| /* Hook for making file descriptor functions close(), ioctl() extensible. | |
| Copyright (C) 2009-2023 Free Software Foundation, Inc. | |
| This file is free software: you can redistribute it and/or modify | |
| it under the terms of the GNU Lesser General Public License as | |
| published by the Free Software Foundation; either version 2.1 of the | |
| License, or (at your option) any later version. | |
| This file 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 Lesser General Public License | |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ | |
| extern "C" { | |
| /* Currently, this entire code is only needed for the handling of sockets | |
| on native Windows platforms. */ | |
| /* Type of function that closes FD. */ | |
| typedef int (*gl_close_fn) (int fd); | |
| /* Type of function that applies a control request to FD. */ | |
| typedef int (*gl_ioctl_fn) (int fd, int request, void *arg); | |
| /* An element of the list of file descriptor hooks. | |
| In CLOS (Common Lisp Object System) speak, it consists of an "around" | |
| method for the close() function and an "around" method for the ioctl() | |
| function. | |
| The fields of this structure are considered private. */ | |
| struct fd_hook | |
| { | |
| /* Doubly linked list. */ | |
| struct fd_hook *private_next; | |
| struct fd_hook *private_prev; | |
| /* Function that treats the types of FD that it knows about and calls | |
| execute_close_hooks (REMAINING_LIST, PRIMARY, FD) as a fallback. */ | |
| int (*private_close_fn) (const struct fd_hook *remaining_list, | |
| gl_close_fn primary, | |
| int fd); | |
| /* Function that treats the types of FD that it knows about and calls | |
| execute_ioctl_hooks (REMAINING_LIST, PRIMARY, FD, REQUEST, ARG) as a | |
| fallback. */ | |
| int (*private_ioctl_fn) (const struct fd_hook *remaining_list, | |
| gl_ioctl_fn primary, | |
| int fd, int request, void *arg); | |
| }; | |
| /* This type of function closes FD, applying special knowledge for the FD | |
| types it knows about, and calls | |
| execute_close_hooks (REMAINING_LIST, PRIMARY, FD) | |
| for the other FD types. | |
| In CLOS speak, REMAINING_LIST is the remaining list of "around" methods, | |
| and PRIMARY is the "primary" method for close(). */ | |
| typedef int (*close_hook_fn) (const struct fd_hook *remaining_list, | |
| gl_close_fn primary, | |
| int fd); | |
| /* Execute the close hooks in REMAINING_LIST, with PRIMARY as "primary" method. | |
| Return 0 or -1, like close() would do. */ | |
| extern int execute_close_hooks (const struct fd_hook *remaining_list, | |
| gl_close_fn primary, | |
| int fd); | |
| /* Execute all close hooks, with PRIMARY as "primary" method. | |
| Return 0 or -1, like close() would do. */ | |
| extern int execute_all_close_hooks (gl_close_fn primary, int fd); | |
| /* This type of function applies a control request to FD, applying special | |
| knowledge for the FD types it knows about, and calls | |
| execute_ioctl_hooks (REMAINING_LIST, PRIMARY, FD, REQUEST, ARG) | |
| for the other FD types. | |
| In CLOS speak, REMAINING_LIST is the remaining list of "around" methods, | |
| and PRIMARY is the "primary" method for ioctl(). */ | |
| typedef int (*ioctl_hook_fn) (const struct fd_hook *remaining_list, | |
| gl_ioctl_fn primary, | |
| int fd, int request, void *arg); | |
| /* Execute the ioctl hooks in REMAINING_LIST, with PRIMARY as "primary" method. | |
| Return 0 or -1, like ioctl() would do. */ | |
| extern int execute_ioctl_hooks (const struct fd_hook *remaining_list, | |
| gl_ioctl_fn primary, | |
| int fd, int request, void *arg); | |
| /* Execute all ioctl hooks, with PRIMARY as "primary" method. | |
| Return 0 or -1, like ioctl() would do. */ | |
| extern int execute_all_ioctl_hooks (gl_ioctl_fn primary, | |
| int fd, int request, void *arg); | |
| /* Add a function pair to the list of file descriptor hooks. | |
| CLOSE_HOOK and IOCTL_HOOK may be NULL, indicating no change. | |
| The LINK variable points to a piece of memory which is guaranteed to be | |
| accessible until the corresponding call to unregister_fd_hook. */ | |
| extern void register_fd_hook (close_hook_fn close_hook, ioctl_hook_fn ioctl_hook, | |
| struct fd_hook *link); | |
| /* Removes a hook from the list of file descriptor hooks. */ | |
| extern void unregister_fd_hook (struct fd_hook *link); | |
| } | |