Event engines refactoring.

1 files changed, 665 insertions, 0 deletions

diff --git a/src/nxt_devpoll_engine.c b/src/nxt_devpoll_engine.c
new file mode 100644
index 00000000..37435661
--- /dev/null
+++ b/src/nxt_devpoll_engine.c
@@ -0,0 +1,665 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ * Copyright (C) NGINX, Inc.
+ */
+
+#include <nxt_main.h>
+
+
+/*
+ * "/dev/poll" has been introduced in Solaris 7 (11/99), HP-UX 11.22 (named
+ * "eventport pseudo driver" internally, not to be confused with Solaris 10
+ * event ports), IRIX 6.5.15, and Tru64 UNIX 5.1A.
+ *
+ * Although "/dev/poll" descriptor is a file descriptor, nevertheless
+ * it cannot be added to another poll set, Solaris poll(7d):
+ *
+ *   The /dev/poll driver does not yet support polling.  Polling on a
+ *   /dev/poll file descriptor will result in POLLERR being returned
+ *   in the revents field of pollfd structure.
+ */
+
+
+#define NXT_DEVPOLL_ADD     0
+#define NXT_DEVPOLL_UPDATE  1
+#define NXT_DEVPOLL_CHANGE  2
+#define NXT_DEVPOLL_DELETE  3
+
+
+static nxt_int_t nxt_devpoll_create(nxt_event_engine_t *engine,
+    nxt_uint_t mchanges, nxt_uint_t mevents);
+static void nxt_devpoll_free(nxt_event_engine_t *engine);
+static void nxt_devpoll_enable(nxt_event_engine_t *engine, nxt_fd_event_t *ev);
+static void nxt_devpoll_disable(nxt_event_engine_t *engine, nxt_fd_event_t *ev);
+static nxt_bool_t nxt_devpoll_close(nxt_event_engine_t *engine,
+    nxt_fd_event_t *ev);
+static void nxt_devpoll_enable_read(nxt_event_engine_t *engine,
+    nxt_fd_event_t *ev);
+static void nxt_devpoll_enable_write(nxt_event_engine_t *engine,
+    nxt_fd_event_t *ev);
+static void nxt_devpoll_disable_read(nxt_event_engine_t *engine,
+    nxt_fd_event_t *ev);
+static void nxt_devpoll_disable_write(nxt_event_engine_t *engine,
+    nxt_fd_event_t *ev);
+static void nxt_devpoll_block_read(nxt_event_engine_t *engine,
+    nxt_fd_event_t *ev);
+static void nxt_devpoll_block_write(nxt_event_engine_t *engine,
+    nxt_fd_event_t *ev);
+static void nxt_devpoll_oneshot_read(nxt_event_engine_t *engine,
+    nxt_fd_event_t *ev);
+static void nxt_devpoll_oneshot_write(nxt_event_engine_t *engine,
+    nxt_fd_event_t *ev);
+static void nxt_devpoll_change(nxt_event_engine_t *engine, nxt_fd_event_t *ev,
+    nxt_uint_t op, nxt_uint_t events);
+static nxt_int_t nxt_devpoll_commit_changes(nxt_event_engine_t *engine);
+static void nxt_devpoll_change_error(nxt_event_engine_t *engine,
+    nxt_fd_event_t *ev);
+static void nxt_devpoll_remove(nxt_event_engine_t *engine, nxt_fd_t fd);
+static nxt_int_t nxt_devpoll_write(nxt_event_engine_t *engine,
+    struct pollfd *pfd, size_t n);
+static void nxt_devpoll_poll(nxt_event_engine_t *engine,
+    nxt_msec_t timeout);
+
+
+const nxt_event_interface_t  nxt_devpoll_engine = {
+    "devpoll",
+    nxt_devpoll_create,
+    nxt_devpoll_free,
+    nxt_devpoll_enable,
+    nxt_devpoll_disable,
+    nxt_devpoll_disable,
+    nxt_devpoll_close,
+    nxt_devpoll_enable_read,
+    nxt_devpoll_enable_write,
+    nxt_devpoll_disable_read,
+    nxt_devpoll_disable_write,
+    nxt_devpoll_block_read,
+    nxt_devpoll_block_write,
+    nxt_devpoll_oneshot_read,
