wic: rawcopy: Add support for packed images

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>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 28 insertions, 1 deletions

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)):