[gdm] session: Prevent memory leaks by removing strdup accessors

[Jasper St. Pierre <jstpierre src gnome org>]

commit 8fda79cda9b8a89ddcfe3a95436c2b92699d1869
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Thu Feb 13 14:48:00 2014 -0500

    session: Prevent memory leaks by removing strdup accessors
    
    gdm_session_get_* dup the strings they return, but not a lot of code
    frees the resulting strings. It's a lot easier to not dup the return
    values and make them const char *, as they won't ever change while
    some code holds onto them...

 daemon/gdm-session-worker.c      |    3 +-
 daemon/gdm-session.c             |   16 +++++++-------
 daemon/gdm-session.h             |   10 ++++----
 daemon/gdm-simple-slave.c        |   43 ++++++++++++++-----------------------
 daemon/gdm-slave.c               |    3 +-
 daemon/gdm-slave.h               |   10 ++++----
 daemon/gdm-xdmcp-chooser-slave.c |   10 ++++----
 7 files changed, 41 insertions(+), 54 deletions(-)
---
diff --git a/daemon/gdm-session-worker.c b/daemon/gdm-session-worker.c
index a664ebd..7c2e004 100644
--- a/daemon/gdm-session-worker.c
+++ b/daemon/gdm-session-worker.c
@@ -2758,7 +2758,7 @@ reauthentication_request_new (GdmSessionWorker      *worker,
 {
         ReauthenticationRequest *request;
         const char * const * environment;
-        char *address;
+        const char *address;
 
         environment = gdm_session_worker_get_environment (worker);
 
@@ -2807,7 +2807,6 @@ reauthentication_request_new (GdmSessionWorker      *worker,
         gdm_dbus_worker_complete_start_reauthentication (GDM_DBUS_WORKER (worker),
                                                          invocation,
                                                          address);
-        g_free (address);
 
         return request;
 }
diff --git a/daemon/gdm-session.c b/daemon/gdm-session.c
index 7beb8a3..7b6b5e2 100644
--- a/daemon/gdm-session.c
+++ b/daemon/gdm-session.c
@@ -2606,31 +2606,31 @@ gdm_session_start_reauthentication (GdmSession *session,
                                                      conversation);
 }
 
-char *
+const char *
 gdm_session_get_server_address (GdmSession *self)
 {
         g_return_val_if_fail (GDM_IS_SESSION (self), NULL);
 
-        return g_strdup (g_dbus_server_get_client_address (self->priv->outside_server));
+        return g_dbus_server_get_client_address (self->priv->outside_server);
 }
 
-char *
+const char *
 gdm_session_get_username (GdmSession *self)
 {
         g_return_val_if_fail (GDM_IS_SESSION (self), NULL);
 
-        return g_strdup (self->priv->selected_user);
+        return self->priv->selected_user;
 }
 
-char *
+const char *
 gdm_session_get_display_device (GdmSession *self)
 {
         g_return_val_if_fail (GDM_IS_SESSION (self), NULL);
 
-        return g_strdup (self->priv->display_device);
+        return self->priv->display_device;
 }
 
-char *
+const char *
 gdm_session_get_display_seat_id (GdmSession *self)
 {
         g_return_val_if_fail (GDM_IS_SESSION (self), NULL);
@@ -2638,7 +2638,7 @@ gdm_session_get_display_seat_id (GdmSession *self)
         return g_strdup (self->priv->display_seat_id);
 }
 
-char *
+const char *
 gdm_session_get_session_id (GdmSession *self)
 {
         GdmSessionConversation *conversation;
diff --git a/daemon/gdm-session.h b/daemon/gdm-session.h
index 33ff43a..fb190bf 100644
--- a/daemon/gdm-session.h
+++ b/daemon/gdm-session.h
@@ -105,11 +105,11 @@ void              gdm_session_start_reauthentication (GdmSession *session,
                                                       GPid        pid_of_caller,
                                                       uid_t       uid_of_caller);
 
