ccan/io: handle errors on poll()

[ccan] / ccan / io / poll.c

diff --git a/ccan/io/poll.c b/ccan/io/poll.c
index 9f9bb4a256168699eecec1dc062855475766e899..42ed67ad278a0c870c9c4a98baa015eb0ed4e60a 100644 (file)
--- a/ccan/io/poll.c
+++ b/ccan/io/poll.c
@@ -12,6 +12,49 @@ static size_t num_fds = 0, max_fds = 0, num_closing = 0, num_waiting = 0;
 static struct pollfd *pollfds = NULL;
 static struct fd **fds = NULL;
 static struct timers timeouts;
+#ifdef DEBUG
+static unsigned int io_loop_level;
+static struct io_conn *free_later;
+static void io_loop_enter(void)
+{
+       io_loop_level++;
+}
+static void io_loop_exit(void)
+{
+       io_loop_level--;
+       if (io_loop_level == 0) {
+               /* Delayed free. */
+               while (free_later) {
+                       struct io_conn *c = free_later;
+                       free_later = c->finish_arg;
+                       free(c);
+               }
+       }
+}
+static void free_conn(struct io_conn *conn)
+{
+       /* Only free on final exit: chain via finish. */
+       if (io_loop_level > 1) {
+               struct io_conn *c;
+               for (c = free_later; c; c = c->finish_arg)
+                       assert(c != conn);
+               conn->finish_arg = free_later;
+               free_later = conn;
+       } else
+               free(conn);
+}
+#else
+static void io_loop_enter(void)
+{
+}
+static void io_loop_exit(void)
+{
+}
+static void free_conn(struct io_conn *conn)
+{
+       free(conn);
+}
+#endif
 
 static bool add_fd(struct fd *fd, short events)
 {
@@ -31,8 +74,12 @@ static bool add_fd(struct fd *fd, short events)
                max_fds = num;
        }
 
-       pollfds[num_fds].fd = fd->fd;
        pollfds[num_fds].events = events;
+       /* In case it's idle. */
+       if (!events)
+               pollfds[num_fds].fd = -fd->fd;
+       else
+               pollfds[num_fds].fd = fd->fd;
        pollfds[num_fds].revents = 0; /* In case we're iterating now */
        fds[num_fds] = fd;
        fd->backend_info = num_fds;
@@ -79,7 +126,13 @@ bool add_listener(struct io_listener *l)
 
 void backend_plan_changed(struct io_conn *conn)
 {
-       struct pollfd *pfd = &pollfds[conn->fd.backend_info];
+       struct pollfd *pfd;
+
+       /* This can happen with debugging and delayed free... */
+       if (conn->fd.backend_info == -1)
+               return;
+
+       pfd = &pollfds[conn->fd.backend_info];
 
        if (pfd->events)
                num_waiting--;
@@ -91,8 +144,11 @@ void backend_plan_changed(struct io_conn *conn)
                assert(!mask || pfd->events != mask);
                pfd->events |= mask;
        }
-       if (pfd->events)
+       if (pfd->events) {
                num_waiting++;
+               pfd->fd = conn->fd.fd;
+       } else
+               pfd->fd = -conn->fd.fd;
 
        if (!conn->plan.next)
                num_closing++;
@@ -126,6 +182,7 @@ static void del_conn(struct io_conn *conn)
                /* In case fds[] pointed to the other one. */
                fds[conn->fd.backend_info] = &conn->duplex->fd;
                conn->duplex->duplex = NULL;
+               conn->fd.backend_info = -1;
        } else
                del_fd(&conn->fd);
        num_closing--;
@@ -169,7 +226,7 @@ static void finish_conns(void)
                for (duplex = c->duplex; c; c = duplex, duplex = NULL) {
                        if (!c->plan.next) {
                                del_conn(c);
-                               free(c);
+                               free_conn(c);
                                i--;
                        }
                }
@@ -197,9 +254,12 @@ void *io_loop(void)
 {
        void *ret;
 
+       io_loop_enter();
+
        while (!io_loop_return) {
                int i, r, timeout = INT_MAX;
                struct timespec now;
+               bool some_timeouts = false;
 
                if (timeouts.base) {
                        struct timespec first;
@@ -214,7 +274,9 @@ void *io_loop(void)
                                struct io_conn *conn = t->conn;
                                /* Clear, in case timer re-adds */
                                t->conn = NULL;
+                               set_current(conn);
                                set_plan(conn, t->next(conn, t->next_arg));
+                               some_timeouts = true;
                        }
 
                        /* Now figure out how long to wait for the next one. */
@@ -231,6 +293,10 @@ void *io_loop(void)
                        continue;
                }
 
+               /* debug can recurse on io_loop; anything can change. */
+               if (doing_debug() && some_timeouts)
+                       continue;
+
                if (num_fds == 0)
                        break;
 
@@ -260,17 +326,26 @@ void *io_loop(void)
                                        if (events & mask) {
                                                io_ready(c->duplex);
                                                events &= ~mask;
+                                               /* debug can recurse;
+                                                * anything can change. */
+                                               if (doing_debug())
+                                                       break;
                                                if (!(events&(POLLIN|POLLOUT)))
                                                        continue;
                                        }
                                }
                                io_ready(c);
-                       } else if (events & POLLHUP) {
+                               /* debug can recurse; anything can change. */
+                               if (doing_debug())
+                                       break;
+                       } else if (events & (POLLHUP|POLLNVAL|POLLERR)) {
                                r--;
-                               set_plan(c, io_close(c, NULL));
-                               if (c->duplex)
-                                       set_plan(c->duplex,
-                                                io_close(c->duplex, NULL));
+                               set_current(c);
+                               set_plan(c, io_close());
+                               if (c->duplex) {
+                                       set_current(c->duplex);
+                                       set_plan(c->duplex, io_close());
+                               }
                        }
                }
        }
@@ -280,5 +355,7 @@ void *io_loop(void)
 
        ret = io_loop_return;
        io_loop_return = NULL;
+
+       io_loop_exit();
        return ret;
 }