1// Copyright 2014 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5// +build dragonfly freebsd linux netbsd openbsd 6 7package unix 8 9import "unsafe" 10 11// fcntl64Syscall is usually SYS_FCNTL, but is overridden on 32-bit Linux 12// systems by fcntl_linux_32bit.go to be SYS_FCNTL64. 13var fcntl64Syscall uintptr = SYS_FCNTL 14 15func fcntl(fd int, cmd, arg int) (int, error) { 16 valptr, _, errno := Syscall(fcntl64Syscall, uintptr(fd), uintptr(cmd), uintptr(arg)) 17 var err error 18 if errno != 0 { 19 err = errno 20 } 21 return int(valptr), err 22} 23 24// FcntlInt performs a fcntl syscall on fd with the provided command and argument. 25func FcntlInt(fd uintptr, cmd, arg int) (int, error) { 26 return fcntl(int(fd), cmd, arg) 27} 28 29// FcntlFlock performs a fcntl syscall for the F_GETLK, F_SETLK or F_SETLKW command. 30func FcntlFlock(fd uintptr, cmd int, lk *Flock_t) error { 31 _, _, errno := Syscall(fcntl64Syscall, fd, uintptr(cmd), uintptr(unsafe.Pointer(lk))) 32 if errno == 0 { 33 return nil 34 } 35 return errno 36} 37