Index: main/manager.c
===================================================================
--- main/manager.c	(revision 49023)
+++ main/manager.c	(working copy)
@@ -106,6 +106,7 @@
 static AST_LIST_HEAD_STATIC(all_events, eventqent);
 
 static int displayconnects = 1;
+static int allowmultiplelogin;
 static int timestampevents;
 static int httptimeout = 60;
 
@@ -165,6 +166,7 @@
 	char *read;
 	char *write;
 	int displayconnects;	/*!< XXX unused */
+	int allowmultiplelogin; /* allow or disallow duplicate logins */
 	int keep;	/*!< mark entries created on a reload */
 	AST_LIST_ENTRY(ast_manager_user) list;
 };
@@ -398,6 +400,23 @@
 	return ret;
 }
 
+static int ast_get_manager_session_count_by_name(const char *name)
+{
+	struct mansession *session = NULL;
+	int count = 0;
+	
+	AST_LIST_TRAVERSE(&sessions, session, list)
+		if (!strcasecmp(session->username, name)) {
+			count++;
+			ast_verbose(VERBOSE_PREFIX_2 "Manager '%s' session count %d\n", name, count);
+		}
+			
+			
+	
+	return count;
+}
+
+
 /*!
  * lookup an entry in the list of registered users.
  * must be called with the list lock held.
@@ -2025,6 +2044,7 @@
 	char action[80] = "";
 	int ret = 0;
 	struct manager_action *tmp;
+	char *user = astman_get_header(m, "Username");
 
 	ast_copy_string(action, astman_get_header(m, "Action"), sizeof(action));
 	if (option_debug)
@@ -2039,6 +2059,17 @@
 		astman_send_error(s, m, "Permission denied");
 		return 0;
 	}
+	if (!strcasecmp(action, "Login")) {
+		/* Check for duplicate logins IF option is set */
+		if (!allowmultiplelogin) {
+        		if (ast_get_manager_session_count_by_name(user) > 0) {
+        			sleep(1);
+        			astman_send_error(s, m, "Login Already In Use");
+                        	return -1;
+                	}
+
+		}	
+	}
 	/* XXX should we protect the list navigation ? */
 	for (tmp = first_action ; tmp; tmp = tmp->next) {
 		if (!strcasecmp(action, tmp->action)) {
@@ -2985,6 +3016,8 @@
 				ast_log(LOG_WARNING, "Invalid address '%s' specified, using 0.0.0.0\n", val);
 				memset(&ami_desc.sin.sin_addr, 0, sizeof(ami_desc.sin.sin_addr));
 			}
+		} else if (!strcasecmp(var->name, "allowmultiplelogin")) { 
+			allowmultiplelogin = ast_true(val);
 		} else if (!strcasecmp(var->name, "displayconnects")) {
 			displayconnects = ast_true(val);
 		} else if (!strcasecmp(var->name, "timestampevents")) {
Index: configs/manager.conf.sample
===================================================================
--- configs/manager.conf.sample	(revision 49023)
+++ configs/manager.conf.sample	(working copy)
@@ -27,6 +27,7 @@
 ;httptimeout = 60
 bindaddr = 0.0.0.0
 
+
 ; Parameters that control AMI over TLS. ("enabled" must be set too).
 ; You can open a connection to this socket with e.g.
 ;
@@ -38,6 +39,8 @@
 ;   sslcert=/tmp/asterisk.pem	; path to the certificate.
 
 
+;
+allowmultiplelogin = yes		; IF set to no, rejects manager logins that are already in use.
 ;displayconnects = yes
 ;
 ; Add a Unix epoch timestamp to events (not action responses)