| /* |
| * |
| * Copyright 2017 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include "src/core/lib/iomgr/port.h" |
| |
| #include "src/core/lib/iomgr/is_epollexclusive_available.h" |
| |
| #ifdef GRPC_LINUX_EPOLL_CREATE1 |
| |
| #include <grpc/support/log.h> |
| |
| #include <errno.h> |
| #include <sys/epoll.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_DEBUG, |
| "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_DEBUG, |
| "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 */ |
| ev.events = |
| static_cast<uint32_t>(EPOLLET | EPOLLIN | EPOLLEXCLUSIVE | EPOLLONESHOT); |
| ev.data.ptr = nullptr; |
| 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_DEBUG, |
| "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 |