github.com/goproxy0/go@v0.0.0-20171111080102-49cc0c489d2c/src/os/executable_freebsd.go (about)

     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  }