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