2 * Macros to hook functions.
4 * Copyright (C) 2013 Simon Ruderich
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
23 /* Hook the function by creating a function with the same name. With
24 * LD_PRELOAD our function will be preferred. The original function is stored
25 * in a static variable (real_*). Any function called in these macros must
26 * make sure to restore the errno if it changes it.
28 * "Pseudo code" for the following macros. <name> is the name of the hooked
29 * function, <fd> is either a file descriptor or a FILE pointer.
32 * real_<name> = dlsym_function(<name>);
34 * init_from_environment();
37 * if (tracked_fds_find(<fd>)) {
38 * if (force_write_to_non_tty) {
41 * handle = isatty_noinline(<fd>);
48 * handle_<fd>_pre(<fd>);
50 * <type> result = real_<name>(<args>);
52 * handle_<fd>_post(<fd>);
57 #define _HOOK_PRE(type, name) \
59 if (unlikely(!(real_ ## name ))) { \
60 *(void **) (&(real_ ## name)) = dlsym_function(#name); \
61 /* Initialize our data while we're at it. */ \
62 if (unlikely(!initialized)) { \
63 init_from_environment(); \
66 #define _HOOK_PRE_FD(type, name, fd) \
68 _HOOK_PRE_FD_(type, name, fd)
69 #define _HOOK_PRE_FD_(type, name, fd) \
70 _HOOK_PRE(type, name) \
71 if (unlikely(tracked_fds_find(fd))) { \
72 if (unlikely(force_write_to_non_tty)) { \
75 handle = isatty_noinline(fd); \
80 if (unlikely(handle)) { \
83 #define _HOOK_PRE_FILE(type, name, file) \
85 _HOOK_PRE(type, name) \
86 if (unlikely(tracked_fds_find(fileno(file)))) { \
87 if (unlikely(force_write_to_non_tty)) { \
90 handle = isatty_noinline(fileno(file)); \
95 if (unlikely(handle)) { \
96 handle_file_pre(file); \
98 #define _HOOK_POST_FD_(fd) \
99 if (unlikely(handle)) { \
100 handle_fd_post(fd); \
102 #define _HOOK_POST_FD(fd) \
105 #define _HOOK_POST_FILE(file) \
106 if (unlikely(handle)) { \
107 handle_file_post(file); \
112 #define HOOK_VOID1(type, name, fd, type1, arg1) \
113 static type (*real_ ## name)(type1); \
114 type name(type1 arg1) { \
115 _HOOK_PRE_FD_(type, name, fd) \
116 real_ ## name(arg1); \
120 #define HOOK_FD3(type, name, fd, type1, arg1, type2, arg2, type3, arg3) \
121 static type (*real_ ## name)(type1, type2, type3); \
122 type name(type1 arg1, type2 arg2, type3 arg3) { \
123 _HOOK_PRE_FD(type, name, fd) \
124 result = real_ ## name(arg1, arg2, arg3); \
128 #define HOOK_FILE1(type, name, file, type1, arg1) \
129 static type (*real_ ## name)(type1); \
130 type name(type1 arg1) { \
131 _HOOK_PRE_FILE(type, name, file) \
132 result = real_ ## name(arg1); \
133 _HOOK_POST_FILE(file) \
135 #define HOOK_FILE2(type, name, file, type1, arg1, type2, arg2) \
136 static type (*real_ ## name)(type1, type2); \
137 type name(type1 arg1, type2 arg2) { \
138 _HOOK_PRE_FILE(type, name, file) \
139 result = real_ ## name(arg1, arg2); \
140 _HOOK_POST_FILE(file) \
142 #define HOOK_FILE3(type, name, file, type1, arg1, type2, arg2, type3, arg3) \
143 static type (*real_ ## name)(type1, type2, type3); \
144 type name(type1 arg1, type2 arg2, type3 arg3) { \
145 _HOOK_PRE_FILE(type, name, file) \
146 result = real_ ## name(arg1, arg2, arg3); \
147 _HOOK_POST_FILE(file) \
149 #define HOOK_FILE4(type, name, file, type1, arg1, type2, arg2, type3, arg3, type4, arg4) \
150 static type (*real_ ## name)(type1, type2, type3, type4); \
151 type name(type1 arg1, type2 arg2, type3 arg3, type4 arg4) { \
152 _HOOK_PRE_FILE(type, name, file) \
153 result = real_ ## name(arg1, arg2, arg3, arg4); \
154 _HOOK_POST_FILE(file) \
157 #define HOOK_VAR_FILE1(type, name, file, func, type1, arg1) \
158 static type (*real_ ## func)(type1, va_list); \
159 type name(type1 arg1, ...) { \
161 _HOOK_PRE_FILE(type, func, file) \
162 va_start(ap, arg1); \
163 result = real_ ## func(arg1, ap); \
165 _HOOK_POST_FILE(file) \
167 #define HOOK_VAR_FILE2(type, name, file, func, type1, arg1, type2, arg2) \
168 static type (*real_ ## func)(type1, type2, va_list); \
169 type name(type1 arg1, type2 arg2, ...) { \
171 _HOOK_PRE_FILE(type, func, file) \
172 va_start(ap, arg2); \
173 result = real_ ## func(arg1, arg2, ap); \
175 _HOOK_POST_FILE(file) \
177 #define HOOK_VAR_FILE3(type, name, file, func, type1, arg1, type2, arg2, type3, arg3) \
178 static type (*real_ ## func)(type1, type2, type3, va_list); \
179 type name(type1 arg1, type2 arg2, type3 arg3, ...) { \
181 _HOOK_PRE_FILE(type, func, file) \
182 va_start(ap, arg3); \
183 result = real_ ## func(arg1, arg2, arg3, ap); \
185 _HOOK_POST_FILE(file) \