discover: Add configuration methods

We'd like to be able to download petitboot configurations from other
sources (not just local files), but we'll need some way to indicate to
the parsers that a chunk of config data is from a specific source.

This change adds "configuration methods". At present, we have only one:
CONF_METHOD_LOCAL_FILE. For any incoming configuration data, we only run
parsers that have registered themselves with that configuration method.

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

7 files changed, 25 insertions, 8 deletions

diff --git a/discover/device-handler.c b/discover/device-handler.c
index a8df295..6ff70c1 100644
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -388,7 +388,7 @@ static int handle_add_udev_event(struct device_handler *handler,
 	}
 
 	/* run the parsers. This will populate the ctx's boot_option list. */
-	iterate_parsers(ctx);
+	iterate_parsers(ctx, CONF_METHOD_LOCAL_FILE);
 
 	/* add discovered stuff to the handler */
 	context_commit(handler, ctx);
diff --git a/discover/device-handler.h b/discover/device-handler.h
index be55f73..ad9f50a 100644
--- a/discover/device-handler.h
+++ b/discover/device-handler.h
@@ -11,6 +11,11 @@ struct boot_command;
 struct event;
 struct device;
 
+enum conf_method {
+	CONF_METHOD_LOCAL_FILE,	/* discover by looking at local files on this
+				   block device */
+};
+
 struct discover_device {
 	struct device		*device;
 
@@ -43,6 +48,7 @@ struct discover_context {
 	struct event		*event;
 	struct discover_device	*device;
 	struct list		boot_options;
+	enum conf_method	method;
 };
 
 struct device_handler *device_handler_init(struct discover_server *server,
diff --git a/discover/grub2-parser.c b/discover/grub2-parser.c
index 4a1acf5..0589329 100644
--- a/discover/grub2-parser.c
+++ b/discover/grub2-parser.c
@@ -193,6 +193,7 @@ static int grub2_parse(struct discover_context *dc, char *buf, int len)
 
 static struct parser grub2_parser = {
 	.name		= "grub2",
+	.method		= CONF_METHOD_LOCAL_FILE,
 	.parse		= grub2_parse,
 	.filenames	= grub2_conf_files,
 };
diff --git a/discover/kboot-parser.c b/discover/kboot-parser.c
index 884658e..f097674 100644
--- a/discover/kboot-parser.c
+++ b/discover/kboot-parser.c
@@ -159,6 +159,7 @@ static int kboot_parse(struct discover_context *dc, char *buf, int len)
 
 static struct parser kboot_parser = {
 	.name			= "kboot",
+	.method			= CONF_METHOD_LOCAL_FILE,
 	.parse			= kboot_parse,
 	.filenames		= kboot_conf_files,
 	.resolve_resource	= resolve_devpath_resource,
diff --git a/discover/parser.c b/discover/parser.c
index 641e06b..c04a0af 100644
--- a/discover/parser.c
+++ b/discover/parser.c
@@ -98,18 +98,23 @@ static void iterate_parser_files(struct discover_context *ctx,
 	}
 }
 
-void iterate_parsers(struct discover_context *ctx)
+void iterate_parsers(struct discover_context *ctx, enum conf_method method)
 {
 	int i;
 
 	pb_log("trying parsers for %s\n", ctx->device->device->id);
 
-	for (i = 0; i < n_parsers; i++) {
-		pb_log("\ttrying parser '%s'\n", parsers[i]->name);
-		ctx->parser = parsers[i];
-		iterate_parser_files(ctx, parsers[i]);
+	if (method == CONF_METHOD_LOCAL_FILE) {
+		for (i = 0; i < n_parsers; i++) {
+			if (parsers[i]->method != CONF_METHOD_LOCAL_FILE)
+				continue;
+
+			pb_log("\ttrying parser '%s'\n", parsers[i]->name);
+			ctx->parser = parsers[i];
+			iterate_parser_files(ctx, ctx->parser);
+		}
+		ctx->parser = NULL;
 	}
-	ctx->parser = NULL;
 }
 
 void __register_parser(struct parser *parser)
diff --git a/discover/parser.h b/discover/parser.h
index 03ba8d4..b738577 100644
--- a/discover/parser.h
+++ b/discover/parser.h
@@ -3,6 +3,8 @@
 
 #include <stdbool.h>
 
+#include "device-handler.h"
+
 struct discover_context;
 struct device_handler;
 struct resource;
@@ -25,6 +27,7 @@ struct resource;
  */
 struct parser {
 	char			*name;
+	enum conf_method	method;
 	const char * const	*filenames;
 	int			(*parse)(struct discover_context *ctx,
 						char *buf, int len);
@@ -45,7 +48,7 @@ enum generic_icon_type {
 
 void parser_init(void);
 
-void iterate_parsers(struct discover_context *ctx);
+void iterate_parsers(struct discover_context *ctx, enum conf_method method);
 int parse_user_event(struct discover_context *ctx, struct event *event);
 
 #endif /* _PARSER_H */
diff --git a/discover/yaboot-parser.c b/discover/yaboot-parser.c
index f51d2c6..816e0c4 100644
--- a/discover/yaboot-parser.c
+++ b/discover/yaboot-parser.c
@@ -315,6 +315,7 @@ static int yaboot_parse(struct discover_context *dc, char *buf, int len)
 
 static struct parser yaboot_parser = {
 	.name		= "yaboot",
+	.method		= CONF_METHOD_LOCAL_FILE,
 	.parse		= yaboot_parse,
 	.filenames	= yaboot_conf_files,
 };