From 4bc7d90d3bff9adbf1f956727cf58dcf7bbba20f Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Fri, 7 Sep 2018 20:07:17 +0200
Subject: [PATCH] MEDIUM: snapshot: merge the captured data after the
 descriptor

Instead of having a separate area for the captured data, we now have a
contigous block made of the descriptor and the data. At the moment, since
the area is dynamically allocated, we can adjust its size to what is
needed, but the idea is to quickly switch to a pool and an LRU list.
---
 include/types/proxy.h |  4 ++--
 src/proxy.c           | 19 ++++++++-----------
 2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/include/types/proxy.h b/include/types/proxy.h
index ca3bc7de2..2d1b88196 100644
--- a/include/types/proxy.h
+++ b/include/types/proxy.h
@@ -225,7 +225,7 @@ struct error_snapshot {
 	/**** common part ****/
 	struct timeval when;            /* date of this event, (tv_sec == 0) means "never" */
 	/* @16 */
-	char *buf;                      /* copy of the beginning of the message (may be NULL) */
+	void (*show)(struct buffer *, const struct error_snapshot *); /* dump function */
 	unsigned long long buf_ofs;     /* relative position of the buffer's input inside its container */
 	/* @32 */
 	unsigned int buf_out;           /* pending output bytes _before_ the buffer's input (0..buf->data-1) */
@@ -239,10 +239,10 @@ struct error_snapshot {
 	unsigned int ev_id;             /* event number (counter incremented for each capture) */
 	/* @68: 4 bytes hole here */
 	struct sockaddr_storage src;    /* client's address */
-	void (*show)(struct buffer *, const struct error_snapshot *); /* dump function */
 
 	/**** protocol-specific part ****/
 	union error_snapshot_ctx ctx;
+	char buf[0];                    /* copy of the beginning of the message for bufsize bytes */
 };
 
 struct email_alert {
diff --git a/src/proxy.c b/src/proxy.c
index 9f9fec878..0fbfce9c6 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -1360,25 +1360,22 @@ void proxy_capture_error(struct proxy *proxy, int is_back,
 
 	ev_id = HA_ATOMIC_XADD(&error_snapshot_id, 1);
 
-	es = malloc(sizeof(*es));
+	buf_len = b_data(buf) - buf_out;
+
+	es = malloc(sizeof(*es) + buf_len);
 	if (!es)
 		return;
 
-	es->ev_id    = ev_id;
+	es->buf_len = buf_len;
+	es->ev_id   = ev_id;
 
-	buf_len = b_data(buf) - buf_out;
 	len1 = b_size(buf) - buf_len;
 	if (len1 > buf_len)
 		len1 = buf_len;
-	len2 = buf_len - len1;
 
-	es->buf_len = buf_len;
-
-	if (!es->buf)
-		es->buf = malloc(global.tune.bufsize);
-
-	if (es->buf) {
+	if (len1) {
 		memcpy(es->buf, b_peek(buf, buf_out), len1);
+		len2 = buf_len - len1;
 		if (len2)
 			memcpy(es->buf + len1, b_orig(buf), len2);
 	}
@@ -2119,7 +2116,7 @@ static int cli_io_handler_show_errors(struct appctx *appctx)
 		}
 
 		/* OK, ptr >= 0, so we have to dump the current line */
-		while (es->buf && appctx->ctx.errors.ptr < es->buf_len && appctx->ctx.errors.ptr < global.tune.bufsize) {
+		while (appctx->ctx.errors.ptr < es->buf_len && appctx->ctx.errors.ptr < global.tune.bufsize) {
 			int newptr;
 			int newline;