discover: Make boot_priorities more flexible

Rather than rely on the ordering of the boot_priorities array to define
which device types have a higher "default boot" priority, this change
introduces a slightly more flexible way of priority lookups, by adding a
separate priority field to struct boot_priority.

This means we can have an unordered array, change priorities without
re-writing the array, and implementing a disable mechanism.

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

3 files changed, 15 insertions, 3 deletions

diff --git a/lib/pb-config/pb-config.c b/lib/pb-config/pb-config.c
index 35008cc..ed84fec 100644
--- a/lib/pb-config/pb-config.c
+++ b/lib/pb-config/pb-config.c
@@ -62,8 +62,11 @@ struct config *config_copy(void *ctx, const struct config *src)
 	dest->boot_priorities = talloc_array(dest, struct boot_priority,
 			src->n_boot_priorities);
 
-	for (i = 0; i < src->n_boot_priorities; i++)
+	for (i = 0; i < src->n_boot_priorities; i++) {
+		dest->boot_priorities[i].priority =
+					src->boot_priorities[i].priority;
 		dest->boot_priorities[i].type = src->boot_priorities[i].type;
+	}
 
 	return dest;
 }
diff --git a/lib/pb-protocol/pb-protocol.c b/lib/pb-protocol/pb-protocol.c
index 5a1cee7..3c472fe 100644
--- a/lib/pb-protocol/pb-protocol.c
+++ b/lib/pb-protocol/pb-protocol.c
@@ -279,7 +279,7 @@ int pb_protocol_config_len(const struct config *config)
 		len += 4 + optional_strlen(config->network.dns_servers[i]);
 
 	len += 4;
-	len += config->n_boot_priorities * 4;
+	len += config->n_boot_priorities * 8;
 
 	return len;
 }
@@ -464,7 +464,11 @@ int pb_protocol_serialise_config(const struct config *config,
 	*(uint32_t *)pos = __cpu_to_be32(config->n_boot_priorities);
 	pos += 4;
 	for (i = 0; i < config->n_boot_priorities; i++) {
-		*(uint32_t *)pos = __cpu_to_be32(config->boot_priorities[i].type);
+		*(uint32_t *)pos =
+			__cpu_to_be32(config->boot_priorities[i].type);
+		pos += 4;
+		*(uint32_t *)pos =
+			__cpu_to_be32(config->boot_priorities[i].priority);
 		pos += 4;
 	}
 
diff --git a/lib/types/types.h b/lib/types/types.h
index 3a76cda..a1065ee 100644
--- a/lib/types/types.h
+++ b/lib/types/types.h
@@ -109,6 +109,11 @@ struct network_config {
 };
 
 struct boot_priority {
+	/* Boot options with higher priority values will take precedence over
+	 * lower values. Negative priorities signify "don't boot this by
+	 * default".
+	 */
+	int			priority;
 	enum device_type	type;
 };