X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fio%2Fio.c;h=12df06d82cb6474fed825cd381f7f225fc6213b1;hp=bdcbf9e26b8f9f580fea08c2c0913d31efe9dcc7;hb=HEAD;hpb=fedf515165bfafaf4fb98252ecda1abe050c8da5

diff --git a/ccan/io/io.c b/ccan/io/io.c
index bdcbf9e2..58ae19bd 100644
--- a/ccan/io/io.c
+++ b/ccan/io/io.c
@@ -15,6 +15,7 @@
 void *io_loop_return;
 
 struct io_plan io_conn_freed;
+static bool io_extended_errors;
 
 struct io_listener *io_new_listener_(const tal_t *ctx, int fd,
 				     struct io_plan *(*init)(struct io_conn *,
@@ -61,10 +62,7 @@ static bool next_plan(struct io_conn *conn, struct io_plan *plan)
 	if (plan == &io_conn_freed)
 		return false;
 
-	/* It should have set a plan inside this conn (or duplex) */
-	assert(plan == &conn->plan[IO_IN]
-	       || plan == &conn->plan[IO_OUT]
-	       || plan == &conn->plan[2]);
+	assert(plan == &conn->plan[plan->dir]);
 	assert(conn->plan[IO_IN].status != IO_UNSET
 	       || conn->plan[IO_OUT].status != IO_UNSET);
 
@@ -100,7 +98,6 @@ struct io_conn *io_new_conn_(const tal_t *ctx, int fd,
 	conn->fd.fd = fd;
 	conn->finish = NULL;
 	conn->finish_arg = NULL;
-	list_node_init(&conn->always);
 
 	if (!add_conn(conn))
 		return tal_free(conn);
@@ -108,6 +105,10 @@ struct io_conn *io_new_conn_(const tal_t *ctx, int fd,
 	/* Keep our I/O async. */
 	io_fd_block(fd, false);
 
+	/* So we can get back from plan -> conn later */
+	conn->plan[IO_OUT].dir = IO_OUT;
+	conn->plan[IO_IN].dir = IO_IN;
+
 	/* We start with out doing nothing, and in doing our init. */
 	conn->plan[IO_OUT].status = IO_UNSET;
 
@@ -119,6 +120,16 @@ struct io_conn *io_new_conn_(const tal_t *ctx, int fd,
 	return conn;
 }
 
+bool io_conn_exclusive(struct io_conn *conn, bool exclusive)
+{
+	return backend_set_exclusive(&conn->plan[IO_IN], exclusive);
+}
+
+bool io_conn_out_exclusive(struct io_conn *conn, bool exclusive)
+{
+	return backend_set_exclusive(&conn->plan[IO_OUT], exclusive);
+}
+
 void io_set_finish_(struct io_conn *conn,
 		    void (*finish)(struct io_conn *, void *),
 		    void *arg)
@@ -144,7 +155,9 @@ static struct io_plan *set_always(struct io_conn *conn,
 	struct io_plan *plan = &conn->plan[dir];
 
 	plan->status = IO_ALWAYS;
-	backend_new_always(conn);
+	/* Only happens on OOM, and only with non-default tal_backend. */
+	if (!backend_new_always(plan))
+		return NULL;
 	return io_set_plan(conn, dir, NULL, next, arg);
 }
 
@@ -371,9 +384,19 @@ void io_wake(const void *wait)
 	backend_wake(wait);
 }
 
-/* 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)
+enum plan_result {
+	/* Destroyed, do not touch */
+	FREED,
+	/* Worked, call again. */
+	KEEP_GOING,
+	/* Failed with EAGAIN or did partial. */
+	EXHAUSTED,
+	/* No longer interested in read (or write) */
+	UNINTERESTED
+};
+
+static enum plan_result 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_NOTSTARTED
@@ -381,18 +404,26 @@ static bool do_plan(struct io_conn *conn, struct io_plan *plan,
 
