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/*
*
* Copyright 2015, Google 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 Google Inc. 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 <grpc/support/port_platform.h>
#ifdef GPR_POSIX_SOCKET
#include "src/core/iomgr/pollset_posix.h"
#include <errno.h>
#include <poll.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "src/core/iomgr/alarm_internal.h"
#include "src/core/iomgr/fd_posix.h"
#include "src/core/iomgr/iomgr_internal.h"
#include "src/core/iomgr/socket_utils_posix.h"
#include "src/core/profiling/timers.h"
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/thd.h>
#include <grpc/support/tls.h>
#include <grpc/support/useful.h>
static grpc_pollset g_backup_pollset;
static int g_shutdown_backup_poller;
static gpr_event g_backup_poller_done;
static gpr_event g_backup_pollset_shutdown_done;
GPR_TLS_DECL(g_current_thread_poller);
static void backup_poller(void *p) {
gpr_timespec delta = gpr_time_from_millis(100);
gpr_timespec last_poll = gpr_now();
gpr_mu_lock(&g_backup_pollset.mu);
while (g_shutdown_backup_poller == 0) {
gpr_timespec next_poll = gpr_time_add(last_poll, delta);
grpc_pollset_work(&g_backup_pollset, gpr_time_add(gpr_now(), gpr_time_from_seconds(1)));
gpr_mu_unlock(&g_backup_pollset.mu);
gpr_sleep_until(next_poll);
gpr_mu_lock(&g_backup_pollset.mu);
last_poll = next_poll;
}
gpr_mu_unlock(&g_backup_pollset.mu);
gpr_event_set(&g_backup_poller_done, (void *)1);
}
void grpc_pollset_kick(grpc_pollset *p) {
if (gpr_tls_get(&g_current_thread_poller) != (gpr_intptr)p && p->counter) {
p->vtable->kick(p);
}
}
void grpc_pollset_force_kick(grpc_pollset *p) {
if (gpr_tls_get(&g_current_thread_poller) != (gpr_intptr)p) {
grpc_pollset_kick_kick(&p->kick_state);
}
}
static void kick_using_pollset_kick(grpc_pollset *p) {
if (gpr_tls_get(&g_current_thread_poller) != (gpr_intptr)p) {
grpc_pollset_kick_kick(&p->kick_state);
}
}
/* global state management */
grpc_pollset *grpc_backup_pollset(void) { return &g_backup_pollset; }
void grpc_pollset_global_init(void) {
gpr_thd_id id;
gpr_tls_init(&g_current_thread_poller);
/* Initialize kick fd state */
grpc_pollset_kick_global_init();
/* initialize the backup pollset */
grpc_pollset_init(&g_backup_pollset);
/* start the backup poller thread */
g_shutdown_backup_poller = 0;
gpr_event_init(&g_backup_poller_done);
gpr_event_init(&g_backup_pollset_shutdown_done);
gpr_thd_new(&id, backup_poller, NULL, NULL);
}
static void on_backup_pollset_shutdown_done(void *arg) {
gpr_event_set(&g_backup_pollset_shutdown_done, (void *)1);
}
void grpc_pollset_global_shutdown(void) {
/* terminate the backup poller thread */
gpr_mu_lock(&g_backup_pollset.mu);
g_shutdown_backup_poller = 1;
gpr_mu_unlock(&g_backup_pollset.mu);
gpr_event_wait(&g_backup_poller_done, gpr_inf_future);
grpc_pollset_shutdown(&g_backup_pollset, on_backup_pollset_shutdown_done,
NULL);
gpr_event_wait(&g_backup_pollset_shutdown_done, gpr_inf_future);
/* destroy the backup pollset */
grpc_pollset_destroy(&g_backup_pollset);
/* destroy the kick pipes */
grpc_pollset_kick_global_destroy();
gpr_tls_destroy(&g_current_thread_poller);
}
/* main interface */
static void become_empty_pollset(grpc_pollset *pollset);
static void become_unary_pollset(grpc_pollset *pollset, grpc_fd *fd);
void grpc_pollset_init(grpc_pollset *pollset) {
gpr_mu_init(&pollset->mu);
gpr_cv_init(&pollset->cv);
grpc_pollset_kick_init(&pollset->kick_state);
