io: allow freeing of io_conn at any time.

io_close() currently marks the io_conn for freeing, but doesn't
actually do it.  This is a problem for tal() users, because we can't
just call it in the parent's constructor.

Make io_close() just tal_free() + return &io_conn_freed (a magic
io_plan pointer).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/ccan/io/backend.h b/ccan/io/backend.h
index aace0f2bad38d96a6835da31a2a2edf9f020ea6a..f57d24950a7693554bdb104ba58d0ef81294df14 100644 (file)
--- a/ccan/io/backend.h
+++ b/ccan/io/backend.h
@@ -31,9 +31,7 @@ enum io_plan_status {
        /* Waiting for io_wake */
        IO_WAITING,
        /* Always do this. */
        /* Waiting for io_wake */
        IO_WAITING,
        /* Always do this. */

-       IO_ALWAYS,
-       /* Closing (both plans will be the same). */
-       IO_CLOSING
+       IO_ALWAYS

 };
 
 /**
 };
 
 /**


@@ -60,8 +58,8 @@ struct io_plan {
 struct io_conn {
        struct fd fd;
 
 struct io_conn {
        struct fd fd;
 

-       /* always and closing lists. */
-       struct list_node always, closing;
+       /* always list. */
+       struct list_node always;

 
        void (*finish)(struct io_conn *, void *arg);
        void *finish_arg;
 
        void (*finish)(struct io_conn *, void *arg);
        void *finish_arg;


@@ -75,7 +73,6 @@ bool add_listener(struct io_listener *l);
 bool add_conn(struct io_conn *c);
 bool add_duplex(struct io_conn *c);
 void del_listener(struct io_listener *l);
 bool add_conn(struct io_conn *c);
 bool add_duplex(struct io_conn *c);
 void del_listener(struct io_listener *l);

-void backend_new_closing(struct io_conn *conn);

 void backend_new_always(struct io_conn *conn);
 void backend_new_plan(struct io_conn *conn);
 void remove_from_always(struct io_conn *conn);
 void backend_new_always(struct io_conn *conn);
 void backend_new_plan(struct io_conn *conn);
 void remove_from_always(struct io_conn *conn);

diff --git a/ccan/io/io.c b/ccan/io/io.c
index 83f933acd994ce58456bd336f9af24f9622e8dd4..4c41c93a683214fd24b50a647a94b31706d98017 100644 (file)
--- a/ccan/io/io.c
+++ b/ccan/io/io.c
@@ -14,6 +14,8 @@
 
 void *io_loop_return;
 
 
 void *io_loop_return;
 

+struct io_plan io_conn_freed;
+

 struct io_listener *io_new_listener_(const tal_t *ctx, int fd,
                                     struct io_plan *(*init)(struct io_conn *,
                                                             void *),
 struct io_listener *io_new_listener_(const tal_t *ctx, int fd,
                                     struct io_plan *(*init)(struct io_conn *,
                                                             void *),


@@ -35,8 +37,6 @@ struct io_listener *io_new_listener_(const tal_t *ctx, int fd,
 
 void io_close_listener(struct io_listener *l)
 {
 
 void io_close_listener(struct io_listener *l)
 {

-       close(l->fd.fd);
-       del_listener(l);

        tal_free(l);
 }
 
        tal_free(l);
 }
 


@@ -45,7 +45,8 @@ static struct io_plan *io_never_called(struct io_conn *conn, void *arg)
        abort();
 }
 
        abort();
 }
 

-static void next_plan(struct io_conn *conn, struct io_plan *plan)
+/* Returns false if conn was freed. */
+static bool next_plan(struct io_conn *conn, struct io_plan *plan)

 {
        struct io_plan *(*next)(struct io_conn *, void *arg);
 
 {
        struct io_plan *(*next)(struct io_conn *, void *arg);
 


@@ -57,6 +58,9 @@ static void next_plan(struct io_conn *conn, struct io_plan *plan)
 
        plan = next(conn, plan->next_arg);
 
 
        plan = next(conn, plan->next_arg);
 

