os: add userInfo() method

os.userInfo() calls libuv's uv_os_get_passwd() function. It returns
an object containing the current effective user's username, uid,
gid, shell, and home directory. On Windows, the uid and gid are
-1, and the shell is null.

Refs: https://github.com/nodejs/node/issues/5582
PR-URL: https://github.com/nodejs/node/pull/6104
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/os.markdown

@@ -182,5 +182,21 @@ on OS X and `'Windows_NT'` on Windows.
 
 Returns the system uptime in seconds.
 
+## os.userInfo([options])
+
+* `options` {Object}
+  * `encoding` {String} Character encoding used to interpret resulting strings.
+    If `encoding` is set to `'buffer'`, the `username`, `shell`, and `homedir`
+    values will be `Buffer` instances. (Default: 'utf8')
+
+Returns a subset of the password file entry for the current effective user. The
+returned object includes the `username`, `uid`, `gid`, `shell`, and `homedir`.
+On Windows, the `uid` and `gid` fields are `-1`, and `shell` is `null`.
+
+The value of `homedir` returned by `userInfo()` comes directly from the
+operating system. This differs from the result of `os.homedir()`, which queries
+several environment variables for the home directory before falling back to the
+operating system response.
+
 [`process.arch`]: process.html#process_process_arch
 [`process.platform`]: process.html#process_process_platform

lib/os.js

@@ -14,6 +14,7 @@ exports.type = binding.getOSType;
 exports.release = binding.getOSRelease;
 exports.networkInterfaces = binding.getInterfaceAddresses;
 exports.homedir = binding.getHomeDirectory;
+exports.userInfo = binding.getUserInfo;
 
 
 exports.arch = function() {

src/env.h

@@ -94,6 +94,7 @@ namespace node {
   V(exchange_string, "exchange")                                              \
   V(idle_string, "idle")                                                      \
   V(irq_string, "irq")                                                        \
+  V(encoding_string, "encoding")                                              \
   V(enter_string, "enter")                                                    \
   V(env_pairs_string, "envPairs")                                             \
   V(env_string, "env")                                                        \
@@ -121,6 +122,7 @@ namespace node {
   V(handle_string, "handle")                                                  \
   V(heap_total_string, "heapTotal")                                           \
   V(heap_used_string, "heapUsed")                                             \
+  V(homedir_string, "homedir")                                                \
   V(hostmaster_string, "hostmaster")                                          \
   V(ignore_string, "ignore")                                                  \
   V(immediate_callback_string, "_immediateCallback")                          \
@@ -206,6 +208,7 @@ namespace node {
   V(service_string, "service")                                                \
   V(servername_string, "servername")                                          \
   V(session_id_string, "sessionId")                                           \
+  V(shell_string, "shell")                                                    \
   V(signal_string, "signal")                                                  \
   V(size_string, "size")                                                      \
   V(sni_context_err_string, "Invalid SNI context")                            \
@@ -235,6 +238,7 @@ namespace node {
   V(uid_string, "uid")                                                        \
   V(unknown_string, "<unknown>")                                              \
   V(user_string, "user")                                                      \
+  V(username_string, "username")                                              \
   V(uv_string, "uv")                                                          \
   V(valid_from_string, "valid_from")                                          \
   V(valid_to_string, "valid_to")                                              \

src/node_os.cc

@@ -2,6 +2,7 @@
 #include "v8.h"
 #include "env.h"
 #include "env-inl.h"
+#include "string_bytes.h"
 
 #include <errno.h>
 #include <string.h>
@@ -32,6 +33,7 @@ using v8::Context;
 using v8::FunctionCallbackInfo;
 using v8::Integer;
 using v8::Local;
+using v8::Null;
 using v8::Number;
 using v8::Object;
 using v8::String;
@@ -290,6 +292,72 @@ static void GetHomeDirectory(const FunctionCallbackInfo<Value>& args) {
 }
 