 	switch (plan->io(conn->fd.fd, &plan->arg)) {
 	case -1:
+		/* This is expected, as we call optimistically! */
+		if (errno == EAGAIN)
+			return EXHAUSTED;
 		if (errno == EPIPE && idle_on_epipe) {
 			plan->status = IO_UNSET;
 			backend_new_plan(conn);
-			return false;
+			return UNINTERESTED;
 		}
 		io_close(conn);
-		return false;
+		return FREED;
 	case 0:
 		plan->status = IO_POLLING_STARTED;
-		return true;
+		/* If it started but didn't finish, don't call again. */
+		return EXHAUSTED;
 	case 1:
-		return next_plan(conn, plan);
+		if (!next_plan(conn, plan))
+			return FREED;
+		if (plan->status == IO_POLLING_NOTSTARTED)
+			return KEEP_GOING;
+		return UNINTERESTED;
 	default:
 		/* IO should only return -1, 0 or 1 */
 		abort();
@@ -401,41 +432,55 @@ 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], false))
-			return;
-
-	if (pollflags & POLLOUT)
-		/* 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_NOTSTARTED
-			|| conn->plan[IO_IN].status == IO_POLLING_STARTED);
-}
-
-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 (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]);
+	enum plan_result res;
+
+	if (pollflags & POLLIN) {
+		for (;;) {
+			res = do_plan(conn, &conn->plan[IO_IN], false);
+			switch (res) {
+			case FREED:
+				return;
+			case EXHAUSTED:
+			case UNINTERESTED:
+				goto try_write;
+			case KEEP_GOING:
+				continue;
+			}
+			abort();
+		}
+	}
+
+try_write:
+	if (pollflags & POLLOUT) {
+		for (;;) {
+			/* 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! */
+			res = do_plan(conn, &conn->plan[IO_OUT],
+				      conn->plan[IO_IN].status == IO_POLLING_NOTSTARTED
+				      || conn->plan[IO_IN].status == IO_POLLING_STARTED);
+			switch (res) {
+			case FREED:
+			case EXHAUSTED:
+			case UNINTERESTED:
+				return;
+			case KEEP_GOING:
+				continue;
+			}
+			abort();
+		}
 	}
 }
 
+void io_do_always(struct io_plan *plan)
+{
+	struct io_conn *conn;
+
+	assert(plan->status == IO_ALWAYS);
+	conn = container_of(plan, struct io_conn, plan[plan->dir]);
+
+	next_plan(conn, plan);
+}
+
 void io_do_wakeup(struct io_conn *conn, enum io_direction dir)
 {
 	struct io_plan *plan = &conn->plan[dir];
@@ -488,7 +533,7 @@ struct io_plan *io_duplex(struct io_conn *conn,
 	assert(conn == container_of(in_plan, struct io_conn, plan[IO_IN]));
 	/* in_plan must be conn->plan[IO_IN], out_plan must be [IO_OUT] */
 	assert(out_plan == in_plan + 1);
-	return out_plan + 1;
+	return in_plan;
 }
 
 struct io_plan *io_halfclose(struct io_conn *conn)
@@ -530,6 +575,18 @@ bool io_plan_out_started(const struct io_conn *conn)
 	return conn->plan[IO_OUT].status == IO_POLLING_STARTED;
 }
 
+/* Despite being a TCP expert, I missed the full extent of this
+ * problem.  The legendary ZmnSCPxj implemented it (with the URL
+ * pointing to the explanation), and I imitate that here. */
+struct io_plan *io_sock_shutdown(struct io_conn *conn)
+{
+	if (shutdown(io_conn_fd(conn), SHUT_WR) != 0)
+		return io_close(conn);
+
+	/* And leave unset .*/
+	return &conn->plan[IO_IN];
+}
+
 bool io_flush_sync(struct io_conn *conn)
 {
 	struct io_plan *plan = &conn->plan[IO_OUT];
@@ -565,3 +622,13 @@ again:
 	io_fd_block(io_conn_fd(conn), false);
 	return ok;
 }
+
+void io_set_extended_errors(bool state)
+{
+	io_extended_errors = state;
+}
+
+bool io_get_extended_errors(void)
+{
+	return io_extended_errors;
+}