| 1 | /* Hook for making making file descriptor functions close(), ioctl() extensible. |
| 2 | Copyright (C) 2009-2014 Free Software Foundation, Inc. |
| 3 | |
| 4 | This program is free software: you can redistribute it and/or modify it |
| 5 | under the terms of the GNU Lesser General Public License as published |
| 6 | by the Free Software Foundation; either version 3 of the License, or |
| 7 | (at your option) any later version. |
| 8 | |
| 9 | This program is distributed in the hope that it will be useful, |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | Lesser General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU Lesser General Public License |
| 15 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 16 | |
| 17 | |
| 18 | #ifndef FD_HOOK_H |
| 19 | #define FD_HOOK_H |
| 20 | |
| 21 | #ifdef __cplusplus |
| 22 | extern "C" { |
| 23 | #endif |
| 24 | |
| 25 | |
| 26 | /* Currently, this entire code is only needed for the handling of sockets |
| 27 | on native Windows platforms. */ |
| 28 | #if WINDOWS_SOCKETS |
| 29 | |
| 30 | |
| 31 | /* Type of function that closes FD. */ |
| 32 | typedef int (*gl_close_fn) (int fd); |
| 33 | |
| 34 | /* Type of function that applies a control request to FD. */ |
| 35 | typedef int (*gl_ioctl_fn) (int fd, int request, void *arg); |
| 36 | |
| 37 | /* An element of the list of file descriptor hooks. |
| 38 | In CLOS (Common Lisp Object System) speak, it consists of an "around" |
| 39 | method for the close() function and an "around" method for the ioctl() |
| 40 | function. |
| 41 | The fields of this structure are considered private. */ |
| 42 | struct fd_hook |
| 43 | { |
| 44 | /* Doubly linked list. */ |
| 45 | struct fd_hook *private_next; |
| 46 | struct fd_hook *private_prev; |
| 47 | /* Function that treats the types of FD that it knows about and calls |
| 48 | execute_close_hooks (REMAINING_LIST, PRIMARY, FD) as a fallback. */ |
| 49 | int (*private_close_fn) (const struct fd_hook *remaining_list, |
| 50 | gl_close_fn primary, |
| 51 | int fd); |
| 52 | /* Function that treats the types of FD that it knows about and calls |
| 53 | execute_ioctl_hooks (REMAINING_LIST, PRIMARY, FD, REQUEST, ARG) as a |
| 54 | fallback. */ |
| 55 | int (*private_ioctl_fn) (const struct fd_hook *remaining_list, |
| 56 | gl_ioctl_fn primary, |
| 57 | int fd, int request, void *arg); |
| 58 | }; |
| 59 | |
| 60 | /* This type of function closes FD, applying special knowledge for the FD |
| 61 | types it knows about, and calls |
| 62 | execute_close_hooks (REMAINING_LIST, PRIMARY, FD) |
| 63 | for the other FD types. |
| 64 | In CLOS speak, REMAINING_LIST is the remaining list of "around" methods, |
| 65 | and PRIMARY is the "primary" method for close(). */ |
| 66 | typedef int (*close_hook_fn) (const struct fd_hook *remaining_list, |
| 67 | gl_close_fn primary, |
| 68 | int fd); |
| 69 | |
| 70 | /* Execute the close hooks in REMAINING_LIST, with PRIMARY as "primary" method. |
| 71 | Return 0 or -1, like close() would do. */ |
| 72 | extern int execute_close_hooks (const struct fd_hook *remaining_list, |
| 73 | gl_close_fn primary, |
| 74 | int fd); |
| 75 | |
| 76 | /* Execute all close hooks, with PRIMARY as "primary" method. |
| 77 | Return 0 or -1, like close() would do. */ |
| 78 | extern int execute_all_close_hooks (gl_close_fn primary, int fd); |
| 79 | |
| 80 | /* This type of function applies a control request to FD, applying special |
| 81 | knowledge for the FD types it knows about, and calls |
| 82 | execute_ioctl_hooks (REMAINING_LIST, PRIMARY, FD, REQUEST, ARG) |
| 83 | for the other FD types. |
| 84 | In CLOS speak, REMAINING_LIST is the remaining list of "around" methods, |
| 85 | and PRIMARY is the "primary" method for ioctl(). */ |
| 86 | typedef int (*ioctl_hook_fn) (const struct fd_hook *remaining_list, |
| 87 | gl_ioctl_fn primary, |
| 88 | int fd, int request, void *arg); |
| 89 | |
| 90 | /* Execute the ioctl hooks in REMAINING_LIST, with PRIMARY as "primary" method. |
| 91 | Return 0 or -1, like ioctl() would do. */ |
| 92 | extern int execute_ioctl_hooks (const struct fd_hook *remaining_list, |
| 93 | gl_ioctl_fn primary, |
| 94 | int fd, int request, void *arg); |
| 95 | |
| 96 | /* Execute all ioctl hooks, with PRIMARY as "primary" method. |
| 97 | Return 0 or -1, like ioctl() would do. */ |
| 98 | extern int execute_all_ioctl_hooks (gl_ioctl_fn primary, |
| 99 | int fd, int request, void *arg); |
| 100 | |
| 101 | /* Add a function pair to the list of file descriptor hooks. |
| 102 | CLOSE_HOOK and IOCTL_HOOK may be NULL, indicating no change. |
| 103 | The LINK variable points to a piece of memory which is guaranteed to be |
| 104 | accessible until the corresponding call to unregister_fd_hook. */ |
| 105 | extern void register_fd_hook (close_hook_fn close_hook, ioctl_hook_fn ioctl_hook, |
| 106 | struct fd_hook *link); |
| 107 | |
| 108 | /* Removes a hook from the list of file descriptor hooks. */ |
| 109 | extern void unregister_fd_hook (struct fd_hook *link); |
| 110 | |
| 111 | |
| 112 | #endif |
| 113 | |
| 114 | |
| 115 | #ifdef __cplusplus |
| 116 | } |
| 117 | #endif |
| 118 | |
| 119 | #endif /* FD_HOOK_H */ |