misc: small fix or general refactoring i did not bother commenting

Gopkg.lock

@@ -275,6 +275,14 @@
   revision = "8aa92d4e02c501ba21e26fb92cf2fb9f23f56917"
   version = "v1.1.9"
 
+[[projects]]
+  digest = "1:5d231480e1c64a726869bc4142d270184c419749d34f167646baa21008eb0a79"
+  name = "github.com/mitchellh/go-homedir"
+  packages = ["."]
+  pruneopts = "UT"
+  revision = "af06845cf3004701891bf4fdb884bfe4920b3727"
+  version = "v1.1.0"
+
 [[projects]]
   digest = "1:cf31692c14422fa27c83a05292eb5cbe0fb2775972e8f1f8446a71549bd8980b"
   name = "github.com/pkg/errors"
@@ -392,6 +400,7 @@
     "github.com/mdlayher/dhcp6/dhcp6opts",
     "github.com/mdlayher/raw",
     "github.com/miekg/dns",
+    "github.com/mitchellh/go-homedir",
     "github.com/robertkrimen/otto",
     "github.com/tarm/serial",
     "golang.org/x/net/html",

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

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2013 Mitchell Hashimoto
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

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

@@ -0,0 +1,14 @@
+# go-homedir
+
+This is a Go library for detecting the user's home directory without
+the use of cgo, so the library can be used in cross-compilation environments.
+
+Usage is incredibly simple, just call `homedir.Dir()` to get the home directory
+for a user, and `homedir.Expand()` to expand the `~` in a path to the home
+directory.
+
+**Why not just use `os/user`?** The built-in `os/user` package requires
+cgo on Darwin systems. This means that any Go code that uses that package
+cannot cross compile. But 99% of the time the use for `os/user` is just to
+retrieve the home directory, which we can do for the current user without
+cgo. This library does that, enabling cross-compilation.

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

@@ -0,0 +1 @@
+module github.com/mitchellh/go-homedir

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

@@ -0,0 +1,167 @@
+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
+}
+
+// Reset clears the cache, forcing the next call to Dir to re-detect
+// the home directory. This generally never has to be called, but can be
+// useful in tests if you're modifying the home directory via the HOME
+// env var or something.
+func Reset() {
+	cacheLock.Lock()
+	defer cacheLock.Unlock()
+	homedirCache = ""
+}
+
+func dirUnix() (string, error) {
+	homeEnv := "HOME"
+	if runtime.GOOS == "plan9" {
+		// On plan9, env vars are lowercase.
+		homeEnv = "home"
+	}
+
+	// First prefer the HOME environmental variable
+	if home := os.Getenv(homeEnv); home != "" {
+		return home, nil
+	}
+
+	var stdout bytes.Buffer
+
+	// If that fails, try OS specific commands
+	if runtime.GOOS == "darwin" {
+		cmd := exec.Command("sh", "-c", `dscl -q . -read /Users/"$(whoami)" NFSHomeDirectory | sed 's/^[^ ]*: //'`)
+		cmd.Stdout = &stdout
+		if err := cmd.Run(); err == nil {
+			result := strings.TrimSpace(stdout.String())
+			if result != "" {
+				return result, nil
+			}
+		}
+	} else {
+		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
+	}
+
+	// Prefer standard environment variable USERPROFILE
+	if home := os.Getenv("USERPROFILE"); home != "" {
+		return home, nil
+	}
+
+	drive := os.Getenv("HOMEDRIVE")
+	path := os.Getenv("HOMEPATH")
+	home := drive + path
+	if drive == "" || path == "" {
+		return "", errors.New("HOMEDRIVE, HOMEPATH, or USERPROFILE are blank")
+	}
+
+	return home, nil
+}