libgo/go/os/executable_sysctl.go

   1 // Copyright 2016 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 //go:build freebsd || dragonfly
   6
   7 package os
   8
   9 import (
  10         "syscall"
  11         "unsafe"
  12 )
  13
  14 func executable() (string, error) {
  15         mib := [4]int32{_CTL_KERN, _KERN_PROC, _KERN_PROC_PATHNAME, -1}
  16
  17         n := uintptr(0)
  18         // get length
  19         _, _, err := syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(unsafe.Pointer(&mib[0])), 4, 0, uintptr(unsafe.Pointer(&n)), 0, 0)
  20         if err != 0 {
  21                 return "", err
  22         }
  23         if n == 0 { // shouldn't happen
  24                 return "", nil
  25         }
  26         buf := make([]byte, n)
  27         _, _, err = syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(unsafe.Pointer(&mib[0])), 4, uintptr(unsafe.Pointer(&buf[0])), uintptr(unsafe.Pointer(&n)), 0, 0)
  28         if err != 0 {
  29                 return "", err
  30         }
  31         if n == 0 { // shouldn't happen
  32                 return "", nil
  33         }
  34         return string(buf[:n-1]), nil
  35 }