1 /* 2 * Copyright 2012, The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #define CONCATENATE(arg1, arg2) CONCATENATE1(arg1, arg2) 18 #define CONCATENATE1(arg1, arg2) CONCATENATE2(arg1, arg2) 19 #define CONCATENATE2(arg1, arg2) arg1##arg2 20 21 #define INTERRUPTER(sym) \ 22 if (real_##sym == NULL) \ 23 __init_##sym(); \ 24 if (maybe_interrupt()) { \ 25 errno = EINTR; \ 26 return -1; \ 27 } 28 29 #define CALL_FUNCTION_1(sym, ret, type1) \ 30 ret (*real_##sym)(type1) = NULL; \ 31 ret sym(type1 arg1) { \ 32 INTERRUPTER(sym) \ 33 return real_##sym(arg1); \ 34 } 35 36 #define CALL_FUNCTION_2(sym, ret, type1, type2) \ 37 ret (*real_##sym)(type1, type2) = NULL; \ 38 ret sym(type1 arg1, type2 arg2) { \ 39 INTERRUPTER(sym) \ 40 return real_##sym(arg1, arg2); \ 41 } 42 43 #define CALL_FUNCTION_3(sym, ret, type1, type2, type3) \ 44 ret (*real_##sym)(type1, type2, type3) = NULL; \ 45 ret sym(type1 arg1, type2 arg2, type3 arg3) { \ 46 INTERRUPTER(sym) \ 47 return real_##sym(arg1, arg2, arg3); \ 48 } 49 50 #define CALL_FUNCTION_4(sym, ret, type1, type2, type3, type4) \ 51 ret (*real_##sym)(type1, type2, type3, type4) = NULL; \ 52 ret sym(type1 arg1, type2 arg2, type3 arg3, type4 arg4) { \ 53 INTERRUPTER(sym) \ 54 return real_##sym(arg1, arg2, arg3, arg4); \ 55 } 56 57 #define CALL_FUNCTION_5(sym, ret, type1, type2, type3, type4, type5) \ 58 ret (*real_##sym)(type1, type2, type3, type4, type5) = NULL; \ 59 ret sym(type1 arg1, type2 arg2, type3 arg3, type4 arg4, type5 arg5) { \ 60 INTERRUPTER(sym) \ 61 return real_##sym(arg1, arg2, arg3, arg4, arg5); \ 62 } 63 64 #define DEFINE_INTERCEPT_N(N, sym, ret, ...) \ 65 static void __init_##sym(void); \ 66 CONCATENATE(CALL_FUNCTION_, N)(sym, ret, __VA_ARGS__) \ 67 static void __init_##sym(void) { \ 68 real_##sym = dlsym(RTLD_NEXT, #sym); \ 69 if (real_##sym == NULL) { \ 70 fprintf(stderr, "Error hooking " #sym ": %s\n", dlerror()); \ 71 } \ 72 } 73 74 #define INTERCEPT_NARG(...) INTERCEPT_NARG_N(__VA_ARGS__, INTERCEPT_RSEQ_N()) 75 #define INTERCEPT_NARG_N(...) INTERCEPT_ARG_N(__VA_ARGS__) 76 #define INTERCEPT_ARG_N(_1, _2, _3, _4, _5, _6, _7, _8, N, ...) N 77 #define INTERCEPT_RSEQ_N() 8, 7, 6, 5, 4, 3, 2, 1, 0 78 79 #define DEFINE_INTERCEPT(sym, ret, ...) DEFINE_INTERCEPT_N(INTERCEPT_NARG(__VA_ARGS__), sym, ret, __VA_ARGS__) 80