Replace mutex for listener->connections with TID check

The controlconf channel runs single-threaded on the main thread.
Replace the listener->connections locking with check that we are still
running on the thread with TID 0.

diff --git a/bin/named/controlconf.c b/bin/named/controlconf.c
index 9044d4dce4f887145bea7940d7dec388a9bf74d4..5dbc97106f30928d37be1a8f92e56c94fd78e94c 100644 (file)
--- a/bin/named/controlconf.c
+++ b/bin/named/controlconf.c
@@ -94,7 +94,6 @@ struct controllistener {
        bool exiting;
        isc_refcount_t references;
        controlkeylist_t keys;
-       isc_mutex_t connections_lock;
        controlconnectionlist_t connections;
        isc_socktype_t type;
        uint32_t perm;
@@ -170,9 +169,9 @@ free_controlkeylist(controlkeylist_t *keylist, isc_mem_t *mctx) {
 
 static void
 free_listener(controllistener_t *listener) {
-       INSIST(listener->exiting);
-       INSIST(ISC_LIST_EMPTY(listener->connections));
-
+       REQUIRE(isc_tid() == 0);
+       REQUIRE(listener->exiting);
+       REQUIRE(ISC_LIST_EMPTY(listener->connections));
        REQUIRE(listener->sock == NULL);
 
        free_controlkeylist(&listener->keys, listener->mctx);
@@ -180,7 +179,6 @@ free_listener(controllistener_t *listener) {
        if (listener->acl != NULL) {
                dns_acl_detach(&listener->acl);
        }
-       isc_mutex_destroy(&listener->connections_lock);
 
        isc_mem_putanddetach(&listener->mctx, listener, sizeof(*listener));
 }
@@ -195,6 +193,7 @@ ISC_REFCOUNT_IMPL(controlconnection, conn_free);
 
 static void
 shutdown_listener(controllistener_t *listener) {
+       REQUIRE(isc_tid() == 0);
        if (!listener->exiting) {
                char socktext[ISC_SOCKADDR_FORMATSIZE];
 
@@ -267,6 +266,8 @@ cleanup_sendhandle:
        if (result != ISC_R_SUCCESS) {
                control_recvmessage(handle, result, conn);
        }
+
+       REQUIRE(isc_tid() == 0);
        controlconnection_detach(&conn);
 }
 
@@ -373,6 +374,7 @@ control_respond(controlconnection_t *conn) {
        r.base = conn->buffer->base;
        r.length = conn->buffer->used;
 
+       REQUIRE(isc_tid() == 0);
        controlconnection_ref(conn);
        isccc_ccmsg_sendmessage(&conn->ccmsg, &r, control_senddone, conn);
 
@@ -390,6 +392,8 @@ control_command(void *arg) {
                        conn->request, listener->readonly, &conn->text);
                control_respond(conn);
        }
+
+       REQUIRE(isc_tid() == 0);
        controlconnection_detach(&conn);
 }
 
@@ -528,6 +532,7 @@ control_recvmessage(isc_nmhandle_t *handle ISC_ATTR_UNUSED, isc_result_t result,
        /*
         * Trigger the command.
         */
+       REQUIRE(isc_tid() == 0);
        controlconnection_ref(conn);
        isc_async_run(named_g_mainloop, control_command, conn);
 
@@ -535,11 +540,15 @@ control_recvmessage(isc_nmhandle_t *handle ISC_ATTR_UNUSED, isc_result_t result,
 
 cleanup:
        conn->shuttingdown = true;
+
+       REQUIRE(isc_tid() == 0);
        controlconnection_detach(&conn);
 }
 
 static void
 conn_free(controlconnection_t *conn) {
+       REQUIRE(isc_tid() == 0);
+
        controllistener_t *listener = conn->listener;
 
        conn_cleanup(conn);
@@ -548,9 +557,7 @@ conn_free(controlconnection_t *conn) {
                isc_buffer_free(&conn->buffer);
        }
 
-       LOCK(&listener->connections_lock);
        ISC_LIST_UNLINK(listener->connections, conn, link);
-       UNLOCK(&listener->connections_lock);
 #ifdef ENABLE_AFL
        if (named_g_fuzz_type == isc_fuzz_rndc) {
                named_fuzz_notify();
@@ -570,6 +577,8 @@ conn_free(controlconnection_t *conn) {
 
 static void
 newconnection(controllistener_t *listener, isc_nmhandle_t *handle) {
+       REQUIRE(isc_tid() == 0);
+
        controlconnection_t *conn = isc_mem_get(listener->mctx, sizeof(*conn));
        isc_log_write(named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
                      NAMED_LOGMODULE_CONTROL, ISC_LOG_DEBUG(3),
@@ -586,9 +595,7 @@ newconnection(controllistener_t *listener, isc_nmhandle_t *handle) {
        /* Set a 32 KiB upper limit on incoming message. */
        isccc_ccmsg_setmaxsize(&conn->ccmsg, 32768);
 
-       LOCK(&listener->connections_lock);
        ISC_LIST_INITANDAPPEND(listener->connections, conn, link);
-       UNLOCK(&listener->connections_lock);
 
        isccc_ccmsg_readmessage(&conn->ccmsg, control_recvmessage, conn);
 }
@@ -1041,7 +1048,6 @@ add_listener(named_controls_t *cp, controllistener_t **listenerp,
                                         .address = *addr,
                                         .type = type };
        isc_mem_attach(mctx, &listener->mctx);
-       isc_mutex_init(&listener->connections_lock);
        ISC_LINK_INIT(listener, link);
        ISC_LIST_INIT(listener->keys);
        ISC_LIST_INIT(listener->connections);