Disallow running as root without --user-data-dir

This commit adds the --user-data-dir argument which allows a custom data dir
for Chromium's user data. This is useful when running as root on Linux since
the root user does not have read or write permissions for the ~/.config/Code
dir.

Part of #3068

resources/linux/bin/code.sh

@@ -3,6 +3,23 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 # Licensed under the MIT License. See License.txt in the project root for license information.
 
+ARGS=$@
+
+# If root, ensure that --user-data-dir is specified
+if [ "$(id -u)" = "0" ]; then
+	while test $# -gt 0
+	do
+		if [[ $1 == --user-data-dir=* ]]; then
+			DATA_DIR_SET=1
+		fi
+		shift
+	done
+	if [ -z $DATA_DIR_SET ]; then
+		echo "It is recommended to start vscode as a normal user. To run as root, you must specify an alternate user data directory with the --user-data-dir argument." 1>&2
+		exit 1
+	fi
+fi
+
 if [ ! -L $0 ]; then
 	# if path is not a symlink, find relatively
 	VSCODE_PATH="$(dirname $0)/.."
@@ -15,7 +32,8 @@ else
 		VSCODE_PATH="/usr/share/@@NAME@@"
 	fi
 fi
+
 ELECTRON="$VSCODE_PATH/@@NAME@@"
 CLI="$VSCODE_PATH/resources/app/out/cli.js"
-ATOM_SHELL_INTERNAL_RUN_AS_NODE=1 "$ELECTRON" "$CLI" "$@"
+ATOM_SHELL_INTERNAL_RUN_AS_NODE=1 "$ELECTRON" "$CLI" $ARGS
 exit $?

src/main.js

@@ -110,6 +110,14 @@ if (process.env.VSCODE_DEV) {
 	app.setPath('userData', path.join(appData, 'Code-Development'));
 }
 
+// Use custom user data dir if specified, required to run as root on Linux
+var args = process.argv;
+args.forEach(function (arg) {
+	if (arg.indexOf('--user-data-dir=') === 0) {
+		app.setPath('userData', arg.split('=')[1]);
+	}
+});
+
 // Mac: when someone drops a file to the not-yet running VSCode, the open-file event fires even before
 // the app-ready event. We listen very early for open-file and remember this upon startup as path to open.
 global.macOpenFiles = [];

src/vs/workbench/electron-main/cli.ts

@@ -40,6 +40,8 @@ ${ indent }--locale=LOCALE       The locale to use (e.g. en-US or zh-TW).
 ${ indent }-n, --new-window      Force a new instance of Code.
 ${ indent }-r, --reuse-window    Force opening a file or folder in the last active
 ${ indent }                      window.
+${ indent }--user-data-dir=DIR   Specifies the directory that user data is kept in,
+${ indent }                      useful when running as root.
 ${ indent }-v, --version         Print version.
 ${ indent }-w, --wait            Wait for the window to be closed before returning.`;
 	}