-char             *gdm_session_get_server_address          (GdmSession     *session);
-char             *gdm_session_get_username                (GdmSession     *session);
-char             *gdm_session_get_display_device          (GdmSession     *session);
-char             *gdm_session_get_display_seat_id         (GdmSession     *session);
-char             *gdm_session_get_session_id              (GdmSession     *session);
+const char       *gdm_session_get_server_address          (GdmSession     *session);
+const char       *gdm_session_get_username                (GdmSession     *session);
+const char       *gdm_session_get_display_device          (GdmSession     *session);
+const char       *gdm_session_get_display_seat_id         (GdmSession     *session);
+const char       *gdm_session_get_session_id              (GdmSession     *session);
 gboolean          gdm_session_bypasses_xsession           (GdmSession     *session);
 
 void              gdm_session_start_conversation          (GdmSession *session,
diff --git a/daemon/gdm-simple-slave.c b/daemon/gdm-simple-slave.c
index a58368d..86a8328 100644
--- a/daemon/gdm-simple-slave.c
+++ b/daemon/gdm-simple-slave.c
@@ -252,8 +252,8 @@ on_session_started (GdmSession       *session,
                     int               pid,
                     GdmSimpleSlave   *slave)
 {
-        char *username;
-        char *session_id;
+        const char *username;
+        const char *session_id;
 
         g_debug ("GdmSimpleSlave: session started %d", pid);
 
@@ -261,14 +261,12 @@ on_session_started (GdmSession       *session,
 
         session_id = gdm_session_get_session_id (session);
         g_object_set (GDM_SLAVE (slave), "session-id", session_id, NULL);
-        g_free (session_id);
 
         /* Run the PreSession script. gdmslave suspends until script has terminated */
         username = gdm_session_get_username (slave->priv->session);
         if (username != NULL) {
                 gdm_slave_run_script (GDM_SLAVE (slave), GDMCONFDIR "/PreSession", username);
         }
-        g_free (username);
 
         /* FIXME: should we do something here?
          * Note that error return status from PreSession script should
@@ -282,8 +280,8 @@ on_session_started (GdmSession       *session,
 static void
 gdm_simple_slave_grant_console_permissions (GdmSimpleSlave *slave)
 {
-        char *username;
-        char *display_device;
+        const char *username;
+        const char *display_device;
         struct passwd *passwd_entry;
 
         username = gdm_session_get_username (slave->priv->session);
@@ -318,8 +316,8 @@ gdm_simple_slave_grant_console_permissions (GdmSimpleSlave *slave)
 static void
 gdm_simple_slave_revoke_console_permissions (GdmSimpleSlave *slave)
 {
-        char *username;
-        char *display_device;
+        const char *username;
+        const char *display_device;
 
         username = gdm_session_get_username (slave->priv->session);
         display_device = gdm_session_get_display_device (slave->priv->session);
@@ -342,9 +340,6 @@ gdm_simple_slave_revoke_console_permissions (GdmSimpleSlave *slave)
                 g_debug ("Not calling di_devperm_logout logout for user %s, device %s",
                          username, display_device);
         }
-
-        g_free (username);
-        g_free (display_device);
 }
 #endif  /* HAVE_LOGINDEVPERM */
 
@@ -376,14 +371,13 @@ static gboolean
 add_user_authorization (GdmSimpleSlave *slave,
                         char          **filename)
 {
-        char    *username;
+        const char *username;
         gboolean ret;
 
         username = gdm_session_get_username (slave->priv->session);
         ret = gdm_slave_add_user_authorization (GDM_SLAVE (slave),
                                                 username,
                                                 filename);
-        g_free (username);
 
         return ret;
 }
@@ -435,8 +429,8 @@ static gboolean
 switch_to_and_unlock_session (GdmSimpleSlave  *slave,
                               gboolean         fail_if_already_switched)
 {
-        char    *username;
-        char    *session_id;
+        const char *username;
+        const char *session_id;
         gboolean res;
 
         username = gdm_session_get_username (slave->priv->session);
@@ -446,8 +440,6 @@ switch_to_and_unlock_session (GdmSimpleSlave  *slave,
 
         /* try to switch to an existing session */
         res = gdm_slave_switch_to_user_session (GDM_SLAVE (slave), username, session_id, 
fail_if_already_switched);
-        g_free (username);
-        g_free (session_id);
 
         return res;
 }
@@ -455,7 +447,7 @@ switch_to_and_unlock_session (GdmSimpleSlave  *slave,
 static void
 stop_greeter (GdmSimpleSlave *slave)
 {
-        char *username;
+        const char *username;
         gboolean script_successful;
 
         g_debug ("GdmSimpleSlave: Stopping greeter");
@@ -476,7 +468,6 @@ stop_greeter (GdmSimpleSlave *slave)
         } else {
                 script_successful = TRUE;
         }
-        g_free (username);
 
