[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>

src/config/config.c

@@ -284,6 +284,9 @@ REQUIRE_OBJECT ( cert_cmd );
 #ifdef IMAGE_MEM_CMD
 REQUIRE_OBJECT ( image_mem_cmd );
 #endif
+#ifdef IMAGE_ARCHIVE_CMD
+REQUIRE_OBJECT ( image_archive_cmd );
+#endif
 
 /*
  * Drag in miscellaneous objects

src/config/config_archive.c

@@ -0,0 +1,32 @@
+/*
+ * 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 (at your option) 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 <config/general.h>
+
+/** @file
+ *
+ * Archive image configuration
+ *
+ */
+
+PROVIDE_REQUIRING_SYMBOL();

src/config/general.h

@@ -156,6 +156,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 //#define NTP_CMD		/* NTP commands */
 //#define CERT_CMD		/* Certificate management commands */
 //#define IMAGE_MEM_CMD		/* Read memory command */
+//#define IMAGE_ARCHIVE_CMD	/* Archive image management commands */
 
 /*
  * ROM-specific options