Kernel: Support sys$connect to LocalSockets with short sockaddr_uns

This is not explicitly specified by POSIX, but is supported by other
*nixes, already supported by our sys$bind, and expected by various
programs. While were here, also clean up the user memory copies a bit.

Kernel/Net/LocalSocket.cpp

@@ -159,29 +159,23 @@ ErrorOr<void> LocalSocket::bind(Userspace<sockaddr const*> user_address, socklen
     return {};
 }
 
-ErrorOr<void> LocalSocket::connect(OpenFileDescription& description, Userspace<sockaddr const*> address, socklen_t address_size, ShouldBlock)
+ErrorOr<void> LocalSocket::connect(OpenFileDescription& description, Userspace<sockaddr const*> user_address, socklen_t address_size, ShouldBlock)
 {
     VERIFY(!m_bound);
-    if (address_size != sizeof(sockaddr_un))
+
+    if (address_size > sizeof(sockaddr_un))
         return set_so_error(EINVAL);
-    u16 sa_family_copy;
-    auto* user_address = reinterpret_cast<sockaddr const*>(address.unsafe_userspace_ptr());
-    SOCKET_TRY(copy_from_user(&sa_family_copy, &user_address->sa_family, sizeof(u16)));
-    if (sa_family_copy != AF_LOCAL)
+
+    sockaddr_un address = {};
+    SOCKET_TRY(copy_from_user(&address, user_address, address_size));
+
+    if (address.sun_family != AF_LOCAL)
         return set_so_error(EINVAL);
+
     if (is_connected())
         return set_so_error(EISCONN);
 
-    OwnPtr<KString> maybe_path;
-    {
-        auto const& local_address = *reinterpret_cast<sockaddr_un const*>(user_address);
-        char safe_address[sizeof(local_address.sun_path) + 1] = { 0 };
-        SOCKET_TRY(copy_from_user(&safe_address[0], &local_address.sun_path[0], sizeof(safe_address) - 1));
-        safe_address[sizeof(safe_address) - 1] = '\0';
-        maybe_path = SOCKET_TRY(KString::try_create(safe_address));
-    }
-
-    auto path = maybe_path.release_nonnull();
+    auto path = SOCKET_TRY(KString::try_create(StringView { address.sun_path, strnlen(address.sun_path, sizeof(address.sun_path)) }));
     dbgln_if(LOCAL_SOCKET_DEBUG, "LocalSocket({}) connect({})", this, *path);
 
     auto file = SOCKET_TRY(VirtualFileSystem::the().open(path->view(), O_RDWR, 0, Process::current().current_directory()));