Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

8 files changed, 2958 insertions, 0 deletions

diff --git a/toolkit/crashreporter/breakpad-client/linux/handler/exception_handler.cc b/toolkit/crashreporter/breakpad-client/linux/handler/exception_handler.cc
new file mode 100644
index 0000000000..92a0443d79
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/handler/exception_handler.cc
@@ -0,0 +1,876 @@
+// Copyright (c) 2010 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// The ExceptionHandler object installs signal handlers for a number of
+// signals. We rely on the signal handler running on the thread which crashed
+// in order to identify it. This is true of the synchronous signals (SEGV etc),
+// but not true of ABRT. Thus, if you send ABRT to yourself in a program which
+// uses ExceptionHandler, you need to use tgkill to direct it to the current
+// thread.
+//
+// The signal flow looks like this:
+//
+//   SignalHandler (uses a global stack of ExceptionHandler objects to find
+//        |         one to handle the signal. If the first rejects it, try
+//        |         the second etc...)
+//        V
+//   HandleSignal ----------------------------| (clones a new process which
+//        |                                   |  shares an address space with
+//   (wait for cloned                         |  the crashed process. This
+//     process)                               |  allows us to ptrace the crashed
+//        |                                   |  process)
+//        V                                   V
+//   (set signal handler to             ThreadEntry (static function to bounce
+//    SIG_DFL and rethrow,                    |      back into the object)
+//    killing the crashed                     |
+//    process)                                V
+//                                          DoDump  (writes minidump)
+//                                            |
+//                                            V
+//                                         sys_exit
+//
+
+// This code is a little fragmented. Different functions of the ExceptionHandler
+// class run in a number of different contexts. Some of them run in a normal
+// context and are easy to code, others run in a compromised context and the
+// restrictions at the top of minidump_writer.cc apply: no libc and use the
+// alternative malloc. Each function should have comment above it detailing the
+// context which it runs in.
+
+#include "linux/handler/exception_handler.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/limits.h>
+#include <pthread.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <sys/syscall.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include <sys/ucontext.h>
+#include <sys/user.h>
+#include <ucontext.h>
+
+#include <algorithm>
+#include <utility>
+#include <vector>
+
+#include "common/basictypes.h"
+#include "common/linux/breakpad_getcontext.h"
+#include "common/linux/linux_libc_support.h"
+#include "common/memory_allocator.h"
+#include "linux/log/log.h"
+#include "linux/microdump_writer/microdump_writer.h"
+#include "linux/minidump_writer/linux_dumper.h"
+#include "linux/minidump_writer/minidump_writer.h"
+#include "common/linux/eintr_wrapper.h"
+#include "third_party/lss/linux_syscall_support.h"
+#if defined(MOZ_OXIDIZED_BREAKPAD)
+#include "nsString.h"
+#include "mozilla/toolkit/crashreporter/rust_minidump_writer_linux_ffi_generated.h"
+#endif
+
+#ifdef MOZ_PHC
+#include "PHC.h"
+#endif
+
+#if defined(__ANDROID__)
+#include "linux/sched.h"
+#endif
+
+#ifndef PR_SET_PTRACER
+#define PR_SET_PTRACER 0x59616d61
+#endif
+
+#define SKIP_SIGILL(sig) if (g_skip_sigill_ && (sig == SIGILL)) continue;
+
+namespace google_breakpad {
+
+namespace {
+// The list of signals which we consider to be crashes. The default action for
+// all these signals must be Core (see man 7 signal) because we rethrow the
+// signal after handling it and expect that it'll be fatal.
+const int kExceptionSignals[] = {
+  SIGSEGV, SIGABRT, SIGFPE, SIGILL, SIGBUS, SIGTRAP
+};
+const int kNumHandledSignals =
+    sizeof(kExceptionSignals) / sizeof(kExceptionSignals[0]);
+struct sigaction old_handlers[kNumHandledSignals];
+bool handlers_installed = false;
+
+// InstallAlternateStackLocked will store the newly installed stack in new_stack
+// and (if it exists) the previously installed stack in old_stack.
+stack_t old_stack;
+stack_t new_stack;
+bool stack_installed = false;
+
+// Create an alternative stack to run the signal handlers on. This is done since
+// the signal might have been caused by a stack overflow.
+// Runs before crashing: normal context.
+void InstallAlternateStackLocked() {
+  if (stack_installed)
+    return;
+
+  memset(&old_stack, 0, sizeof(old_stack));
+  memset(&new_stack, 0, sizeof(new_stack));
+
+  // SIGSTKSZ may be too small to prevent the signal handlers from overrunning
+  // the alternative stack. Ensure that the size of the alternative stack is
+  // large enough.
+  static const size_t kSigStackSize = std::max(size_t(16384), size_t(SIGSTKSZ));
+
+  // Only set an alternative stack if there isn't already one, or if the current
+  // one is too small.
