Introduce connection context for Unix socket (valkey-io#1160)

Hide 'unixsocketgroup' and 'unixsocketperm' into a Unix socket specific
data structure. A single opaque pointer 'void *priv' is enough for a
listener. Once any new config is added, we don't need 'void *priv2',
'void *priv3' and so on.

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

src/config.c

@@ -3140,7 +3140,7 @@ standardConfig static_configs[] = {
     /* String Configs */
     createStringConfig("aclfile", NULL, IMMUTABLE_CONFIG, ALLOW_EMPTY_STRING, server.acl_filename, "", NULL, NULL),
     createStringConfig("unixsocket", NULL, IMMUTABLE_CONFIG, EMPTY_STRING_IS_NULL, server.unixsocket, NULL, NULL, NULL),
-    createStringConfig("unixsocketgroup", NULL, IMMUTABLE_CONFIG, EMPTY_STRING_IS_NULL, server.unixsocketgroup, NULL, NULL, NULL),
+    createStringConfig("unixsocketgroup", NULL, IMMUTABLE_CONFIG, EMPTY_STRING_IS_NULL, server.unix_ctx_config.group, NULL, NULL, NULL),
     createStringConfig("pidfile", NULL, IMMUTABLE_CONFIG, EMPTY_STRING_IS_NULL, server.pidfile, NULL, NULL, NULL),
     createStringConfig("replica-announce-ip", "slave-announce-ip", MODIFIABLE_CONFIG, EMPTY_STRING_IS_NULL, server.replica_announce_ip, NULL, NULL, NULL),
     createStringConfig("primaryuser", "masteruser", MODIFIABLE_CONFIG | SENSITIVE_CONFIG, EMPTY_STRING_IS_NULL, server.primary_user, NULL, NULL, NULL),
@@ -3234,7 +3234,7 @@ standardConfig static_configs[] = {
 
     /* Unsigned int configs */
     createUIntConfig("maxclients", NULL, MODIFIABLE_CONFIG, 1, UINT_MAX, server.maxclients, 10000, INTEGER_CONFIG, NULL, updateMaxclients),
-    createUIntConfig("unixsocketperm", NULL, IMMUTABLE_CONFIG, 0, 0777, server.unixsocketperm, 0, OCTAL_CONFIG, NULL, NULL),
+    createUIntConfig("unixsocketperm", NULL, IMMUTABLE_CONFIG, 0, 0777, server.unix_ctx_config.perm, 0, OCTAL_CONFIG, NULL, NULL),
     createUIntConfig("socket-mark-id", NULL, IMMUTABLE_CONFIG, 0, UINT_MAX, server.socket_mark_id, 0, INTEGER_CONFIG, NULL, NULL),
     createUIntConfig("max-new-connections-per-cycle", NULL, MODIFIABLE_CONFIG, 1, 1000, server.max_new_conns_per_cycle, 10, INTEGER_CONFIG, NULL, NULL),
     createUIntConfig("max-new-tls-connections-per-cycle", NULL, MODIFIABLE_CONFIG, 1, 1000, server.max_new_tls_conns_per_cycle, 1, INTEGER_CONFIG, NULL, NULL),

src/connection.h

@@ -144,8 +144,7 @@ struct connListener {
     int bindaddr_count;
     int port;
     ConnectionType *ct;
-    void *priv1; /* used by connection type specified data */
-    void *priv2; /* used by connection type specified data */
+    void *priv; /* used by connection type specified data */
 };
 
 /* The connection module does not deal with listening and accepting sockets,

src/rdma.c

@@ -748,7 +748,7 @@ static rdma_listener *rdmaFdToListener(connListener *listener, int fd) {
     for (int i = 0; i < listener->count; i++) {
         if (listener->fd[i] != fd) continue;
 
-        return (rdma_listener *)listener->priv1 + i;
+        return (rdma_listener *)listener->priv + i;
     }
 
     return NULL;
@@ -1537,7 +1537,7 @@ int connRdmaListen(connListener *listener) {
         bindaddr = default_bindaddr;
     }
 