 
+static void GetUserInfo(const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+  uv_passwd_t pwd;
+  enum encoding encoding;
+
+  if (args[0]->IsObject()) {
+    Local<Object> options = args[0].As<Object>();
+    Local<Value> encoding_opt = options->Get(env->encoding_string());
+    encoding = ParseEncoding(env->isolate(), encoding_opt, UTF8);
+  } else {
+    encoding = UTF8;
+  }
+
+  const int err = uv_os_get_passwd(&pwd);
+
+  if (err) {
+    return env->ThrowUVException(err, "uv_os_get_passwd");
+  }
+
+  Local<Value> uid = Number::New(env->isolate(), pwd.uid);
+  Local<Value> gid = Number::New(env->isolate(), pwd.gid);
+  Local<Value> username = StringBytes::Encode(env->isolate(),
+                                              pwd.username,
+                                              encoding);
+  Local<Value> homedir = StringBytes::Encode(env->isolate(),
+                                             pwd.homedir,
+                                             encoding);
+  Local<Value> shell;
+
+  if (pwd.shell == NULL)
+    shell = Null(env->isolate());
+  else
+    shell = StringBytes::Encode(env->isolate(), pwd.shell, encoding);
+
+  uv_os_free_passwd(&pwd);
+
+  if (username.IsEmpty()) {
+    return env->ThrowUVException(UV_EINVAL,
+                                 "uv_os_get_passwd",
+                                 "Invalid character encoding for username");
+  }
+
+  if (homedir.IsEmpty()) {
+    return env->ThrowUVException(UV_EINVAL,
+                                 "uv_os_get_passwd",
+                                 "Invalid character encoding for homedir");
+  }
+
+  if (shell.IsEmpty()) {
+    return env->ThrowUVException(UV_EINVAL,
+                                 "uv_os_get_passwd",
+                                 "Invalid character encoding for shell");
+  }
+
+  Local<Object> entry = Object::New(env->isolate());
+
+  entry->Set(env->uid_string(), uid);
+  entry->Set(env->gid_string(), gid);
+  entry->Set(env->username_string(), username);
+  entry->Set(env->homedir_string(), homedir);
+  entry->Set(env->shell_string(), shell);
+
+  args.GetReturnValue().Set(entry);
+}
+
+
 void Initialize(Local<Object> target,
                 Local<Value> unused,
                 Local<Context> context) {
@@ -304,6 +372,7 @@ void Initialize(Local<Object> target,
   env->SetMethod(target, "getOSRelease", GetOSRelease);
   env->SetMethod(target, "getInterfaceAddresses", GetInterfaceAddresses);
   env->SetMethod(target, "getHomeDirectory", GetHomeDirectory);
+  env->SetMethod(target, "getUserInfo", GetUserInfo);
   target->Set(FIXED_ONE_BYTE_STRING(env->isolate(), "isBigEndian"),
               Boolean::New(env->isolate(), IsBigEndian()));
 }

test/parallel/test-os.js

@@ -125,3 +125,27 @@ if (common.isWindows && process.env.USERPROFILE) {
   assert.ok(os.homedir().indexOf(path.sep) !== -1);
   process.env.HOME = home;
 }
+
+const pwd = os.userInfo();
+const pwdBuf = os.userInfo({ encoding: 'buffer' });
+
+if (common.isWindows) {
+  assert.strictEqual(pwd.uid, -1);
+  assert.strictEqual(pwd.gid, -1);
+  assert.strictEqual(pwd.shell, null);
+  assert.strictEqual(pwdBuf.uid, -1);
+  assert.strictEqual(pwdBuf.gid, -1);
+  assert.strictEqual(pwdBuf.shell, null);
+} else {
+  assert.strictEqual(typeof pwd.uid, 'number');
+  assert.strictEqual(typeof pwd.gid, 'number');
+  assert.notStrictEqual(pwd.shell.indexOf(path.sep), -1);
+  assert.strictEqual(pwd.uid, pwdBuf.uid);
+  assert.strictEqual(pwd.gid, pwdBuf.gid);
+  assert.strictEqual(pwd.shell, pwdBuf.shell.toString('utf8'));
+}
+
+assert.strictEqual(typeof pwd.username, 'string');
+assert.notStrictEqual(pwd.homedir.indexOf(path.sep), -1);
+assert.strictEqual(pwd.username, pwdBuf.username.toString('utf8'));
+assert.strictEqual(pwd.homedir, pwdBuf.homedir.toString('utf8'));