1 /* Hook for making making file descriptor functions close(), ioctl() extensible. 2 Copyright (C) 2009-2012 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 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 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 */ 120