+       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]
        /* It should have set a plan inside this conn (or duplex) */
        assert(plan == &conn->plan[IO_IN]
               || plan == &conn->plan[IO_OUT]


@@ -65,6 +69,7 @@ static void next_plan(struct io_conn *conn, struct io_plan *plan)
               || conn->plan[IO_OUT].status != IO_UNSET);
 
        backend_new_plan(conn);
               || conn->plan[IO_OUT].status != IO_UNSET);
 
        backend_new_plan(conn);

+       return true;

 }
 
 static void set_blocking(int fd, bool block)
 }
 
 static void set_blocking(int fd, bool block)


@@ -93,7 +98,6 @@ struct io_conn *io_new_conn_(const tal_t *ctx, int fd,
        conn->finish = NULL;
        conn->finish_arg = NULL;
        list_node_init(&conn->always);
        conn->finish = NULL;
        conn->finish_arg = NULL;
        list_node_init(&conn->always);

-       list_node_init(&conn->closing);

 
        if (!add_conn(conn))
                return tal_free(conn);
 
        if (!add_conn(conn))
                return tal_free(conn);


@@ -106,7 +110,8 @@ struct io_conn *io_new_conn_(const tal_t *ctx, int fd,
 
        conn->plan[IO_IN].next = init;
        conn->plan[IO_IN].next_arg = arg;
 
        conn->plan[IO_IN].next = init;
        conn->plan[IO_IN].next_arg = arg;

-       next_plan(conn, &conn->plan[IO_IN]);
+       if (!next_plan(conn, &conn->plan[IO_IN]))
+               return NULL;

 
        return conn;
 }
 
        return conn;
 }


@@ -355,24 +360,20 @@ void io_wake(const void *wait)
        backend_wake(wait);
 }
 
        backend_wake(wait);
 }
 

-static int do_plan(struct io_conn *conn, struct io_plan *plan)
+/* Returns false if this has been freed. */
+static bool do_plan(struct io_conn *conn, struct io_plan *plan)

 {
 {

-       /* Someone else might have called io_close() on us. */
-       if (plan->status == IO_CLOSING)
-               return -1;
-

        /* 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:
                io_close(conn);
        /* 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:
                io_close(conn);

-               return -1;
+               return false;

        case 0:
        case 0:

-               return 0;
+               return true;

        case 1:
        case 1:

-               next_plan(conn, plan);
-               return 1;
+               return next_plan(conn, plan);

        default:
                /* IO should only return -1, 0 or 1 */
                abort();
        default:
                /* IO should only return -1, 0 or 1 */
                abort();


@@ -382,7 +383,8 @@ static int do_plan(struct io_conn *conn, struct io_plan *plan)
 void io_ready(struct io_conn *conn, int pollflags)
 {
        if (pollflags & POLLIN)
 void io_ready(struct io_conn *conn, int pollflags)
 {
        if (pollflags & POLLIN)

-               do_plan(conn, &conn->plan[IO_IN]);
+               if (!do_plan(conn, &conn->plan[IO_IN]))
+                       return;

 
        if (pollflags & POLLOUT)
                do_plan(conn, &conn->plan[IO_OUT]);
 
        if (pollflags & POLLOUT)
                do_plan(conn, &conn->plan[IO_OUT]);


@@ -391,7 +393,8 @@ void io_ready(struct io_conn *conn, int pollflags)
 void io_do_always(struct io_conn *conn)
 {
        if (conn->plan[IO_IN].status == IO_ALWAYS)
 void io_do_always(struct io_conn *conn)
 {
        if (conn->plan[IO_IN].status == IO_ALWAYS)

-               next_plan(conn, &conn->plan[IO_IN]);
+               if (!next_plan(conn, &conn->plan[IO_IN]))
+                       return;

 
        if (conn->plan[IO_OUT].status == IO_ALWAYS)
                next_plan(conn, &conn->plan[IO_OUT]);
 
        if (conn->plan[IO_OUT].status == IO_ALWAYS)
                next_plan(conn, &conn->plan[IO_OUT]);


