120 lines
4.7 KiB
C
120 lines
4.7 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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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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#ifndef FD_HOOK_H
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#define FD_HOOK_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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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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/* Type of function that closes FD. */
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typedef int (*gl_close_fn) (int fd);
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/* Type of function that applies a control request to FD. */
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typedef int (*gl_ioctl_fn) (int fd, int request, void *arg);
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/* An element of the list of file descriptor hooks.
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In CLOS (Common Lisp Object System) speak, it consists of an "around"
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method for the close() function and an "around" method for the ioctl()
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function.
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The fields of this structure are considered private. */
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struct fd_hook
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{
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/* Doubly linked list. */
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struct fd_hook *private_next;
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struct fd_hook *private_prev;
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/* Function that treats the types of FD that it knows about and calls
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execute_close_hooks (REMAINING_LIST, PRIMARY, FD) as a fallback. */
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int (*private_close_fn) (const struct fd_hook *remaining_list,
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gl_close_fn primary,
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int fd);
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/* Function that treats the types of FD that it knows about and calls
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execute_ioctl_hooks (REMAINING_LIST, PRIMARY, FD, REQUEST, ARG) as a
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fallback. */
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int (*private_ioctl_fn) (const struct fd_hook *remaining_list,
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gl_ioctl_fn primary,
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int fd, int request, void *arg);
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};
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/* This type of function closes FD, applying special knowledge for the FD
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types it knows about, and calls
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execute_close_hooks (REMAINING_LIST, PRIMARY, FD)
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for the other FD types.
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In CLOS speak, REMAINING_LIST is the remaining list of "around" methods,
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and PRIMARY is the "primary" method for close(). */
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typedef int (*close_hook_fn) (const struct fd_hook *remaining_list,
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gl_close_fn primary,
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int fd);
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/* Execute the close hooks in REMAINING_LIST, with PRIMARY as "primary" method.
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Return 0 or -1, like close() would do. */
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extern int execute_close_hooks (const struct fd_hook *remaining_list,
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gl_close_fn primary,
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int fd);
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/* Execute all close hooks, with PRIMARY as "primary" method.
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Return 0 or -1, like close() would do. */
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extern int execute_all_close_hooks (gl_close_fn primary, int fd);
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/* This type of function applies a control request to FD, applying special
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knowledge for the FD types it knows about, and calls
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execute_ioctl_hooks (REMAINING_LIST, PRIMARY, FD, REQUEST, ARG)
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for the other FD types.
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In CLOS speak, REMAINING_LIST is the remaining list of "around" methods,
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and PRIMARY is the "primary" method for ioctl(). */
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typedef int (*ioctl_hook_fn) (const struct fd_hook *remaining_list,
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gl_ioctl_fn primary,
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int fd, int request, void *arg);
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/* Execute the ioctl hooks in REMAINING_LIST, with PRIMARY as "primary" method.
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Return 0 or -1, like ioctl() would do. */
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extern int execute_ioctl_hooks (const struct fd_hook *remaining_list,
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gl_ioctl_fn primary,
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int fd, int request, void *arg);
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/* Execute all ioctl hooks, with PRIMARY as "primary" method.
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Return 0 or -1, like ioctl() would do. */
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extern int execute_all_ioctl_hooks (gl_ioctl_fn primary,
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int fd, int request, void *arg);
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/* Add a function pair to the list of file descriptor hooks.
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CLOSE_HOOK and IOCTL_HOOK may be NULL, indicating no change.
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The LINK variable points to a piece of memory which is guaranteed to be
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accessible until the corresponding call to unregister_fd_hook. */
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extern void register_fd_hook (close_hook_fn close_hook, ioctl_hook_fn ioctl_hook,
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struct fd_hook *link);
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/* Removes a hook from the list of file descriptor hooks. */
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extern void unregister_fd_hook (struct fd_hook *link);
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif /* FD_HOOK_H */
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