1 /* GIO - GLib Input, Output and Streaming Library
3 * Copyright © 2009 Codethink Limited
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU Lesser General Public License as published
7 * by the Free Software Foundation; either version 2 of the licence or (at
8 * your option) any later version.
10 * See the included COPYING file for more information.
12 * Authors: Ryan Lortie <desrt@desrt.ca>
16 * SECTION: gunixfdlist
18 * @short_description: An object containing a set of file descriptors
19 * @see_also: #GUnixFDMessage
21 * A #GUnixFDList contains a list of file descriptors. It owns the file
22 * descriptors that it contains, closing them when finalized.
24 * It may be wrapped in a #GUnixFDMessage and sent over a #GSocket in
25 * the %G_SOCKET_ADDRESS_UNIX family by using g_socket_send_message()
26 * and received using g_socket_receive_message().
29 #define _GNU_SOURCE /* for F_DUPFD_CLOEXEC */
33 #include <sys/types.h>
34 #include <sys/socket.h>
40 #include "gunixfdlist.h"
46 G_DEFINE_TYPE (GUnixFDList, g_unix_fd_list, G_TYPE_OBJECT)
48 struct _GUnixFDListPrivate
55 g_unix_fd_list_init (GUnixFDList *list)
57 list->priv = G_TYPE_INSTANCE_GET_PRIVATE (list,
63 g_unix_fd_list_finalize (GObject *object)
65 GUnixFDList *list = G_UNIX_FD_LIST (object);
68 for (i = 0; i < list->priv->nfd; i++)
69 close (list->priv->fds[i]);
70 g_free (list->priv->fds);
72 G_OBJECT_CLASS (g_unix_fd_list_parent_class)
77 g_unix_fd_list_class_init (GUnixFDListClass *class)
79 GObjectClass *object_class = G_OBJECT_CLASS (class);
81 g_type_class_add_private (class, sizeof (GUnixFDListPrivate));
82 object_class->finalize = g_unix_fd_list_finalize;
86 dup_close_on_exec_fd (gint fd,
92 #ifdef F_DUPFD_CLOEXEC
94 new_fd = fcntl (fd, F_DUPFD_CLOEXEC, 0l);
95 while (new_fd < 0 && (errno == EINTR));
100 /* if that didn't work (new libc/old kernel?), try it the other way. */
105 while (new_fd < 0 && (errno == EINTR));
109 int saved_errno = errno;
111 g_set_error (error, G_IO_ERROR,
112 g_io_error_from_errno (saved_errno),
113 "dup: %s", g_strerror (saved_errno));
121 s = fcntl (new_fd, F_GETFD);
124 s = fcntl (new_fd, F_SETFD, (long) (s | FD_CLOEXEC));
126 while (s < 0 && (errno == EINTR));
130 int saved_errno = errno;
132 g_set_error (error, G_IO_ERROR,
133 g_io_error_from_errno (saved_errno),
134 "fcntl: %s", g_strerror (saved_errno));
144 * g_unix_fd_list_new:
146 * Creates a new #GUnixFDList containing no file descriptors.
148 * Returns: a new #GUnixFDList
153 g_unix_fd_list_new (void)
155 return g_object_new (G_TYPE_UNIX_FD_LIST, NULL);
159 * g_unix_fd_list_new_from_array:
160 * @fds: the initial list of file descriptors
161 * @n_fds: the length of #fds, or -1
163 * Creates a new #GUnixFDList containing the file descriptors given in
164 * @fds. The file descriptors become the property of the new list and
165 * may no longer be used by the caller. The array itself is owned by
168 * Each file descriptor in the array should be set to close-on-exec.
170 * If @n_fds is -1 then @fds must be terminated with -1.
172 * Returns: a new #GUnixFDList
177 g_unix_fd_list_new_from_array (const gint *fds,
182 g_return_val_if_fail (fds != NULL || n_fds == 0, NULL);
185 for (n_fds = 0; fds[n_fds] != -1; n_fds++);
187 list = g_object_new (G_TYPE_UNIX_FD_LIST, NULL);
188 list->priv->fds = g_new (gint, n_fds + 1);
189 list->priv->nfd = n_fds;
191 memcpy (list->priv->fds, fds, sizeof (gint) * n_fds);
192 list->priv->fds[n_fds] = -1;
198 * g_unix_fd_list_steal_fds:
199 * @list: a #GUnixFDList
200 * @length: pointer to the length of the returned array, or %NULL
202 * Returns the array of file descriptors that is contained in this
205 * After this call, the descriptors are no longer contained in
206 * @list. Further calls will return an empty list (unless more
207 * descriptors have been added).
209 * The return result of this function must be freed with g_free().
