package homedir
import (
"bytes"
"errors"
"os"
"os/exec"
"path/filepath"
"runtime"
"strconv"
"strings"
"sync"
)
// DisableCache will disable caching of the home directory. Caching is enabled
// by default.
var DisableCache bool
var homedirCache string
var cacheLock sync.RWMutex
// Dir returns the home directory for the executing user.
//
// This uses an OS-specific method for discovering the home directory.
// An error is returned if a home directory cannot be detected.
func Dir() (string, error) {
if !DisableCache {
cacheLock.RLock()
cached := homedirCache
cacheLock.RUnlock()
if cached != "" {
return cached, nil
}
}
cacheLock.Lock()
defer cacheLock.Unlock()
var result string
var err error
if runtime.GOOS == "windows" {
result, err = dirWindows()
} else {
// Unix-like system, so just assume Unix
result, err = dirUnix()
}
if err != nil {
return "", err
}
homedirCache = result
return result, nil
}
// Expand expands the path to include the home directory if the path
// is prefixed with `~`. If it isn't prefixed with `~`, the path is
// returned as-is.
func Expand(path string) (string, error) {
if len(path) == 0 {
return path, nil
}
if path[0] != '~' {
return path, nil
}
if len(path) > 1 && path[1] != '/' && path[1] != '\\' {
return "", errors.New("cannot expand user-specific home dir")
}
dir, err := Dir()
if err != nil {
return "", err
}
return filepath.Join(dir, path[1:]), nil
}
func dirUnix() (string, error) {
// First prefer the HOME environmental variable
if home := os.Getenv("HOME"); home != "" {
return home, nil
}
// If that fails, try getent
var stdout bytes.Buffer
cmd := exec.Command("getent", "passwd", strconv.Itoa(os.Getuid()))
cmd.Stdout = &stdout
if err := cmd.Run(); err != nil {
// If the error is ErrNotFound, we ignore it. Otherwise, return it.
if err != exec.ErrNotFound {
return "", err
}
} else {
if passwd := strings.TrimSpace(stdout.String()); passwd != "" {
// username:password:uid:gid:gecos:home:shell
passwdParts := strings.SplitN(passwd, ":", 7)
if len(passwdParts) > 5 {
return passwdParts[5], nil
}
}
}
// If all else fails, try the shell
stdout.Reset()
cmd = exec.Command("sh", "-c", "cd && pwd")
cmd.Stdout = &stdout
if err := cmd.Run(); err != nil {
return "", err
}
result := strings.TrimSpace(stdout.String())
if result == "" {
return "", errors.New("blank output when reading home directory")
}
return result, nil
}
func dirWindows() (string, error) {
// First prefer the HOME environmental variable
if home := os.Getenv("HOME"); home != "" {
return home, nil
}
drive := os.Getenv("HOMEDRIVE")
path := os.Getenv("HOMEPATH")
home := drive + path
if drive == "" || path == "" {
home = os.Getenv("USERPROFILE")
}
if home == "" {
return "", errors.New("HOMEDRIVE, HOMEPATH, and USERPROFILE are blank")
}
return home, nil
}