+    nxt_devpoll_oneshot_write,
+    nxt_devpoll_enable_read,
+    NULL,
+    NULL,
+    NULL,
+    NULL,
+    nxt_devpoll_poll,
+
+    &nxt_unix_event_conn_io,
+
+    NXT_NO_FILE_EVENTS,
+    NXT_NO_SIGNAL_EVENTS,
+};
+
+
+static nxt_int_t
+nxt_devpoll_create(nxt_event_engine_t *engine, nxt_uint_t mchanges,
+    nxt_uint_t mevents)
+{
+    void  *changes;
+
+    engine->u.devpoll.fd = -1;
+    engine->u.devpoll.mchanges = mchanges;
+    engine->u.devpoll.mevents = mevents;
+
+    changes = nxt_malloc(sizeof(nxt_devpoll_change_t) * mchanges);
+    if (changes == NULL) {
+        goto fail;
+    }
+
+    engine->u.devpoll.changes = changes;
+
+    /*
+     * NXT_DEVPOLL_CHANGE requires two struct pollfd's:
+     * for POLLREMOVE and subsequent POLLIN or POLLOUT.
+     */
+    changes = nxt_malloc(2 * sizeof(struct pollfd) * mchanges);
+    if (changes == NULL) {
+        goto fail;
+    }
+
+    engine->u.devpoll.write_changes = changes;
+
+    engine->u.devpoll.events = nxt_malloc(sizeof(struct pollfd) * mevents);
+    if (engine->u.devpoll.events == NULL) {
+        goto fail;
+    }
+
+    engine->u.devpoll.fd = open("/dev/poll", O_RDWR);
+
+    if (engine->u.devpoll.fd == -1) {
+        nxt_log(&engine->task, NXT_LOG_CRIT, "open(\"/dev/poll\") failed %E",
+                nxt_errno);
+        goto fail;
+    }
+
+    nxt_debug(&engine->task, "open(\"/dev/poll\"): %d", engine->u.devpoll.fd);
+
+    return NXT_OK;
+
+fail:
+
+    nxt_devpoll_free(engine);
+
+    return NXT_ERROR;
+}
+
+
+static void
+nxt_devpoll_free(nxt_event_engine_t *engine)
+{
+    nxt_fd_t  fd;
+
+    fd = engine->u.devpoll.fd;
+
+    nxt_debug(&engine->task, "devpoll %d free", fd);
+
+    if (fd != -1 &&close(fd) != 0) {
+        nxt_log(&engine->task, NXT_LOG_CRIT, "devpoll close(%d) failed %E",
+                fd, nxt_errno);
+    }
+
+    nxt_free(engine->u.devpoll.events);
+    nxt_free(engine->u.devpoll.write_changes);
+    nxt_free(engine->u.devpoll.changes);
+    nxt_fd_event_hash_destroy(&engine->u.devpoll.fd_hash);
+
+    nxt_memzero(&engine->u.devpoll, sizeof(nxt_devpoll_engine_t));
+}
+
+
+static void
+nxt_devpoll_enable(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    ev->read = NXT_EVENT_ACTIVE;
+    ev->write = NXT_EVENT_ACTIVE;
+
+    nxt_devpoll_change(engine, ev, NXT_DEVPOLL_ADD, POLLIN | POLLOUT);
+}
+
+
+static void
+nxt_devpoll_disable(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    if (ev->read != NXT_EVENT_INACTIVE || ev->write != NXT_EVENT_INACTIVE) {
+
+        ev->read = NXT_EVENT_INACTIVE;
+        ev->write = NXT_EVENT_INACTIVE;
+
+        nxt_devpoll_change(engine, ev, NXT_DEVPOLL_DELETE, POLLREMOVE);
+    }
+}
+
+
+/*
+ * Solaris does not automatically remove a closed file descriptor from
+ * a "/dev/poll" set: ioctl(DP_ISPOLLED) for the descriptor returns 1,
+ * significative of active descriptor.  POLLREMOVE can remove already
+ * closed file descriptor, so the removal can be batched, Solaris poll(7d):
+ *
+ *   When using the "/dev/poll" driver, you should remove a closed file
+ *   descriptor from a monitored poll set.  Failure to do so may result
+ *   in a POLLNVAL revents being returned for the closed file descriptor.
