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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-14 13:40:54 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-14 13:40:54 +0000 |
commit | 317c0644ccf108aa23ef3fd8358bd66c2840bfc0 (patch) | |
tree | c417b3d25c86b775989cb5ac042f37611b626c8a /src/ae_evport.c | |
parent | Initial commit. (diff) | |
download | redis-upstream/5%7.2.4.tar.xz redis-upstream/5%7.2.4.zip |
Adding upstream version 5:7.2.4.upstream/5%7.2.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/ae_evport.c | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/src/ae_evport.c b/src/ae_evport.c new file mode 100644 index 0000000..55393e9 --- /dev/null +++ b/src/ae_evport.c @@ -0,0 +1,321 @@ +/* ae.c module for illumos event ports. + * + * Copyright (c) 2012, Joyent, Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * * Neither the name of Redis nor the names of its contributors may be used + * to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + + +#include <errno.h> +#include <port.h> +#include <poll.h> + +#include <sys/types.h> +#include <sys/time.h> + +#include <stdio.h> + +static 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 descriptors become 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 re-associate 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 fds returned by aeApiPoll and re-associate them next + * time aeApiPoll is invoked. + * + * To summarize, in this module, each fd association is EITHER (a) represented + * only via the in-kernel association OR (b) represented by pending_fds and + * pending_masks. (b) is only true for the last fds we returned from aeApiPoll, + * and only until we enter aeApiPoll again (at which point we restore the + * in-kernel association). + */ +#define MAX_EVENT_BATCHSZ 512 + +typedef struct aeApiState { + int portfd; /* event port */ + uint_t npending; /* # of pending fds */ + int pending_fds[MAX_EVENT_BATCHSZ]; /* pending fds */ + int pending_masks[MAX_EVENT_BATCHSZ]; /* pending fds' masks */ +} aeApiState; + +static int aeApiCreate(aeEventLoop *eventLoop) { + int i; + aeApiState *state = zmalloc(sizeof(aeApiState)); + if (!state) return -1; + + state->portfd = port_create(); + if (state->portfd == -1) { + zfree(state); + return -1; + } + anetCloexec(state->portfd); + + state->npending = 0; + + for (i = 0; i < MAX_EVENT_BATCHSZ; i++) { + state->pending_fds[i] = -1; + state->pending_masks[i] = AE_NONE; + } + + eventLoop->apidata = state; + return 0; +} + +static int aeApiResize(aeEventLoop *eventLoop, int setsize) { + (void) eventLoop; + (void) setsize; + /* Nothing to resize here. */ + return 0; +} + +static void aeApiFree(aeEventLoop *eventLoop) { + aeApiState *state = eventLoop->apidata; + + close(state->portfd); + zfree(state); +} + +static int aeApiLookupPending(aeApiState *state, int fd) { + uint_t i; + + for (i = 0; i < state->npending; i++) { + if (state->pending_fds[i] == fd) + return (i); + } + + return (-1); +} + +/* + * 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 *)(uintptr_t)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, pfd; + + 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; + pfd = aeApiLookupPending(state, fd); + + if (pfd != -1) { + /* + * 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 + * re-associated as usual when aeApiPoll is called again. + */ + if (evport_debug) + fprintf(stderr, "aeApiAddEvent: adding to pending fd %d\n", fd); + state->pending_masks[pfd] |= 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, pfd; + + if (evport_debug) + fprintf(stderr, "del fd %d mask 0x%x\n", fd, mask); + + pfd = aeApiLookupPending(state, fd); + + if (pfd != -1) { + 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_masks[pfd] &= ~mask; + + if (state->pending_masks[pfd] == AE_NONE) + state->pending_fds[pfd] = -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 a resource limit, for which it doesn't make sense to + * retry (counter-intuitively). 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; + uint_t mask, i; + uint_t nevents; + port_event_t event[MAX_EVENT_BATCHSZ]; + + /* + * If we've returned fd events before, we must re-associate them with the + * port now, before calling port_get(). See the block comment at the top of + * this file for an explanation of why. + */ + for (i = 0; i < state->npending; i++) { + if (state->pending_fds[i] == -1) + /* This fd has since been deleted. */ + continue; + + if (aeApiAssociate("aeApiPoll", state->portfd, + state->pending_fds[i], state->pending_masks[i]) != 0) { + /* See aeApiDelEvent for why this case is fatal. */ + abort(); + } + + state->pending_masks[i] = AE_NONE; + state->pending_fds[i] = -1; + } + + state->npending = 0; + + if (tvp != NULL) { + timeout.tv_sec = tvp->tv_sec; + timeout.tv_nsec = tvp->tv_usec * 1000; + tsp = &timeout; + } else { + tsp = NULL; + } + + /* + * port_getn can return with errno == ETIME having returned some events (!). + * So if we get ETIME, we check nevents, too. + */ + nevents = 1; + if (port_getn(state->portfd, event, MAX_EVENT_BATCHSZ, &nevents, + tsp) == -1 && (errno != ETIME || nevents == 0)) { + if (errno == ETIME || errno == EINTR) + return 0; + + /* Any other error indicates a bug. */ + panic("aeApiPoll: port_getn, %s", strerror(errno)); + } + + state->npending = nevents; + + for (i = 0; i < nevents; i++) { + mask = 0; + if (event[i].portev_events & POLLIN) + mask |= AE_READABLE; + if (event[i].portev_events & POLLOUT) + mask |= AE_WRITABLE; + + eventLoop->fired[i].fd = event[i].portev_object; + eventLoop->fired[i].mask = mask; + + if (evport_debug) + fprintf(stderr, "aeApiPoll: fd %d mask 0x%x\n", + (int)event[i].portev_object, mask); + + state->pending_fds[i] = event[i].portev_object; + state->pending_masks[i] = (uintptr_t)event[i].portev_user; + } + + return nevents; +} + +static char *aeApiName(void) { + return "evport"; +} |