libgo/go/os/executable_test.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_test
   6
   7 import (
   8         "fmt"
   9         "internal/testenv"
  10         "os"
  11         osexec "os/exec"
  12         "path/filepath"
  13         "runtime"
  14         "testing"
  15 )
  16
  17 const executable_EnvVar = "OSTEST_OUTPUT_EXECPATH"
  18
  19 func TestExecutable(t *testing.T) {
  20         testenv.MustHaveExec(t) // will also exclude nacl, which doesn't support Executable anyway
  21         ep, err := os.Executable()
  22         if err != nil {
  23                 t.Fatalf("Executable failed: %v", err)
  24         }
  25         // we want fn to be of the form "dir/prog"
  26         dir := filepath.Dir(filepath.Dir(ep))
  27         fn, err := filepath.Rel(dir, ep)
  28         if err != nil {
  29                 t.Fatalf("filepath.Rel: %v", err)
  30         }
  31
  32         cmd := &osexec.Cmd{}
  33         // make child start with a relative program path
  34         cmd.Dir = dir
  35         cmd.Path = fn
  36         // forge argv[0] for child, so that we can verify we could correctly
  37         // get real path of the executable without influenced by argv[0].
  38         cmd.Args = []string{"-", "-test.run=XXXX"}
  39         if runtime.GOOS == "openbsd" || runtime.GOOS == "aix" {
  40                 // OpenBSD and AIX rely on argv[0]
  41                 cmd.Args[0] = fn
  42         }
  43         cmd.Env = append(os.Environ(), fmt.Sprintf("%s=1", executable_EnvVar))
  44         out, err := cmd.CombinedOutput()
  45         if err != nil {
  46                 t.Fatalf("exec(self) failed: %v", err)
  47         }
  48         outs := string(out)
  49         if !filepath.IsAbs(outs) {
  50                 t.Fatalf("Child returned %q, want an absolute path", out)
  51         }
  52         if !sameFile(outs, ep) {
  53                 t.Fatalf("Child returned %q, not the same file as %q", out, ep)
  54         }
  55 }
  56
  57 func sameFile(fn1, fn2 string) bool {
  58         fi1, err := os.Stat(fn1)
  59         if err != nil {
  60                 return false
  61         }
  62         fi2, err := os.Stat(fn2)
  63         if err != nil {
  64                 return false
  65         }
  66         return os.SameFile(fi1, fi2)
  67 }
  68
  69 func init() {
  70         if e := os.Getenv(executable_EnvVar); e != "" {
  71                 // first chdir to another path
  72                 dir := "/"
  73                 if runtime.GOOS == "windows" {
  74                         cwd, err := os.Getwd()
  75                         if err != nil {
  76                                 panic(err)
  77                         }
  78                         dir = filepath.VolumeName(cwd)
  79                 }
  80                 os.Chdir(dir)
  81                 if ep, err := os.Executable(); err != nil {
  82                         fmt.Fprint(os.Stderr, "ERROR: ", err)
  83                 } else {
  84                         fmt.Fprint(os.Stderr, ep)
  85                 }
  86                 os.Exit(0)
  87         }
  88 }