+ *   When a file descriptor is closed but not removed from the monitored
+ *   set, and is reused in subsequent open of a different device, you
+ *   will be polling the device associated with the reused file descriptor.
+ *   In a multithreaded application, careful coordination among threads
+ *   doing close and DP_POLL ioctl is recommended for consistent results.
+ *
+ * Besides Solaris and HP-UX allow to add invalid descriptors to an
+ * "/dev/poll" set, although the descriptors are not marked as polled,
+ * that is, ioctl(DP_ISPOLLED) returns 0.
+ *
+ * HP-UX poll(7):
+ *
+ *   When a polled file descriptor is closed, it is automatically
+ *   deregistered.
+ */
+
+static nxt_bool_t
+nxt_devpoll_close(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    nxt_devpoll_disable(engine, ev);
+
+    return ev->changing;
+}
+
+
+/*
+ * Solaris poll(7d):
+ *
+ *   The fd field specifies the file descriptor being polled.  The events
+ *   field indicates the interested poll events on the file descriptor.
+ *   If a pollfd array contains multiple pollfd entries with the same fd field,
+ *   the "events" field in each pollfd entry is OR'ed.  A special POLLREMOVE
+ *   event in the events field of the pollfd structure removes the fd from
+ *   the monitored set. The revents field is not used.
+ */
+
+static void
+nxt_devpoll_enable_read(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    nxt_uint_t  op, events;
+
+    if (ev->read != NXT_EVENT_BLOCKED) {
+
+        events = POLLIN;
+
+        if (ev->write == NXT_EVENT_INACTIVE) {
+            op = NXT_DEVPOLL_ADD;
+
+        } else if (ev->write == NXT_EVENT_BLOCKED) {
+            ev->write = NXT_EVENT_INACTIVE;
+            op = NXT_DEVPOLL_CHANGE;
+
+        } else {
+            op = NXT_DEVPOLL_UPDATE;
+            events = POLLIN | POLLOUT;
+        }
+
+        nxt_devpoll_change(engine, ev, op, events);
+    }
+
+    ev->read = NXT_EVENT_ACTIVE;
+}
+
+
+static void
+nxt_devpoll_enable_write(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    nxt_uint_t  op, events;
+
+    if (ev->write != NXT_EVENT_BLOCKED) {
+
+        events = POLLOUT;
+
+        if (ev->read == NXT_EVENT_INACTIVE) {
+            op = NXT_DEVPOLL_ADD;
+
+        } else if (ev->read == NXT_EVENT_BLOCKED) {
+            ev->read = NXT_EVENT_INACTIVE;
+            op = NXT_DEVPOLL_CHANGE;
+
+        } else {
+            op = NXT_DEVPOLL_UPDATE;
+            events = POLLIN | POLLOUT;
+        }
+
+        nxt_devpoll_change(engine, ev, op, events);
+    }
+
+    ev->write = NXT_EVENT_ACTIVE;
+}
+
+
+static void
+nxt_devpoll_disable_read(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    nxt_uint_t  op, events;
+
+    ev->read = NXT_EVENT_INACTIVE;
+
+    if (ev->write <= NXT_EVENT_BLOCKED) {
+        ev->write = NXT_EVENT_INACTIVE;
+        op = NXT_DEVPOLL_DELETE;
+        events = POLLREMOVE;
+
+    } else {
+        op = NXT_DEVPOLL_CHANGE;
+        events = POLLOUT;
+    }
+
+    nxt_devpoll_change(engine, ev, op, events);
+}
+
+
+static void