-    listener->priv1 = rdma_listener = zcalloc_num(bindaddr_count, sizeof(*rdma_listener));
+    listener->priv = rdma_listener = zcalloc_num(bindaddr_count, sizeof(*rdma_listener));
     for (j = 0; j < bindaddr_count; j++) {
         char *addr = bindaddr[j];
         int optional = *addr == '-';
@@ -1757,13 +1757,13 @@ static int rdmaChangeListener(void) {
 
         aeDeleteFileEvent(server.el, listener->fd[i], AE_READABLE);
         listener->fd[i] = -1;
-        struct rdma_listener *rdma_listener = (struct rdma_listener *)listener->priv1 + i;
+        struct rdma_listener *rdma_listener = (struct rdma_listener *)listener->priv + i;
         rdma_destroy_id(rdma_listener->cm_id);
         rdma_destroy_event_channel(rdma_listener->cm_channel);
     }
 
     listener->count = 0;
-    zfree(listener->priv1);
+    zfree(listener->priv);
 
     closeListener(listener);
 

src/server.c

@@ -2818,8 +2818,7 @@ void initListeners(void) {
         listener->bindaddr = &server.unixsocket;
         listener->bindaddr_count = 1;
         listener->ct = connectionByType(CONN_TYPE_UNIX);
-        listener->priv1 = &server.unixsocketperm; /* Unix socket specified */
-        listener->priv2 = server.unixsocketgroup; /* Unix socket group specified */
+        listener->priv = &server.unix_ctx_config; /* Unix socket specified */
     }
 
     /* create all the configured listener, and add handler to start to accept */

src/server.h

@@ -1593,6 +1593,15 @@ typedef struct serverTLSContextConfig {
     int session_cache_timeout;
 } serverTLSContextConfig;
 
+/*-----------------------------------------------------------------------------
+ * Unix Context Configuration
+ *----------------------------------------------------------------------------*/
+
+typedef struct serverUnixContextConfig {
+    char *group;       /* UNIX socket group */
+    unsigned int perm; /* UNIX socket permission (see mode_t) */
+} serverUnixContextConfig;
+
 /*-----------------------------------------------------------------------------
  * AOF manifest definition
  *----------------------------------------------------------------------------*/
@@ -1704,8 +1713,6 @@ struct valkeyServer {
     int bindaddr_count;                    /* Number of addresses in server.bindaddr[] */
     char *bind_source_addr;                /* Source address to bind on for outgoing connections */
     char *unixsocket;                      /* UNIX socket path */
-    char *unixsocketgroup;                 /* UNIX socket group */
-    unsigned int unixsocketperm;           /* UNIX socket permission (see mode_t) */
     connListener listeners[CONN_TYPE_MAX]; /* TCP/Unix/TLS even more types */
     uint32_t socket_mark_id;               /* ID for listen socket marking */
     connListener clistener;                /* Cluster bus listener */
@@ -2202,6 +2209,7 @@ struct valkeyServer {
     int tls_replication;
     int tls_auth_clients;
     serverTLSContextConfig tls_ctx_config;
+    serverUnixContextConfig unix_ctx_config;
     /* cpu affinity */
     char *server_cpulist;      /* cpu affinity list of server main/io thread. */
     char *bio_cpulist;         /* cpu affinity list of bio thread. */

src/unix.c

@@ -51,8 +51,9 @@ static int connUnixIsLocal(connection *conn) {
 
 static int connUnixListen(connListener *listener) {
     int fd;
-    mode_t *perm = (mode_t *)listener->priv1;
-    char *group = (char *)listener->priv2;
+    serverUnixContextConfig *ctx_cfg = listener->priv;
+    mode_t perm = ctx_cfg->perm;
+    char *group = ctx_cfg->group;
 
     if (listener->bindaddr_count == 0) return C_OK;
 
@@ -62,7 +63,7 @@ static int connUnixListen(connListener *listener) {
         char *addr = listener->bindaddr[j];
 
         unlink(addr); /* don't care if this fails */
-        fd = anetUnixServer(server.neterr, addr, *perm, server.tcp_backlog, group);
+        fd = anetUnixServer(server.neterr, addr, perm, server.tcp_backlog, group);
         if (fd == ANET_ERR) {
             serverLog(LL_WARNING, "Failed opening Unix socket: %s", server.neterr);
             exit(1);