117 lines
3.5 KiB
C
117 lines
3.5 KiB
C
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/* Hook for making file descriptor functions close(), ioctl() extensible.
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Copyright (C) 2009-2022 Free Software Foundation, Inc.
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Written by Bruno Haible <bruno@clisp.org>, 2009.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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/* Specification. */
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#include "fd-hook.h"
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#include <stdlib.h>
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/* Currently, this entire code is only needed for the handling of sockets
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on native Windows platforms. */
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#if WINDOWS_SOCKETS
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/* The first and last link in the doubly linked list.
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Initially the list is empty. */
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static struct fd_hook anchor = { &anchor, &anchor, NULL, NULL };
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int
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execute_close_hooks (const struct fd_hook *remaining_list, gl_close_fn primary,
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int fd)
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{
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if (remaining_list == &anchor)
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/* End of list reached. */
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return primary (fd);
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else
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return remaining_list->private_close_fn (remaining_list->private_next,
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primary, fd);
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}
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int
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execute_all_close_hooks (gl_close_fn primary, int fd)
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{
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return execute_close_hooks (anchor.private_next, primary, fd);
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}
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int
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execute_ioctl_hooks (const struct fd_hook *remaining_list, gl_ioctl_fn primary,
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int fd, int request, void *arg)
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{
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if (remaining_list == &anchor)
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/* End of list reached. */
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return primary (fd, request, arg);
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else
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return remaining_list->private_ioctl_fn (remaining_list->private_next,
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primary, fd, request, arg);
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}
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int
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execute_all_ioctl_hooks (gl_ioctl_fn primary,
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int fd, int request, void *arg)
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{
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return execute_ioctl_hooks (anchor.private_next, primary, fd, request, arg);
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}
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void
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register_fd_hook (close_hook_fn close_hook, ioctl_hook_fn ioctl_hook, struct fd_hook *link)
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{
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if (close_hook == NULL)
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close_hook = execute_close_hooks;
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if (ioctl_hook == NULL)
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ioctl_hook = execute_ioctl_hooks;
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if (link->private_next == NULL && link->private_prev == NULL)
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{
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/* Add the link to the doubly linked list. */
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link->private_next = anchor.private_next;
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link->private_prev = &anchor;
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link->private_close_fn = close_hook;
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link->private_ioctl_fn = ioctl_hook;
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anchor.private_next->private_prev = link;
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anchor.private_next = link;
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}
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else
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{
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/* The link is already in use. */
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if (link->private_close_fn != close_hook
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|| link->private_ioctl_fn != ioctl_hook)
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abort ();
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}
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}
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void
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unregister_fd_hook (struct fd_hook *link)
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{
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struct fd_hook *next = link->private_next;
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struct fd_hook *prev = link->private_prev;
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if (next != NULL && prev != NULL)
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{
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/* The link is in use. Remove it from the doubly linked list. */
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prev->private_next = next;
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next->private_prev = prev;
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/* Clear the link, to mark it unused. */
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link->private_next = NULL;
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link->private_prev = NULL;
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link->private_close_fn = NULL;
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link->private_ioctl_fn = NULL;
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}
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}
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#endif
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