Add listeners info string for 'INFO' command

Suggested by Oran, add necessary listeners information in 'INFO'
command. It would be helpful for debug.

Example of this:
127.0.0.1:6379> INFO SERVER
redis_version:255.255.255
...
listener0:name=tcp,bind=127.0.0.1,port=6380
listener1:name=unix,bind=/run/redis.sock
listener2:name=tls,bind=127.0.0.1,port=6379
...

Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>

src/connection.c

@@ -183,3 +183,22 @@ int connTypeProcessPendingData(void) {
     return ret;
 }
 
+sds getListensInfoString(sds info) {
+    for (int j = 0; j < CONN_TYPE_MAX; j++) {
+        connListener *listener = &server.listeners[j];
+        if (listener->ct == NULL)
+            continue;
+
+        info = sdscatfmt(info, "listener%i:name=%s", j, listener->ct->get_type(NULL));
+        for (int i = 0; i < listener->count; i++) {
+            info = sdscatfmt(info, ",bind=%s", listener->bindaddr[i]);
+        }
+
+        if (listener->port)
+            info = sdscatfmt(info, ",port=%i", listener->port);
+
+        info = sdscatfmt(info, "\r\n");
+    }
+
+    return info;
+}

src/connection.h

@@ -275,7 +275,7 @@ static inline int connLastErrorRetryable(connection *conn) {
 }
 
 /* Get address information of a connection.
- * @remote works as boolean type to get local/remote address */
+ * remote works as boolean type to get local/remote address */
 static inline int connAddr(connection *conn, char *ip, size_t ip_len, int *port, int remote) {
     if (conn && conn->type->addr) {
         return conn->type->addr(conn, ip, ip_len, port, remote);
@@ -287,8 +287,8 @@ static inline int connAddr(connection *conn, char *ip, size_t ip_len, int *port,
 /* Format an IP,port pair into something easy to parse. If IP is IPv6
  * (matches for ":"), the ip is surrounded by []. IP and port are just
  * separated by colons. This the standard to display addresses within Redis. */
-static  inline int formatAddr(char *buf, size_t buf_len, char *ip, int port) {
+static inline int formatAddr(char *buf, size_t buf_len, char *ip, int port) {
-    return snprintf(buf,buf_len, strchr(ip,':') ?
+    return snprintf(buf, buf_len, strchr(ip,':') ?
            "[%s]:%d" : "%s:%d", ip, port);
 }
 
@@ -400,19 +400,19 @@ static inline connection *connCreate(ConnectionType *ct) {
 }
 
 /* Create a accepted connection of specified type.
- * @priv is connection type specified argument */
+ * priv is connection type specified argument */
 static inline connection *connCreateAccepted(ConnectionType *ct, int fd, void *priv) {
     return ct->conn_create_accepted(fd, priv);
 }
 
 /* Configure a connection type. A typical case is to configure TLS.
- * @priv is connection type specified,
+ * priv is connection type specified,
- * @reconfigure is boolean type to specify if overwrite the original config */
+ * reconfigure is boolean type to specify if overwrite the original config */
 static inline int connTypeConfigure(ConnectionType *ct, void *priv, int reconfigure) {
     return ct->configure(priv, reconfigure);
 }
 
-/* Walk all the connection type, and cleanup them all if possible */
+/* Walk all the connection types and cleanup them all if possible */
 void connTypeCleanupAll();
 
 /* Test all the connection type has pending data or not. */
@@ -433,6 +433,9 @@ static inline aeFileProc *connAcceptHandler(ConnectionType *ct) {
     return NULL;
 }
 
+/* Get Listeners information, note that caller should free the non-empty string */
+sds getListensInfoString(sds info);
+
 int RedisRegisterConnectionTypeSocket();
 int RedisRegisterConnectionTypeUnix();
 int RedisRegisterConnectionTypeTLS();

src/server.c

@@ -5426,6 +5426,9 @@ sds genRedisInfoString(dict *section_dict, int all_sections, int everything) {
                 "shutdown_in_milliseconds:%I\r\n",
                 (int64_t)(server.shutdown_mstime - server.mstime));
         }
+
+        /* get all the listeners information */
+        info = getListensInfoString(info);
     }
 
     /* Clients */