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1 | /* Hook for making making file descriptor functions close(), ioctl() extensible. |
2 | Copyright (C) 2009-2016 Free Software Foundation, Inc. | |
6ec2e0f5 SDJ |
3 | |
4 | This program is free software: you can redistribute it and/or modify it | |
5 | under the terms of the GNU 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 | General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
5e8754f9 | 15 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
6ec2e0f5 SDJ |
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 */ |