pollset->in_flight_cbs = 0;
pollset->shutting_down = 0;
become_empty_pollset(pollset);
}
void grpc_pollset_add_fd(grpc_pollset *pollset, grpc_fd *fd) {
gpr_mu_lock(&pollset->mu);
pollset->vtable->add_fd(pollset, fd);
gpr_cv_broadcast(&pollset->cv);
gpr_mu_unlock(&pollset->mu);
}
void grpc_pollset_del_fd(grpc_pollset *pollset, grpc_fd *fd) {
gpr_mu_lock(&pollset->mu);
pollset->vtable->del_fd(pollset, fd);
gpr_cv_broadcast(&pollset->cv);
gpr_mu_unlock(&pollset->mu);
}
int grpc_pollset_work(grpc_pollset *pollset, gpr_timespec deadline) {
/* pollset->mu already held */
gpr_timespec now = gpr_now();
/* FIXME(ctiller): see below */
gpr_timespec maximum_deadline = gpr_time_add(now, gpr_time_from_seconds(1));
int r;
if (gpr_time_cmp(now, deadline) > 0) {
return 0;
}
if (grpc_maybe_call_delayed_callbacks(&pollset->mu, 1)) {
return 1;
}
if (grpc_alarm_check(&pollset->mu, now, &deadline)) {
return 1;
}
/* FIXME(ctiller): we should not clamp deadline, however we have some
stuck at shutdown bugs that this resolves */
if (gpr_time_cmp(deadline, maximum_deadline) > 0) {
deadline = maximum_deadline;
}
gpr_tls_set(&g_current_thread_poller, (gpr_intptr)pollset);
r = pollset->vtable->maybe_work(pollset, deadline, now, 1);
gpr_tls_set(&g_current_thread_poller, 0);
return r;
}
void grpc_pollset_shutdown(grpc_pollset *pollset,
void (*shutdown_done)(void *arg),
void *shutdown_done_arg) {
int in_flight_cbs;
gpr_mu_lock(&pollset->mu);
pollset->shutting_down = 1;
in_flight_cbs = pollset->in_flight_cbs;
pollset->shutdown_done_cb = shutdown_done;
pollset->shutdown_done_arg = shutdown_done_arg;
gpr_mu_unlock(&pollset->mu);
if (in_flight_cbs == 0) {
shutdown_done(shutdown_done_arg);
}
}
void grpc_pollset_destroy(grpc_pollset *pollset) {
GPR_ASSERT(pollset->shutting_down);
GPR_ASSERT(pollset->in_flight_cbs == 0);
pollset->vtable->destroy(pollset);
grpc_pollset_kick_destroy(&pollset->kick_state);
gpr_mu_destroy(&pollset->mu);
gpr_cv_destroy(&pollset->cv);
}
/*
* empty_pollset - a vtable that provides polling for NO file descriptors
*/
static void empty_pollset_add_fd(grpc_pollset *pollset, grpc_fd *fd) {
become_unary_pollset(pollset, fd);
}
static void empty_pollset_del_fd(grpc_pollset *pollset, grpc_fd *fd) {}
static int empty_pollset_maybe_work(grpc_pollset *pollset,
gpr_timespec deadline, gpr_timespec now,
int allow_synchronous_callback) {
return 0;
}
static void empty_pollset_destroy(grpc_pollset *pollset) {}
static const grpc_pollset_vtable empty_pollset = {
empty_pollset_add_fd, empty_pollset_del_fd, empty_pollset_maybe_work,
kick_using_pollset_kick, empty_pollset_destroy};
static void become_empty_pollset(grpc_pollset *pollset) {
pollset->vtable = &empty_pollset;
}
/*
* unary_poll_pollset - a vtable that provides polling for one file descriptor
* via poll()
*/
typedef struct grpc_unary_promote_args {
const grpc_pollset_vtable *original_vtable;
grpc_pollset *pollset;
grpc_fd *fd;
} grpc_unary_promote_args;
static void unary_poll_do_promote(void *args, int success) {
grpc_unary_promote_args *up_args = args;
const grpc_pollset_vtable *original_vtable = up_args->original_vtable;
grpc_pollset *pollset = up_args->pollset;
grpc_fd *fd = up_args->fd;
int do_shutdown_cb = 0;
/*
* This is quite tricky. There are a number of cases to keep in mind here:
* 1. fd may have been orphaned
* 2. The pollset may no longer be a unary poller (and we can't let case #1
* leak to other pollset types!)