+  if (sys_sigaltstack(NULL, &old_stack) == -1 || !old_stack.ss_sp ||
+      old_stack.ss_size < kSigStackSize) {
+    new_stack.ss_sp = calloc(1, kSigStackSize);
+    new_stack.ss_size = kSigStackSize;
+
+    if (sys_sigaltstack(&new_stack, NULL) == -1) {
+      free(new_stack.ss_sp);
+      return;
+    }
+    stack_installed = true;
+  }
+}
+
+// Runs before crashing: normal context.
+void RestoreAlternateStackLocked() {
+  if (!stack_installed)
+    return;
+
+  stack_t current_stack;
+  if (sys_sigaltstack(NULL, &current_stack) == -1)
+    return;
+
+  // Only restore the old_stack if the current alternative stack is the one
+  // installed by the call to InstallAlternateStackLocked.
+  if (current_stack.ss_sp == new_stack.ss_sp) {
+    if (old_stack.ss_sp) {
+      if (sys_sigaltstack(&old_stack, NULL) == -1)
+        return;
+    } else {
+      stack_t disable_stack;
+      disable_stack.ss_flags = SS_DISABLE;
+      if (sys_sigaltstack(&disable_stack, NULL) == -1)
+        return;
+    }
+  }
+
+  free(new_stack.ss_sp);
+  stack_installed = false;
+}
+
+void InstallDefaultHandler(int sig) {
+#if defined(__ANDROID__)
+  // Android L+ expose signal and sigaction symbols that override the system
+  // ones. There is a bug in these functions where a request to set the handler
+  // to SIG_DFL is ignored. In that case, an infinite loop is entered as the
+  // signal is repeatedly sent to breakpad's signal handler.
+  // To work around this, directly call the system's sigaction.
+  struct kernel_sigaction sa;
+  memset(&sa, 0, sizeof(sa));
+  sys_sigemptyset(&sa.sa_mask);
+  sa.sa_handler_ = SIG_DFL;
+  sa.sa_flags = SA_RESTART;
+  sys_rt_sigaction(sig, &sa, NULL, sizeof(kernel_sigset_t));
+#else
+  signal(sig, SIG_DFL);
+#endif
+}
+
+// The global exception handler stack. This is needed because there may exist
+// multiple ExceptionHandler instances in a process. Each will have itself
+// registered in this stack.
+std::vector<ExceptionHandler*>* g_handler_stack_ = NULL;
+pthread_mutex_t g_handler_stack_mutex_ = PTHREAD_MUTEX_INITIALIZER;
+
+// sizeof(CrashContext) can be too big w.r.t the size of alternatate stack
+// for SignalHandler(). Keep the crash context as a .bss field. Exception
+// handlers are serialized by the |g_handler_stack_mutex_| and at most one at a
+// time can use |g_crash_context_|.
+ExceptionHandler::CrashContext g_crash_context_;
+
+FirstChanceHandler g_first_chance_handler_ = nullptr;
+bool g_skip_sigill_ = false;
+}  // namespace
+
+// Runs before crashing: normal context.
+ExceptionHandler::ExceptionHandler(const MinidumpDescriptor& descriptor,
+                                   FilterCallback filter,
+                                   MinidumpCallback callback,
+                                   void* callback_context,
+                                   bool install_handler,
+                                   const int server_fd)
+    : filter_(filter),
+      callback_(callback),
+      callback_context_(callback_context),
+      minidump_descriptor_(descriptor),
+      crash_handler_(NULL) {
+
+  g_skip_sigill_ = getenv("MOZ_DISABLE_EXCEPTION_HANDLER_SIGILL") ? true : false;
+  if (server_fd >= 0)
+    crash_generation_client_.reset(CrashGenerationClient::TryCreate(server_fd));
+
+  if (!IsOutOfProcess() && !minidump_descriptor_.IsFD() &&
+      !minidump_descriptor_.IsMicrodumpOnConsole())
+    minidump_descriptor_.UpdatePath();
+
+#if defined(__ANDROID__)
+  if (minidump_descriptor_.IsMicrodumpOnConsole())
+    logger::initializeCrashLogWriter();
+#endif
+
+  pthread_mutex_lock(&g_handler_stack_mutex_);
+
+  // Pre-fault the crash context struct. This is to avoid failing due to OOM
+  // if handling an exception when the process ran out of virtual memory.
+  memset(&g_crash_context_, 0, sizeof(g_crash_context_));
+
+  if (!g_handler_stack_)
+    g_handler_stack_ = new std::vector<ExceptionHandler*>;
+  if (install_handler) {
+    InstallAlternateStackLocked();
+    InstallHandlersLocked();
+  }
+  g_handler_stack_->push_back(this);
+  pthread_mutex_unlock(&g_handler_stack_mutex_);
+}
+
+// Runs before crashing: normal context.
