Added (fixed) support for abstract Unix sockets.

docs/changes.xml

@@ -37,6 +37,18 @@ increased the applications' startup timeout.
 </para>
 </change>
 
+<change type="change">
+<para>
+disallowed abstract Unix domain socket syntax in non-Linux systems.
+</para>
+</change>
+
+<change type="feature">
+<para>
+supporting abstract UNIX sockets.
+</para>
+</change>
+
 <change type="feature">
 <para>
 supporting UNIX sockets in address matching.

src/nxt_conf_validation.c

@@ -1480,9 +1480,14 @@ nxt_conf_vldt_listener(nxt_conf_validation_t *vldt, nxt_str_t *name,
     nxt_conf_value_t *value)
 {
     nxt_int_t       ret;
+    nxt_str_t       str;
     nxt_sockaddr_t  *sa;
 
-    sa = nxt_sockaddr_parse(vldt->pool, name);
+    if (nxt_slow_path(nxt_str_dup(vldt->pool, &str, name) == NULL)) {
+        return NXT_ERROR;
+    }
+
+    sa = nxt_sockaddr_parse(vldt->pool, &str);
     if (nxt_slow_path(sa == NULL)) {
         return nxt_conf_vldt_error(vldt,
                                    "The listener address \"%V\" is invalid.",

src/nxt_main_process.c

@@ -1187,7 +1187,9 @@ nxt_main_listening_socket(nxt_sockaddr_t *sa, nxt_listening_socket_t *ls)
 
 #if (NXT_HAVE_UNIX_DOMAIN)
 
-    if (sa->u.sockaddr.sa_family == AF_UNIX) {
+    if (sa->u.sockaddr.sa_family == AF_UNIX
+        && sa->u.sockaddr_un.sun_path[0] != '\0')
+    {
         char     *filename;
         mode_t   access;
 

src/nxt_sockaddr.c

@@ -601,8 +601,6 @@ nxt_sockaddr_unix_parse(nxt_mp_t *mp, nxt_str_t *addr)
 
     socklen = offsetof(struct sockaddr_un, sun_path) + length + 1;
 
-#if (NXT_LINUX)
-
     /*
      * Linux unix(7):
      *
@@ -612,12 +610,18 @@ nxt_sockaddr_unix_parse(nxt_mp_t *mp, nxt_str_t *addr)
      *   are covered by the specified length of the address structure.
      *   (Null bytes in the name have no special significance.)
      */
-    if (path[0] == '@') {
+    switch (path[0]) {
+    case '@':
         path[0] = '\0';
+        /* fall through */
+    case '\0':
         socklen--;
-    }
-
+#if !(NXT_LINUX)
+        nxt_thread_log_error(NXT_LOG_ERR,
+                             "abstract unix domain sockets are not supported");
+        return NULL;
 #endif
+    }
 
     sa = nxt_sockaddr_alloc(mp, socklen, addr->length);