ccan/io: go linear for debugging.

[ccan] / ccan / io / poll.c

diff --git a/ccan/io/poll.c b/ccan/io/poll.c
index 7f3df7ed301728965cbc2fc203f0bcc46262ec11..85407f62a8e32bafef27bb735b31992b3c1d2c66 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)
 {
@@ -83,7 +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--;
@@ -133,6 +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--;
@@ -176,7 +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--;
                        }
                }
@@ -204,9 +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;
@@ -221,7 +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. */
@@ -238,6 +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;
 
@@ -267,17 +326,27 @@ 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);
+                               /* debug can recurse; anything can change. */
+                               if (doing_debug())
+                                       break;
                        } else if (events & POLLHUP) {
                                r--;
+                               set_current(c);
                                set_plan(c, io_close(c, NULL));
-                               if (c->duplex)
+                               if (c->duplex) {
+                                       set_current(c->duplex);
                                        set_plan(c->duplex,
                                                 io_close(c->duplex, NULL));
+                               }
                        }
                }
        }
@@ -287,5 +356,7 @@ void *io_loop(void)
 
        ret = io_loop_return;
        io_loop_return = NULL;
+
+       io_loop_exit();
        return ret;
 }