Use separate section for parsers array

Instead of hardcoding the array of parsers, use the linker to do the
work for us.

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

5 files changed, 41 insertions, 15 deletions

diff --git a/discover/device-handler.c b/discover/device-handler.c
index 593b8e0..c7e0227 100644
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -395,6 +395,8 @@ struct device_handler *device_handler_init(struct discover_server *server)
 	for (i = 0; i < sizeof(options) / sizeof(options[0]); i++)
 		list_add(&device.boot_options, &options[i].list);
 
+	parser_init();
+
 	return handler;
 }
 
diff --git a/discover/kboot-parser.c b/discover/kboot-parser.c
index f227ee3..f8cd61d 100644
--- a/discover/kboot-parser.c
+++ b/discover/kboot-parser.c
@@ -290,8 +290,4 @@ out:
 	return rc;
 }
 
-struct parser kboot_parser = {
-	.name	  = "kboot.conf parser",
-	.priority = 98,
-	.parse	  = parse
-};
+define_parser(kboot, 98, parse);
diff --git a/discover/parser-utils.h b/discover/parser-utils.h
index e82e3f9..955f5f4 100644
--- a/discover/parser-utils.h
+++ b/discover/parser-utils.h
@@ -7,6 +7,16 @@
 
 #define artwork_pathname(file) (PKG_SHARE_DIR "/artwork/" file)
 
+#define define_parser(__name, __priority, __parse_fn)			\
+	struct parser 							\
+		__attribute__((unused, section("parsers")))		\
+	__ ## __name ## _parser = {					\
+		.name		= #__name,				\
+		.priority	= __priority,				\
+		.parse		= __parse_fn,				\
+	};
+
+
 void device_add_boot_option(struct device *device,
 		struct boot_option *boot_option);
 
diff --git a/discover/parser.c b/discover/parser.c
index 5b1a7ab..87241a9 100644
--- a/discover/parser.c
+++ b/discover/parser.c
@@ -6,25 +6,41 @@
 #include "device-handler.h"
 #include "log.h"
 #include "parser.h"
-extern struct parser kboot_parser;
+#include "parser-utils.h"
 
-/* array of parsers, ordered by priority */
-static struct parser *parsers[] = {
-	&kboot_parser,
-	NULL
-};
+extern struct parser __start_parsers[], __stop_parsers[];
 
 void iterate_parsers(struct discover_context *ctx)
 {
-	int i;
+	struct parser *parser;
 
 	pb_log("trying parsers for %s\n", ctx->device_path);
 
-	for (i = 0; parsers[i]; i++) {
-		pb_log("\ttrying parser '%s'\n", parsers[i]->name);
+	for (parser = __start_parsers; parser < __stop_parsers; parser++) {
+		pb_log("\ttrying parser '%s'\n", parser->name);
 		/* just use a dummy device path for now */
-		if (parsers[i]->parse(ctx))
+		if (parser->parse(ctx))
 			return;
 	}
 	pb_log("\tno boot_options found\n");
 }
+
+static int compare_parsers(const void *a, const void *b)
+{
+	const struct parser *parser_a = a, *parser_b = b;
+
+	if (parser_a->priority > parser_b->priority)
+		return -1;
+
+	if (parser_a->priority < parser_b->priority)
+		return 1;
+
+	return 0;
+}
+
+void parser_init(void)
+{
+	/* sort our parsers into descending priority order */
+	qsort(__start_parsers, __stop_parsers - __start_parsers,
+			sizeof(struct parser), compare_parsers);
+}
diff --git a/discover/parser.h b/discover/parser.h
index bf9a4d0..ff86578 100644
--- a/discover/parser.h
+++ b/discover/parser.h
@@ -20,6 +20,8 @@ enum generic_icon_type {
 
 #define streq(a,b) (!strcasecmp((a),(b)))
 
+void parser_init(void);
+
 void iterate_parsers(struct discover_context *ctx);
 
 #endif /* _PARSER_H */