* 3. pollset's fd (which may have changed) may have been orphaned
* 4. The pollset may be shutting down.
*/
gpr_mu_lock(&pollset->mu);
/* First we need to ensure that nobody is polling concurrently */
while (pollset->counter != 0) {
grpc_pollset_kick(pollset);
grpc_iomgr_add_callback(unary_poll_do_promote, up_args);
gpr_mu_unlock(&pollset->mu);
return;
}
gpr_free(up_args);
/* At this point the pollset may no longer be a unary poller. In that case
* we should just call the right add function and be done. */
/* TODO(klempner): If we're not careful this could cause infinite recursion.
* That's not a problem for now because empty_pollset has a trivial poller
* and we don't have any mechanism to unbecome multipoller. */
pollset->in_flight_cbs--;
if (pollset->shutting_down) {
/* We don't care about this pollset anymore. */
if (pollset->in_flight_cbs == 0) {
do_shutdown_cb = 1;
}
} else if (grpc_fd_is_orphaned(fd)) {
/* Don't try to add it to anything, we'll drop our ref on it below */
} else if (pollset->vtable != original_vtable) {
pollset->vtable->add_fd(pollset, fd);
} else if (fd != pollset->data.ptr) {
grpc_fd *fds[2];
fds[0] = pollset->data.ptr;
fds[1] = fd;
if (!grpc_fd_is_orphaned(fds[0])) {
grpc_platform_become_multipoller(pollset, fds, GPR_ARRAY_SIZE(fds));
grpc_fd_unref(fds[0]);
} else {
/* old fd is orphaned and we haven't cleaned it up until now, so remain a
* unary poller */
/* Note that it is possible that fds[1] is also orphaned at this point.
* That's okay, we'll correct it at the next add or poll. */
grpc_fd_unref(fds[0]);
pollset->data.ptr = fd;
grpc_fd_ref(fd);
}
}
gpr_cv_broadcast(&pollset->cv);
gpr_mu_unlock(&pollset->mu);
if (do_shutdown_cb) {
pollset->shutdown_done_cb(pollset->shutdown_done_arg);
}
/* Matching ref in unary_poll_pollset_add_fd */
grpc_fd_unref(fd);
}
static void unary_poll_pollset_add_fd(grpc_pollset *pollset, grpc_fd *fd) {
grpc_unary_promote_args *up_args;
if (fd == pollset->data.ptr) return;
if (!pollset->counter) {
/* Fast path -- no in flight cbs */
/* TODO(klempner): Comment this out and fix any test failures or establish
* they are due to timing issues */
grpc_fd *fds[2];
fds[0] = pollset->data.ptr;
fds[1] = fd;
if (!grpc_fd_is_orphaned(fds[0])) {
grpc_platform_become_multipoller(pollset, fds, GPR_ARRAY_SIZE(fds));
grpc_fd_unref(fds[0]);
} else {
/* old fd is orphaned and we haven't cleaned it up until now, so remain a
* unary poller */
grpc_fd_unref(fds[0]);
pollset->data.ptr = fd;
grpc_fd_ref(fd);
}
return;
}
/* Now we need to promote. This needs to happen when we're not polling. Since
* this may be called from poll, the wait needs to happen asynchronously. */
grpc_fd_ref(fd);
pollset->in_flight_cbs++;
