src/common/file-descriptor.hpp

   1 /*
   2  * Copyright (C) 2023 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #include <common/error.hpp>
   9 #include <common/format.hpp>
  10
  11 #include <algorithm>
  12
  13 #include <unistd.h>
  14
  15 namespace lttng {
  16
  17 /*
  18  * RAII wrapper around a UNIX file descriptor. A file_descriptor's underlying
  19  * file descriptor
  20  */
  21 class file_descriptor {
  22 public:
  23         explicit file_descriptor(int raw_fd) noexcept : _raw_fd{raw_fd}
  24         {
  25                 LTTNG_ASSERT(_is_valid_fd(_raw_fd));
  26         }
  27
  28         file_descriptor(const file_descriptor&) = delete;
  29
  30         file_descriptor(file_descriptor&& other) : _raw_fd{-1}
  31         {
  32                 LTTNG_ASSERT(_is_valid_fd(_raw_fd));
  33                 std::swap(_raw_fd, other._raw_fd);
  34         }
  35
  36         ~file_descriptor()
  37         {
  38                 if (!_is_valid_fd(_raw_fd)) {
  39                         return;
  40                 }
  41
  42                 const auto ret = ::close(_raw_fd);
  43                 if (ret) {
  44                         PERROR("%s",
  45                                         fmt::format("Failed to close file descriptor: fd = {}",
  46                                                         _raw_fd)
  47                                                         .c_str());
  48                 }
  49         }
  50
  51         int fd() const noexcept
  52         {
  53                 LTTNG_ASSERT(_is_valid_fd(_raw_fd));
  54                 return _raw_fd;
  55         }
  56
  57 private:
  58         static bool _is_valid_fd(int fd)
  59         {
  60                 return fd >= 0;
  61         }
  62
  63         int _raw_fd;
  64 };
  65
  66 } /* namespace lttng */