discover: Change parsers to emit resources rather than filenames

This change switches the parsers over to populate the resources in
discover_boot_option, rather than the string parameters in boot_option.

To do this, we need a few things:

 * Add struct resources to discover_boot_option for the boot_image,
   initrd and icon data.

 * Have the parsers populate the resources, rather than the strings.
   Currently, parsers can all use the devpath resource type.

 * Add a resolve_resource callback to parsers; this is how the device
   handler will attempt to resolve resources.

 * Change load_file to load_url, as we should be only accessing
   (resolved) resources by URLs.

This then allows us to remove the mount map, and associated lookup code,
as well as the UUID and label links to devices.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/discover/parser.h b/discover/parser.h
index 18c9963..03ba8d4 100644
--- a/discover/parser.h
+++ b/discover/parser.h
@@ -1,13 +1,36 @@
 #ifndef _PARSER_H
 #define _PARSER_H
 
+#include <stdbool.h>
+
 struct discover_context;
+struct device_handler;
+struct resource;
 
+/**
+ * Our config parser.
+ *
+ * Each parser is responsible for creating discover_boot_options from config
+ * files found on new devices. The boot items discovered during parse will have
+ * 'resources' attached (see @discover_boot_option), which may already be
+ * resolved (in the case of a device-local filename, or a URL), or unresolved
+ * (in the case of a filename on another device).
+ *
+ * If the boot option contains references to unresolved resources, the
+ * device handler will not inform clients about the boot options, as
+ * they're not properly "available" at this stage. The handler will attempt to
+ * resolve them whenever new devices are discovered, by calling the parser's
+ * resolve_resource function. Once a boot option's resources are full resolved,
+ * the option can be sent to clients.
+ */
 struct parser {
 	char			*name;
 	const char * const	*filenames;
 	int			(*parse)(struct discover_context *ctx,
 						char *buf, int len);
+	bool			(*resolve_resource)(
+						struct device_handler *handler,
+						struct resource *res);
 };
 
 enum generic_icon_type {