71 lines
1.9 KiB
C
71 lines
1.9 KiB
C
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/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* Work around the lack of <sys/eventfd.h> on glibc 2.5.1 which we still
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* need to support, sigh.
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*/
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#pragma once
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#include <folly/portability/Config.h>
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#if defined(__GLIBC__) && !defined(__APPLE__)
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#if __GLIBC_PREREQ(2, 9)
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#define FOLLY_GLIBC_2_9
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#endif
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#endif
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// <sys/eventfd.h> doesn't exist on older glibc versions
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#ifdef FOLLY_GLIBC_2_9
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#include <sys/eventfd.h>
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#else /* !def FOLLY_GLIBC_2_9 */
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#include <fcntl.h>
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#include <sys/syscall.h>
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#include <unistd.h>
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// Use existing __NR_eventfd2 if already defined
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// Values from the Linux kernel source:
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// arch/x86/include/asm/unistd_{32,64}.h
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#ifndef __NR_eventfd2
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#if FOLLY_X64
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/* nolint */
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#define __NR_eventfd2 290
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#elif defined(__i386__)
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/* nolint */
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#define __NR_eventfd2 328
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#else
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#error "Can't define __NR_eventfd2 for your architecture."
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#endif
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#endif
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enum {
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EFD_SEMAPHORE = 1,
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#define EFD_SEMAPHORE EFD_SEMAPHORE
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EFD_CLOEXEC = 02000000,
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#define EFD_CLOEXEC EFD_CLOEXEC
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EFD_NONBLOCK = 04000
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#define EFD_NONBLOCK EFD_NONBLOCK
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};
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// http://www.kernel.org/doc/man-pages/online/pages/man2/eventfd.2.html
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// Use the eventfd2 system call, as in glibc 2.9+
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// (requires kernel 2.6.30+)
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#define eventfd(initval, flags) syscall(__NR_eventfd2, (initval), (flags))
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#endif /* !(defined(__GLIBC__) && __GLIBC_PREREQ(2, 9)) */
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