Improve setuser: set auxilliary groups and more environment variables

image/setuser

@@ -1,12 +1,26 @@
-#!/bin/bash
-set -e
+#!/usr/bin/python2
+import sys, os, pwd
 
-user="$1"
-shift
+if len(sys.argv) < 3:
+	sys.stderr.write("Usage: /sbin/setuser USERNAME COMMAND [args..]\n")
+	sys.exit(1)
 
-if [[ "$user" == "root" ]]; then
-	export HOME=/root
-else
-	export HOME=/home/$user
-fi
-exec chpst -u "$user" "$@"
+def abort(message):
+	sys.stderr.write("setuser: %s\n" % message)
+	sys.exit(1)
+
+username = sys.argv[1]
+try:
+	user = pwd.getpwnam(username)
+except KeyError:
+	abort("user %s not found" % username)
+os.initgroups(username, user.pw_gid)
+os.setgid(user.pw_gid)
+os.setuid(user.pw_uid)
+os.environ['USER'] = username
+os.environ['HOME'] = user.pw_dir
+os.environ['UID']  = str(user.pw_uid)
+try:
+	os.execvp(sys.argv[2], sys.argv[2:])
+except OSError as e:
+	abort("cannot execute %s: %s" % (sys.argv[2], str(e)))