+ExceptionHandler::~ExceptionHandler() {
+  pthread_mutex_lock(&g_handler_stack_mutex_);
+  std::vector<ExceptionHandler*>::iterator handler =
+      std::find(g_handler_stack_->begin(), g_handler_stack_->end(), this);
+  g_handler_stack_->erase(handler);
+  if (g_handler_stack_->empty()) {
+    delete g_handler_stack_;
+    g_handler_stack_ = NULL;
+    RestoreAlternateStackLocked();
+    RestoreHandlersLocked();
+  }
+  pthread_mutex_unlock(&g_handler_stack_mutex_);
+}
+
+// Runs before crashing: normal context.
+// static
+bool ExceptionHandler::InstallHandlersLocked() {
+  if (handlers_installed)
+    return false;
+
+  // Fail if unable to store all the old handlers.
+  for (int i = 0; i < kNumHandledSignals; ++i) {
+    SKIP_SIGILL(kExceptionSignals[i]);
+    if (sigaction(kExceptionSignals[i], NULL, &old_handlers[i]) == -1)
+      return false;
+  }
+
+  struct sigaction sa;
+  memset(&sa, 0, sizeof(sa));
+  sigemptyset(&sa.sa_mask);
+
+  // Mask all exception signals when we're handling one of them.
+  for (int i = 0; i < kNumHandledSignals; ++i) {
+    SKIP_SIGILL(kExceptionSignals[i]);
+    sigaddset(&sa.sa_mask, kExceptionSignals[i]);
+  }
+
+  sa.sa_sigaction = SignalHandler;
+  sa.sa_flags = SA_ONSTACK | SA_SIGINFO;
+
+  for (int i = 0; i < kNumHandledSignals; ++i) {
+    SKIP_SIGILL(kExceptionSignals[i]);
+    if (sigaction(kExceptionSignals[i], &sa, NULL) == -1) {
+      // At this point it is impractical to back out changes, and so failure to
+      // install a signal is intentionally ignored.
+    }
+  }
+  handlers_installed = true;
+  return true;
+}
+
+// This function runs in a compromised context: see the top of the file.
+// Runs on the crashing thread.
+// static
+void ExceptionHandler::RestoreHandlersLocked() {
+  if (!handlers_installed)
+    return;
+
+  for (int i = 0; i < kNumHandledSignals; ++i) {
+    SKIP_SIGILL(kExceptionSignals[i]);
+    if (sigaction(kExceptionSignals[i], &old_handlers[i], NULL) == -1) {
+      InstallDefaultHandler(kExceptionSignals[i]);
+    }
+  }
+  handlers_installed = false;
+}
+
+// void ExceptionHandler::set_crash_handler(HandlerCallback callback) {
+//   crash_handler_ = callback;
+// }
+
+// This function runs in a compromised context: see the top of the file.
+// Runs on the crashing thread.
+// static
+void ExceptionHandler::SignalHandler(int sig, siginfo_t* info, void* uc) {
+
+  // Give the first chance handler a chance to recover from this signal
+  //
+  // This is primarily used by V8. V8 uses guard regions to guarantee memory
+  // safety in WebAssembly. This means some signals might be expected if they
+  // originate from Wasm code while accessing the guard region. We give V8 the
+  // chance to handle and recover from these signals first.
+  if (g_first_chance_handler_ != nullptr &&
+      g_first_chance_handler_(sig, info, uc)) {
+    return;
+  }
+
+  // All the exception signals are blocked at this point.
+  pthread_mutex_lock(&g_handler_stack_mutex_);
+
+  // Sometimes, Breakpad runs inside a process where some other buggy code
+  // saves and restores signal handlers temporarily with 'signal'
+  // instead of 'sigaction'. This loses the SA_SIGINFO flag associated
+  // with this function. As a consequence, the values of 'info' and 'uc'
+  // become totally bogus, generally inducing a crash.
+  //
+  // The following code tries to detect this case. When it does, it
+  // resets the signal handlers with sigaction + SA_SIGINFO and returns.
+  // This forces the signal to be thrown again, but this time the kernel
+  // will call the function with the right arguments.
+  struct sigaction cur_handler;
+  if (sigaction(sig, NULL, &cur_handler) == 0 &&
+      cur_handler.sa_sigaction == SignalHandler &&
+      (cur_handler.sa_flags & SA_SIGINFO) == 0) {
+    // Reset signal handler with the right flags.
+    sigemptyset(&cur_handler.sa_mask);
+    sigaddset(&cur_handler.sa_mask, sig);
+
+    cur_handler.sa_sigaction = SignalHandler;
+    cur_handler.sa_flags = SA_ONSTACK | SA_SIGINFO;
+
+    if (sigaction(sig, &cur_handler, NULL) == -1) {
+      // When resetting the handler fails, try to reset the
+      // default one to avoid an infinite loop here.