@@ -409,15 +412,8 @@ void io_do_wakeup(struct io_conn *conn, enum io_direction dir)
 /* Close the connection, we're done. */
 struct io_plan *io_close(struct io_conn *conn)
 {
 /* Close the connection, we're done. */
 struct io_plan *io_close(struct io_conn *conn)
 {

-       /* Already closing?  Don't close twice. */
-       if (conn->plan[IO_IN].status == IO_CLOSING)
-               return &conn->plan[IO_IN];
-
-       conn->plan[IO_IN].status = conn->plan[IO_OUT].status = IO_CLOSING;
-       conn->plan[IO_IN].arg.u1.s = errno;
-       backend_new_closing(conn);
-
-       return io_set_plan(conn, IO_IN, NULL, NULL, NULL);
+       tal_free(conn);
+       return &io_conn_freed;

 }
 
 struct io_plan *io_close_cb(struct io_conn *conn, void *next_arg)
 }
 
 struct io_plan *io_close_cb(struct io_conn *conn, void *next_arg)


@@ -453,10 +449,6 @@ struct io_plan *io_duplex(struct io_conn *conn,
 
 struct io_plan *io_halfclose(struct io_conn *conn)
 {
 
 struct io_plan *io_halfclose(struct io_conn *conn)
 {

-       /* Already closing?  Don't close twice. */
-       if (conn->plan[IO_IN].status == IO_CLOSING)
-               return &conn->plan[IO_IN];
-

        /* Both unset?  OK. */
        if (conn->plan[IO_IN].status == IO_UNSET
            && conn->plan[IO_OUT].status == IO_UNSET)
        /* Both unset?  OK. */
        if (conn->plan[IO_IN].status == IO_UNSET
            && conn->plan[IO_OUT].status == IO_UNSET)


@@ -479,7 +471,7 @@ struct io_plan *io_set_plan(struct io_conn *conn, enum io_direction dir,
        plan->io = io;
        plan->next = next;
        plan->next_arg = next_arg;
        plan->io = io;
        plan->next = next;
        plan->next_arg = next_arg;

-       assert(plan->status == IO_CLOSING || next != NULL);
+       assert(next != NULL);

 
        return plan;
 }
 
        return plan;
 }

diff --git a/ccan/io/poll.c b/ccan/io/poll.c
index 36af33ef0854de3323c8f29c4dc522c976091764..6738f720ec0782f7ade4d67f1f4eba30e8f4b3ef 100644 (file)
--- a/ccan/io/poll.c
+++ b/ccan/io/poll.c
@@ -95,10 +95,17 @@ static void del_fd(struct fd *fd)
        close(fd->fd);
 }
 
        close(fd->fd);
 }
 

+static void destroy_listener(struct io_listener *l)
+{
+       close(l->fd.fd);
+       del_fd(&l->fd);
+}
+

 bool add_listener(struct io_listener *l)
 {
        if (!add_fd(&l->fd, POLLIN))
                return false;
 bool add_listener(struct io_listener *l)
 {
        if (!add_fd(&l->fd, POLLIN))
                return false;

+       tal_add_destructor(l, destroy_listener);

        return true;
 }
 
        return true;
 }
 


@@ -107,13 +114,6 @@ void remove_from_always(struct io_conn *conn)
        list_del_init(&conn->always);
 }
 
        list_del_init(&conn->always);
 }
 

-void backend_new_closing(struct io_conn *conn)
-{
-       /* In case it's on always list, remove it. */
-       list_del_init(&conn->always);
-       list_add_tail(&closing, &conn->closing);
-}
-

 void backend_new_always(struct io_conn *conn)
 {
        /* In case it's already in always list. */
 void backend_new_always(struct io_conn *conn)
 {
        /* In case it's already in always list. */


