io: don't leave errno as a random value when we hit EOF.

[ccan] / ccan / io / io.c

diff --git a/ccan/io/io.c b/ccan/io/io.c
index 7eea9c35442cbbcb4386b430929195d1454b49a0..bdcbf9e26b8f9f580fea08c2c0913d31efe9dcc7 100644 (file)
--- a/ccan/io/io.c
+++ b/ccan/io/io.c
@@ -131,7 +131,7 @@ 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;
 }
 
@@ -202,8 +202,12 @@ 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 +234,12 @@ 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;
@@ -368,7 +376,8 @@ 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:
@@ -380,6 +389,7 @@ static bool do_plan(struct io_conn *conn, struct io_plan *plan,
                io_close(conn);
                return false;
        case 0:
+               plan->status = IO_POLLING_STARTED;
                return true;
        case 1:
                return next_plan(conn, plan);
@@ -399,8 +409,8 @@ void io_ready(struct io_conn *conn, int pollflags)
                /* 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));
+                       conn->plan[IO_IN].status == IO_POLLING_NOTSTARTED
+                       || conn->plan[IO_IN].status == IO_POLLING_STARTED);
 }
 
 void io_do_always(struct io_conn *conn)
@@ -510,13 +520,24 @@ 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;
+}
+
 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. */
@@ -529,6 +550,7 @@ again:
                break;
        /* Incomplete, try again. */
        case 0:
+               plan->status = IO_POLLING_STARTED;
                goto again;
        case 1:
                ok = true;