linux: fix bind/connect for abstract sockets (#4266)

The `\0` character has no special significance in abstract sockets, so
the addrlen field in both `bind()` and `connect()` should take that into
account.

src/unix/pipe.c

@@ -66,6 +66,7 @@ int uv_pipe_bind2(uv_pipe_t* handle,
   char* pipe_fname;
   int sockfd;
   int err;
+  socklen_t addrlen;
 
   pipe_fname = NULL;
 
@@ -100,12 +101,15 @@ int uv_pipe_bind2(uv_pipe_t* handle,
    * We unlink the file later but abstract sockets disappear
    * automatically since they're not real file system entities.
    */
-  if (*name != '\0') {
+  if (*name == '\0') {
+    addrlen = offsetof(struct sockaddr_un, sun_path) + namelen;
+  } else {
     pipe_fname = uv__malloc(namelen + 1);
     if (pipe_fname == NULL)
       return UV_ENOMEM;
     memcpy(pipe_fname, name, namelen);
     pipe_fname[namelen] = '\0';
+    addrlen = sizeof saddr;
   }
 
   err = uv__socket(AF_UNIX, SOCK_STREAM, 0);
@@ -117,7 +121,7 @@ int uv_pipe_bind2(uv_pipe_t* handle,
   memcpy(&saddr.sun_path, name, namelen);
   saddr.sun_family = AF_UNIX;
 
-  if (bind(sockfd, (struct sockaddr*)&saddr, sizeof saddr)) {
+  if (bind(sockfd, (struct sockaddr*)&saddr, addrlen)) {
     err = UV__ERR(errno);
     /* Convert ENOENT to EACCES for compatibility with Windows. */
     if (err == UV_ENOENT)
@@ -251,6 +255,7 @@ int uv_pipe_connect2(uv_connect_t* req,
   int new_sock;
   int err;
   int r;
+  socklen_t addrlen;
 
   if (flags & ~UV_PIPE_NO_TRUNCATE)
     return UV_EINVAL;
@@ -285,9 +290,13 @@ int uv_pipe_connect2(uv_connect_t* req,
   memcpy(&saddr.sun_path, name, namelen);
   saddr.sun_family = AF_UNIX;
 
+  if (*name == '\0')
+    addrlen = offsetof(struct sockaddr_un, sun_path) + namelen;
+  else
+    addrlen = sizeof saddr;
+
   do {
-    r = connect(uv__stream_fd(handle),
-                (struct sockaddr*)&saddr, sizeof saddr);
+    r = connect(uv__stream_fd(handle), (struct sockaddr*)&saddr, addrlen);
   }
   while (r == -1 && errno == EINTR);
 

test/test-pipe-getsockname.c

@@ -60,8 +60,8 @@ static void pipe_client_connect_cb(uv_connect_t* req, int status) {
 
   if (*buf == '\0') {  /* Linux abstract socket. */
     const char expected[] = "\0" TEST_PIPENAME;
-    ASSERT_GE(len, sizeof(expected));
-    ASSERT_MEM_EQ(buf, expected, sizeof(expected));
+    ASSERT_EQ(len, sizeof(expected) - 1);
+    ASSERT_MEM_EQ(buf, expected, len);
   } else {
     ASSERT_NE(0, buf[len - 1]);
     ASSERT_MEM_EQ(buf, TEST_PIPENAME, len);
@@ -191,7 +191,8 @@ TEST_IMPL(pipe_getsockname_abstract) {
   ASSERT_OK(uv_pipe_init(uv_default_loop(), &pipe_server, 0));
   ASSERT_OK(uv_pipe_bind2(&pipe_server, name, sizeof(name) - 1, 0));
   ASSERT_OK(uv_pipe_getsockname(&pipe_server, buf, &buflen));
-  ASSERT_MEM_EQ(name, buf, sizeof(name));
+  ASSERT_UINT64_EQ(sizeof(name) - 1, buflen);
+  ASSERT_MEM_EQ(name, buf, buflen);
   ASSERT_OK(uv_listen((uv_stream_t*) &pipe_server,
                       0,
                       pipe_server_connection_cb));