Adding this (optional) feature to 1.4 stable because it seems quite

a few people really need it.

config-dist.php

@@ -170,6 +170,13 @@
 // Seconds for files to remain in caches. Decrease this if you are worried
 // about students being served outdated versions of uploaded files.
 //      $CFG->filelifetime = 86400;
+//
+// The following two settings allow you to specify allowed domains for 
+// email addresses.  If the first one is set, then Moodle will DISALLOW
+// all domains EXCEPT those listed.  Otherwise, if the second one is set
+// then all addresses are ALLOWED EXCEPT those listed.
+//      $CFG->allowemailaddresses = "myschool.edu.au hotmail.com";
+//      $CFG->denyemailaddresses = "hotmail.com yahoo.com";
 
 //=========================================================================
 // ALL DONE!  To continue installation, visit your main page with a browser

lang/en/moodle.php

@@ -372,6 +372,8 @@
 $string['emailexists'] = 'This email address is already registered.';
 $string['emailformat'] = 'Email format';
 $string['emailmustbereal'] = 'Note: your email address must be a real one';
+$string['emailnotallowed'] = 'Email addresses in these domains are not allowed ($a)';
+$string['emailonlyallowed'] = 'This email is not one of those that are allowed ($a)';
 $string['emailpasswordconfirmation'] = 'Hi $a->firstname,
 
 Someone (probably you) has requested a new password for your

lib/moodlelib.php

@@ -752,6 +752,12 @@ function create_user_record($username, $password, $auth='') {
         }
     }
 
+    if (!empty($newuser->email)) {
+        if (email_is_not_allowed($newuser->email)) {
+            unset($newuser->email);
+        }
+    }
+
     $newuser->auth = (empty($auth)) ? $CFG->auth : $auth;
     $newuser->username = $username;
     $newuser->password = md5($password);
@@ -1630,6 +1636,40 @@ function send_password_change_confirmation_email($user) {
 }
 
 
+function email_is_not_allowed($email) {
+/// Check that an email is allowed.  It returns an error message if there 
+/// was a problem.
+
+    global $CFG;
+
+    if (!empty($CFG->allowemailaddresses)) {
+        $allowed = explode(' ', $CFG->allowemailaddresses);
+        foreach ($allowed as $allowedpattern) {
+            $allowedpattern = trim($allowedpattern);
+            if (!$allowedpattern) {
+                continue;
+            }
+            if (strpos($email, $allowedpattern) !== false) {  // Match!
+                return false;
+            }
+        }
+        return get_string("emailonlyallowed", '', $CFG->allowemailaddresses);
+
+    } else if (!empty($CFG->denyemailaddresses)) {
+        $denied = explode(' ', $CFG->denyemailaddresses);
+        foreach ($denied as $deniedpattern) {
+            $deniedpattern = trim($deniedpattern);
+            if (!$deniedpattern) {
+                continue;
+            }
+            if (strpos($email, $deniedpattern) !== false) {   // Match!
+                return get_string("emailnotallowed", '', $CFG->denyemailaddresses);
+            }
+        }
+    }
+
+    return false;
+}
 
 
 /// FILE HANDLING  /////////////////////////////////////////////

login/signup.php

@@ -146,6 +146,12 @@ function validate_form($user, &$err) {
         $err->country = get_string("missingcountry");
     }
 
+    if (empty($err->email)) {
+        if ($error = email_is_not_allowed($user->email)) {
+            $err->email = $error;
+        }
+    }
+
     return;
 }
 

user/edit.php

@@ -246,15 +246,21 @@ function find_form_errors(&$user, &$usernew, &$err) {
     if (empty($usernew->country))
         $err["country"] = get_string("missingcountry");
 
-    if (! validate_email($usernew->email))
+    if (! validate_email($usernew->email)) {
         $err["email"] = get_string("invalidemail");
 
-    else if ($otheruser = get_record("user", "email", $usernew->email)) {
+    } else if ($otheruser = get_record("user", "email", $usernew->email)) {
         if ($otheruser->id <> $user->id) {
             $err["email"] = get_string("emailexists");
         }
     }
 
+    if (empty($err["email"]) and !isadmin()) {
+        if ($error = email_is_not_allowed($usernew->email)) {
+            $err["email"] = $error;
+        }
+    }
+
     $user->email = $usernew->email;
 
     return count($err);