tailscale/logtail/filch/filch_windows.go

45 lines
936 B
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package filch
import (
"fmt"
"os"
"syscall"
)
var kernel32 = syscall.MustLoadDLL("kernel32.dll")
var procSetStdHandle = kernel32.MustFindProc("SetStdHandle")
func setStdHandle(stdHandle int32, handle syscall.Handle) error {
r, _, e := syscall.Syscall(procSetStdHandle.Addr(), 2, uintptr(stdHandle), uintptr(handle), 0)
if r == 0 {
if e != 0 {
return error(e)
}
return syscall.EINVAL
}
return nil
}
func saveStderr() (*os.File, error) {
return os.Stderr, nil
}
func unsaveStderr(f *os.File) error {
os.Stderr = f
return nil
}
func dup2Stderr(f *os.File) error {
fd := int(f.Fd())
err := setStdHandle(syscall.STD_ERROR_HANDLE, syscall.Handle(fd))
if err != nil {
return fmt.Errorf("dup2Stderr: %w", err)
}
os.Stderr = f
return nil
}