executable_sysctl.go

Documentation: os

     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  // +build freebsd dragonfly
     7  
     8  package os
     9  
    10  import (
    11  	"syscall"
    12  	"unsafe"
    13  )
    14  
    15  func executable() (string, error) {
    16  	mib := [4]int32{_CTL_KERN, _KERN_PROC, _KERN_PROC_PATHNAME, -1}
    17  
    18  	n := uintptr(0)
    19  	// get length
    20  	_, _, err := syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(unsafe.Pointer(&mib[0])), 4, 0, uintptr(unsafe.Pointer(&n)), 0, 0)
    21  	if err != 0 {
    22  		return "", err
    23  	}
    24  	if n == 0 { // shouldn't happen
    25  		return "", nil
    26  	}
    27  	buf := make([]byte, n)
    28  	_, _, err = syscall.Syscall6(syscall.SYS___SYSCTL, uintptr(unsafe.Pointer(&mib[0])), 4, uintptr(unsafe.Pointer(&buf[0])), uintptr(unsafe.Pointer(&n)), 0, 0)
    29  	if err != 0 {
    30  		return "", err
    31  	}
    32  	if n == 0 { // shouldn't happen
    33  		return "", nil
    34  	}
    35  	return string(buf[:n-1]), nil
    36  }
    37
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