--- /dev/null
+/* ae.c module for illumos event ports.
+ * Copyright (c) 2012, Joyent, Inc. All rights reserved.
+ * Released under the BSD license. See the COPYING file for more info. */
+
+#include <assert.h>
+#include <errno.h>
+#include <port.h>
+#include <poll.h>
+
+#include <sys/types.h>
+#include <sys/time.h>
+
+#include <stdio.h>
+
+int evport_debug = 0;
+
+/*
+ * This file implements the ae API using event ports, present on Solaris-based
+ * systems since Solaris 10. Using the event port interface, we associate file
+ * descriptors with the port. Each association also includes the set of poll(2)
+ * events that the consumer is interested in (e.g., POLLIN and POLLOUT).
+ *
+ * There's one tricky piece to this implementation: when we return events via
+ * aeApiPoll, the corresponding file descriptor becomes dissociated from the
+ * port. This is necessary because poll events are level-triggered, so if the
+ * fd didn't become dissociated, it would immediately fire another event since
+ * the underlying state hasn't changed yet. We must reassociate the file
+ * descriptor, but only after we know that our caller has actually read from it.
+ * The ae API does not tell us exactly when that happens, but we do know that
+ * it must happen by the time aeApiPoll is called again. Our solution is to
+ * keep track of the last fd returned by aeApiPoll and reassociate it next time
+ * aeApiPoll is invoked.
+ *
+ * To summarize, in this module, each fd association is EITHER (a) represented
+ * only via the in-kernel assocation OR (b) represented by pending_fd and
+ * pending_mask. (b) is only true for the last fd we returned from aeApiPoll,
+ * and only until we enter aeApiPoll again (at which point we restore the
+ * in-kernel association).
+ *
+ * We currently only return one fd event per call to aeApiPoll. This could be
+ * extended to return more than one by extending the corresponding pending
+ * fields and using port_getn().
+ */
+typedef struct aeApiState {
+ int portfd; /* event port */
+ int pending_fd; /* pending fd */
+ int pending_mask; /* pending fd's mask */
+} aeApiState;
+
+static int aeApiCreate(aeEventLoop *eventLoop) {
+ aeApiState *state = zmalloc(sizeof(aeApiState));
+ if (!state) return -1;
+
+ state->portfd = port_create();
+ if (state->portfd == -1) {
+ zfree(state);
+ return -1;
+ }
+
+ state->pending_fd = -1;
+ state->pending_mask = AE_NONE;
+
+ eventLoop->apidata = state;
+ return 0;
+}
+
+static void aeApiFree(aeEventLoop *eventLoop) {
+ aeApiState *state = eventLoop->apidata;
+
+ close(state->portfd);
+ zfree(state);
+}
+
+/*
+ * Helper function to invoke port_associate for the given fd and mask.
+ */
+static int aeApiAssociate(const char *where, int portfd, int fd, int mask)
+{
+ int events = 0;
+ int rv, err;
+
+ if (mask & AE_READABLE)
+ events |= POLLIN;
+ if (mask & AE_WRITABLE)
+ events |= POLLOUT;
+
+ if (evport_debug)
+ fprintf(stderr, "%s: port_associate(%d, 0x%x) = ", where, fd, events);
+
+ rv = port_associate(portfd, PORT_SOURCE_FD, fd, events, (void *)mask);
+ err = errno;
+
+ if (evport_debug)
+ fprintf(stderr, "%d (%s)\n", rv, rv == 0 ? "no error" : strerror(err));
+
+ if (rv == -1) {
+ fprintf(stderr, "%s: port_associate: %s\n", where, strerror(err));
+
+ if (err == EAGAIN)
+ fprintf(stderr, "aeApiAssociate: event port limit exceeded.");
+ }
+
+ return rv;
+}
+
+static int aeApiAddEvent(aeEventLoop *eventLoop, int fd, int mask) {
+ aeApiState *state = eventLoop->apidata;
+ int fullmask;
+
+ if (evport_debug)
+ fprintf(stderr, "aeApiAddEvent: fd %d mask 0x%x\n", fd, mask);
+
+ /*
+ * Since port_associate's "events" argument replaces any existing events, we
+ * must be sure to include whatever events are already associated when
+ * we call port_associate() again.
+ */
+ fullmask = mask | eventLoop->events[fd].mask;
+
+ if (fd == state->pending_fd) {
+ /*
+ * This fd was recently returned from aeApiPoll. It should be safe to
+ * assume that the consumer has processed that poll event, but we play
+ * it safer by simply updating pending_mask. The fd will be
+ * reassociated as usual when aeApiPoll is called again.
