journald: allow additional payload in server_driver_message

The code to format the iovec is shared with log.c. All call sites to
server_driver_message are changed to include the additional "MESSAGE="
part, but the new functionality is not used and change in functionality
is not expected.

iovec is preallocated, so the maximum number of messages is limited.
In server_driver_message N_IOVEC_PAYLOAD_FIELDS is currently set to 1.

New code is not oom safe, it will fail if memory cannot be allocated.
This will be fixed in subsequent commit.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/journal/journald-server.h b/src/journal/journald-server.h
index 1822765228..0ef83d161f 100644
--- a/src/journal/journald-server.h
+++ b/src/journal/journald-server.h
@@ -157,9 +157,10 @@ struct Server {
 #define N_IOVEC_KERNEL_FIELDS 64
 #define N_IOVEC_UDEV_FIELDS 32
 #define N_IOVEC_OBJECT_FIELDS 12
+#define N_IOVEC_PAYLOAD_FIELDS 1
 
 void server_dispatch_message(Server *s, struct iovec *iovec, unsigned n, unsigned m, const struct ucred *ucred, const struct timeval *tv, const char *label, size_t label_len, const char *unit_id, int priority, pid_t object_pid);
-void server_driver_message(Server *s, sd_id128_t message_id, const char *format, ...) _printf_(3,4);
+void server_driver_message(Server *s, sd_id128_t message_id, const char *format, ...) _printf_(3,0) _sentinel_;
 
 /* gperf lookup function */
 const struct ConfigPerfItem* journald_gperf_lookup(const char *key, unsigned length);