// Copyright 2015 The rkt 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.

package sys

import (
	"syscall"
)

// CloseOnExec sets or clears FD_CLOEXEC flag on a file descriptor
func CloseOnExec(fd int, set bool) error {
	flag := uintptr(0)
	if set {
		flag = syscall.FD_CLOEXEC
	}
	_, _, err := syscall.RawSyscall(syscall.SYS_FCNTL, uintptr(fd), syscall.F_SETFD, flag)
	if err != 0 {
		return syscall.Errno(err)
	}
	return nil
}