io: io_always, and zero-length operations support.
[ccan] / ccan / io / poll.c
index 85407f62a8e32bafef27bb735b31992b3c1d2c66..d7b9eb56b950b5a1b4772525c86bb944b3a60c6f 100644 (file)
@@ -7,8 +7,10 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <limits.h>
+#include <errno.h>
 
 static size_t num_fds = 0, max_fds = 0, num_closing = 0, num_waiting = 0;
+static bool some_always = false;
 static struct pollfd *pollfds = NULL;
 static struct fd **fds = NULL;
 static struct timers timeouts;
@@ -27,7 +29,7 @@ static void io_loop_exit(void)
                while (free_later) {
                        struct io_conn *c = free_later;
                        free_later = c->finish_arg;
-                       free(c);
+                       io_alloc.free(c);
                }
        }
 }
@@ -41,7 +43,7 @@ static void free_conn(struct io_conn *conn)
                conn->finish_arg = free_later;
                free_later = conn;
        } else
-               free(conn);
+               io_alloc.free(conn);
 }
 #else
 static void io_loop_enter(void)
@@ -52,7 +54,7 @@ static void io_loop_exit(void)
 }
 static void free_conn(struct io_conn *conn)
 {
-       free(conn);
+       io_alloc.free(conn);
 }
 #endif
 
@@ -63,11 +65,11 @@ static bool add_fd(struct fd *fd, short events)
                struct fd **newfds;
                size_t num = max_fds ? max_fds * 2 : 8;
 
-               newpollfds = realloc(pollfds, sizeof(*newpollfds) * num);
+               newpollfds = io_alloc.realloc(pollfds, sizeof(*newpollfds)*num);
                if (!newpollfds)
                        return false;
                pollfds = newpollfds;
-               newfds = realloc(fds, sizeof(*newfds) * num);
+               newfds = io_alloc.realloc(fds, sizeof(*newfds) * num);
                if (!newfds)
                        return false;
                fds = newfds;
@@ -104,10 +106,18 @@ static void del_fd(struct fd *fd)
                fds[n] = fds[num_fds-1];
                assert(fds[n]->backend_info == num_fds-1);
                fds[n]->backend_info = n;
+               /* If that happens to be a duplex, move that too. */
+               if (!fds[n]->listener) {
+                       struct io_conn *c = (void *)fds[n];
+                       if (c->duplex) {
+                               assert(c->duplex->fd.backend_info == num_fds-1);
+                               c->duplex->fd.backend_info = n;
+                       }
+               }
        } else if (num_fds == 1) {
                /* Free everything when no more fds. */
-               free(pollfds);
-               free(fds);
+               io_alloc.free(pollfds);
+               io_alloc.free(fds);
                pollfds = NULL;
                fds = NULL;
                max_fds = 0;
@@ -137,9 +147,9 @@ void backend_plan_changed(struct io_conn *conn)
        if (pfd->events)
                num_waiting--;
 
-       pfd->events = conn->plan.pollflag;
+       pfd->events = conn->plan.pollflag & (POLLIN|POLLOUT);
        if (conn->duplex) {
-               int mask = conn->duplex->plan.pollflag;
+               int mask = conn->duplex->plan.pollflag & (POLLIN|POLLOUT);
                /* You can't *both* read/write. */
                assert(!mask || pfd->events != mask);
                pfd->events |= mask;
@@ -152,15 +162,20 @@ void backend_plan_changed(struct io_conn *conn)
 
        if (!conn->plan.next)
                num_closing++;
+
+       if (conn->plan.pollflag == POLLALWAYS)
+               some_always = true;
 }
 
 bool add_conn(struct io_conn *c)
 {
-       if (!add_fd(&c->fd, c->plan.pollflag))
+       if (!add_fd(&c->fd, c->plan.pollflag & (POLLIN|POLLOUT)))
                return false;
        /* Immediate close is allowed. */
        if (!c->plan.next)
                num_closing++;
+       if (c->plan.pollflag == POLLALWAYS)
+               some_always = true;
        return true;
 }
 
@@ -171,21 +186,26 @@ bool add_duplex(struct io_conn *c)
        return true;
 }
 
-static void del_conn(struct io_conn *conn)
+void backend_del_conn(struct io_conn *conn)
 {
-       if (conn->finish)
+       if (conn->finish) {
+               /* Saved by io_close */
+               errno = conn->plan.u1.s;
                conn->finish(conn, conn->finish_arg);
+       }
        if (timeout_active(conn))
                backend_del_timeout(conn);
-       free(conn->timeout);
+       io_alloc.free(conn->timeout);
        if (conn->duplex) {
                /* In case fds[] pointed to the other one. */
+               assert(conn->duplex->fd.backend_info == conn->fd.backend_info);
                fds[conn->fd.backend_info] = &conn->duplex->fd;
                conn->duplex->duplex = NULL;
                conn->fd.backend_info = -1;
        } else
                del_fd(&conn->fd);
        num_closing--;
+       free_conn(conn);
 }
 
 void del_listener(struct io_listener *l)
@@ -210,7 +230,7 @@ static void accept_conn(struct io_listener *l)
 }
 
