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/* Hook for making the close() function extensible.
Copyright (C) 2009, 2010 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2009.
This program is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "close-hook.h"
#include <stdlib.h>
#include <unistd.h>
#undef close
/* Currently, this entire code is only needed for the handling of sockets
on native Windows platforms. */
#if WINDOWS_SOCKETS
/* The first and last link in the doubly linked list.
Initially the list is empty. */
static struct close_hook anchor = { &anchor, &anchor, NULL };
int
execute_close_hooks (int fd, const struct close_hook *remaining_list)
{
if (remaining_list == &anchor)
/* End of list reached. */
return close (fd);
else
return remaining_list->private_fn (fd, remaining_list->private_next);
}
int
execute_all_close_hooks (int fd)
{
return execute_close_hooks (fd, anchor.private_next);
}
void
register_close_hook (close_hook_fn hook, struct close_hook *link)
{
if (link->private_next == NULL && link->private_prev == NULL)
{
/* Add the link to the doubly linked list. */
link->private_next = anchor.private_next;
link->private_prev = &anchor;
link->private_fn = hook;
anchor.private_next->private_prev = link;
anchor.private_next = link;
}
else
{
/* The link is already in use. */
if (link->private_fn != hook)
abort ();
}
}
void
unregister_close_hook (struct close_hook *link)
{
struct close_hook *next = link->private_next;
struct close_hook *prev = link->private_prev;
if (next != NULL && prev != NULL)
{
/* The link is in use. Remove it from the doubly linked list. */
prev->private_next = next;
next->private_prev = prev;
/* Clear the link, to mark it unused. */
link->private_next = NULL;
link->private_prev = NULL;
link->private_fn = NULL;
}
}
#endif
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