+      InstallDefaultHandler(sig);
+    }
+    pthread_mutex_unlock(&g_handler_stack_mutex_);
+    return;
+  }
+
+  bool handled = false;
+  for (int i = g_handler_stack_->size() - 1; !handled && i >= 0; --i) {
+    handled = (*g_handler_stack_)[i]->HandleSignal(sig, info, uc);
+  }
+
+  // Upon returning from this signal handler, sig will become unmasked and then
+  // it will be retriggered. If one of the ExceptionHandlers handled it
+  // successfully, restore the default handler. Otherwise, restore the
+  // previously installed handler. Then, when the signal is retriggered, it will
+  // be delivered to the appropriate handler.
+  if (handled) {
+    InstallDefaultHandler(sig);
+  } else {
+    RestoreHandlersLocked();
+  }
+
+  pthread_mutex_unlock(&g_handler_stack_mutex_);
+
+  // info->si_code <= 0 iff SI_FROMUSER (SI_FROMKERNEL otherwise).
+  if (info->si_code <= 0 || sig == SIGABRT) {
+    // This signal was triggered by somebody sending us the signal with kill().
+    // In order to retrigger it, we have to queue a new signal by calling
+    // kill() ourselves.  The special case (si_pid == 0 && sig == SIGABRT) is
+    // due to the kernel sending a SIGABRT from a user request via SysRQ.
+    if (sys_tgkill(getpid(), syscall(__NR_gettid), sig) < 0) {
+      // If we failed to kill ourselves (e.g. because a sandbox disallows us
+      // to do so), we instead resort to terminating our process. This will
+      // result in an incorrect exit code.
+      _exit(1);
+    }
+  } else {
+    // This was a synchronous signal triggered by a hard fault (e.g. SIGSEGV).
+    // No need to reissue the signal. It will automatically trigger again,
+    // when we return from the signal handler.
+  }
+}
+
+struct ThreadArgument {
+  pid_t pid;  // the crashing process
+  const MinidumpDescriptor* minidump_descriptor;
+  ExceptionHandler* handler;
+  const void* context;  // a CrashContext structure
+  size_t context_size;
+};
+
+// This is the entry function for the cloned process. We are in a compromised
+// context here: see the top of the file.
+// static
+int ExceptionHandler::ThreadEntry(void *arg) {
+  const ThreadArgument *thread_arg = reinterpret_cast<ThreadArgument*>(arg);
+
+  // Close the write end of the pipe. This allows us to fail if the parent dies
+  // while waiting for the continue signal.
+  sys_close(thread_arg->handler->fdes[1]);
+
+  // Block here until the crashing process unblocks us when
+  // we're allowed to use ptrace
+  thread_arg->handler->WaitForContinueSignal();
+  sys_close(thread_arg->handler->fdes[0]);
+
+  return thread_arg->handler->DoDump(thread_arg->pid, thread_arg->context,
+                                     thread_arg->context_size) == false;
+}
+
+#ifdef MOZ_PHC
+static void GetPHCAddrInfo(siginfo_t* siginfo,
+                           mozilla::phc::AddrInfo* addr_info) {
+  // Is this a crash involving a PHC allocation?
+  if (siginfo->si_signo == SIGSEGV || siginfo->si_signo == SIGBUS) {
+    mozilla::phc::IsPHCAllocation(siginfo->si_addr, addr_info);
+  }
+}
+#endif
+
+// This function runs in a compromised context: see the top of the file.
+// Runs on the crashing thread.
+bool ExceptionHandler::HandleSignal(int /*sig*/, siginfo_t* info, void* uc) {
+  mozilla::phc::AddrInfo* addr_info = nullptr;
+#ifdef MOZ_PHC
+  addr_info = &mozilla::phc::gAddrInfo;
+  GetPHCAddrInfo(info, addr_info);
+#endif
+
+  if (filter_ && !filter_(callback_context_))
+    return false;
+
+  // Allow ourselves to be dumped if the signal is trusted.
+  bool signal_trusted = info->si_code > 0;
+  bool signal_pid_trusted = info->si_code == SI_USER ||
+      info->si_code == SI_TKILL;
+  if (signal_trusted || (signal_pid_trusted && info->si_pid == getpid())) {
+    sys_prctl(PR_SET_DUMPABLE, 1, 0, 0, 0);
+  }
+
+  // Fill in all the holes in the struct to make Valgrind happy.
+  memset(&g_crash_context_, 0, sizeof(g_crash_context_));
+  memcpy(&g_crash_context_.siginfo, info, sizeof(siginfo_t));
+  memcpy(&g_crash_context_.context, uc, sizeof(ucontext_t));
+#if defined(__aarch64__)
+  ucontext_t* uc_ptr = (ucontext_t*)uc;
+  struct fpsimd_context* fp_ptr =
+      (struct fpsimd_context*)&uc_ptr->uc_mcontext.__reserved;
+  if (fp_ptr->head.magic == FPSIMD_MAGIC) {
+    memcpy(&g_crash_context_.float_state, fp_ptr,
+           sizeof(g_crash_context_.float_state));
+  }
+#elif !defined(__ARM_EABI__) && !defined(__mips__)
+  // FP state is not part of user ABI on ARM Linux.
