shard_connection: Support abstract Unix socket clients

Author: LINKIWI

shard_connection.cpp

@@ -128,7 +128,7 @@ verify_request::~verify_request(void)
 
 shard_connection::shard_connection(unsigned int id, connections_manager* conns_man, benchmark_config* config,
                                    struct event_base* event_base, abstract_protocol* abs_protocol) :
-        m_address(NULL), m_port(NULL), m_unix_sockaddr(NULL),
+        m_address(NULL), m_port(NULL), m_unix_sockaddr(NULL), m_unix_sockaddrlen(0),
         m_bev(NULL), m_request_per_cur_interval(0), m_pending_resp(0), m_connection_state(conn_disconnected),
         m_hello(setup_done), m_authentication(setup_done), m_db_selection(setup_done), m_cluster_slots(setup_done) {
     m_id = id;
@@ -140,9 +140,19 @@ shard_connection::shard_connection(unsigned int id, connections_manager* conns_m
         m_unix_sockaddr = (struct sockaddr_un *) malloc(sizeof(struct sockaddr_un));
         assert(m_unix_sockaddr != NULL);
 
+        memset(m_unix_sockaddr, 0, sizeof(struct sockaddr_un));
         m_unix_sockaddr->sun_family = AF_UNIX;
-        strncpy(m_unix_sockaddr->sun_path, m_config->unix_socket, sizeof(m_unix_sockaddr->sun_path)-1);
-        m_unix_sockaddr->sun_path[sizeof(m_unix_sockaddr->sun_path)-1] = '\0';
+
+        // Consider any Unix socket path prefixed with @ an abstract socket.
+        // In this scenario, sun_path[0] must be a null byte, and addrlen should be terminated at
+        // exactly the socket name length; see the manpage for unix(7).
+        if (m_config->unix_socket[0] == '@') {
+            strncpy(&m_unix_sockaddr->sun_path[1], &m_config->unix_socket[1], strlen(m_config->unix_socket)-1);
+            m_unix_sockaddrlen = offsetof(struct sockaddr_un, sun_path) + strlen(m_config->unix_socket);
+        } else {
+            strncpy(m_unix_sockaddr->sun_path, m_config->unix_socket, sizeof(m_unix_sockaddr->sun_path)-1);
+            m_unix_sockaddrlen = sizeof(struct sockaddr_un);
+        }
     }
 
     m_protocol = abs_protocol->clone();
@@ -279,7 +289,7 @@ int shard_connection::connect(struct connect_info* addr) {
 
     if (bufferevent_socket_connect(m_bev,
                   m_unix_sockaddr ? (struct sockaddr *) m_unix_sockaddr : addr->ci_addr,
-                  m_unix_sockaddr ? sizeof(struct sockaddr_un) : addr->ci_addrlen) == -1) {
+                  m_unix_sockaddr ? m_unix_sockaddrlen : addr->ci_addrlen) == -1) {
         disconnect();
 
         benchmark_error_log("connect failed, error = %s\n", strerror(errno));

shard_connection.h

@@ -160,6 +160,7 @@ class shard_connection {
     std::string m_readable_id;
 
     struct sockaddr_un* m_unix_sockaddr;
+    int m_unix_sockaddrlen;
     struct bufferevent *m_bev;
     struct event_base* m_event_base;
     struct event* m_event_timer;