From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Mon, 3 May 2021 11:07:44 +0000 (+0300)
Subject: login-common: Add client.list_type to better track which linked list client belongs to
X-Git-Tag: 2.3.15~29
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a88734f71ddb2d2f0e90da53655f3196a01edb7d;p=thirdparty%2Fdovecot%2Fcore.git

login-common: Add client.list_type to better track which linked list client belongs to

Add asserts to make sure the client is always in the expected list.
---

diff --git a/src/login-common/client-common.c b/src/login-common/client-common.c
index 1d264d9f75..272de90158 100644
--- a/src/login-common/client-common.c
+++ b/src/login-common/client-common.c
@@ -233,6 +233,7 @@ void client_init(struct client *client, void **other_sets)
 {
 	if (last_client == NULL)
 		last_client = client;
+	client->list_type = CLIENT_LIST_TYPE_ACTIVE;
 	DLLIST_PREPEND(&clients, client);
 	clients_count++;
 
@@ -291,7 +292,9 @@ void client_disconnect(struct client *client, const char *reason,
 		if (client->iostream_fd_proxy != NULL) {
 			i_assert(!client->fd_proxying);
 			client->fd_proxying = TRUE;
+			i_assert(client->list_type == CLIENT_LIST_TYPE_DESTROYED);
 			DLLIST_REMOVE(&destroyed_clients, client);
+			client->list_type = CLIENT_LIST_TYPE_FD_PROXY;
 			DLLIST_PREPEND(&client_fd_proxies, client);
 			client_fd_proxies_count++;
 		}
@@ -311,7 +314,9 @@ void client_destroy(struct client *client, const char *reason)
 	/* move to destroyed_clients linked list before it's potentially
 	   added to client_fd_proxies. */
 	i_assert(!client->fd_proxying);
+	i_assert(client->list_type == CLIENT_LIST_TYPE_ACTIVE);
 	DLLIST_REMOVE(&clients, client);
+	client->list_type = CLIENT_LIST_TYPE_DESTROYED;
 	DLLIST_PREPEND(&destroyed_clients, client);
 
 	client_disconnect(client, reason, !client->login_success);
@@ -408,12 +413,15 @@ bool client_unref(struct client **_client)
 	ssl_iostream_destroy(&client->ssl_iostream);
 	iostream_proxy_unref(&client->iostream_fd_proxy);
 	if (client->fd_proxying) {
+		i_assert(client->list_type == CLIENT_LIST_TYPE_FD_PROXY);
 		DLLIST_REMOVE(&client_fd_proxies, client);
 		i_assert(client_fd_proxies_count > 0);
 		client_fd_proxies_count--;
 	} else {
+		i_assert(client->list_type == CLIENT_LIST_TYPE_DESTROYED);
 		DLLIST_REMOVE(&destroyed_clients, client);
 	}
+	client->list_type = CLIENT_LIST_TYPE_NONE;
 	i_stream_unref(&client->input);
 	o_stream_unref(&client->output);
 	i_close_fd(&client->fd);
diff --git a/src/login-common/client-common.h b/src/login-common/client-common.h
index 2c7c6ee036..bee965a4b8 100644
--- a/src/login-common/client-common.h
+++ b/src/login-common/client-common.h
@@ -81,6 +81,18 @@ enum client_auth_result {
 	CLIENT_AUTH_RESULT_ANONYMOUS_DENIED
 };
 
+enum client_list_type {
+	CLIENT_LIST_TYPE_NONE = 0,
+	/* clients (disconnected=FALSE, fd_proxying=FALSE, destroyed=FALSE) */
+	CLIENT_LIST_TYPE_ACTIVE,
+	/* destroyed_clients (destroyed=TRUE, fd_proxying=FALSE). Either the
+	   client will soon be freed or it's only referenced via
+	   "login_proxies". */
+	CLIENT_LIST_TYPE_DESTROYED,
+	/* client_fd_proxies (fd_proxying=TRUE) */
+	CLIENT_LIST_TYPE_FD_PROXY,
+};
+
 struct client_auth_reply {
 	const char *master_user, *reason;
 	enum client_auth_fail_code fail_code;
@@ -139,11 +151,9 @@ struct client_vfuncs {
 };
 
 struct client {
-	/* If disconnected=FALSE, the client is in "clients" list.
-	   If fd_proxying=TRUE, the client is in "client_fd_proxies" list.
-	   Otherwise, either the client will soon be freed or it's only
-	   referenced via "login_proxies" which doesn't use these pointers. */
 	struct client *prev, *next;
+	/* Specifies which linked list the client is in */
+	enum client_list_type list_type;
 
 	pool_t pool;
 	/* this pool gets free'd once proxying starts */