+  // In case of MIPS Linux FP state is already part of ucontext_t
+  // and 'float_state' is not a member of CrashContext.
+  ucontext_t* uc_ptr = (ucontext_t*)uc;
+  if (uc_ptr->uc_mcontext.fpregs) {
+    memcpy(&g_crash_context_.float_state, uc_ptr->uc_mcontext.fpregs,
+           sizeof(g_crash_context_.float_state));
+  }
+#endif
+  g_crash_context_.tid = syscall(__NR_gettid);
+  if (crash_handler_ != NULL) {
+    if (crash_handler_(&g_crash_context_, sizeof(g_crash_context_),
+                       callback_context_)) {
+      return true;
+    }
+  }
+
+  return GenerateDump(&g_crash_context_, addr_info);
+}
+
+// This is a public interface to HandleSignal that allows the client to
+// generate a crash dump. This function may run in a compromised context.
+bool ExceptionHandler::SimulateSignalDelivery(int sig) {
+  siginfo_t siginfo = {};
+  // Mimic a trusted signal to allow tracing the process (see
+  // ExceptionHandler::HandleSignal().
+  siginfo.si_code = SI_USER;
+  siginfo.si_pid = getpid();
+  ucontext_t context;
+  getcontext(&context);
+  return HandleSignal(sig, &siginfo, &context);
+}
+
+// This function may run in a compromised context: see the top of the file.
+bool ExceptionHandler::GenerateDump(
+    CrashContext *context, const mozilla::phc::AddrInfo* addr_info) {
+  if (IsOutOfProcess()) {
+    bool success =
+      crash_generation_client_->RequestDump(context, sizeof(*context));
+
+    if (callback_) {
+      success =
+        callback_(minidump_descriptor_, callback_context_, addr_info, success);
+    }
+
+    return success;
+  }
+
+  // Allocating too much stack isn't a problem, and better to err on the side
+  // of caution than smash it into random locations.
+  static const unsigned kChildStackSize = 16000;
+  PageAllocator allocator;
+  uint8_t* stack = reinterpret_cast<uint8_t*>(allocator.Alloc(kChildStackSize));
+  if (!stack)
+    return false;
+  // clone() needs the top-most address. (scrub just to be safe)
+  stack += kChildStackSize;
+  my_memset(stack - 16, 0, 16);
+
+  ThreadArgument thread_arg;
+  thread_arg.handler = this;
+  thread_arg.minidump_descriptor = &minidump_descriptor_;
+  thread_arg.pid = getpid();
+  thread_arg.context = context;
+  thread_arg.context_size = sizeof(*context);
+
+  // We need to explicitly enable ptrace of parent processes on some
+  // kernels, but we need to know the PID of the cloned process before we
+  // can do this. Create a pipe here which we can use to block the
+  // cloned process after creating it, until we have explicitly enabled ptrace
+  if (sys_pipe(fdes) == -1) {
+    // Creating the pipe failed. We'll log an error but carry on anyway,
+    // as we'll probably still get a useful crash report. All that will happen
+    // is the write() and read() calls will fail with EBADF
+    static const char no_pipe_msg[] = "ExceptionHandler::GenerateDump "
+                                      "sys_pipe failed:";
+    logger::write(no_pipe_msg, sizeof(no_pipe_msg) - 1);
+    logger::write(strerror(errno), strlen(strerror(errno)));
+    logger::write("\n", 1);
+
+    // Ensure fdes[0] and fdes[1] are invalid file descriptors.
+    fdes[0] = fdes[1] = -1;
+  }
+
+  const pid_t child = sys_clone(
+      ThreadEntry, stack, CLONE_FS | CLONE_UNTRACED, &thread_arg, NULL, NULL,
+      NULL);
+  if (child == -1) {
+    sys_close(fdes[0]);
+    sys_close(fdes[1]);
+    return false;
+  }
+
+  if (child != 0) {
+    static const char clonedMsg[] =
+      "ExceptionHandler::GenerateDump cloned child ";
+    char pidMsg[32] = {};
+
+    unsigned int pidLen = my_uint_len(child);
+    my_uitos(pidMsg, child, pidLen);
+
+    logger::write(clonedMsg, my_strlen(clonedMsg));
+    logger::write(pidMsg, pidLen);
+    logger::write("\n", 1);
+  } else {
+    static const char childMsg[] =
+      "ExceptionHandler::GenerateDump I'm the child\n";
+    logger::write(childMsg, my_strlen(childMsg));
+  }
+
+  // Close the read end of the pipe.
