From: Willy Tarreau <w@1wt.eu>
Date: Mon, 12 Aug 2019 15:27:09 +0000 (+0200)
Subject: MINOR: trace: add the file name and line number in the prefix
X-Git-Tag: v2.1-dev2~188
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=419bd49f0b55fd71bb39b905d9e59f29aa9484a7;p=thirdparty%2Fhaproxy.git

MINOR: trace: add the file name and line number in the prefix

We now pass an extra argument "where" to the trace() call, which
is supposed to be an ist made of the concatenation of the filename
and the line number. We only keep the last 10 chars from this string
since the end of file names is most often easy to recognize. This
gives developers useful information at very low cost.
---

diff --git a/include/proto/trace.h b/include/proto/trace.h
index 6767952cd2..7673892e89 100644
--- a/include/proto/trace.h
+++ b/include/proto/trace.h
@@ -34,7 +34,7 @@
 extern struct list trace_sources;
 extern THREAD_LOCAL struct buffer trace_buf;
 
-void __trace(uint64_t mask, struct trace_source *src, const struct ist msg);
+void __trace(uint64_t mask, struct trace_source *src, const struct ist where, const struct ist msg);
 
 /* return a single char to describe a trace state */
 static inline char trace_state_char(enum trace_state st)
@@ -66,10 +66,10 @@ static inline void trace_register_source(struct trace_source *source)
 }
 
 /* sends a trace for the given source */
-static inline void trace(uint64_t mask, struct trace_source *src, const struct ist msg)
+static inline void trace(uint64_t mask, struct trace_source *src, const struct ist where, const struct ist msg)
 {
 	if (unlikely(src->state != TRACE_STATE_STOPPED))
-		__trace(mask, src, msg);
+		__trace(mask, src, where, msg);
 }
 
 #endif /* _PROTO_TRACE_H */
diff --git a/src/trace.c b/src/trace.c
index 4f6a913cf3..f68ff10582 100644
--- a/src/trace.c
+++ b/src/trace.c
@@ -49,8 +49,10 @@ REGISTER_PER_THREAD_ALLOC(alloc_trace_buffers_per_thread);
 REGISTER_PER_THREAD_FREE(free_trace_buffers_per_thread);
 
 /* write a message for the given trace source */
-void __trace(uint64_t mask, struct trace_source *src, const struct ist msg)
+void __trace(uint64_t mask, struct trace_source *src, const struct ist where, const struct ist msg)
 {
+	struct ist line[8];
+
 	if (likely(src->state == TRACE_STATE_STOPPED))
 		return;
 
@@ -75,8 +77,20 @@ void __trace(uint64_t mask, struct trace_source *src, const struct ist msg)
 	if ((src->report_events & mask) == 0)
 		goto end;
 
+	/* log the logging location truncated to 10 chars from the right so that
+	 * the line number and the end of the file name are there.
+	 */
+	line[0] = ist("[");
+	line[1] = where;
+	if (line[1].len > 10) {
+		line[1].ptr += (line[1].len - 10);
+		line[1].len = 10;
+	}
+	line[2] = ist("] ");
+	line[3] = msg;
+
 	if (src->sink)
-		sink_write(src->sink, &msg, 1);
+		sink_write(src->sink, line, 4);
 
  end:
 	/* check if we need to stop the trace now */