--- masquerade.module.orig	2010-04-17 09:07:29.000000000 -0400
+++ masquerade.module	2010-04-17 09:23:59.000000000 -0400
@@ -67,7 +67,7 @@ function masquerade_menu() {
     $items['masquerade/switch/' . $default_test_user->uid] = array(
       'title' => 'Masquerade as @testuser',
       'title arguments' => array('@testuser' => $default_test_user->name),
-      'page callback' => 'masquerade_switch_user',
+      'page callback' => 'masquerade_switch_user_page',
       'page arguments' => array(2),
   	  'access callback' => 'masquerade_access',
       'access arguments' => array('switch'),
@@ -77,7 +77,7 @@ function masquerade_menu() {
 
   $items['masquerade/switch/%'] = array(
     'title' => 'Masquerading',
-    'page callback' => 'masquerade_switch_user',
+    'page callback' => 'masquerade_switch_user_page',
     'page arguments' => array(2),
     'access callback' => 'masquerade_access',
     'access arguments' => array('switch', 2),
@@ -85,7 +85,7 @@ function masquerade_menu() {
   );
   $items['masquerade/unswitch'] = array(
     'title' => 'Switch back',
-    'page callback' => 'masquerade_switch_back',
+    'page callback' => 'masquerade_switch_back_page',
     'access callback' => 'masquerade_access',
     'access arguments' => array('unswitch'),
     'type' => MENU_NORMAL_ITEM,
@@ -150,6 +150,9 @@ function masquerade_access($type, $uid =
     case 'switch':
       global $user;
       if ($uid) {
+        if (!is_numeric($uid)) {
+          return FALSE;
+        }
         $account = user_load(array('uid' => $uid));
         $switch_to_account = db_result(db_query("SELECT TRUE FROM {masquerade_users} WHERE uid_from = %d AND uid_to = %d", $user->uid, $account->uid));
       }
@@ -497,6 +500,7 @@ function masquerade_block_1_submit($form
   unset($form);
   $masq_user = user_load(array('name' => $form_state['values']['masquerade_user_field']));
   masquerade_switch_user($masq_user->uid);
+  drupal_goto(referer_uri());
 }
 
 /**
@@ -571,18 +575,26 @@ function masquerade_autocomplete_user($s
 }
 
 /**
- * Page callback that allows a user with the right permissions to become
+ * Page callback to switch users.
+ */
+function masquerade_switch_user_page($uid) {
+  masquerade_switch_user($uid);
+  drupal_goto(refer_uri());
+}
+
+/**
+ * Function that allows a user with the right permissions to become
  * the selected user.
+ *
+ * @param $uid
+ *   The user ID to switch to.
+ *
+ * @return
+ *   TRUE if the user was sucessfully switched, or FALSE if there was an error.
  */
 function masquerade_switch_user($uid) {
   global $user;
 
-  if (!is_numeric($uid)) {
-    drupal_set_message(t('A user id was not correctly passed to the switching function.'));
-    watchdog('masquerade', 'The user id provided to switch users was not numeric.', NULL, WATCHDOG_ERROR);
-    return drupal_goto(referer_uri());
-  }
-
   $new_user = user_load(array('uid' => $uid));
 
   $roles = array_keys(array_filter(variable_get('masquerade_admin_roles', array())));
@@ -592,16 +604,18 @@ function masquerade_switch_user($uid) {
 
   // check to see if we need admin permission
   if (!user_access($perm) && !$_SESSION['masquerading'] && !db_result(db_query("SELECT TRUE FROM {masquerade_users} WHERE uid_from = %d AND uid_to = %d", $user->uid, $new_user->uid))) {
-    return drupal_access_denied();
+    watchdog('masquerade', 'This user requires administrative permissions to switch to the user %user.', array('%user' => $new_user->name), WATCHDOG_ERROR);
+    return FALSE;
   }
 
   if ($user->uid == $uid || isset($user->masquerading)) {
-    return drupal_access_denied();
+    watchdog('masquerade', 'This user is all ready %user.', array('%user' => $new_user->name), WATCHDOG_ERROR);
+    return FALSE;
   }
 
   if (variable_get('site_offline', 0) && !user_access('administer site configuration', $new_user)) {
     drupal_set_message(t('This user is not allowed to access the site while the site is in off-line mode. Please <a href="@site-maintenance">set the site status</a> to "online" to switch to this user.', array('@site-maintenance' => url('admin/settings/site-maintenance'))), 'error');
-    return drupal_access_denied();
+    return FALSE;
   }
 
   db_query("INSERT INTO {masquerade} (uid_from, uid_as, sid) VALUES (%d, %d, '%s')",
@@ -612,13 +626,22 @@ function masquerade_switch_user($uid) {
   drupal_set_message(t('You are now masquerading as %masq_as.', array('%masq_as' => $new_user->name ? $new_user->name : variable_get('anonymous', 'Anonymous'))));
   $user->masquerading = $new_user->uid;
   $user = $new_user;
-  drupal_goto(referer_uri());
+  return TRUE;
 }
 
 /**
  * Page callback that allows a user who is currently masquerading to become
  * a new user.
  */
+function masquerade_switch_back_page() {
+  masquerade_switch_back();
+  drupal_set_message(t('You are no longer masquerading as %masq_as and are now logged in as %user.', array('%user' => $user->name, '%masq_as' => $oldname)));
+  drupal_goto(referer_uri());
+}
+
+/**
+ * Function for a masquerading user to switch back to the previous user.
+ */
 function masquerade_switch_back() {
   // switch user
   global $user;
@@ -629,6 +652,5 @@ function masquerade_switch_back() {
   $oldname = ($user->uid == 0 ? variable_get('anonymous', 'Anonymous') : $user->name); 
   $user = user_load(array('uid' => $uid));
   watchdog('masquerade', 'User %user no longer masquerading as %masq_as.', array('%user' => $user->name, '%masq_as' => $oldname), WATCHDOG_INFO);
-  drupal_set_message(t('You are no longer masquerading as %masq_as and are now logged in as %user.', array('%user' => $user->name, '%masq_as' => $oldname)));
-  drupal_goto(referer_uri());
 }
+