X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fio%2Fio.c;h=7eea9c35442cbbcb4386b430929195d1454b49a0;hp=68b95e82467194f13e87302e907cda5020fe37db;hb=e2e70f5566cb8978b74de517c24a0f236d3d01ee;hpb=3f642347378afc9e1db1768d88c9f5b2baffe9ba

diff --git a/ccan/io/io.c b/ccan/io/io.c
index 68b95e82..7eea9c35 100644
--- a/ccan/io/io.c
+++ b/ccan/io/io.c
@@ -72,16 +72,19 @@ static bool next_plan(struct io_conn *conn, struct io_plan *plan)
 	return true;
 }
 
-static void set_blocking(int fd, bool block)
+bool io_fd_block(int fd, bool block)
 {
 	int flags = fcntl(fd, F_GETFL);
 
+	if (flags == -1)
+		return false;
+
 	if (block)
 		flags &= ~O_NONBLOCK;
 	else
 		flags |= O_NONBLOCK;
 
-	fcntl(fd, F_SETFL, flags);
+	return fcntl(fd, F_SETFL, flags) != -1;
 }
 
 struct io_conn *io_new_conn_(const tal_t *ctx, int fd,
@@ -103,7 +106,7 @@ struct io_conn *io_new_conn_(const tal_t *ctx, int fd,
 		return tal_free(conn);
 
 	/* Keep our I/O async. */
-	set_blocking(fd, false);
+	io_fd_block(fd, false);
 
 	/* We start with out doing nothing, and in doing our init. */
 	conn->plan[IO_OUT].status = IO_UNSET;
@@ -360,14 +363,20 @@ void io_wake(const void *wait)
 	backend_wake(wait);
 }
 
-/* Returns false if this has been freed. */
-static bool do_plan(struct io_conn *conn, struct io_plan *plan)
+/* Returns false if this should not be touched (eg. freed). */
+static bool do_plan(struct io_conn *conn, struct io_plan *plan,
+		    bool idle_on_epipe)
 {
 	/* We shouldn't have polled for this event if this wasn't true! */
 	assert(plan->status == IO_POLLING);
 
 	switch (plan->io(conn->fd.fd, &plan->arg)) {
 	case -1:
+		if (errno == EPIPE && idle_on_epipe) {
+			plan->status = IO_UNSET;
+			backend_new_plan(conn);
+			return false;
+		}
 		io_close(conn);
 		return false;
 	case 0:
@@ -383,21 +392,38 @@ static bool do_plan(struct io_conn *conn, struct io_plan *plan)
 void io_ready(struct io_conn *conn, int pollflags)
 {
 	if (pollflags & POLLIN)
-		if (!do_plan(conn, &conn->plan[IO_IN]))
+		if (!do_plan(conn, &conn->plan[IO_IN], false))
 			return;
 
 	if (pollflags & POLLOUT)
-		do_plan(conn, &conn->plan[IO_OUT]);
+		/* If we're writing to a closed pipe, we need to wait for
+		 * read to fail if we're duplex: we want to drain it! */
+		do_plan(conn, &conn->plan[IO_OUT],
+			(conn->plan[IO_IN].status == IO_POLLING
+			 || conn->plan[IO_IN].status == IO_ALWAYS));
 }
 
 void io_do_always(struct io_conn *conn)
 {
+	/* There's a corner case where the in next_plan wakes up the
+	 * out, placing it in IO_ALWAYS and we end up processing it immediately,
+	 * only to leave it in the always list.
+	 *
+	 * Yet we can't just process one, in case they are both supposed
+	 * to be done, so grab state beforehand.
+	 */
+	bool always_out = (conn->plan[IO_OUT].status == IO_ALWAYS);
+
 	if (conn->plan[IO_IN].status == IO_ALWAYS)
 		if (!next_plan(conn, &conn->plan[IO_IN]))
 			return;
 
-	if (conn->plan[IO_OUT].status == IO_ALWAYS)
+	if (always_out) {
+		/* You can't *unalways* a conn (except by freeing, in which
+		 * case next_plan() returned false */
+		assert(conn->plan[IO_OUT].status == IO_ALWAYS);
 		next_plan(conn, &conn->plan[IO_OUT]);
+	}
 }
 
 void io_do_wakeup(struct io_conn *conn, enum io_direction dir)
@@ -423,7 +449,7 @@ struct io_plan *io_close_cb(struct io_conn *conn, void *next_arg)
 
 struct io_plan *io_close_taken_fd(struct io_conn *conn)
 {
-	set_blocking(conn->fd.fd, true);
+	io_fd_block(conn->fd.fd, true);
 
 	cleanup_conn_without_close(conn);
 	return io_close(conn);
@@ -483,3 +509,37 @@ struct io_plan *io_set_plan(struct io_conn *conn, enum io_direction dir,
 
 	return plan;
 }
+
+bool io_flush_sync(struct io_conn *conn)
+{
+	struct io_plan *plan = &conn->plan[IO_OUT];
+	bool ok;
+
+	/* Not writing?  Nothing to do. */
+	if (plan->status != IO_POLLING)
+		return true;
+
+	/* Synchronous please. */
+	io_fd_block(io_conn_fd(conn), true);
+
+again:
+	switch (plan->io(conn->fd.fd, &plan->arg)) {
+	case -1:
+		ok = false;
+		break;
+	/* Incomplete, try again. */
+	case 0:
+		goto again;
+	case 1:
+		ok = true;
+		/* In case they come back. */
+		set_always(conn, IO_OUT, plan->next, plan->next_arg);
+		break;
+	default:
+		/* IO should only return -1, 0 or 1 */
+		abort();
+	}
+
+	io_fd_block(io_conn_fd(conn), false);
+	return ok;
+}