vendor/github.com/mitchellh/go-homedir/homedir.go

   1 package homedir
   2
   3 import (
   4         "bytes"
   5         "errors"
   6         "os"
   7         "os/exec"
   8         "path/filepath"
   9         "runtime"
  10         "strconv"
  11         "strings"
  12         "sync"
  13 )
  14
  15 // DisableCache will disable caching of the home directory. Caching is enabled
  16 // by default.
  17 var DisableCache bool
  18
  19 var homedirCache string
  20 var cacheLock sync.RWMutex
  21
  22 // Dir returns the home directory for the executing user.
  23 //
  24 // This uses an OS-specific method for discovering the home directory.
  25 // An error is returned if a home directory cannot be detected.
  26 func Dir() (string, error) {
  27         if !DisableCache {
  28                 cacheLock.RLock()
  29                 cached := homedirCache
  30                 cacheLock.RUnlock()
  31                 if cached != "" {
  32                         return cached, nil
  33                 }
  34         }
  35
  36         cacheLock.Lock()
  37         defer cacheLock.Unlock()
  38
  39         var result string
  40         var err error
  41         if runtime.GOOS == "windows" {
  42                 result, err = dirWindows()
  43         } else {
  44                 // Unix-like system, so just assume Unix
  45                 result, err = dirUnix()
  46         }
  47
  48         if err != nil {
  49                 return "", err
  50         }
  51         homedirCache = result
  52         return result, nil
  53 }
  54
  55 // Expand expands the path to include the home directory if the path
  56 // is prefixed with `~`. If it isn't prefixed with `~`, the path is
  57 // returned as-is.
  58 func Expand(path string) (string, error) {
  59         if len(path) == 0 {
  60                 return path, nil
  61         }
  62
  63         if path[0] != '~' {
  64                 return path, nil
  65         }
  66
  67         if len(path) > 1 && path[1] != '/' && path[1] != '\\' {
  68                 return "", errors.New("cannot expand user-specific home dir")
  69         }
  70
  71         dir, err := Dir()
  72         if err != nil {
  73                 return "", err
  74         }
  75
  76         return filepath.Join(dir, path[1:]), nil
  77 }
  78
  79 func dirUnix() (string, error) {
  80         // First prefer the HOME environmental variable
  81         if home := os.Getenv("HOME"); home != "" {
  82                 return home, nil
  83         }
  84
  85         // If that fails, try getent
  86         var stdout bytes.Buffer
  87         cmd := exec.Command("getent", "passwd", strconv.Itoa(os.Getuid()))
  88         cmd.Stdout = &stdout
  89         if err := cmd.Run(); err != nil {
  90                 // If the error is ErrNotFound, we ignore it. Otherwise, return it.
  91                 if err != exec.ErrNotFound {
  92                         return "", err
  93                 }
  94         } else {
  95                 if passwd := strings.TrimSpace(stdout.String()); passwd != "" {
  96                         // username:password:uid:gid:gecos:home:shell
  97                         passwdParts := strings.SplitN(passwd, ":", 7)
  98                         if len(passwdParts) > 5 {
  99                                 return passwdParts[5], nil
 100                         }
 101                 }
 102         }
 103
 104         // If all else fails, try the shell
 105         stdout.Reset()
 106         cmd = exec.Command("sh", "-c", "cd && pwd")
 107         cmd.Stdout = &stdout
 108         if err := cmd.Run(); err != nil {
 109                 return "", err
 110         }
 111
 112         result := strings.TrimSpace(stdout.String())
 113         if result == "" {
 114                 return "", errors.New("blank output when reading home directory")
 115         }
 116
 117         return result, nil
 118 }
 119
 120 func dirWindows() (string, error) {
 121         // First prefer the HOME environmental variable
 122         if home := os.Getenv("HOME"); home != "" {
 123                 return home, nil
 124         }
 125
 126         drive := os.Getenv("HOMEDRIVE")
 127         path := os.Getenv("HOMEPATH")
 128         home := drive + path
 129         if drive == "" || path == "" {
 130                 home = os.Getenv("USERPROFILE")
 131         }
 132         if home == "" {
 133                 return "", errors.New("HOMEDRIVE, HOMEPATH, and USERPROFILE are blank")
 134         }
 135
 136         return home, nil
 137 }