res_pjsip_session: Prevent crash during shutdown.

pjproject does not have a function to reverse pjsip_inv_usage_init.
This means we need to ignore any calls to the functions once shutdown is
final.

ASTERISK-27571 #close

Change-Id: Ia550fcba563e2328f03162d79fb185f16b7c9b9d

diff --git a/res/res_pjsip_session.c b/res/res_pjsip_session.c
index b4fe0be775d25b7f570fa1f641c70d33fee17ea2..8939f4345bfa1e358589c5bbe4ffd2f17a5c5ba1 100644 (file)
--- a/res/res_pjsip_session.c
+++ b/res/res_pjsip_session.c
@@ -2601,9 +2601,13 @@ static void handle_incoming_before_media(pjsip_inv_session *inv,
 
 static void session_inv_on_state_changed(pjsip_inv_session *inv, pjsip_event *e)
 {
-       struct ast_sip_session *session = inv->mod_data[session_module.id];
+       struct ast_sip_session *session;
        pjsip_event_id_e type;
 
+       if (ast_shutdown_final()) {
+               return;
+       }
+
        if (e) {
                print_debug_details(inv, NULL, e);
                type = e->type;
@@ -2611,6 +2615,7 @@ static void session_inv_on_state_changed(pjsip_inv_session *inv, pjsip_event *e)
                type = PJSIP_EVENT_UNKNOWN;
        }
 
+       session = inv->mod_data[session_module.id];
        if (!session) {
                return;
        }
@@ -2703,13 +2708,7 @@ static void session_inv_on_tsx_state_changed(pjsip_inv_session *inv, pjsip_trans
        struct ast_sip_session *session;
        pjsip_tx_data *tdata;
 
-       /*
-        * A race condition exists at shutdown where the res_pjsip_session can be
-        * unloaded but this callback may still get called afterwards. In this case
-        * the id may end up being -1 which is useless to us. To work around this
-        * we store the current value and check/use it.
-        */
-       if (id < 0) {
+       if (ast_shutdown_final()) {
                return;
        }
 
@@ -3021,9 +3020,14 @@ static struct pjmedia_sdp_session *create_local_sdp(pjsip_inv_session *inv, stru
 
 static void session_inv_on_rx_offer(pjsip_inv_session *inv, const pjmedia_sdp_session *offer)
 {
-       struct ast_sip_session *session = inv->mod_data[session_module.id];
+       struct ast_sip_session *session;
        pjmedia_sdp_session *answer;
 
+       if (ast_shutdown_final()) {
+               return;
+       }
+
+       session = inv->mod_data[session_module.id];
        if (handle_incoming_sdp(session, offer)) {
                return;
        }
@@ -3042,9 +3046,14 @@ static void session_inv_on_create_offer(pjsip_inv_session *inv, pjmedia_sdp_sess
 
 static void session_inv_on_media_update(pjsip_inv_session *inv, pj_status_t status)
 {
-       struct ast_sip_session *session = inv->mod_data[session_module.id];
+       struct ast_sip_session *session;
        const pjmedia_sdp_session *local, *remote;
 
+       if (ast_shutdown_final()) {
+               return;
+       }
+
+       session = inv->mod_data[session_module.id];
        if (!session || !session->channel) {
                /*
                 * If we don't have a session or channel then we really
@@ -3067,10 +3076,15 @@ static void session_inv_on_media_update(pjsip_inv_session *inv, pj_status_t stat
 
 static pjsip_redirect_op session_inv_on_redirected(pjsip_inv_session *inv, const pjsip_uri *target, const pjsip_event *e)
 {
-       struct ast_sip_session *session = inv->mod_data[session_module.id];
+       struct ast_sip_session *session;
        const pjsip_sip_uri *uri;
 
-       if (!session->channel) {
+       if (ast_shutdown_final()) {
+               return PJSIP_REDIRECT_STOP;
+       }
+
+       session = inv->mod_data[session_module.id];
+       if (!session || !session->channel) {
                return PJSIP_REDIRECT_STOP;
        }