+  sys_close(fdes[0]);
+  // Allow the child to ptrace us
+  sys_prctl(PR_SET_PTRACER, child, 0, 0, 0);
+  SendContinueSignalToChild();
+  int status = 0;
+  const int r = HANDLE_EINTR(sys_waitpid(child, &status, __WALL));
+
+  sys_close(fdes[1]);
+
+  if (r == -1) {
+    static const char msg[] = "ExceptionHandler::GenerateDump waitpid failed:";
+    logger::write(msg, sizeof(msg) - 1);
+    logger::write(strerror(errno), strlen(strerror(errno)));
+    logger::write("\n", 1);
+  }
+
+  bool success = r != -1 && WIFEXITED(status) && WEXITSTATUS(status) == 0;
+  if (callback_)
+    success =
+      callback_(minidump_descriptor_, callback_context_, addr_info, success);
+  return success;
+}
+
+// This function runs in a compromised context: see the top of the file.
+void ExceptionHandler::SendContinueSignalToChild() {
+  static const char okToContinueMessage = 'a';
+  int r;
+  r = HANDLE_EINTR(sys_write(fdes[1], &okToContinueMessage, sizeof(char)));
+  if (r == -1) {
+    static const char msg[] = "ExceptionHandler::SendContinueSignalToChild "
+                              "sys_write failed:";
+    logger::write(msg, sizeof(msg) - 1);
+    logger::write(strerror(errno), strlen(strerror(errno)));
+    logger::write("\n", 1);
+  }
+
+  const char* msg = "ExceptionHandler::SendContinueSignalToChild sent continue signal to child\n";
+  logger::write(msg, my_strlen(msg));
+}
+
+// This function runs in a compromised context: see the top of the file.
+// Runs on the cloned process.
+void ExceptionHandler::WaitForContinueSignal() {
+  int r;
+  char receivedMessage;
+
+  const char* waitMsg = "ExceptionHandler::WaitForContinueSignal waiting for continue signal...\n";
+  logger::write(waitMsg, my_strlen(waitMsg));
+
+  r = HANDLE_EINTR(sys_read(fdes[0], &receivedMessage, sizeof(char)));
+  if (r == -1) {
+    static const char msg[] = "ExceptionHandler::WaitForContinueSignal "
+                              "sys_read failed:";
+    logger::write(msg, sizeof(msg) - 1);
+    logger::write(strerror(errno), strlen(strerror(errno)));
+    logger::write("\n", 1);
+  }
+}
+
+// This function runs in a compromised context: see the top of the file.
+// Runs on the cloned process.
+bool ExceptionHandler::DoDump(pid_t crashing_process, const void* context,
+                              size_t context_size) {
+  const bool may_skip_dump =
+      minidump_descriptor_.skip_dump_if_principal_mapping_not_referenced();
+  const uintptr_t principal_mapping_address =
+      minidump_descriptor_.address_within_principal_mapping();
+  const bool sanitize_stacks = minidump_descriptor_.sanitize_stacks();
+  if (minidump_descriptor_.IsMicrodumpOnConsole()) {
+    return google_breakpad::WriteMicrodump(
+        crashing_process,
+        context,
+        context_size,
+        mapping_list_,
+        may_skip_dump,
+        principal_mapping_address,
+        sanitize_stacks,
+        *minidump_descriptor_.microdump_extra_info());
+  }
+  if (minidump_descriptor_.IsFD()) {
+    return google_breakpad::WriteMinidump(minidump_descriptor_.fd(),
+                                          minidump_descriptor_.size_limit(),
+                                          crashing_process,
+                                          context,
+                                          context_size,
+                                          mapping_list_,
+                                          app_memory_list_,
+                                          may_skip_dump,
+                                          principal_mapping_address,
+                                          sanitize_stacks);
+  }
+  return google_breakpad::WriteMinidump(minidump_descriptor_.path(),
+                                        minidump_descriptor_.size_limit(),
+                                        crashing_process,
+                                        context,
+                                        context_size,
+                                        mapping_list_,
+                                        app_memory_list_,
+                                        may_skip_dump,
+                                        principal_mapping_address,
+                                        sanitize_stacks);
+}
+
+// static
+bool ExceptionHandler::WriteMinidump(const string& dump_path,
+                                     MinidumpCallback callback,
+                                     void* callback_context) {
+  MinidumpDescriptor descriptor(dump_path);
+  ExceptionHandler eh(descriptor, NULL, callback, callback_context, false, -1);
+  return eh.WriteMinidump();
+}
+
+// In order to making using EBP to calculate the desired value for ESP
+// a valid operation, ensure that this function is compiled with a
+// frame pointer using the following attribute. This attribute
+// is supported on GCC but not on clang.
+#if defined(__i386__) && defined(__GNUC__) && !defined(__clang__)
+__attribute__((optimize("no-omit-frame-pointer")))
+#endif
+bool ExceptionHandler::WriteMinidump() {
+  if (!IsOutOfProcess() && !minidump_descriptor_.IsFD() &&
+      !minidump_descriptor_.IsMicrodumpOnConsole()) {
+    // Update the path of the minidump so that this can be called multiple times
+    // and new files are created for each minidump.  This is done before the
+    // generation happens, as clients may want to access the MinidumpDescriptor
+    // after this call to find the exact path to the minidump file.