+nxt_devpoll_disable_write(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    nxt_uint_t  op, events;
+
+    ev->write = NXT_EVENT_INACTIVE;
+
+    if (ev->read <= NXT_EVENT_BLOCKED) {
+        ev->read = NXT_EVENT_INACTIVE;
+        op = NXT_DEVPOLL_DELETE;
+        events = POLLREMOVE;
+
+    } else {
+        op = NXT_DEVPOLL_CHANGE;
+        events = POLLIN;
+    }
+
+    nxt_devpoll_change(engine, ev, op, events);
+}
+
+
+static void
+nxt_devpoll_block_read(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    if (ev->read != NXT_EVENT_INACTIVE) {
+        ev->read = NXT_EVENT_BLOCKED;
+    }
+}
+
+
+static void
+nxt_devpoll_block_write(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    if (ev->write != NXT_EVENT_INACTIVE) {
+        ev->write = NXT_EVENT_BLOCKED;
+    }
+}
+
+
+static void
+nxt_devpoll_oneshot_read(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    nxt_devpoll_enable_read(engine, ev);
+
+    ev->read = NXT_EVENT_ONESHOT;
+}
+
+
+static void
+nxt_devpoll_oneshot_write(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    nxt_devpoll_enable_write(engine, ev);
+
+    ev->write = NXT_EVENT_ONESHOT;
+}
+
+
+static void
+nxt_devpoll_change(nxt_event_engine_t *engine, nxt_fd_event_t *ev,
+    nxt_uint_t op, nxt_uint_t events)
+{
+    nxt_devpoll_change_t  *change;
+
+    nxt_debug(ev->task, "devpoll %d change fd:%d op:%ui ev:%04Xi",
+              engine->u.devpoll.fd, ev->fd, op, events);
+
+    if (engine->u.devpoll.nchanges >= engine->u.devpoll.mchanges) {
+        (void) nxt_devpoll_commit_changes(engine);
+    }
+
+    ev->changing = 1;
+
+    change = &engine->u.devpoll.changes[engine->u.devpoll.nchanges++];
+    change->op = op;
+    change->events = events;
+    change->event = ev;
+}
+
+
+static nxt_int_t
+nxt_devpoll_commit_changes(nxt_event_engine_t *engine)
+{
+    size_t                n;
+    nxt_int_t             ret, retval;
+    struct pollfd         *pfd, *write_changes;
+    nxt_fd_event_t        *ev;
+    nxt_devpoll_change_t  *change, *end;
+
+    nxt_debug(&engine->task, "devpoll %d changes:%ui",
+              engine->u.devpoll.fd, engine->u.devpoll.nchanges);
+
+    retval = NXT_OK;
+    n = 0;
+    write_changes = engine->u.devpoll.write_changes;
+    change = engine->u.devpoll.changes;
+    end = change + engine->u.devpoll.nchanges;
+
+    do {
+        ev = change->event;
+
+        nxt_debug(&engine->task, "devpoll fd:%d op:%d ev:%04Xd",
+                  ev->fd, change->op, change->events);
+
+        if (change->op == NXT_DEVPOLL_CHANGE) {
+            pfd = &write_changes[n++];
+            pfd->fd = ev->fd;
+            pfd->events = POLLREMOVE;
+            pfd->revents = 0;
+        }
+
+        pfd = &write_changes[n++];
+        pfd->fd = ev->fd;
+        pfd->events = change->events;
+        pfd->revents = 0;
+
+        ev->changing = 0;
+
+        change++;
+
+    } while (change < end);
+
+    change = engine->u.devpoll.changes;
+    end = change + engine->u.devpoll.nchanges;
+
+    ret = nxt_devpoll_write(engine, write_changes, n);
+
+    if (nxt_slow_path(ret != NXT_OK)) {
+
+        do {
