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, fd) \
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 /* Check if this fd should be handled. */ \
67 if (unlikely(tracked_fds_find(fd))) { \
68 if (unlikely(force_write_to_non_tty)) { \
71 handle = isatty_noinline(fd); \
76 #define _HOOK_PRE_FD(type, name, fd) \
78 _HOOK_PRE_FD_(type, name, fd)
79 #define _HOOK_PRE_FD_(type, name, fd) \
80 _HOOK_PRE(type, name, fd) \
81 if (unlikely(handle)) { \
84 #define _HOOK_PRE_FILE(type, name, file) \
86 _HOOK_PRE(type, name, fileno(file)) \
87 if (unlikely(handle)) { \
88 handle_file_pre(file); \
90 #define _HOOK_POST_FD_(fd) \
91 if (unlikely(handle)) { \
94 #define _HOOK_POST_FD(fd) \
97 #define _HOOK_POST_FILE(file) \
98 if (unlikely(handle)) { \
99 handle_file_post(file); \
104 #define HOOK_FUNC_DEF1(type, name, type1, arg1) \
105 static type (*real_ ## name)(type1); \
106 type name(type1) visibility_protected; \
107 type name(type1 arg1)
108 #define HOOK_FUNC_DEF2(type, name, type1, arg1, type2, arg2) \
109 static type (*real_ ## name)(type1, type2); \
110 type name(type1, type2) visibility_protected; \
111 type name(type1 arg1, type2 arg2)
112 #define HOOK_FUNC_DEF3(type, name, type1, arg1, type2, arg2, type3, arg3) \
113 static type (*real_ ## name)(type1, type2, type3); \
114 type name(type1, type2, type3) visibility_protected; \
115 type name(type1 arg1, type2 arg2, type3 arg3)
116 #define HOOK_FUNC_DEF4(type, name, type1, arg1, type2, arg2, type3, arg3, type4, arg4) \
117 static type (*real_ ## name)(type1, type2, type3, type4); \
118 type name(type1, type2, type3, type4) visibility_protected; \
119 type name(type1 arg1, type2 arg2, type3 arg3, type4 arg4)
121 #define HOOK_FUNC_VAR_DEF2(type, name, type1, arg1, type2, arg2) \
122 static type (*real_ ## name)(type1, type2, ...); \
123 type name(type1, type2, ...) visibility_protected; \
124 type name(type1 arg1, type2 arg2, ...)
126 #define HOOK_FUNC_SIMPLE3(type, name, type1, arg1, type2, arg2, type3, arg3) \
127 type name(type1, type2, type3) visibility_protected; \
128 type name(type1 arg1, type2 arg2, type3 arg3)
130 #define HOOK_FUNC_VAR_SIMPLE1(type, name, type1, arg1) \
131 type name(type1, ...) visibility_protected; \
132 type name(type1 arg1, ...)
133 #define HOOK_FUNC_VAR_SIMPLE2(type, name, type1, arg1, type2, arg2) \
134 type name(type1, type2, ...) visibility_protected; \
135 type name(type1 arg1, type2 arg2, ...)
136 #define HOOK_FUNC_VAR_SIMPLE3(type, name, type1, arg1, type2, arg2, type3, arg3) \
137 type name(type1, type2, type3, ...) visibility_protected; \
138 type name(type1 arg1, type2 arg2, type3 arg3, ...)
140 #define HOOK_VOID1(type, name, fd, type1, arg1) \
141 HOOK_FUNC_DEF1(type, name, type1, arg1) { \
142 _HOOK_PRE_FD_(type, name, fd) \
143 real_ ## name(arg1); \
146 #define HOOK_VOID2(type, name, fd, type1, arg1, type2, arg2) \
147 HOOK_FUNC_DEF2(type, name, type1, arg1, type2, arg2) { \
148 _HOOK_PRE_FD_(type, name, fd) \
149 real_ ## name(arg1, arg2); \
152 #define HOOK_VOID3(type, name, fd, type1, arg1, type2, arg2, type3, arg3) \
153 HOOK_FUNC_DEF3(type, name, type1, arg1, type2, arg2, type3, arg3) { \
154 _HOOK_PRE_FD_(type, name, fd) \
155 real_ ## name(arg1, arg2, arg3); \
159 #define HOOK_VAR_VOID1(type, name, fd, func, type1, arg1) \
160 HOOK_FUNC_VAR_SIMPLE1(type, name, type1, arg1) { \
162 va_start(ap, arg1); \
166 #define HOOK_VAR_VOID2(type, name, fd, func, type1, arg1, type2, arg2) \
167 HOOK_FUNC_VAR_SIMPLE2(type, name, type1, arg1, type2, arg2) { \
169 va_start(ap, arg2); \
170 func(arg1, arg2, ap); \
174 #define HOOK_FD3(type, name, fd, type1, arg1, type2, arg2, type3, arg3) \
175 HOOK_FUNC_DEF3(type, name, type1, arg1, type2, arg2, type3, arg3) { \
176 _HOOK_PRE_FD(type, name, fd) \
177 result = real_ ## name(arg1, arg2, arg3); \
181 #define HOOK_FILE1(type, name, file, type1, arg1) \
182 HOOK_FUNC_DEF1(type, name, type1, arg1) { \
183 _HOOK_PRE_FILE(type, name, file) \
184 result = real_ ## name(arg1); \
185 _HOOK_POST_FILE(file) \
187 #define HOOK_FILE2(type, name, file, type1, arg1, type2, arg2) \
188 HOOK_FUNC_DEF2(type, name, type1, arg1, type2, arg2) { \
189 _HOOK_PRE_FILE(type, name, file) \
190 result = real_ ## name(arg1, arg2); \
191 _HOOK_POST_FILE(file) \
193 #define HOOK_FILE3(type, name, file, type1, arg1, type2, arg2, type3, arg3) \
194 HOOK_FUNC_DEF3(type, name, type1, arg1, type2, arg2, type3, arg3) { \
195 _HOOK_PRE_FILE(type, name, file) \
196 result = real_ ## name(arg1, arg2, arg3); \
197 _HOOK_POST_FILE(file) \
199 #define HOOK_FILE4(type, name, file, type1, arg1, type2, arg2, type3, arg3, type4, arg4) \
200 HOOK_FUNC_DEF4(type, name, type1, arg1, type2, arg2, type3, arg3, type4, arg4) { \
201 _HOOK_PRE_FILE(type, name, file) \
202 result = real_ ## name(arg1, arg2, arg3, arg4); \
203 _HOOK_POST_FILE(file) \
206 #define HOOK_VAR_FILE1(type, name, file, func, type1, arg1) \
207 HOOK_FUNC_VAR_SIMPLE1(type, name, type1, arg1) { \
209 va_start(ap, arg1); \
210 type result = func(arg1, ap); \
214 #define HOOK_VAR_FILE2(type, name, file, func, type1, arg1, type2, arg2) \
215 HOOK_FUNC_VAR_SIMPLE2(type, name, type1, arg1, type2, arg2) { \
217 va_start(ap, arg2); \
218 type result = func(arg1, arg2, ap); \
222 #define HOOK_VAR_FILE3(type, name, file, func, type1, arg1, type2, arg2, type3, arg3) \
223 HOOK_FUNC_VAR_SIMPLE3(type, name, type1, arg1, type2, arg2, type3, arg3) { \
225 va_start(ap, arg3); \
226 type result = func(arg1, arg2, arg3, ap); \