+    minidump_descriptor_.UpdatePath();
+  } else if (minidump_descriptor_.IsFD()) {
+    // Reposition the FD to its beginning and resize it to get rid of the
+    // previous minidump info.
+    lseek(minidump_descriptor_.fd(), 0, SEEK_SET);
+    ignore_result(ftruncate(minidump_descriptor_.fd(), 0));
+  }
+
+  // Allow this process to be dumped.
+  sys_prctl(PR_SET_DUMPABLE, 1, 0, 0, 0);
+
+  CrashContext context;
+  int getcontext_result = getcontext(&context.context);
+  if (getcontext_result)
+    return false;
+
+#if defined(__i386__)
+  // In CPUFillFromUContext in minidumpwriter.cc the stack pointer is retrieved
+  // from REG_UESP instead of from REG_ESP. REG_UESP is the user stack pointer
+  // and it only makes sense when running in kernel mode with a different stack
+  // pointer. When WriteMiniDump is called during normal processing REG_UESP is
+  // zero which leads to bad minidump files.
+  if (!context.context.uc_mcontext.gregs[REG_UESP]) {
+    // If REG_UESP is set to REG_ESP then that includes the stack space for the
+    // CrashContext object in this function, which is about 128 KB. Since the
+    // Linux dumper only records 32 KB of stack this would mean that nothing
+    // useful would be recorded. A better option is to set REG_UESP to REG_EBP,
+    // perhaps with a small negative offset in case there is any code that
+    // objects to them being equal.
+    context.context.uc_mcontext.gregs[REG_UESP] =
+      context.context.uc_mcontext.gregs[REG_EBP] - 16;
+    // The stack saving is based off of REG_ESP so it must be set to match the
+    // new REG_UESP.
+    context.context.uc_mcontext.gregs[REG_ESP] =
+      context.context.uc_mcontext.gregs[REG_UESP];
+  }
+#endif
+
+#if !defined(__ARM_EABI__) && !defined(__aarch64__) && !defined(__mips__)
+  // FPU state is not part of ARM EABI ucontext_t.
+  memcpy(&context.float_state, context.context.uc_mcontext.fpregs,
+         sizeof(context.float_state));
+#endif
+  context.tid = sys_gettid();
+
+  // Add an exception stream to the minidump for better reporting.
+  memset(&context.siginfo, 0, sizeof(context.siginfo));
+  context.siginfo.si_signo = MD_EXCEPTION_CODE_LIN_DUMP_REQUESTED;
+#if defined(__i386__)
+  context.siginfo.si_addr =
+      reinterpret_cast<void*>(context.context.uc_mcontext.gregs[REG_EIP]);
+#elif defined(__x86_64__)
+  context.siginfo.si_addr =
+      reinterpret_cast<void*>(context.context.uc_mcontext.gregs[REG_RIP]);
+#elif defined(__arm__)
+  context.siginfo.si_addr =
+      reinterpret_cast<void*>(context.context.uc_mcontext.arm_pc);
+#elif defined(__aarch64__)
+  context.siginfo.si_addr =
+      reinterpret_cast<void*>(context.context.uc_mcontext.pc);
+#elif defined(__mips__)
+  context.siginfo.si_addr =
+      reinterpret_cast<void*>(context.context.uc_mcontext.pc);
+#else
+#error "This code has not been ported to your platform yet."
+#endif
+
+  // nullptr here for phc::AddrInfo* is ok because this is not a crash.
+  return GenerateDump(&context, nullptr);
+}
+
+void ExceptionHandler::AddMappingInfo(const string& name,
+                                      const wasteful_vector<uint8_t>& identifier,
+                                      uintptr_t start_address,
+                                      size_t mapping_size,
+                                      size_t file_offset) {
+  MappingInfo info;
+  info.start_addr = start_address;
+  info.size = mapping_size;
+  info.offset = file_offset;
+  strncpy(info.name, name.c_str(), sizeof(info.name) - 1);
+  info.name[sizeof(info.name) - 1] = '\0';
+
+  MappingEntry mapping;
+  mapping.first = info;
+  mapping.second.assign(identifier.begin(), identifier.end());
+  mapping_list_.push_back(mapping);
+}
+
+void ExceptionHandler::RegisterAppMemory(void* ptr, size_t length) {
+  AppMemoryList::iterator iter =
+    std::find(app_memory_list_.begin(), app_memory_list_.end(), ptr);
+  if (iter != app_memory_list_.end()) {
+    // Don't allow registering the same pointer twice.
+    return;
+  }
+
+  AppMemory app_memory;
+  app_memory.ptr = ptr;
+  app_memory.length = length;
+  app_memory_list_.push_back(app_memory);
+}
+
+void ExceptionHandler::UnregisterAppMemory(void* ptr) {
+  AppMemoryList::iterator iter =
+    std::find(app_memory_list_.begin(), app_memory_list_.end(), ptr);
+  if (iter != app_memory_list_.end()) {
+    app_memory_list_.erase(iter);
+  }
+}
+
+// static
+bool ExceptionHandler::WriteMinidumpForChild(pid_t child,
+                                             pid_t child_blamed_thread,
+                                             const string& dump_path,
+                                             MinidumpCallback callback,
+                                             void* callback_context) {
+  // This function is not run in a compromised context.
