lib: add a few more bits to live log header

... and add some comments explaining the individual fields.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

2 files changed, 47 insertions, 5 deletions

diff --git a/lib/zlog_live.c b/lib/zlog_live.c
index 7abf1a801..fd2291a86 100644
--- a/lib/zlog_live.c
+++ b/lib/zlog_live.c
@@ -64,14 +64,16 @@ static void zlog_live(struct zlog_target *zt, struct zlog_msg *msgs[],
 
 	for (i = 0; i < nmsgs; i++) {
 		const struct fmt_outpos *argpos;
-		size_t n_argpos, arghdrlen;
+		size_t n_argpos, texthdrlen;
 		struct zlog_msg *msg = msgs[i];
 		int prio = zlog_msg_prio(msg);
+		const struct xref_logmsg *xref;
+		intmax_t pid, tid;
 
 		if (prio > zt->prio_min)
 			continue;
 
-		zlog_msg_args(msg, &arghdrlen, &n_argpos, &argpos);
+		zlog_msg_args(msg, &texthdrlen, &n_argpos, &argpos);
 
 		mmh->msg_hdr.msg_iov = iov;
 
@@ -90,14 +92,27 @@ static void zlog_live(struct zlog_target *zt, struct zlog_msg *msgs[],
 		iov++;
 
 		zlog_msg_tsraw(msg, &ts);
+		zlog_msg_pid(msg, &pid, &tid);
+		xref = zlog_msg_xref(msg);
 
 		hdr->ts_sec = ts.tv_sec;
 		hdr->ts_nsec = ts.tv_nsec;
-		hdr->prio = zlog_msg_prio(msg);
+		hdr->pid = pid;
+		hdr->tid = tid;
+		hdr->prio = prio;
 		hdr->flags = 0;
 		hdr->textlen = textlen;
-		hdr->arghdrlen = arghdrlen;
+		hdr->texthdrlen = texthdrlen;
 		hdr->n_argpos = n_argpos;
+		if (xref) {
+			memcpy(hdr->uid, xref->xref.xrefdata->uid,
+			       sizeof(hdr->uid));
+			hdr->ec = xref->ec;
+		} else {
+			memset(hdr->uid, 0, sizeof(hdr->uid));
+			hdr->ec = 0;
+		}
+		hdr->hdrlen = sizeof(*hdr) + sizeof(*argpos) * n_argpos;
 
 		mmh->msg_hdr.msg_iovlen = iov - mmh->msg_hdr.msg_iov;
 		mmh++;
diff --git a/lib/zlog_live.h b/lib/zlog_live.h
index c948baeab..5e80f016f 100644
--- a/lib/zlog_live.h
+++ b/lib/zlog_live.h
@@ -20,13 +20,40 @@
 #include "printfrr.h"
 
 struct zlog_live_hdr {
+	/* timestamp (CLOCK_REALTIME) */
 	uint64_t ts_sec;
 	uint32_t ts_nsec;
+
+	/* length of zlog_live_hdr, including variable length bits and
+	 * possible future extensions - aka start of text
+	 */
+	uint32_t hdrlen;
+
+	/* process & thread ID, meaning depends on OS */
+	int64_t pid;
+	int64_t tid;
+
+	/* syslog priority value */
 	uint32_t prio;
+	/* flags: currently unused */
 	uint32_t flags;
+	/* length of message text - extra data (e.g. future key/value metadata)
+	 * may follow after it
+	 */
 	uint32_t textlen;
+	/* length of "[XXXXX-XXXXX][EC 0] " header; consumer may want to skip
+	 * over it if using the raw values below.  Note that this text may be
+	 * absent depending on "log error-category" and "log unique-id"
+	 * settings
+	 */
+	uint32_t texthdrlen;
+
+	/* xref unique identifier, "XXXXX-XXXXX\0" = 12 bytes */
+	char uid[12];
+	/* EC value */
+	uint32_t ec;
 
-	uint32_t arghdrlen;
+	/* recorded printf formatting argument positions (variable length) */
 	uint32_t n_argpos;
 	struct fmt_outpos argpos[0];
 };