[image] Allow single-member archive images to be executed transparently

Provide image_extract_exec() as a helper method to allow single-member
archive images (such as gzip compressed images) to be executed without
an explicit "imgextract" step.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/archive.c

@@ -97,6 +97,36 @@ int image_extract ( struct image *image, const char *name,
 	return rc;
 }
 
+/**
+ * Extract and execute image
+ *
+ * @v image		Image
+ * @ret rc		Return status code
+ */
+int image_extract_exec ( struct image *image ) {
+	struct image *extracted;
+	int rc;
+
+	/* Extract image */
+	if ( ( rc = image_extract ( image, NULL, &extracted ) ) != 0 )
+		goto err_extract;
+
+	/* Set image command line */
+	if ( ( rc = image_set_cmdline ( extracted, image->cmdline ) ) != 0 )
+		goto err_set_cmdline;
+
+	/* Set auto-unregister flag */
+	extracted->flags |= IMAGE_AUTO_UNREGISTER;
+
+	/* Tail-recurse into extracted image */
+	return image_exec ( extracted );
+
+ err_set_cmdline:
+	unregister_image ( extracted );
+ err_extract:
+	return rc;
+}
+
 /* Drag in objects via image_extract() */
 REQUIRING_SYMBOL ( image_extract );
 

src/image/gzip.c

@@ -163,4 +163,5 @@ struct image_type gzip_image_type __image_type ( PROBE_NORMAL ) = {
 	.name = "gzip",
 	.probe = gzip_probe,
 	.extract = gzip_extract,
+	.exec = image_extract_exec,
 };

src/image/zlib.c

@@ -159,4 +159,5 @@ struct image_type zlib_image_type __image_type ( PROBE_NORMAL ) = {
 	.name = "zlib",
 	.probe = zlib_probe,
 	.extract = zlib_extract,
+	.exec = image_extract_exec,
 };

src/include/ipxe/image.h

@@ -200,6 +200,7 @@ extern int image_asn1 ( struct image *image, size_t offset,
 			struct asn1_cursor **cursor );
 extern int image_extract ( struct image *image, const char *name,
 			   struct image **extracted );
+extern int image_extract_exec ( struct image *image );
 
 /**
  * Increment reference count on an image