libcxx/test/std/input.output/filesystems/fs.op.funcs/fs.op.copy_file/copy_file_procfs.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14
  10 // REQUIRES: linux
  11 // UNSUPPORTED: no-filesystem
  12 // XFAIL: no-localization
  13 // UNSUPPORTED: availability-filesystem-missing
  14
  15 // <filesystem>
  16
  17 // bool copy_file(const path& from, const path& to);
  18 // bool copy_file(const path& from, const path& to, error_code& ec) noexcept;
  19 // bool copy_file(const path& from, const path& to, copy_options options);
  20 // bool copy_file(const path& from, const path& to, copy_options options,
  21 //           error_code& ec) noexcept;
  22
  23 #include <cassert>
  24 #include <filesystem>
  25 #include <system_error>
  26
  27 #include "test_macros.h"
  28 #include "filesystem_test_helper.h"
  29
  30 namespace fs = std::filesystem;
  31
  32 // Linux has various virtual filesystems such as /proc and /sys
  33 // where files may have no length (st_size == 0), but still contain data.
  34 // This is because the to-be-read data is usually generated ad-hoc by the reading syscall
  35 // These files can not be copied with kernel-side copies like copy_file_range or sendfile,
  36 // and must instead be copied via a traditional userspace read + write loop.
  37 int main(int, char** argv) {
  38   const fs::path procfile{"/proc/self/comm"};
  39   assert(file_size(procfile) == 0);
  40
  41   scoped_test_env env;
  42   std::error_code ec = GetTestEC();
  43
  44   const fs::path dest = env.make_env_path("dest");
  45
  46   assert(copy_file(procfile, dest, ec));
  47   assert(!ec);
  48
  49   // /proc/self/comm contains the filename of the executable, plus a null terminator
  50   assert(file_size(dest) == fs::path(argv[0]).filename().string().size() + 1);
  51
  52   return 0;
  53 }