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// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build dragonfly || freebsd || linux || netbsd
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package unix
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import "unsafe"
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// fcntl64Syscall is usually SYS_FCNTL, but is overridden on 32-bit Linux
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// systems by fcntl_linux_32bit.go to be SYS_FCNTL64.
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var fcntl64Syscall uintptr = SYS_FCNTL
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func fcntl(fd int, cmd, arg int) (int, error) {
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	valptr, _, errno := Syscall(fcntl64Syscall, uintptr(fd), uintptr(cmd), uintptr(arg))
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	var err error
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	if errno != 0 {
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		err = errno
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	}
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	return int(valptr), err
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}
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// FcntlInt performs a fcntl syscall on fd with the provided command and argument.
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func FcntlInt(fd uintptr, cmd, arg int) (int, error) {
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	return fcntl(int(fd), cmd, arg)
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}
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// FcntlFlock performs a fcntl syscall for the F_GETLK, F_SETLK or F_SETLKW command.
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func FcntlFlock(fd uintptr, cmd int, lk *Flock_t) error {
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	_, _, errno := Syscall(fcntl64Syscall, fd, uintptr(cmd), uintptr(unsafe.Pointer(lk)))
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	if errno == 0 {
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		return nil
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	}
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	return errno
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}
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