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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 "src/core/iomgr/pollset_kick_posix.h"
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include "src/core/iomgr/socket_utils_posix.h"
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
/* This implementation is based on a freelist of pipes. */
#define GRPC_MAX_CACHED_PIPES 50
#define GRPC_PIPE_LOW_WATERMARK 25
typedef struct grpc_kick_pipe_info {
int pipe_read_fd;
int pipe_write_fd;
struct grpc_kick_pipe_info *next;
} grpc_kick_pipe_info;
static grpc_kick_pipe_info *pipe_freelist = NULL;
static int pipe_freelist_count = 0;
static gpr_mu pipe_freelist_mu;
static grpc_kick_pipe_info *allocate_pipe(void) {
grpc_kick_pipe_info *info;
gpr_mu_lock(&pipe_freelist_mu);
if (pipe_freelist != NULL) {
info = pipe_freelist;
pipe_freelist = pipe_freelist->next;
--pipe_freelist_count;
} else {
int pipefd[2];
/* TODO(klempner): Make this nonfatal */
GPR_ASSERT(0 == pipe(pipefd));
GPR_ASSERT(grpc_set_socket_nonblocking(pipefd[0], 1));
GPR_ASSERT(grpc_set_socket_nonblocking(pipefd[1], 1));
info = gpr_malloc(sizeof(*info));
info->pipe_read_fd = pipefd[0];
info->pipe_write_fd = pipefd[1];
info->next = NULL;
}
gpr_mu_unlock(&pipe_freelist_mu);
return info;
}
static void destroy_pipe(void) {
/* assumes pipe_freelist_mu is held */
grpc_kick_pipe_info *current = pipe_freelist;
pipe_freelist = pipe_freelist->next;
pipe_freelist_count--;
close(current->pipe_read_fd);
close(current->pipe_write_fd);
gpr_free(current);
}
static void free_pipe(grpc_kick_pipe_info *pipe_info) {
gpr_mu_lock(&pipe_freelist_mu);
pipe_info->next = pipe_freelist;
pipe_freelist = pipe_info;
pipe_freelist_count++;
if (pipe_freelist_count > GRPC_MAX_CACHED_PIPES) {
while (pipe_freelist_count > GRPC_PIPE_LOW_WATERMARK) {
destroy_pipe();
}
}
gpr_mu_unlock(&pipe_freelist_mu);
}
void grpc_pollset_kick_global_init() {
pipe_freelist = NULL;
gpr_mu_init(&pipe_freelist_mu);
}
void grpc_pollset_kick_global_destroy() {
while (pipe_freelist != NULL) {
destroy_pipe();
}
gpr_mu_destroy(&pipe_freelist_mu);
}
void grpc_pollset_kick_init(grpc_pollset_kick_state *kick_state) {
gpr_mu_init(&kick_state->mu);
kick_state->kicked = 0;
kick_state->pipe_info = NULL;
}
void grpc_pollset_kick_destroy(grpc_pollset_kick_state *kick_state) {
gpr_mu_destroy(&kick_state->mu);
GPR_ASSERT(kick_state->pipe_info == NULL);
}
int grpc_pollset_kick_pre_poll(grpc_pollset_kick_state *kick_state) {
gpr_mu_lock(&kick_state->mu);
if (kick_state->kicked) {
kick_state->kicked = 0;
gpr_mu_unlock(&kick_state->mu);
return -1;
}
kick_state->pipe_info = allocate_pipe();
gpr_mu_unlock(&kick_state->mu);
return kick_state->pipe_info->pipe_read_fd;
}
void grpc_pollset_kick_consume(grpc_pollset_kick_state *kick_state) {
char buf[128];
int r;
for (;;) {
r = read(kick_state->pipe_info->pipe_read_fd, buf, sizeof(buf));
if (r > 0) continue;
if (r == 0) return;
switch (errno) {
case EAGAIN:
return;
case EINTR:
continue;
default:
gpr_log(GPR_ERROR, "error reading pipe: %s", strerror(errno));
return;
}
}
}
void grpc_pollset_kick_post_poll(grpc_pollset_kick_state *kick_state) {
gpr_mu_lock(&kick_state->mu);
free_pipe(kick_state->pipe_info);
kick_state->pipe_info = NULL;
gpr_mu_unlock(&kick_state->mu);
}
void grpc_pollset_kick_kick(grpc_pollset_kick_state *kick_state) {
gpr_mu_lock(&kick_state->mu);
if (kick_state->pipe_info != NULL) {
char c = 0;
while (write(kick_state->pipe_info->pipe_write_fd, &c, 1) != 1 &&
errno == EINTR)
;
} else {
kick_state->kicked = 1;
}
gpr_mu_unlock(&kick_state->mu);
}
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