up_args = gpr_malloc(sizeof(*up_args));
up_args->pollset = pollset;
up_args->fd = fd;
up_args->original_vtable = pollset->vtable;
grpc_iomgr_add_callback(unary_poll_do_promote, up_args);
grpc_pollset_kick(pollset);
}
static void unary_poll_pollset_del_fd(grpc_pollset *pollset, grpc_fd *fd) {
if (fd == pollset->data.ptr) {
grpc_fd_unref(pollset->data.ptr);
become_empty_pollset(pollset);
}
}
static int unary_poll_pollset_maybe_work(grpc_pollset *pollset,
gpr_timespec deadline,
gpr_timespec now,
int allow_synchronous_callback) {
struct pollfd pfd[2];
grpc_fd *fd;
grpc_fd_watcher fd_watcher;
int timeout;
int r;
if (pollset->counter) {
return 0;
}
if (pollset->in_flight_cbs) {
/* Give do_promote priority so we don't starve it out */
return 0;
}
fd = pollset->data.ptr;
if (grpc_fd_is_orphaned(fd)) {
grpc_fd_unref(fd);
become_empty_pollset(pollset);
return 0;
}
if (gpr_time_cmp(deadline, gpr_inf_future) == 0) {
timeout = -1;
} else {
timeout = gpr_time_to_millis(gpr_time_sub(deadline, now));
if (timeout <= 0) {
return 1;
}
}
pfd[0].fd = grpc_pollset_kick_pre_poll(&pollset->kick_state);
if (pfd[0].fd < 0) {
/* Already kicked */
return 1;
}
pfd[0].events = POLLIN;
pfd[0].revents = 0;
pfd[1].fd = fd->fd;
pfd[1].revents = 0;
pollset->counter = 1;
gpr_mu_unlock(&pollset->mu);
pfd[1].events = grpc_fd_begin_poll(fd, pollset, POLLIN, POLLOUT, &fd_watcher);
r = poll(pfd, GPR_ARRAY_SIZE(pfd), timeout);
GRPC_TIMER_MARK(GRPC_PTAG_POLL_FINISHED, r);
grpc_fd_end_poll(&fd_watcher);
if (r < 0) {
if (errno != EINTR) {
gpr_log(GPR_ERROR, "poll() failed: %s", strerror(errno));
}
} else if (r == 0) {
/* do nothing */
} else {
if (pfd[0].revents & POLLIN) {
grpc_pollset_kick_consume(&pollset->kick_state);
}
if (pfd[1].revents & (POLLIN | POLLHUP | POLLERR)) {
grpc_fd_become_readable(fd, allow_synchronous_callback);
}
if (pfd[1].revents & (POLLOUT | POLLHUP | POLLERR)) {
grpc_fd_become_writable(fd, allow_synchronous_callback);
}
}
grpc_pollset_kick_post_poll(&pollset->kick_state);
gpr_mu_lock(&pollset->mu);
pollset->counter = 0;
gpr_cv_broadcast(&pollset->cv);
return 1;
}
static void unary_poll_pollset_destroy(grpc_pollset *pollset) {
GPR_ASSERT(pollset->counter == 0);
grpc_fd_unref(pollset->data.ptr);
}
static const grpc_pollset_vtable unary_poll_pollset = {
unary_poll_pollset_add_fd, unary_poll_pollset_del_fd,
unary_poll_pollset_maybe_work, kick_using_pollset_kick,
unary_poll_pollset_destroy};
static void become_unary_pollset(grpc_pollset *pollset, grpc_fd *fd) {
pollset->vtable = &unary_poll_pollset;
pollset->counter = 0;
pollset->data.ptr = fd;
grpc_fd_ref(fd);
}
#endif /* GPR_POSIX_POLLSET */
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