[image] Add "imgextract" command for extracting archive images

Add the concept of extracting an image from an archive (which could be
a single-file archive such as a gzip-compressed file), along with an
"imgextract" command to expose this functionality to scripts.

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

1 files changed, 104 insertions, 0 deletions

diff --git a/src/core/archive.c b/src/core/archive.c
new file mode 100644
index 000000000..cd024bde3
--- /dev/null
+++ b/src/core/archive.c
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2021 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <string.h>
+#include <errno.h>
+#include <ipxe/image.h>
+
+/** @file
+ *
+ * Archive images
+ *
+ */
+
+/**
+ * Extract archive image
+ *
+ * @v image		Image
+ * @v name		Extracted image name
+ * @v extracted		Extracted image to fill in
+ * @ret rc		Return status code
+ */
+int image_extract ( struct image *image, const char *name,
+		    struct image **extracted ) {
+	char *dot;
+	int rc;
+
+	/* Check that this image can be used to extract an archive image */
+	if ( ! ( image->type && image->type->extract ) ) {
+		rc = -ENOTSUP;
+		goto err_unsupported;
+	}
+
+	/* Allocate new image */
+	*extracted = alloc_image ( image->uri );
+	if ( ! *extracted ) {
+		rc = -ENOMEM;
+		goto err_alloc;
+	}
+
+	/* Set image name */
+	if ( ( rc = image_set_name ( *extracted,
+				     ( name ? name : image->name ) ) ) != 0 ) {
+		goto err_set_name;
+	}
+
+	/* Strip any archive or compression suffix from implicit name */
+	if ( ( ! name ) && ( (*extracted)->name ) &&
+	     ( ( dot = strrchr ( (*extracted)->name, '.' ) ) != NULL ) ) {
+		*dot = '\0';
+	}
+
+	/* Try extracting archive image */
+	if ( ( rc = image->type->extract ( image, *extracted ) ) != 0 ) {
+		DBGC ( image, "IMAGE %s could not extract image: %s\n",
+		       image->name, strerror ( rc ) );
+		goto err_extract;
+	}
+
+	/* Register image */
+	if ( ( rc = register_image ( *extracted ) ) != 0 )
+		goto err_register;
+
+	/* Drop local reference to image */
+	image_put ( *extracted );
+
+	return 0;
+
+	unregister_image ( *extracted );
+ err_register:
+ err_extract:
+ err_set_name:
+	image_put ( *extracted );
+ err_alloc:
+ err_unsupported:
+	return rc;
+}
+
+/* Drag in objects via image_extract() */
+REQUIRING_SYMBOL ( image_extract );
+
+/* Drag in archive image formats */
+REQUIRE_OBJECT ( config_archive );