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         file_descriptor& operator=(const file_descriptor&) = delete;
  30         file_descriptor& operator=(file_descriptor&&) = delete;
  31
  32         file_descriptor(file_descriptor&& other) noexcept {
  33                 LTTNG_ASSERT(_is_valid_fd(_raw_fd));
  34                 std::swap(_raw_fd, other._raw_fd);
  35         }
  36
  37         ~file_descriptor()
  38         {
  39                 if (!_is_valid_fd(_raw_fd)) {
  40                         return;
  41                 }
  42
  43                 const auto ret = ::close(_raw_fd);
  44                 if (ret) {
  45                         PERROR("Failed to close file descriptor: fd=%i", _raw_fd);
  46                 }
  47         }
  48
  49         int fd() const noexcept
  50         {
  51                 LTTNG_ASSERT(_is_valid_fd(_raw_fd));
  52                 return _raw_fd;
  53         }
  54
  55 private:
  56         static bool _is_valid_fd(int fd)
  57         {
  58                 return fd >= 0;
  59         }
  60
  61         int _raw_fd = -1;
  62 };
  63
  64 } /* namespace lttng */