tree-wide: add SD_ID128_MAKE_STR, remove LOG_MESSAGE_ID

Embedding sd_id128_t's in constant strings was rather cumbersome. We had
SD_ID128_CONST_STR which returned a const char[], but it had two problems:
- it wasn't possible to statically concatanate this array with a normal string
- gcc wasn't really able to optimize this, and generated code to perform the
  "conversion" at runtime.
Because of this, even our own code in coredumpctl wasn't using
SD_ID128_CONST_STR.

Add a new macro to generate a constant string: SD_ID128_MAKE_STR.
It is not as elegant as SD_ID128_CONST_STR, because it requires a repetition
of the numbers, but in practice it is more convenient to use, and allows gcc
to generate smarter code:

$ size .libs/systemd{,-logind,-journald}{.old,}
   text	   data	    bss	    dec	    hex	filename
1265204	 149564	   4808	1419576	 15a938	.libs/systemd.old
1260268	 149564	   4808	1414640	 1595f0	.libs/systemd
 246805	  13852	    209	 260866	  3fb02	.libs/systemd-logind.old
 240973	  13852	    209	 255034	  3e43a	.libs/systemd-logind
 146839	   4984	     34	 151857	  25131	.libs/systemd-journald.old
 146391	   4984	     34	 151409	  24f71	.libs/systemd-journald

It is also much easier to check if a certain binary uses a certain MESSAGE_ID:

$ strings .libs/systemd.old|grep MESSAGE_ID
MESSAGE_ID=%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x
MESSAGE_ID=%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x
MESSAGE_ID=%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x
MESSAGE_ID=%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x

$ strings .libs/systemd|grep MESSAGE_ID
MESSAGE_ID=c7a787079b354eaaa9e77b371893cd27
MESSAGE_ID=b07a249cd024414a82dd00cd181378ff
MESSAGE_ID=641257651c1b4ec9a8624d7a40a9e1e7
MESSAGE_ID=de5b426a63be47a7b6ac3eaac82e2f6f
MESSAGE_ID=d34d037fff1847e6ae669a370e694725
MESSAGE_ID=7d4958e842da4a758f6c1cdc7b36dcc5
MESSAGE_ID=1dee0369c7fc4736b7099b38ecb46ee7
MESSAGE_ID=39f53479d3a045ac8e11786248231fbf
MESSAGE_ID=be02cf6855d2428ba40df7e9d022f03d
MESSAGE_ID=7b05ebc668384222baa8881179cfda54
MESSAGE_ID=9d1aaa27d60140bd96365438aad20286

5 files changed, 15 insertions, 15 deletions

diff --git a/src/journal/journald-kmsg.c b/src/journal/journald-kmsg.c
index 18c8644507..8afaec0ced 100644
--- a/src/journal/journald-kmsg.c
+++ b/src/journal/journald-kmsg.c
@@ -156,7 +156,8 @@ static void dev_kmsg_record(Server *s, const char *p, size_t l) {
 
                 /* Did we lose any? */
                 if (serial > *s->kernel_seqnum)
-                        server_driver_message(s, SD_MESSAGE_JOURNAL_MISSED,
+                        server_driver_message(s,
+                                              "MESSAGE_ID=" SD_MESSAGE_JOURNAL_MISSED_STR,
                                               LOG_MESSAGE("Missed %"PRIu64" kernel messages",
                                                           serial - *s->kernel_seqnum),
                                               NULL);
diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c
index 8b92ea3def..451f16483f 100644
--- a/src/journal/journald-server.c
+++ b/src/journal/journald-server.c
@@ -214,7 +214,7 @@ void server_space_usage_message(Server *s, JournalStorage *storage) {
         format_bytes(fb5, sizeof(fb5), storage->space.limit);
         format_bytes(fb6, sizeof(fb6), storage->space.available);
 
-        server_driver_message(s, SD_MESSAGE_JOURNAL_USAGE,
+        server_driver_message(s, "MESSAGE_ID=" SD_MESSAGE_JOURNAL_USAGE_STR,
                               LOG_MESSAGE("%s (%s) is %s, max %s, %s free.",
                                           storage->name, storage->path, fb1, fb5, fb6),
                               "JOURNAL_NAME=%s", storage->name,
@@ -1061,8 +1061,7 @@ static void dispatch_message_real(
         write_to_journal(s, journal_uid, iovec, n, priority);
 }
 
