Introduce new host_flags field

While we're at it with migration, might as well add a host_flags field
so that if we have host-specific configuration flags we want to add
later on, we only have to do a migration once.

keydb.c

@@ -298,8 +298,10 @@ static bool keydb_migrate_v2_to_v3(void **keydb_data, unsigned int *keydb_data_s
 		.host_count = old_db->host_count,
 	};
 	for (unsigned int i = 0; i < new_db->host_count; i++) {
+		/* Do not copy over host_flags or volumes */
 		memcpy(&new_db->hosts[i], &old_db->hosts[i], sizeof(old_db->hosts[i]) - sizeof(old_db->hosts[i].volumes));
 		for (unsigned int j = 0; j < new_db->hosts[i].volume_count; j++) {
+			/* Do not copy over volume_flags */
 			memcpy(&new_db->hosts[i].volumes[j], &old_db->hosts[i].volumes[j], sizeof(old_db->hosts[i].volumes[j]));
 		}
 	}

keydb.h

@@ -30,20 +30,26 @@
 #include "file_encryption.h"
 #include "global.h"
 
+#define ALIGNED		__attribute__ ((aligned(4)))
 
 enum volume_flag_t {
 	VOLUME_FLAG_ALLOW_DISCARD = (1 << 0),
 };
 
+/* Unused so far */
+enum host_flag_t {
+	HOST_FLAG_UNUSED = 0,
+};
+
 struct keydb_common_header_t {
 	unsigned int keydb_version;
-};
+} ALIGNED;
 
 struct volume_entry_v2_t {
 	uint8_t volume_uuid[16];										/* UUID of crypt_LUKS volume */
 	char devmapper_name[MAX_DEVMAPPER_NAME_LENGTH];					/* dmsetup name when unlocked. Zero-terminated string. */
 	uint8_t luks_passphrase_raw[LUKS_PASSPHRASE_RAW_SIZE_BYTES];	/* LUKS passphrase used to unlock volume; raw byte data */
-};
+} ALIGNED;
 
 struct host_entry_v2_t {
 	uint8_t host_uuid[16];											/* Host UUID */
@@ -51,36 +57,37 @@ struct host_entry_v2_t {
 	uint8_t tls_psk[PSK_SIZE_BYTES];								/* Raw byte data of TLS-PSK that is used */
 	unsigned int volume_count;										/* Number of volumes of this host */
 	struct volume_entry_v2_t volumes[MAX_VOLUMES_PER_HOST];			/* Volumes of this host */
-};
+} ALIGNED;
 
 struct keydb_v2_t {
 	struct keydb_common_header_t common;
 	bool server_database;
 	unsigned int host_count;
 	struct host_entry_v2_t hosts[];
-};
+} ALIGNED;
 
 struct volume_entry_v3_t {
 	uint8_t volume_uuid[16];										/* UUID of crypt_LUKS volume */
 	char devmapper_name[MAX_DEVMAPPER_NAME_LENGTH];					/* dmsetup name when unlocked. Zero-terminated string. */
 	uint8_t luks_passphrase_raw[LUKS_PASSPHRASE_RAW_SIZE_BYTES];	/* LUKS passphrase used to unlock volume; raw byte data */
 	unsigned int volume_flags;										/* Bitset of enum volume_flag_t */
-};
+} ALIGNED;
 
 struct host_entry_v3_t {
 	uint8_t host_uuid[16];											/* Host UUID */
 	char host_name[MAX_HOST_NAME_LENGTH];							/* Descriptive name of host */
 	uint8_t tls_psk[PSK_SIZE_BYTES];								/* Raw byte data of TLS-PSK that is used */
 	unsigned int volume_count;										/* Number of volumes of this host */
+	unsigned int host_flags;										/* Bitset of enum host_flag_t */
 	struct volume_entry_v3_t volumes[MAX_VOLUMES_PER_HOST];			/* Volumes of this host */
-};
+} ALIGNED;
 
 struct keydb_v3_t {
 	struct keydb_common_header_t common;
 	bool server_database;
 	unsigned int host_count;
 	struct host_entry_v3_t hosts[];
-};
+} ALIGNED;
 
 
 #define KEYDB_CURRENT_VERSION						3