1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 // 5 // Fake Address Sanitizer run-time support. 6 // Enough for programs to link and run, but will not find any errors. 7 // Also, linking this to shared libraries voids the warranty. 8 // 9 // We need this fake thunks if we build Chrome with ASAN support because 10 // pyautolib DSO is instrumented with ASAN and is loaded to regular python 11 // process that has no ASAN runtime. 12 // 13 // We have three options here: 14 // 1) use our custom build of Python that have ASAN runtime linked in, 15 // 2) do not instrument pyautolib with ASAN support, 16 // 3) use this fake asan thunks linked to pyautolib so that instrumented code 17 // does not complain. 18 // 19 // Note that we should not use real ASAN runtime linked with DSO because it will 20 // not have information about memory allocations made prior to DSO load. 21 // 22 // Option (2) is not easy because pyautolib uses code from Chrome 23 // (see chrome_tests.gypi, dependencies for target_name: pyautolib) that 24 // has been instrumented with ASAN. So even if we disable -sanitize=address 25 // for pyautolib own sources, ASAN instrumentation will creep in from there. 26 // To avoid ASAN instrumentation, we might force Chrome build to compile all our 27 // dependencies one more time without -fsanitize=address. 28 // 29 // Note also that using these empty stubs prevents ASAN from catching bugs in 30 // Python-pyautolib process. But we do not need it, we are interested in Chrome 31 // bugs. 32 33 34 #include <stdio.h> 35 #include <stdlib.h> 36 #include <sys/mman.h> 37 38 void __asan_init() { 39 static int inited = 0; 40 if (inited) return; 41 inited = 1; 42 #if __WORDSIZE == 64 43 unsigned long start = 0x100000000000; 44 unsigned long size = 0x100000000000; 45 #else 46 unsigned long start = 0x20000000; 47 unsigned long size = 0x20000000; 48 #endif 49 void *res = mmap((void*)start, size, 50 PROT_READ | PROT_WRITE, 51 MAP_PRIVATE | MAP_ANON | MAP_FIXED | MAP_NORESERVE, 52 0, 0); 53 if (res == (void*)start) { 54 fprintf(stderr, "Fake AddressSanitizer run-time initialized ok at %p\n", 55 res); 56 } else { 57 fprintf(stderr, "Fake AddressSanitizer run-time failed to initialize.\n" 58 "You have been warned. Aborting."); 59 abort(); 60 } 61 } 62 63 // Update the name when asan api updates. 64 void __asan_init_v1() { 65 __asan_init(); 66 } 67 68 void __asan_handle_no_return() { } 69 void __asan_register_globals() { } 70 void __asan_report_load1() { } 71 void __asan_report_load16() { } 72 void __asan_report_load2() { } 73 void __asan_report_load4() { } 74 void __asan_report_load8() { } 75 void __asan_report_load_n() { } 76 void __asan_report_store1() { } 77 void __asan_report_store16() { } 78 void __asan_report_store2() { } 79 void __asan_report_store4() { } 80 void __asan_report_store8() { } 81 void __asan_report_store_n() { } 82 void __asan_set_error_report_callback() { } 83 void __asan_unregister_globals() { } 84 void __sanitizer_sandbox_on_notify() { } 85
