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/*
*
* Copyright 2017, 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/lib/iomgr/port.h"
#include "src/core/lib/iomgr/is_epollexclusive_available.h"
#ifdef GRPC_LINUX_EPOLL
#include <grpc/support/log.h>
#include <errno.h>
#include <sys/eventfd.h>
#include <unistd.h>
#include "src/core/lib/iomgr/sys_epoll_wrapper.h"
/* This polling engine is only relevant on linux kernels supporting epoll() */
bool grpc_is_epollexclusive_available(void) {
static bool logged_why_not = false;
int fd = epoll_create1(EPOLL_CLOEXEC);
if (fd < 0) {
if (!logged_why_not) {
gpr_log(GPR_ERROR,
"epoll_create1 failed with error: %d. Not using epollex polling "
"engine.",
fd);
logged_why_not = true;
}
return false;
}
int evfd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
if (evfd < 0) {
if (!logged_why_not) {
gpr_log(GPR_ERROR,
"eventfd failed with error: %d. Not using epollex polling "
"engine.",
fd);
logged_why_not = true;
}
close(fd);
return false;
}
struct epoll_event ev = {
/* choose events that should cause an error on
EPOLLEXCLUSIVE enabled kernels - specifically the combination of
EPOLLONESHOT and EPOLLEXCLUSIVE */
.events = (uint32_t)(EPOLLET | EPOLLIN | EPOLLEXCLUSIVE | EPOLLONESHOT),
.data.ptr = NULL};
if (epoll_ctl(fd, EPOLL_CTL_ADD, evfd, &ev) != 0) {
if (errno != EINVAL) {
if (!logged_why_not) {
gpr_log(
GPR_ERROR,
"epoll_ctl with EPOLLEXCLUSIVE | EPOLLONESHOT failed with error: "
"%d. Not using epollex polling engine.",
errno);
logged_why_not = true;
}
close(fd);
close(evfd);
return false;
}
} else {
if (!logged_why_not) {
gpr_log(GPR_ERROR,
"epoll_ctl with EPOLLEXCLUSIVE | EPOLLONESHOT succeeded. This is "
"evidence of no EPOLLEXCLUSIVE support. Not using "
"epollex polling engine.");
logged_why_not = true;
}
close(fd);
close(evfd);
return false;
}
close(evfd);
close(fd);
return true;
}
#else
bool grpc_is_epollexclusive_available(void) { return false; }
#endif
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