Takahiro Suzuki | d7bf820 | 2020-12-17 20:21:59 +0900 | [diff] [blame] | 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 | // Reset clears the cache, forcing the next call to Dir to re-detect |
| 80 | // the home directory. This generally never has to be called, but can be |
| 81 | // useful in tests if you're modifying the home directory via the HOME |
| 82 | // env var or something. |
| 83 | func Reset() { |
| 84 | cacheLock.Lock() |
| 85 | defer cacheLock.Unlock() |
| 86 | homedirCache = "" |
| 87 | } |
| 88 | |
| 89 | func dirUnix() (string, error) { |
| 90 | homeEnv := "HOME" |
| 91 | if runtime.GOOS == "plan9" { |
| 92 | // On plan9, env vars are lowercase. |
| 93 | homeEnv = "home" |
| 94 | } |
| 95 | |
| 96 | // First prefer the HOME environmental variable |
| 97 | if home := os.Getenv(homeEnv); home != "" { |
| 98 | return home, nil |
| 99 | } |
| 100 | |
| 101 | var stdout bytes.Buffer |
| 102 | |
| 103 | // If that fails, try OS specific commands |
| 104 | if runtime.GOOS == "darwin" { |
| 105 | cmd := exec.Command("sh", "-c", `dscl -q . -read /Users/"$(whoami)" NFSHomeDirectory | sed 's/^[^ ]*: //'`) |
| 106 | cmd.Stdout = &stdout |
| 107 | if err := cmd.Run(); err == nil { |
| 108 | result := strings.TrimSpace(stdout.String()) |
| 109 | if result != "" { |
| 110 | return result, nil |
| 111 | } |
| 112 | } |
| 113 | } else { |
| 114 | cmd := exec.Command("getent", "passwd", strconv.Itoa(os.Getuid())) |
| 115 | cmd.Stdout = &stdout |
| 116 | if err := cmd.Run(); err != nil { |
| 117 | // If the error is ErrNotFound, we ignore it. Otherwise, return it. |
| 118 | if err != exec.ErrNotFound { |
| 119 | return "", err |
| 120 | } |
| 121 | } else { |
| 122 | if passwd := strings.TrimSpace(stdout.String()); passwd != "" { |
| 123 | // username:password:uid:gid:gecos:home:shell |
| 124 | passwdParts := strings.SplitN(passwd, ":", 7) |
| 125 | if len(passwdParts) > 5 { |
| 126 | return passwdParts[5], nil |
| 127 | } |
| 128 | } |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | // If all else fails, try the shell |
| 133 | stdout.Reset() |
| 134 | cmd := exec.Command("sh", "-c", "cd && pwd") |
| 135 | cmd.Stdout = &stdout |
| 136 | if err := cmd.Run(); err != nil { |
| 137 | return "", err |
| 138 | } |
| 139 | |
| 140 | result := strings.TrimSpace(stdout.String()) |
| 141 | if result == "" { |
| 142 | return "", errors.New("blank output when reading home directory") |
| 143 | } |
| 144 | |
| 145 | return result, nil |
| 146 | } |
| 147 | |
| 148 | func dirWindows() (string, error) { |
| 149 | // First prefer the HOME environmental variable |
| 150 | if home := os.Getenv("HOME"); home != "" { |
| 151 | return home, nil |
| 152 | } |
| 153 | |
| 154 | // Prefer standard environment variable USERPROFILE |
| 155 | if home := os.Getenv("USERPROFILE"); home != "" { |
| 156 | return home, nil |
| 157 | } |
| 158 | |
| 159 | drive := os.Getenv("HOMEDRIVE") |
| 160 | path := os.Getenv("HOMEPATH") |
| 161 | home := drive + path |
| 162 | if drive == "" || path == "" { |
| 163 | return "", errors.New("HOMEDRIVE, HOMEPATH, or USERPROFILE are blank") |
| 164 | } |
| 165 | |
| 166 | return home, nil |
| 167 | } |