         if (!script_successful) {
                 g_debug ("GdmSimpleSlave: PostLogin script unsuccessful");
@@ -1554,11 +1545,11 @@ gdm_simple_slave_run (GdmSimpleSlave *slave)
 }
 
 static gboolean
-gdm_simple_slave_open_session (GdmSlave  *slave,
-                               GPid       pid_of_caller,
-                               uid_t      uid_of_caller,
-                               char     **address,
-                               GError   **error)
+gdm_simple_slave_open_session (GdmSlave    *slave,
+                               GPid         pid_of_caller,
+                               uid_t        uid_of_caller,
+                               const char **address,
+                               GError     **error)
 {
         GdmSimpleSlave     *self = GDM_SIMPLE_SLAVE (slave);
         uid_t               allowed_user;
@@ -1582,7 +1573,6 @@ gdm_simple_slave_open_session (GdmSlave  *slave,
         }
 
         *address = gdm_session_get_server_address (self->priv->session);
-
         return TRUE;
 }
 
@@ -1694,7 +1684,7 @@ gdm_simple_slave_stop (GdmSlave *slave)
                          (GDestroyNotify) g_free);
 
         if (self->priv->session_is_running) {
-                char *username;
+                const char *username;
 
                 /* Run the PostSession script. gdmslave suspends until script
                  * has terminated
@@ -1703,7 +1693,6 @@ gdm_simple_slave_stop (GdmSlave *slave)
                 if (username != NULL) {
                         gdm_slave_run_script (slave, GDMCONFDIR "/PostSession", username);
                 }
-                g_free (username);
 
 #ifdef  HAVE_LOGINDEVPERM
                 gdm_simple_slave_revoke_console_permissions (self);
diff --git a/daemon/gdm-slave.c b/daemon/gdm-slave.c
index b1ba04f..a592ab0 100644
--- a/daemon/gdm-slave.c
+++ b/daemon/gdm-slave.c
@@ -1681,7 +1681,7 @@ handle_open_session (GdmDBusSlave          *skeleton,
 {
         GError        *error;
         GdmSlaveClass *slave_class;
-        char          *address;
+        const char    *address;
 
         slave_class = GDM_SLAVE_GET_CLASS (slave);
         if (slave_class->open_session == NULL) {
@@ -1705,7 +1705,6 @@ handle_open_session (GdmDBusSlave          *skeleton,
 
         gdm_dbus_slave_complete_open_session (skeleton, invocation, address);
 
-        g_free (address);
         return TRUE;
 }
 
diff --git a/daemon/gdm-slave.h b/daemon/gdm-slave.h
index 9808433..c442806 100644
--- a/daemon/gdm-slave.h
+++ b/daemon/gdm-slave.h
@@ -50,11 +50,11 @@ typedef struct
         gboolean (*start) (GdmSlave *slave);
         gboolean (*stop)  (GdmSlave *slave);
 
-        gboolean     (*open_session)       (GdmSlave   *slave,
-                                            GPid        pid_of_caller,
-                                            uid_t       uid_of_caller,
-                                            char      **address,
-                                            GError    **error);
+        gboolean     (*open_session)       (GdmSlave    *slave,
+                                            GPid         pid_of_caller,
+                                            uid_t        uid_of_caller,
+                                            const char **address,
+                                            GError     **error);
 
         void     (*open_reauthentication_channel) (GdmSlave            *slave,
                                                    const char          *username,
diff --git a/daemon/gdm-xdmcp-chooser-slave.c b/daemon/gdm-xdmcp-chooser-slave.c
index 0a90130..53baf9a 100644
--- a/daemon/gdm-xdmcp-chooser-slave.c
+++ b/daemon/gdm-xdmcp-chooser-slave.c
@@ -346,11 +346,11 @@ gdm_xdmcp_chooser_slave_stop (GdmSlave *slave)
 }
 
 static gboolean
-gdm_xdmcp_chooser_slave_open_session (GdmSlave  *slave,
-                                      GPid       pid_of_caller,
-                                      uid_t      uid_of_caller,
-                                      char     **address,
-                                      GError   **error)
+gdm_xdmcp_chooser_slave_open_session (GdmSlave    *slave,
+                                      GPid         pid_of_caller,
+                                      uid_t        uid_of_caller,
+                                      const char **address,
+                                      GError     **error)
 {
         GdmXdmcpChooserSlave *self = GDM_XDMCP_CHOOSER_SLAVE (slave);
         GdmSession           *session;