github.com/camlistore/go4@v0.0.0-20200104003542-c7e774b10ea0/osutil/exec_windows.go (about)

     1  /*
     2  Copyright 2015 The go4 Authors
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8       http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package osutil
    18  
    19  import (
    20  	"path/filepath"
    21  	"syscall"
    22  	"unsafe"
    23  )
    24  
    25  var (
    26  	modkernel32            = syscall.MustLoadDLL("kernel32.dll")
    27  	procGetModuleFileNameW = modkernel32.MustFindProc("GetModuleFileNameW")
    28  )
    29  
    30  func getModuleFileName(handle syscall.Handle) (string, error) {
    31  	n := uint32(1024)
    32  	var buf []uint16
    33  	for {
    34  		buf = make([]uint16, n)
    35  		r, err := syscallGetModuleFileName(handle, &buf[0], n)
    36  		if err != nil {
    37  			return "", err
    38  		}
    39  		if r < n {
    40  			break
    41  		}
    42  		// r == n means n not big enough
    43  		n += 1024
    44  	}
    45  	return syscall.UTF16ToString(buf), nil
    46  }
    47  
    48  func executable() (string, error) {
    49  	p, err := getModuleFileName(0)
    50  	return filepath.Clean(p), err
    51  }
    52  
    53  func syscallGetModuleFileName(module syscall.Handle, fn *uint16, len uint32) (n uint32, err error) {
    54  	r0, _, e1 := syscall.Syscall(procGetModuleFileNameW.Addr(), 3, uintptr(module), uintptr(unsafe.Pointer(fn)), uintptr(len))
    55  	n = uint32(r0)
    56  	if n == 0 {
    57  		if e1 != 0 {
    58  			err = error(e1)
    59  		} else {
    60  			err = syscall.EINVAL
    61  		}
    62  	}
    63  	return
    64  }