X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fio%2Fio.c;h=12df06d82cb6474fed825cd381f7f225fc6213b1;hp=cc2b1afa3b27720adff4e3aa0b0c1d4fd4a393a3;hb=HEAD;hpb=3ffb94e9aad84dc0d8e19a5a7d709589d7956ddf

diff --git a/ccan/io/io.c b/ccan/io/io.c
index cc2b1afa..12df06d8 100644
--- a/ccan/io/io.c
+++ b/ccan/io/io.c
@@ -61,10 +61,7 @@ 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 +97,6 @@ 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 +104,10 @@ 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 +119,16 @@ 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)
@@ -131,7 +141,7 @@ struct io_plan_arg *io_plan_arg(struct io_conn *conn, enum io_direction dir)
 {
 	assert(conn->plan[dir].status == IO_UNSET);
 
-	conn->plan[dir].status = IO_POLLING;
+	conn->plan[dir].status = IO_POLLING_NOTSTARTED;
 	return &conn->plan[dir].arg;
 }
 
@@ -144,7 +154,9 @@ 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);
 }
 
@@ -202,8 +214,12 @@ struct io_plan *io_write_(struct io_conn *conn, const void *data, size_t len,
 static int do_read(int fd, struct io_plan_arg *arg)
 {
 	ssize_t ret = read(fd, arg->u1.cp, arg->u2.s);
-	if (ret <= 0)
+	if (ret <= 0) {
+		/* Errno isn't set if we hit EOF, so set it to distinct value */
+		if (ret == 0)
+			errno = 0;
 		return -1;
+	}
 
 	arg->u1.cp += ret;
 	arg->u2.s -= ret;
@@ -230,8 +246,12 @@ struct io_plan *io_read_(struct io_conn *conn,
 static int do_read_partial(int fd, struct io_plan_arg *arg)
 {
 	ssize_t ret = read(fd, arg->u1.cp, *(size_t *)arg->u2.vp);
-	if (ret <= 0)
+	if (ret <= 0) {
+		/* Errno isn't set if we hit EOF, so set it to distinct value */
+		if (ret == 0)
+			errno = 0;
 		return -1;
+	}
 
 	*(size_t *)arg->u2.vp = ret;
 	return 1;
@@ -363,17 +383,25 @@ 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);
+	assert(plan->status == IO_POLLING_NOTSTARTED
+	       || plan->status == IO_POLLING_STARTED);
 
 	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:
+		plan->status = IO_POLLING_STARTED;
 		return true;
 	case 1:
 		return next_plan(conn, plan);
@@ -386,34 +414,25 @@ 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_NOTSTARTED
+			|| conn->plan[IO_IN].status == IO_POLLING_STARTED);
 }
 
-void io_do_always(struct io_conn *conn)
+void io_do_always(struct io_plan *plan)
 {
-	/* 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);
+	struct io_conn *conn;
 
-	if (conn->plan[IO_IN].status == IO_ALWAYS)
-		if (!next_plan(conn, &conn->plan[IO_IN]))
-			return;
+	assert(plan->status == IO_ALWAYS);
+	conn = container_of(plan, struct io_conn, plan[plan->dir]);
 
-	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]);
-	}
+	next_plan(conn, plan);
 }
 
 void io_do_wakeup(struct io_conn *conn, enum io_direction dir)
@@ -468,7 +487,7 @@ 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)
@@ -500,13 +519,36 @@ struct io_plan *io_set_plan(struct io_conn *conn, enum io_direction dir,
 	return plan;
 }
 
+bool io_plan_in_started(const struct io_conn *conn)
+{
+	return conn->plan[IO_IN].status == IO_POLLING_STARTED;
+}
+
+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];
 	bool ok;
 
 	/* Not writing?  Nothing to do. */
-	if (plan->status != IO_POLLING)
+	if (plan->status != IO_POLLING_STARTED
+	    && plan->status != IO_POLLING_NOTSTARTED)
 		return true;
 
 	/* Synchronous please. */
@@ -519,6 +561,7 @@ again:
 		break;
 	/* Incomplete, try again. */
 	case 0:
+		plan->status = IO_POLLING_STARTED;
 		goto again;
 	case 1:
 		ok = true;