blob: 25378537eade7bdd92c07191614e56d0ea982eac [file] [log] [blame]
divyadesai19009132020-03-04 12:58:08 +00001package homedir
2
3import (
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.
17var DisableCache bool
18
19var homedirCache string
20var 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.
26func 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.
58func 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.
83func Reset() {
84 cacheLock.Lock()
85 defer cacheLock.Unlock()
86 homedirCache = ""
87}
88
89func 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
148func 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}