPlugin(SourcePlugin):
         if 'file' not in source_params:
             raise WicError("No file specified")
 
-        src = os.path.join(kernel_dir, source_params['file'])
+        if 'unpack' in source_params:
+            img = os.path.join(kernel_dir, source_params['file'])
+            src = os.path.join(cr_workdir, os.path.splitext(source_params['file'])[0])
+            RawCopyPlugin.do_image_uncompression(img, src, cr_workdir)
+        else:
+            src = os.path.join(kernel_dir, source_params['file'])
+
         dst = os.path.join(cr_workdir, "%s.%s" % (os.path.basename(source_params['file']), part.lineno))
 
         if not os.path.exists(os.path.dirname(dst)):
-- 
2.30.2