src/common/fd-handle.h

   1 /*
   2  * Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: LGPL-2.1-only
   5  *
   6  */
   7
   8 #ifndef FD_HANDLE_H
   9 #define FD_HANDLE_H
  10
  11 #include <common/macros.h>
  12
  13 /*
  14  * Wrapper around a file descriptor providing reference counting semantics.
  15  *
  16  * An fd_handle will close() the underlying file descriptor when its reference
  17  * count reaches zero.
  18  */
  19 struct fd_handle;
  20
  21 /* Create a file descriptor handle. */
  22 LTTNG_HIDDEN
  23 struct fd_handle *fd_handle_create(int fd);
  24
  25 /* Acquire reference to a file descriptor handle. */
  26 LTTNG_HIDDEN
  27 void fd_handle_get(struct fd_handle *handle);
  28
  29 /* Release reference to a file descriptor handle. */
  30 LTTNG_HIDDEN
  31 void fd_handle_put(struct fd_handle *handle);
  32
  33 /*
  34  * Return the underlying file descriptor of a file descriptor handle.
  35  *
  36  * This function can't fail.
  37  */
  38 LTTNG_HIDDEN
  39 int fd_handle_get_fd(struct fd_handle *handle);
  40
  41 /*
  42  * Obtain a copy of a file descriptor handle.
  43  *
  44  * On success, the caller becomes the sole owner of the returned file descriptor
  45  * handle. The underlying file descriptor is duplicated using dup(). Refer to
  46  * the system documentation for the semantics of dup() for this particular file
  47  * descriptor type.
  48  */
  49 LTTNG_HIDDEN
  50 struct fd_handle *fd_handle_copy(const struct fd_handle *handle);
  51
  52 #endif /* FS_HANDLE_H */