handle ttyfd out event priorly when write buffer is full

Signed-off-by: Gao feng <omarapazanadi@gmail.com>

src/event.c

@@ -96,6 +96,26 @@ int hyper_modify_event(int efd, struct hyper_event *he, int flag)
 	return 0;
 }
 
+int hyper_requeue_event(int efd, struct hyper_event *ev)
+{
+	struct epoll_event event = {
+		.events		= ev->flag,
+		.data.ptr	= ev,
+	};
+
+	if (epoll_ctl(efd, EPOLL_CTL_DEL, ev->fd, NULL) < 0) {
+		perror("epoll_ctl del fd failed");
+		return -1;
+	}
+
+	if (epoll_ctl(efd, EPOLL_CTL_ADD, ev->fd, &event) < 0) {
+		perror("epoll_ctl add fd failed");
+		return -1;
+	}
+
+	return 0;
+}
+
 static int hyper_getmsg_len(struct hyper_event *he, uint32_t *len)
 {
 	struct hyper_buf *buf = &he->rbuf;
@@ -210,7 +230,9 @@ int hyper_event_write(struct hyper_event *he, int efd)
 	memmove(buf->data, buf->data + len, buf->get);
 
 	if (buf->get == 0) {
-		hyper_modify_event(ctl.efd, he, EPOLLIN);
+		hyper_modify_event(ctl.efd, he, he->flag & ~(EPOLLOUT| EPOLLPRI));
+	} else if (!FULL(buf)) {
+		hyper_modify_event(ctl.efd, he, he->flag & ~EPOLLPRI);
 	}
 
 	return 0;

src/event.h

@@ -32,8 +32,12 @@ struct hyper_event {
 	void			*ptr;
 };
 
+#define FULL(buf) \
+	(buf->size - buf->get <= 12)
+
 int hyper_add_event(int efd, struct hyper_event *de, int flag);
 int hyper_modify_event(int efd, struct hyper_event *de, int flag);
+int hyper_requeue_event(int efd, struct hyper_event *ev);
 int hyper_init_event(struct hyper_event *de, struct hyper_event_ops *ops,
 		     void *arg);
 int hyper_handle_event(int efd, struct epoll_event *event);

src/exec.c

@@ -106,9 +106,15 @@ static void stderr_hup(struct hyper_event *de, int efd)
 static int pts_loop(struct hyper_event *de, uint64_t seq, int efd, struct hyper_exec *exec)
 {
 	int size = -1;
+	int flag = de->flag | EPOLLOUT;
 	struct hyper_buf *buf = &ctl.tty.wbuf;
 
-	while ((buf->get + 12 < buf->size) && size) {
+	if (FULL(buf)) {
+		flag |= EPOLLPRI;
+		goto out;
+	}
+
+	do {
 		size = read(de->fd, buf->data + buf->get + 12, buf->size - buf->get - 12);
 		fprintf(stdout, "%s: read %d data\n", __func__, size);
 		if (size < 0) {
@@ -124,16 +130,23 @@ static int pts_loop(struct hyper_event *de, uint64_t seq, int efd, struct hyper_
 		}
 		if (size == 0) { // eof
 			pts_hup(de, efd, exec);
-			break;
+			return 0;
 		}
 
 		hyper_set_be64(buf->data + buf->get, seq);
 		hyper_set_be32(buf->data + buf->get + 8, size + 12);
 		buf->get += size + 12;
-	}
+	} while (!FULL(buf));
 
-	if (hyper_modify_event(ctl.efd, &ctl.tty, EPOLLIN | EPOLLOUT) < 0) {
-		fprintf(stderr, "modify ctl tty event to in & out failed\n");
+	if (FULL(buf)) {
+		flag |= EPOLLPRI;
+		/* del & add event to move event to tail, this gives
+		 * other event a chance to write data to wbuf of tty. */
+		hyper_requeue_event(ctl.efd, de);
+	}
+out:
+	if (hyper_modify_event(ctl.efd, &ctl.tty, flag) < 0) {
+		fprintf(stderr, "modify ctl tty event to %d failed\n", flag);
 		return -1;
 	}