+            nxt_devpoll_change_error(engine, change->event);
+            change++;
+        } while (change < end);
+
+        engine->u.devpoll.nchanges = 0;
+
+        return NXT_ERROR;
+    }
+
+    do {
+        ev = change->event;
+
+        if (change->op == NXT_DEVPOLL_ADD) {
+            ret = nxt_fd_event_hash_add(&engine->u.devpoll.fd_hash, ev->fd, ev);
+
+            if (nxt_slow_path(ret != NXT_OK)) {
+                nxt_devpoll_change_error(engine, ev);
+                retval = NXT_ERROR;
+            }
+
+        } else if (change->op == NXT_DEVPOLL_DELETE) {
+            nxt_fd_event_hash_delete(&engine->task, &engine->u.devpoll.fd_hash,
+                                     ev->fd, 0);
+        }
+
+        /* Nothing tp do for NXT_DEVPOLL_UPDATE and NXT_DEVPOLL_CHANGE. */
+
+        change++;
+
+    } while (change < end);
+
+    engine->u.devpoll.nchanges = 0;
+
+    return retval;
+}
+
+
+static void
+nxt_devpoll_change_error(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
+{
+    ev->read = NXT_EVENT_INACTIVE;
+    ev->write = NXT_EVENT_INACTIVE;
+
+    nxt_work_queue_add(&engine->fast_work_queue, ev->error_handler,
+                       ev->task, ev, ev->data);
+
+    nxt_fd_event_hash_delete(ev->task, &engine->u.devpoll.fd_hash, ev->fd, 1);
+
+    nxt_devpoll_remove(engine, ev->fd);
+}
+
+
+static void
+nxt_devpoll_remove(nxt_event_engine_t *engine, nxt_fd_t fd)
+{
+    int            n;
+    struct pollfd  pfd;
+
+    pfd.fd = fd;
+    pfd.events = 0;
+    pfd.revents = 0;
+
+    n = ioctl(engine->u.devpoll.fd, DP_ISPOLLED, &pfd);
+
+    nxt_debug(&engine->task, "ioctl(%d, DP_ISPOLLED, %d): %d",
+              engine->u.devpoll.fd, fd, n);
+
+    if (n == 0) {
+        /* The file descriptor is not in the set. */
+        return;
+    }
+
+    if (n == -1) {
+        nxt_log(&engine->task, NXT_LOG_CRIT,
+                "ioctl(%d, DP_ISPOLLED, %d) failed %E",
+                engine->u.devpoll.fd, fd, nxt_errno);
+        /* Fall through. */
+    }
+
+    /* n == 1: the file descriptor is in the set. */
+
+    nxt_debug(&engine->task, "devpoll %d remove fd:%d",
+              engine->u.devpoll.fd, fd);
+
+    pfd.fd = fd;
+    pfd.events = POLLREMOVE;
+    pfd.revents = 0;
+
+    nxt_devpoll_write(engine, &pfd, 1);
+}
+
+
+static nxt_int_t
+nxt_devpoll_write(nxt_event_engine_t *engine, struct pollfd *pfd, size_t n)
+{
+    int  fd;
+
+    fd = engine->u.devpoll.fd;
+
+    nxt_debug(&engine->task, "devpoll write(%d) changes:%uz", fd, n);
+
+    n *= sizeof(struct pollfd);
+
+    if (nxt_slow_path(write(fd, pfd, n) == (ssize_t) n)) {
+        return NXT_OK;
+    }
+
+    nxt_log(&engine->task, NXT_LOG_CRIT, "devpoll write(%d) failed %E",
+            fd, nxt_errno);
+
+    return NXT_ERROR;
+}
+
+
+static void
+nxt_devpoll_poll(nxt_event_engine_t *engine, nxt_msec_t timeout)
+{
+    int             nevents;
+    nxt_fd_t        fd;
+    nxt_int_t       i;
+    nxt_err_t       err;
+    nxt_uint_t      events, level;
+    struct dvpoll   dvp;
+    struct pollfd   *pfd;
+    nxt_fd_event_t  *ev;
