From 6ca9e01ab2c35c0e6890c7aa6712b0e13ded3db0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cyril=20Bont=C3=A9?= <cyril.bonte@free.fr>
Date: Fri, 6 May 2016 12:18:49 +0200
Subject: [PATCH] BUG/MEDIUM: stats: show backend may show an empty or
 incomplete result

This is the same issue as "show servers state", where the result is incorrect
it the data can't fit in one buffer. The similar fix is applied, to restart
the data processing where it stopped as buffers are sent to the client.

This fix should be backported to haproxy 1.6
---
 include/types/applet.h |  3 +++
 src/dumpstats.c        | 25 ++++++++++++++++++-------
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/include/types/applet.h b/include/types/applet.h
index bf801f41d..eb1545606 100644
--- a/include/types/applet.h
+++ b/include/types/applet.h
@@ -135,6 +135,9 @@ struct appctx {
 			struct proxy *px;	/* current proxy being dumped, NULL = not started yet. */
 			struct server *sv;	/* current server being dumped, NULL = not started yet. */
 		} server_state;
+		struct {
+			struct proxy *px;	/* current proxy being dumped, NULL = not started yet. */
+		} be;				/* used by "show backends" command */
 		struct {
 			char **var;
 		} env;
diff --git a/src/dumpstats.c b/src/dumpstats.c
index a6d021bfc..4f0c43880 100644
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -1304,6 +1304,7 @@ static int stats_sock_parse_request(struct stream_interface *si, char *line)
 	appctx->ctx.stats.flags = 0;
 	if (strcmp(args[0], "show") == 0) {
 		if (strcmp(args[1], "backend") == 0) {
+			appctx->ctx.be.px = NULL;
 			appctx->st2 = STAT_ST_INIT;
 			appctx->st0 = STAT_CLI_O_BACKEND;
 		}
@@ -3117,13 +3118,24 @@ static int dump_servers_state(struct stream_interface *si, struct chunk *buf)
 /* Parses backend list and simply report backend names */
 static int stats_dump_backend_to_buffer(struct stream_interface *si)
 {
+	struct appctx *appctx = __objt_appctx(si->end);
 	extern struct proxy *proxy;
 	struct proxy *curproxy;
 
 	chunk_reset(&trash);
-	chunk_printf(&trash, "# name\n");
 
-	for (curproxy = proxy; curproxy != NULL; curproxy = curproxy->next) {
+	if (!appctx->ctx.be.px) {
+		chunk_printf(&trash, "# name\n");
+		if (bi_putchk(si_ic(si), &trash) == -1) {
+			si_applet_cant_put(si);
+			return 0;
+		}
+		appctx->ctx.be.px = proxy;
+	}
+
+	for (; appctx->ctx.be.px != NULL; appctx->ctx.be.px = curproxy->next) {
+		curproxy = appctx->ctx.be.px;
+
 		/* looking for backends only */
 		if (!(curproxy->cap & PR_CAP_BE))
 			continue;
@@ -3133,11 +3145,10 @@ static int stats_dump_backend_to_buffer(struct stream_interface *si)
 			continue;
 
 		chunk_appendf(&trash, "%s\n", curproxy->id);
-	}
-
-	if (bi_putchk(si_ic(si), &trash) == -1) {
-		si_applet_cant_put(si);
-		return 0;
+		if (bi_putchk(si_ic(si), &trash) == -1) {
+			si_applet_cant_put(si);
+			return 0;
+		}
 	}
 
 	return 1;