zipl: Allow optional entries that are left out when files are missing.

Debian carried a patch forever that allowed zipl to run even if not all
menu items had files attached. If a required file is missing for an
entry (e.g. vmlinuz.old or initrd.img.old) and it is marked as
"optional" in the config, the section will be skipped. This allows
zipl to install after bootstrapping, as booting on s390 still relies
on the kernel/initrd symlinks in the root directory.

Closes: https://github.com/ibm-s390-linux/s390-tools/pull/2
Signed-off-by: Philipp Kern <pkern@debian.org>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
[sth@linux.ibm.com: adapted patches to latest changes, merged patches]
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

zipl/include/job.h

@@ -13,6 +13,8 @@
 #ifndef JOB_H
 #define JOB_H
 
+#include <stdbool.h>
+
 #include "disk.h"
 #include "zipl.h"
 
@@ -46,6 +48,8 @@ struct job_common_ipl_data {
 	address_t image_addr;
 	address_t parm_addr;
 	address_t ramdisk_addr;
+	bool optional;
+	bool ignore;
 };
 
 struct job_ipl_data {

zipl/include/scan.h

@@ -16,7 +16,7 @@
 
 
 #define SCAN_SECTION_NUM		9
-#define SCAN_KEYWORD_NUM		22
+#define SCAN_KEYWORD_NUM		23
 #define SCAN_KEYWORD_ONLY_NUM		1
 #define SCAN_AUTOMENU_NAME		"zipl-automatic-menu"
 
@@ -52,6 +52,7 @@ enum scan_keyword_id {
 	scan_keyword_defaultauto = 19,
 	scan_keyword_kdump = 20,
 	scan_keyword_secure = 21,
+	scan_keyword_optional = 22,
 };
 
 enum scan_section_type {