From: Krzysztof Piotr Oledzki <ole@ans.pl>
Date: Sun, 20 Apr 2008 19:34:47 +0000 (+0200)
Subject: [BUG] Flush buffers also where there are exactly 0 bytes left
X-Git-Tag: v1.3.16-rc1~276
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8e4b21d5eb9d3084425ffc4e22a2c513c590b517;p=thirdparty%2Fhaproxy.git

[BUG] Flush buffers also where there are exactly 0 bytes left

I noticed it was possible to get truncated http/csv stats. Sometimes.
Usually the problem disappeared as fast as it appeared, but once it
happend that my http-stats page was truncated for about one hour.
It was quite weird as it happened independently for csv and http
output and it took me some time to track & fix this bug.

Both buffer_write & buffer_write_chunk used to return 0 in two
situations: is case of success or where there was exactly 0 bytes
left. The first one is intentional but I believe the second one
is not as it was not possible to distinguish between successful
write and unsuccessful one, which means that if the buffer was 100%
filled, it was never flushed and it was not possible to write
more data.

This patch fixes this problem.
---

diff --git a/src/buffers.c b/src/buffers.c
index 8b2c4d33eb..fa6b8a906a 100644
--- a/src/buffers.c
+++ b/src/buffers.c
@@ -29,7 +29,7 @@ int init_buffer()
 }
 
 
-/* writes <len> bytes from message <msg> to buffer <buf>. Returns 0 in case of
+/* writes <len> bytes from message <msg> to buffer <buf>. Returns -1 in case of
  * success, or the number of bytes available otherwise.
  * FIXME-20060521: handle unaligned data.
  */
@@ -48,10 +48,11 @@ int buffer_write(struct buffer *buf, const char *msg, int len)
 	buf->total += len;
 	if (buf->r == buf->data + BUFSIZE)
 		buf->r = buf->data;
-	return 0;
+
+	return -1;
 }
 
-/* writes the chunk <chunk> to buffer <buf>. Returns 0 in case of
+/* writes the chunk <chunk> to buffer <buf>. Returns -1 in case of
  * success, or the number of bytes available otherwise. If the chunk
  * has been written, its size is automatically reset to zero.
  */
@@ -60,7 +61,7 @@ int buffer_write_chunk(struct buffer *buf, struct chunk *chunk)
 	int max;
 
 	if (chunk->len == 0)
-		return 0;
+		return -1;
 
 	max = buffer_realign(buf);
 
@@ -74,7 +75,8 @@ int buffer_write_chunk(struct buffer *buf, struct chunk *chunk)
 	if (buf->r == buf->data + BUFSIZE)
 		buf->r = buf->data;
 	chunk->len = 0;
-	return 0;
+
+	return -1;
 }
 
 /*
diff --git a/src/dumpstats.c b/src/dumpstats.c
index a9fb84dc76..ddadddd1d6 100644
--- a/src/dumpstats.c
+++ b/src/dumpstats.c
@@ -204,7 +204,7 @@ int stats_dump_raw(struct session *s, struct uri_auth *uri)
 	case DATA_ST_HEAD:
 		if (s->data_ctx.stats.flags & STAT_SHOW_STAT) {
 			print_csv_header(&msg, sizeof(trash));
-			if (buffer_write_chunk(rep, &msg) != 0)
+			if (buffer_write_chunk(rep, &msg) >= 0)
 				return 0;
 		}
 
@@ -240,7 +240,7 @@ int stats_dump_raw(struct session *s, struct uri_auth *uri)
 				     global.maxconn,
 				     actconn
 				     );
-			if (buffer_write_chunk(rep, &msg) != 0)
+			if (buffer_write_chunk(rep, &msg) >= 0)
 				return 0;
 		}
 
@@ -422,7 +422,7 @@ int stats_dump_http(struct session *s, struct uri_auth *uri)
 		} else {
 			print_csv_header(&msg, sizeof(trash));
 		}
-		if (buffer_write_chunk(rep, &msg) != 0)
+		if (buffer_write_chunk(rep, &msg) >= 0)
 			return 0;
 
 		s->data_state = DATA_ST_INFO;
@@ -532,7 +532,7 @@ int stats_dump_http(struct session *s, struct uri_auth *uri)
 			     ""
 			     );
 	    
-			if (buffer_write_chunk(rep, &msg) != 0)
+			if (buffer_write_chunk(rep, &msg) >= 0)
 				return 0;
 		}
 
@@ -561,7 +561,7 @@ int stats_dump_http(struct session *s, struct uri_auth *uri)
 	case DATA_ST_END:
 		if (!(s->data_ctx.stats.flags & STAT_FMT_CSV)) {
 			chunk_printf(&msg, sizeof(trash), "</body></html>\n");
-			if (buffer_write_chunk(rep, &msg) != 0)
+			if (buffer_write_chunk(rep, &msg) >= 0)
 				return 0;
 		}
 
@@ -656,7 +656,7 @@ int stats_dump_proxy(struct session *s, struct proxy *px, struct uri_auth *uri)
 				     "</tr>",
 				     px->id);
 
-			if (buffer_write_chunk(rep, &msg) != 0)
+			if (buffer_write_chunk(rep, &msg) >= 0)
 				return 0;
 		}
 
@@ -725,7 +725,7 @@ int stats_dump_proxy(struct session *s, struct proxy *px, struct uri_auth *uri)
 				     relative_pid, px->uuid, STATS_TYPE_FE);
 			}
 
-			if (buffer_write_chunk(rep, &msg) != 0)
+			if (buffer_write_chunk(rep, &msg) >= 0)
 				return 0;
 		}
 
@@ -942,7 +942,7 @@ int stats_dump_proxy(struct session *s, struct proxy *px, struct uri_auth *uri)
 				/* type, then EOL */
 				chunk_printf(&msg, sizeof(trash), "%d,\n", STATS_TYPE_SV);
 			}
-			if (buffer_write_chunk(rep, &msg) != 0)
+			if (buffer_write_chunk(rep, &msg) >= 0)
 				return 0;
 		} /* for sv */
 
@@ -1039,7 +1039,7 @@ int stats_dump_proxy(struct session *s, struct proxy *px, struct uri_auth *uri)
 				     relative_pid, px->uuid,
 				     px->cum_lbconn, STATS_TYPE_BE);
 			}
-			if (buffer_write_chunk(rep, &msg) != 0)
+			if (buffer_write_chunk(rep, &msg) >= 0)
 				return 0;
 		}
 		
@@ -1050,7 +1050,7 @@ int stats_dump_proxy(struct session *s, struct proxy *px, struct uri_auth *uri)
 		if (!(s->data_ctx.stats.flags & STAT_FMT_CSV)) {
 			chunk_printf(&msg, sizeof(trash), "</table><p>\n");
 
-			if (buffer_write_chunk(rep, &msg) != 0)
+			if (buffer_write_chunk(rep, &msg) >= 0)
 				return 0;
 		}