chrome/test/pyautolib/asan_stub.c

   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() { }