mozalloc_abort.cpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-

 * vim: sw=2 ts=4 et :

*/

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/mozalloc_abort.h"

#ifdef ANDROID

#  include <android/log.h>

#endif

#ifdef MOZ_WIDGET_ANDROID

#  include "APKOpen.h"

#  include "dlfcn.h"

#endif

#include <stdio.h>

#include <string.h>

#include "mozilla/Assertions.h"

#include "mozilla/Sprintf.h"

void mozalloc_abort(const char* const msg) {

#ifndef ANDROID

  fputs(msg, stderr);

  fputs("\n", stderr);

#else

  __android_log_print(ANDROID_LOG_ERROR, "Gecko", "mozalloc_abort: %s", msg);

#endif

#ifdef MOZ_WIDGET_ANDROID

  abortThroughJava(msg);

#endif

  MOZ_CRASH_UNSAFE(msg);

#ifdef MOZ_WIDGET_ANDROID

template <size_t N>

void fillAbortMessage(char (&msg)[N], uintptr_t retAddress) {

/*

   * On Android, we often don't have reliable backtrace when crashing inside

   * abort(). Therefore, we try to find out who is calling abort() and add

   * that to the message.

*/

  Dl_info info = {};

  dladdr(reinterpret_cast<void*>(retAddress), &info);

  const char* const module = info.dli_fname ? info.dli_fname : "";

  const char* const base_module = strrchr(module, '/');

  const void* const module_offset =

      reinterpret_cast<void*>(retAddress - uintptr_t(info.dli_fbase));

  const char* const sym = info.dli_sname ? info.dli_sname : "";

  SprintfLiteral(msg, "abort() called from %s:%p (%s)",

                 base_module ? base_module + 1 : module, module_offset, sym);

#endif

#if defined(XP_UNIX) && !defined(MOZ_ASAN) && !defined(MOZ_TSAN) && \

    !defined(LIBFUZZER)

// Define abort() here, so that it is used instead of the system abort(). This

// lets us control the behavior when aborting, in order to get better results

// on *NIX platforms. See mozalloc_abort for details.

//

// For AddressSanitizer, we must not redefine system abort because the ASan

// option "abort_on_error=1" calls abort() and therefore causes the following

// call chain with our redefined abort:

//

// ASan -> abort() -> moz_abort() -> MOZ_CRASH() -> Segmentation fault

//

// That segmentation fault will be interpreted as another bug by ASan and as a

// result, ASan will just exit(1) instead of aborting.

//

// The same applies to ThreadSanitizer when run with "halt_on_error=1" in

// combination with "abort_on_error=1".

//

// When building with libFuzzer, it pulls in the UndefinedBehaviorSanitizer

// runtime which also requires the same workaround as with ASan or TSan.

extern "C" void abort(void) {

#  ifdef MOZ_WIDGET_ANDROID

  char msg[64] = {};

  fillAbortMessage(msg, uintptr_t(__builtin_return_address(0)));

#  else

  const char* const msg = "Redirecting call to abort() to mozalloc_abort\n";

#  endif

  mozalloc_abort(msg);

  // We won't reach here because mozalloc_abort() is MOZ_NORETURN. But that

  // annotation isn't used on ARM (see mozalloc_abort.h for why) so we add a

  // unreachable marker here to avoid a "'noreturn' function does return"

  // warning.

  MOZ_ASSUME_UNREACHABLE_MARKER();

#endif