210 * The caller is also responsible for closing all of the file
211 * descriptors. The file descriptors in the array are set to
214 * If @length is non-%NULL then it is set to the number of file
215 * descriptors in the returned array. The returned array is also
216 * terminated with -1.
218 * This function never returns %NULL. In case there are no file
219 * descriptors contained in @list, an empty array is returned.
221 * Returns: an array of file descriptors
226 g_unix_fd_list_steal_fds (GUnixFDList *list,
231 g_return_val_if_fail (G_IS_UNIX_FD_LIST (list), NULL);
233 /* will be true for fresh object or if we were just called */
234 if (list->priv->fds == NULL)
236 list->priv->fds = g_new (gint, 1);
237 list->priv->fds[0] = -1;
242 *length = list->priv->nfd;
243 result = list->priv->fds;
245 list->priv->fds = NULL;
252 * g_unix_fd_list_peek_fds:
253 * @list: a #GUnixFDList
254 * @length: pointer to the length of the returned array, or %NULL
256 * Returns the array of file descriptors that is contained in this
259 * After this call, the descriptors remain the property of @list. The
260 * caller must not close them and must not free the array. The array is
261 * valid only until @list is changed in any way.
263 * If @length is non-%NULL then it is set to the number of file
264 * descriptors in the returned array. The returned array is also
265 * terminated with -1.
267 * This function never returns %NULL. In case there are no file
268 * descriptors contained in @list, an empty array is returned.
270 * Returns: an array of file descriptors
275 g_unix_fd_list_peek_fds (GUnixFDList *list,
278 g_return_val_if_fail (G_IS_UNIX_FD_LIST (list), NULL);
280 /* will be true for fresh object or if steal() was just called */
281 if (list->priv->fds == NULL)
283 list->priv->fds = g_new (gint, 1);
284 list->priv->fds[0] = -1;
289 *length = list->priv->nfd;
291 return list->priv->fds;
295 * g_unix_fd_list_append:
296 * @list: a #GUnixFDList
297 * @fd: a valid open file descriptor
298 * @error: a #GError pointer
300 * Adds a file descriptor to @list.
302 * The file descriptor is duplicated using dup(). You keep your copy
303 * of the descriptor and the copy contained in @list will be closed
304 * when @list is finalized.
306 * A possible cause of failure is exceeding the per-process or
307 * system-wide file descriptor limit.
309 * The index of the file descriptor in the list is returned. If you use
310 * this index with g_unix_fd_list_get() then you will receive back a
311 * duplicated copy of the same file descriptor.
313 * Returns: the index of the appended fd in case of success, else -1
314 * (and @error is set)
319 g_unix_fd_list_append (GUnixFDList *list,
325 g_return_val_if_fail (G_IS_UNIX_FD_LIST (list), -1);
326 g_return_val_if_fail (fd >= 0, -1);
327 g_return_val_if_fail (error == NULL || *error == NULL, -1);
329 if ((new_fd = dup_close_on_exec_fd (fd, error)) < 0)
332 list->priv->fds = g_realloc (list->priv->fds,
334 (list->priv->nfd + 2));
335 list->priv->fds[list->priv->nfd++] = new_fd;
336 list->priv->fds[list->priv->nfd] = -1;
338 return list->priv->nfd - 1;
342 * g_unix_fd_list_get:
343 * @list: a #GUnixFDList
344 * @index_: the index into the list
345 * @error: a #GError pointer
347 * Gets a file descriptor out of @list.
349 * @index_ specifies the index of the file descriptor to get. It is a
350 * programmer error for @index_ to be out of range; see
351 * g_unix_fd_list_get_length().
353 * The file descriptor is duplicated using dup() and set as
354 * close-on-exec before being returned. You must call close() on it
357 * A possible cause of failure is exceeding the per-process or
358 * system-wide file descriptor limit.
360 * Returns: the file descriptor, or -1 in case of error
365 g_unix_fd_list_get (GUnixFDList *list,
369 g_return_val_if_fail (G_IS_UNIX_FD_LIST (list), -1);
370 g_return_val_if_fail (index_ < list->priv->nfd, -1);
371 g_return_val_if_fail (error == NULL || *error == NULL, -1);
373 return dup_close_on_exec_fd (list->priv->fds[index_], error);
377 * g_unix_fd_list_get_length:
378 * @list: a #GUnixFDList
380 * Gets the length of @list (ie: the number of file descriptors
383 * Returns: the length of @list
388 g_unix_fd_list_get_length (GUnixFDList *list)
390 g_return_val_if_fail (G_IS_UNIX_FD_LIST (list), 0);
392 return list->priv->nfd;
395 #define __G_UNIX_FD_LIST_C__
396 #include "gioaliasdef.c"