@@ -164,25 +164,28 @@ void backend_wake(const void *wait)
        }
 }
 
        }
 }
 

-bool add_conn(struct io_conn *c)
+static void destroy_conn(struct io_conn *conn)

 {
 {

-       return add_fd(&c->fd, 0);
-}
+       int saved_errno = errno;

 
 

-static void del_conn(struct io_conn *conn)
-{
+       close(conn->fd.fd);

        del_fd(&conn->fd);
        del_fd(&conn->fd);

+       /* In case it's on always list, remove it. */
+       list_del_init(&conn->always);
+
+       /* errno saved/restored by tal_free itself. */

        if (conn->finish) {
        if (conn->finish) {

-               /* Saved by io_close */
-               errno = conn->plan[IO_IN].arg.u1.s;
+               errno = saved_errno;

                conn->finish(conn, conn->finish_arg);
        }
                conn->finish(conn, conn->finish_arg);
        }

-       tal_free(conn);

 }
 
 }
 

-void del_listener(struct io_listener *l)
+bool add_conn(struct io_conn *c)

 {
 {

-       del_fd(&l->fd);
+       if (!add_fd(&c->fd, 0))
+               return false;
+       tal_add_destructor(c, destroy_conn);
+       return true;

 }
 
 static void accept_conn(struct io_listener *l)
 }
 
 static void accept_conn(struct io_listener *l)


@@ -196,22 +199,6 @@ static void accept_conn(struct io_listener *l)
        io_new_conn(l->ctx, fd, l->init, l->arg);
 }
 
        io_new_conn(l->ctx, fd, l->init, l->arg);
 }
 

-/* It's OK to miss some, as long as we make progress. */
-static bool close_conns(void)
-{
-       bool ret = false;
-       struct io_conn *conn;
-
-       while ((conn = list_pop(&closing, struct io_conn, closing)) != NULL) {
-               assert(conn->plan[IO_IN].status == IO_CLOSING);
-               assert(conn->plan[IO_OUT].status == IO_CLOSING);
-
-               del_conn(conn);
-               ret = true;
-       }
-       return ret;
-}
-

 static bool handle_always(void)
 {
        bool ret = false;
 static bool handle_always(void)
 {
        bool ret = false;


@@ -244,11 +231,6 @@ void *io_loop(struct timers *timers, struct timer **expired)
        while (!io_loop_return) {
                int i, r, ms_timeout = -1;
 
        while (!io_loop_return) {
                int i, r, ms_timeout = -1;
 

-               if (close_conns()) {
-                       /* Could have started/finished more. */
-                       continue;
-               }
-

                if (handle_always()) {
                        /* Could have started/finished more. */
                        continue;
                if (handle_always()) {
                        /* Could have started/finished more. */
                        continue;


@@ -309,8 +291,6 @@ void *io_loop(struct timers *timers, struct timer **expired)
                }
        }
 
                }
        }
 

-       close_conns();
-

        ret = io_loop_return;
        io_loop_return = NULL;
 
        ret = io_loop_return;
        io_loop_return = NULL;
 

diff --git a/ccan/io/test/run-18-errno.c b/ccan/io/test/run-18-errno.c
index 75d84cca1f64a5520698597352769ca3e14f1e92..904a20cafc4cc735339e216c1fcd93c99e528216 100644 (file)
--- a/ccan/io/test/run-18-errno.c
+++ b/ccan/io/test/run-18-errno.c
@@ -27,8 +27,8 @@ static struct io_plan *init_conn(struct io_conn *conn, int *state)
 {
        if (*state == 0) {
                (*state)++;
 {
        if (*state == 0) {
                (*state)++;

-               errno = 100;

                io_set_finish(conn, finish_100, state);
                io_set_finish(conn, finish_100, state);

+               errno = 100;

                return io_close(conn);
        } else {
                ok1(*state == 2);
                return io_close(conn);
        } else {
                ok1(*state == 2);