+ */
+ if (evport_debug)
+ fprintf(stderr, "aeApiAddEvent: adding to pending fd %d\n", fd);
+ state->pending_mask |= fullmask;
+ return 0;
+ }
+
+ return (aeApiAssociate("aeApiAddEvent", state->portfd, fd, fullmask));
+}
+
+static void aeApiDelEvent(aeEventLoop *eventLoop, int fd, int mask) {
+ aeApiState *state = eventLoop->apidata;
+ int fullmask;
+
+ if (evport_debug)
+ fprintf(stderr, "del fd %d mask 0x%x\n", fd, mask);
+
+ if (fd == state->pending_fd) {
+ if (evport_debug)
+ fprintf(stderr, "deleting event from pending fd %d\n", fd);
+
+ /*
+ * This fd was just returned from aeApiPoll, so it's not currently
+ * associated with the port. All we need to do is update
+ * pending_mask appropriately.
+ */
+ state->pending_mask &= ~mask;
+
+ if (state->pending_mask == AE_NONE)
+ state->pending_fd = -1;
+
+ return;
+ }
+
+ /*
+ * The fd is currently associated with the port. Like with the add case
+ * above, we must look at the full mask for the file descriptor before
+ * updating that association. We don't have a good way of knowing what the
+ * events are without looking into the eventLoop state directly. We rely on
+ * the fact that our caller has already updated the mask in the eventLoop.
+ */
+
+ fullmask = eventLoop->events[fd].mask;
+ if (fullmask == AE_NONE) {
+ /*
+ * We're removing *all* events, so use port_dissociate to remove the
+ * association completely. Failure here indicates a bug.
+ */
+ if (evport_debug)
+ fprintf(stderr, "aeApiDelEvent: port_dissociate(%d)\n", fd);
+
+ if (port_dissociate(state->portfd, PORT_SOURCE_FD, fd) != 0) {
+ perror("aeApiDelEvent: port_dissociate");
+ abort(); /* will not return */
+ }
+ } else if (aeApiAssociate("aeApiDelEvent", state->portfd, fd,
+ fullmask) != 0) {
+ /*
+ * ENOMEM is a potentially transient condition, but the kernel won't
+ * generally return it unless things are really bad. EAGAIN indicates
+ * we've reached an resource limit, for which it doesn't make sense to
+ * retry (counterintuitively). All other errors indicate a bug. In any
+ * of these cases, the best we can do is to abort.
+ */
+ abort(); /* will not return */
+ }
+}
+
+static int aeApiPoll(aeEventLoop *eventLoop, struct timeval *tvp) {
+ aeApiState *state = eventLoop->apidata;
+ struct timespec timeout, *tsp;
+ int mask;
+ port_event_t event;
+
+ /*
+ * If we've returned an fd event before, we must reassociated that fd with
+ * the port now, before calling port_get(). See the block comment at the
+ * top of this file for an explanation of why.
+ */
+ if (state->pending_mask != AE_NONE) {
+ if (aeApiAssociate("aeApiPoll", state->portfd, state->pending_fd,
+ state->pending_mask) != 0) {
+ /* See aeApiDelEvent for why this case is fatal. */
+ abort();
+ }
+
+ state->pending_mask = AE_NONE;
+ state->pending_fd = -1;
+ }
+
+ if (tvp != NULL) {
+ timeout.tv_sec = tvp->tv_sec;
+ timeout.tv_nsec = tvp->tv_usec * 1000;
+ tsp = &timeout;
+ } else {
+ tsp = NULL;
+ }
+
+ if (port_get(state->portfd, &event, tsp) == -1) {
+ if (errno == ETIME || errno == EINTR)
+ return 0;
+
+ /* Any other error indicates a bug. */
+ perror("aeApiPoll: port_get");
+ abort();
+ }
+
+ mask = 0;
+ if (event.portev_events & POLLIN)
+ mask |= AE_READABLE;
+ if (event.portev_events & POLLOUT)
+ mask |= AE_WRITABLE;
+
+ eventLoop->fired[0].fd = event.portev_object;
+ eventLoop->fired[0].mask = mask;
+
+ if (evport_debug)
+ fprintf(stderr, "aeApiPoll: fd %d mask 0x%x\n", event.portev_object,
+ mask);
+
+ state->pending_fd = event.portev_object;
+ state->pending_mask = (uintptr_t)event.portev_user;
+
+ return 1;
+}
+
+static char *aeApiName(void) {
+ return "evport";
+}
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