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