+
+    if (engine->u.devpoll.nchanges != 0) {
+        if (nxt_devpoll_commit_changes(engine) != NXT_OK) {
+            /* Error handlers have been enqueued on failure. */
+            timeout = 0;
+        }
+    }
+
+    nxt_debug(&engine->task, "ioctl(%d, DP_POLL) timeout:%M",
+              engine->u.devpoll.fd, timeout);
+
+    dvp.dp_fds = engine->u.devpoll.events;
+    dvp.dp_nfds = engine->u.devpoll.mevents;
+    dvp.dp_timeout = timeout;
+
+    nevents = ioctl(engine->u.devpoll.fd, DP_POLL, &dvp);
+
+    err = (nevents == -1) ? nxt_errno : 0;
+
+    nxt_thread_time_update(engine->task.thread);
+
+    nxt_debug(&engine->task, "ioctl(%d, DP_POLL): %d",
+              engine->u.devpoll.fd, nevents);
+
+    if (nevents == -1) {
+        level = (err == NXT_EINTR) ? NXT_LOG_INFO : NXT_LOG_CRIT;
+
+        nxt_log(&engine->task, level, "ioctl(%d, DP_POLL) failed %E",
+                engine->u.devpoll.fd, err);
+
+        return;
+    }
+
+    for (i = 0; i < nevents; i++) {
+
+        pfd = &engine->u.devpoll.events[i];
+        fd = pfd->fd;
+        events = pfd->revents;
+
+        ev = nxt_fd_event_hash_get(&engine->task, &engine->u.devpoll.fd_hash,
+                                   fd);
+
+        if (nxt_slow_path(ev == NULL)) {
+            nxt_log(&engine->task, NXT_LOG_CRIT,
+                    "ioctl(%d, DP_POLL) returned invalid "
+                    "fd:%d ev:%04Xd rev:%04uXi",
+                    engine->u.devpoll.fd, fd, pfd->events, events);
+
+            nxt_devpoll_remove(engine, fd);
+            continue;
+        }
+
+        nxt_debug(ev->task, "devpoll: fd:%d ev:%04uXi rd:%d wr:%d",
+                  fd, events, ev->read, ev->write);
+
+        if (nxt_slow_path(events & (POLLERR | POLLHUP | POLLNVAL)) != 0) {
+            nxt_log(ev->task, NXT_LOG_CRIT,
+                    "ioctl(%d, DP_POLL) error fd:%d ev:%04Xd rev:%04uXi",
+                    engine->u.devpoll.fd, fd, pfd->events, events);
+
+            nxt_work_queue_add(&engine->fast_work_queue, ev->error_handler,
+                               ev->task, ev, ev->data);
+            continue;
+        }
+
+        if (events & POLLIN) {
+            ev->read_ready = 1;
+
+            if (ev->read != NXT_EVENT_BLOCKED) {
+                nxt_work_queue_add(ev->read_work_queue, ev->read_handler,
+                                   ev->task, ev, ev->data);
+            }
+
+            if (ev->read == NXT_EVENT_BLOCKED
+                || ev->read == NXT_EVENT_ONESHOT)
+            {
+                nxt_devpoll_disable_read(engine, ev);
+            }
+        }
+
+        if (events & POLLOUT) {
+            ev->write_ready = 1;
+
+            if (ev->write != NXT_EVENT_BLOCKED) {
+                nxt_work_queue_add(ev->write_work_queue, ev->write_handler,
+                                   ev->task, ev, ev->data);
+            }
+
+            if (ev->write == NXT_EVENT_BLOCKED
+                || ev->write == NXT_EVENT_ONESHOT)
+            {
+                nxt_devpoll_disable_write(engine, ev);
+            }
+        }
+    }
+}