[MEDIUM] reintroduce BF_HIJACK with produce_content

The stats dump are back. Even very large config files with
5000 servers work fast and well. The SN_SELF_GEN flag has
completely been removed.

include/proto/buffers.h

@@ -108,6 +108,18 @@ static inline void buffer_abort(struct buffer *buf)
 	buf->flags |= BF_SHUTR_NOW | BF_SHUTW_NOW;
 }
 
+/* set the buffer to hijacking mode */
+static inline void buffer_start_hijack(struct buffer *buf)
+{
+	buf->flags |= BF_HIJACK;
+}
+
+/* releases the buffer from hijacking mode */
+static inline void buffer_stop_hijack(struct buffer *buf)
+{
+	buf->flags &= ~BF_HIJACK;
+}
+
 /* returns the maximum number of bytes writable at once in this buffer */
 static inline int buffer_max(const struct buffer *buf)
 {

include/types/buffers.h

@@ -72,6 +72,7 @@
 #define BF_MASK_INTERFACE       (BF_MASK_INTF_I | BF_MASK_INTF_O)
 
 #define BF_MASK_ANALYSER        (BF_FULL|BF_READ_NULL|BF_READ_ERROR|BF_READ_TIMEOUT|BF_SHUTR|BF_WRITE_ERROR)
+#define BF_MASK_INJECTER        (BF_FULL|BF_WRITE_STATUS|BF_WRITE_TIMEOUT|BF_SHUTW)
 
 /* Analysers (buffer->analysers).
  * Those bits indicate that there are some processing to do on the buffer

include/types/session.h

@@ -47,7 +47,7 @@
 #define SN_BE_ASSIGNED	0x00000008	/* a backend was assigned. Conns are accounted. */
 #define SN_CONN_CLOSED	0x00000010	/* "Connection: close" was present or added */
 #define SN_MONITOR	0x00000020	/* this session comes from a monitoring system */
-#define SN_SELF_GEN	0x00000040	/* the proxy generates data for the client (eg: stats) */
+/* unused:              0x00000040 */
 #define SN_FRT_ADDR_SET	0x00000080	/* set if the frontend address has been filled */
 #define SN_REDISP	0x00000100	/* set if this session was redispatched from one server to another */
 #define SN_CONN_TAR	0x00000200	/* set if this session is turning around before reconnecting */

src/dumpstats.c

@@ -290,7 +290,7 @@ int stats_dump_raw(struct session *s, struct uri_auth *uri)
 /*
  * Produces statistics data for the session <s>. Expects to be called with
  * client socket shut down on input. It stops by itself by unsetting the
- * SN_SELF_GEN flag from the session, which it uses to keep on being called
+ * BF_HIJACK flag from the buffer, which it uses to keep on being called
  * when there is free space in the buffer, of simply by letting an empty buffer
  * upon return.s->data_ctx must have been zeroed before the first call, and the
  * flags set. It returns 0 if it had to stop writing data and an I/O is needed,
@@ -310,7 +310,7 @@ int stats_dump_http(struct session *s, struct uri_auth *uri)
 	switch (s->data_state) {
 	case DATA_ST_INIT:
 		/* the function had not been called yet */
-		s->flags |= SN_SELF_GEN;  // more data will follow
+		buffer_start_hijack(rep);
 
 		chunk_printf(&msg, sizeof(trash),
 			     "HTTP/1.0 200 OK\r\n"
@@ -337,7 +337,7 @@ int stats_dump_http(struct session *s, struct uri_auth *uri)
 		if (s->txn.meth == HTTP_METH_HEAD) {
 			/* that's all we return in case of HEAD request */
 			s->data_state = DATA_ST_FIN;
-			s->flags &= ~SN_SELF_GEN;
+			buffer_stop_hijack(rep);
 			return 1;
 		}
 
@@ -570,12 +570,12 @@ int stats_dump_http(struct session *s, struct uri_auth *uri)
 		/* fall through */
 
 	case DATA_ST_FIN:
-		s->flags &= ~SN_SELF_GEN;
+		buffer_stop_hijack(rep);
 		return 1;
 
 	default:
 		/* unknown state ! */
-		s->flags &= ~SN_SELF_GEN;
+		buffer_stop_hijack(rep);
 		return -1;
 	}
 }

src/proto_http.c

@@ -772,15 +772,25 @@ void process_session(struct task *t, int *next)
 			rqf_req = s->req->flags;
 		}
 
-		if ((rpf_rep ^ s->rep->flags) & BF_MASK_ANALYSER) {
-			/* the analysers must block it themselves */
-			if (s->rep->prod->state >= SI_ST_EST) {
+		if (unlikely(s->rep->flags & BF_HIJACK)) {
+			/* In inject mode, we wake up everytime something has
+			 * happened on the write side of the buffer.
+			 */
+			if ((s->rep->flags & (BF_PARTIAL_WRITE|BF_WRITE_ERROR|BF_SHUTW)) &&
+			    !(s->rep->flags & BF_FULL)) {
+				if (produce_content(s) != 0)
+					resync = 1; /* completed, better re-check flags */
+			}
+		}
+		else if (s->rep->prod->state >= SI_ST_EST) {
+			if ((rpf_rep ^ s->rep->flags) & BF_MASK_ANALYSER) {
+				/* the analysers must block it themselves */
 				resync = 1;
 				s->rep->flags |= BF_MAY_FORWARD;
 				if (s->rep->analysers)
 					process_response(s);
+				rpf_rep = s->rep->flags;
 			}
-			rpf_rep = s->rep->flags;
 		}
 
 	} while (resync);
@@ -3895,15 +3905,15 @@ int process_srv_conn(struct session *t)
 /*
  * Produces data for the session <s> depending on its source. Expects to be
  * called with client socket shut down on input. Right now, only statistics can
- * be produced. It stops by itself by unsetting the SN_SELF_GEN flag from the
- * session, which it uses to keep on being called when there is free space in
+ * be produced. It stops by itself by unsetting the BF_HIJACK flag from the
+ * buffer, which it uses to keep on being called when there is free space in
  * the buffer, or simply by letting an empty buffer upon return. It returns 1
  * when it wants to stop sending data, otherwise 0.
  */
 int produce_content(struct session *s)
 {
 	if (s->data_source == DATA_SRC_NONE) {
-		s->flags &= ~SN_SELF_GEN;
+		buffer_stop_hijack(s->rep);
 		return 1;
 	}
 	else if (s->data_source == DATA_SRC_STATS) {
@@ -3922,7 +3932,7 @@ int produce_content(struct session *s)
 		s->flags |= SN_ERR_PRXCOND;
 	if (!(s->flags & SN_FINST_MASK))
 		s->flags |= SN_FINST_R;
-	s->flags &= ~SN_SELF_GEN;
+	buffer_stop_hijack(s->rep);
 	return 1;
 }
 
@@ -5297,10 +5307,9 @@ int stats_check_uri_auth(struct session *t, struct proxy *backend)
 	/* The request is valid, the user is authenticated. Let's start sending
 	 * data.
 	 */
-	EV_FD_CLR(t->req->prod->fd, DIR_RD);
-	buffer_shutr(t->req);
-	buffer_shutr(t->rep);
-	buffer_set_rlim(t->req, BUFSIZE); /* no more rewrite needed */
+	buffer_shutw_now(t->req);
+	buffer_shutr_now(t->rep);
+	buffer_start_hijack(t->rep);
 	t->logs.tv_request = now;
 	t->data_source = DATA_SRC_STATS;
 	t->data_state  = DATA_ST_INIT;