-void server_driver_message(Server *s, sd_id128_t message_id, const char *format, ...) {
-        char mid[11 + 32 + 1];
+void server_driver_message(Server *s, const char *message_id, const char *format, ...) {
         struct iovec iovec[N_IOVEC_META_FIELDS + 5 + N_IOVEC_PAYLOAD_FIELDS];
         unsigned n = 0, m;
         int r;
@@ -1080,11 +1079,8 @@ void server_driver_message(Server *s, sd_id128_t message_id, const char *format,
         assert_cc(6 == LOG_INFO);
         IOVEC_SET_STRING(iovec[n++], "PRIORITY=6");
 
-        if (!sd_id128_is_null(message_id)) {
-                snprintf(mid, sizeof(mid), LOG_MESSAGE_ID(message_id));
-                IOVEC_SET_STRING(iovec[n++], mid);
-        }
-
+        if (message_id)
+                IOVEC_SET_STRING(iovec[n++], message_id);
         m = n;
 
         va_start(ap, format);
@@ -1174,7 +1170,7 @@ void server_dispatch_message(
 
         /* Write a suppression message if we suppressed something */
         if (rl > 1)
-                server_driver_message(s, SD_MESSAGE_JOURNAL_DROPPED,
+                server_driver_message(s, "MESSAGE_ID=" SD_MESSAGE_JOURNAL_DROPPED_STR,
                                       LOG_MESSAGE("Suppressed %u messages from %s", rl - 1, path),
                                       NULL);
 
@@ -1273,7 +1269,7 @@ finish:
 
         sd_journal_close(j);
 
-        server_driver_message(s, SD_ID128_NULL,
+        server_driver_message(s, NULL,
                               LOG_MESSAGE("Time spent on flushing to /var is %s for %u entries.",
                                           format_timespan(ts, sizeof(ts), now(CLOCK_MONOTONIC) - start, 0),
                                           n),
diff --git a/src/journal/journald-server.h b/src/journal/journald-server.h
index 716e758b7c..75ac114d24 100644
--- a/src/journal/journald-server.h
+++ b/src/journal/journald-server.h
@@ -176,7 +176,7 @@ struct Server {
 #define N_IOVEC_PAYLOAD_FIELDS 15
 
 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_(3,0) _sentinel_;
+void server_driver_message(Server *s, const char *message_id, const char *format, ...) _printf_(3,0) _sentinel_;
 
 /* gperf lookup function */
 const struct ConfigPerfItem* journald_gperf_lookup(const char *key, GPERF_LEN_TYPE length);
diff --git a/src/journal/journald-syslog.c b/src/journal/journald-syslog.c
index 896303fb85..474369039a 100644
--- a/src/journal/journald-syslog.c
+++ b/src/journal/journald-syslog.c
@@ -444,7 +444,8 @@ void server_maybe_warn_forward_syslog_missed(Server *s) {
         if (s->last_warn_forward_syslog_missed + WARN_FORWARD_SYSLOG_MISSED_USEC > n)
                 return;
 
-        server_driver_message(s, SD_MESSAGE_FORWARD_SYSLOG_MISSED,
+        server_driver_message(s,
+                              "MESSAGE_ID=" SD_MESSAGE_FORWARD_SYSLOG_MISSED_STR,
                               LOG_MESSAGE("Forwarding to syslog missed %u messages.",
                                           s->n_forward_syslog_missed),
                               NULL);
diff --git a/src/journal/journald.c b/src/journal/journald.c
index 54fd1f999d..1aaef387b4 100644
--- a/src/journal/journald.c
+++ b/src/journal/journald.c
@@ -56,7 +56,8 @@ int main(int argc, char *argv[]) {
         server_flush_dev_kmsg(&server);
 
         log_debug("systemd-journald running as pid "PID_FMT, getpid());
-        server_driver_message(&server, SD_MESSAGE_JOURNAL_START,
+        server_driver_message(&server,
+                              "MESSAGE_ID=" SD_MESSAGE_JOURNAL_START_STR,
                               LOG_MESSAGE("Journal started"),
                               NULL);
 
@@ -114,7 +115,8 @@ int main(int argc, char *argv[]) {
         }
 
         log_debug("systemd-journald stopped as pid "PID_FMT, getpid());
-        server_driver_message(&server, SD_MESSAGE_JOURNAL_STOP,
+        server_driver_message(&server,
+                              "MESSAGE_ID=" SD_MESSAGE_JOURNAL_STOP_STR,
                               LOG_MESSAGE("Journal stopped"),
                               NULL);