From 0771475394887e3635e67196fa6f56486fa2126c Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 24 Jun 2011 20:46:22 +0200
Subject: [PATCH] logind: when generating session ids with a counter, retry if
 session is already allocated

---
 src/logind-dbus.c | 33 ++++++++++++++++++++++-----------
 src/logind.h      |  1 +
 2 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/src/logind-dbus.c b/src/logind-dbus.c
index 0f3de41fff2..2bad549fc52 100644
--- a/src/logind-dbus.c
+++ b/src/logind-dbus.c
@@ -176,7 +176,7 @@ static int bus_manager_create_session(Manager *m, DBusMessage *message, DBusMess
         Seat *s;
         DBusMessageIter iter;
         int r;
-        char *id, *p;
+        char *id = NULL, *p;
         int vtnr = -1;
         int pipe_fds[2] = { -1, -1 };
         DBusMessage *reply = NULL;
@@ -306,19 +306,30 @@ static int bus_manager_create_session(Manager *m, DBusMessage *message, DBusMess
 
         audit_session_from_pid(leader, &audit_id);
 
-        if (audit_id > 0)
+        if (audit_id > 0) {
                 asprintf(&id, "%lu", (unsigned long) audit_id);
-        else
-                asprintf(&id, "c%lu", ++m->session_counter);
 
-        if (!id) {
-                r = -ENOMEM;
-                goto fail;
-        }
+                if (!id) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
 
-        if (hashmap_get(m->sessions, id)) {
-                r = -EEXIST;
-                goto fail;
+                if (hashmap_get(m->sessions, id)) {
+                        r = -EEXIST;
+                        goto fail;
+                }
+
+        } else {
+                do {
+                        free(id);
+                        asprintf(&id, "c%lu", ++m->session_counter);
+
+                        if (!id) {
+                                r = -ENOMEM;
+                                goto fail;
+                        }
+
+                } while (hashmap_get(m->sessions, id));
         }
 
         r = manager_add_session(m, user, id, &session);
diff --git a/src/logind.h b/src/logind.h
index d8674e75116..2b9b702f3d9 100644
--- a/src/logind.h
+++ b/src/logind.h
@@ -40,6 +40,7 @@
  * subscribe to fd HUP
  * D-Bus method: AttachDevice(seat, device);
  * D-Bus method: PermitLinger(user, bool b);
+ * properly handle if two sessions with the same loginuid are attempted to be created
  *
  * non-local X11 server
  * reboot/shutdown halt management