 /* It's OK to miss some, as long as we make progress. */
-static void finish_conns(void)
+static bool finish_conns(struct io_conn **ready)
 {
        unsigned int i;
 
@@ -225,12 +245,16 @@ static void finish_conns(void)
                c = (void *)fds[i];
                for (duplex = c->duplex; c; c = duplex, duplex = NULL) {
                        if (!c->plan.next) {
-                               del_conn(c);
-                               free_conn(c);
+                               if (doing_debug_on(c) && ready) {
+                                       *ready = c;
+                                       return true;
+                               }
+                               backend_del_conn(c);
                                i--;
                        }
                }
        }
+       return false;
 }
 
 void backend_add_timeout(struct io_conn *conn, struct timespec duration)
@@ -249,8 +273,28 @@ void backend_del_timeout(struct io_conn *conn)
        conn->timeout->conn = NULL;
 }
 
+static void handle_always(void)
+{
+       int i;
+
+       some_always = false;
+
+       for (i = 0; i < num_fds && !io_loop_return; i++) {
+               struct io_conn *c = (void *)fds[i];
+
+               if (fds[i]->listener)
+                       continue;
+
+               if (c->plan.pollflag == POLLALWAYS)
+                       io_ready(c);
+
+               if (c->duplex && c->duplex->plan.pollflag == POLLALWAYS)
+                       io_ready(c->duplex);
+       }
+}
+
 /* This is the main loop. */
-void *io_loop(void)
+void *do_io_loop(struct io_conn **ready)
 {
        void *ret;
 
@@ -288,7 +332,9 @@ void *io_loop(void)
                }
 
                if (num_closing) {
-                       finish_conns();
+                       /* If this finishes a debugging con, return now. */
+                       if (finish_conns(ready))
+                               return NULL;
                        /* Could have started/finished more. */
                        continue;
                }
@@ -297,6 +343,11 @@ void *io_loop(void)
                if (doing_debug() && some_timeouts)
                        continue;
 
+               if (some_always) {
+                       handle_always();
+                       continue;
+               }
+
                if (num_fds == 0)
                        break;
 
@@ -324,35 +375,50 @@ void *io_loop(void)
                                if (c->duplex) {
                                        int mask = c->duplex->plan.pollflag;
                                        if (events & mask) {
+                                               if (doing_debug_on(c->duplex)
+                                                       && ready) {
+                                                       *ready = c->duplex;
+                                                       return NULL;
+                                               }
                                                io_ready(c->duplex);
                                                events &= ~mask;
                                                /* debug can recurse;
                                                 * anything can change. */
                                                if (doing_debug())
                                                        break;
-                                               if (!(events&(POLLIN|POLLOUT)))
+
+                                               /* If no events, or it closed
+                                                * the duplex, continue. */
+                                               if (!(events&(POLLIN|POLLOUT))
+                                                   || !c->plan.next)
                                                        continue;
                                        }
                                }
+                               if (doing_debug_on(c) && ready) {
+                                       *ready = c;
+                                       return NULL;
+                               }
                                io_ready(c);
                                /* debug can recurse; anything can change. */
                                if (doing_debug())
                                        break;
-                       } else if (events & POLLHUP) {
+                       } else if (events & (POLLHUP|POLLNVAL|POLLERR)) {
                                r--;
                                set_current(c);
-                               set_plan(c, io_close(c, NULL));
+                               errno = EBADF;
+                               set_plan(c, io_close());
                                if (c->duplex) {
                                        set_current(c->duplex);
-                                       set_plan(c->duplex,
-                                                io_close(c->duplex, NULL));
+                                       set_plan(c->duplex, io_close());
                                }
                        }
                }
        }
 
-       while (num_closing)
-               finish_conns();
+       while (num_closing && !io_loop_return) {
+               if (finish_conns(ready))
+                       return NULL;
+       }
 
        ret = io_loop_return;
        io_loop_return = NULL;
@@ -360,3 +426,8 @@ void *io_loop(void)
        io_loop_exit();
        return ret;
 }
+
+void *io_loop(void)
+{
+       return do_io_loop(NULL);
+}