+  MinidumpDescriptor descriptor(dump_path);
+  descriptor.UpdatePath();
+#if defined(MOZ_OXIDIZED_BREAKPAD)
+  nsCString error_msg;
+  if (!write_minidump_linux(descriptor.path(), child, child_blamed_thread, &error_msg))
+      return false;
+#else
+  if (!google_breakpad::WriteMinidump(descriptor.path(),
+                                      child,
+                                      child_blamed_thread))
+      return false;
+#endif
+
+  // nullptr here for phc::AddrInfo* is ok because this is not a crash.
+  return callback ? callback(descriptor, callback_context, nullptr, true)
+                  : true;
+}
+
+void SetFirstChanceExceptionHandler(FirstChanceHandler callback) {
+  g_first_chance_handler_ = callback;
+}
+
+}  // namespace google_breakpad
diff --git a/toolkit/crashreporter/breakpad-client/linux/handler/exception_handler.h b/toolkit/crashreporter/breakpad-client/linux/handler/exception_handler.h
new file mode 100644
index 0000000000..46ad399419
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/handler/exception_handler.h
@@ -0,0 +1,289 @@
+// Copyright (c) 2010 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_HANDLER_EXCEPTION_HANDLER_H_
+#define CLIENT_LINUX_HANDLER_EXCEPTION_HANDLER_H_
+
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <sys/ucontext.h>
+
+#include <string>
+
+#include "linux/crash_generation/crash_generation_client.h"
+#include "linux/handler/minidump_descriptor.h"
+#include "linux/minidump_writer/minidump_writer.h"
+#include "common/scoped_ptr.h"
+#include "common/using_std_string.h"
+#include "google_breakpad/common/minidump_format.h"
+
+#ifdef MOZ_PHC
+#include "PHC.h"
+#else
+namespace mozilla { namespace phc { class AddrInfo {}; } }
+#endif
+
+namespace google_breakpad {
+
+// ExceptionHandler
+//
+// ExceptionHandler can write a minidump file when an exception occurs,
+// or when WriteMinidump() is called explicitly by your program.
+//
+// To have the exception handler write minidumps when an uncaught exception
+// (crash) occurs, you should create an instance early in the execution
+// of your program, and keep it around for the entire time you want to
+// have crash handling active (typically, until shutdown).
+// (NOTE): There should be only be one this kind of exception handler
+// object per process.
+//
+// If you want to write minidumps without installing the exception handler,
+// you can create an ExceptionHandler with install_handler set to false,
+// then call WriteMinidump.  You can also use this technique if you want to
+// use different minidump callbacks for different call sites.
+//
+// In either case, a callback function is called when a minidump is written,
+// which receives the full path or file descriptor of the minidump.  The
+// caller can collect and write additional application state to that minidump,
+// and launch an external crash-reporting application.
+//
+// Caller should try to make the callbacks as crash-friendly as possible,
+// it should avoid use heap memory allocation as much as possible.
+
+class ExceptionHandler {
+ public:
+  // A callback function to run before Breakpad performs any substantial
+  // processing of an exception.  A FilterCallback is called before writing
+  // a minidump.  |context| is the parameter supplied by the user as
+  // callback_context when the handler was created.
+  //
+  // If a FilterCallback returns true, Breakpad will continue processing,
+  // attempting to write a minidump.  If a FilterCallback returns false,
+  // Breakpad  will immediately report the exception as unhandled without
+  // writing a minidump, allowing another handler the opportunity to handle it.
+  typedef bool (*FilterCallback)(void *context);
+
+  // A callback function to run after the minidump has been written.
+  // |descriptor| contains the file descriptor or file path containing the
+  // minidump. |context| is the parameter supplied by the user as
+  // callback_context when the handler was created.  |succeeded| indicates
+  // whether a minidump file was successfully written.
+  //
+  // If an exception occurred and the callback returns true, Breakpad will
+  // treat the exception as fully-handled, suppressing any other handlers from
+  // being notified of the exception.  If the callback returns false, Breakpad
+  // will treat the exception as unhandled, and allow another handler to handle
+  // it. If there are no other handlers, Breakpad will report the exception to
+  // the system as unhandled, allowing a debugger or native crash dialog the
+  // opportunity to handle the exception.  Most callback implementations
+  // should normally return the value of |succeeded|, or when they wish to
+  // not report an exception of handled, false.  Callbacks will rarely want to
+  // return true directly (unless |succeeded| is true).
+  typedef bool (*MinidumpCallback)(const MinidumpDescriptor& descriptor,
+                                   void* context,
+                                   const mozilla::phc::AddrInfo* addr_info,
+                                   bool succeeded);
+
+  // In certain cases, a user may wish to handle the generation of the minidump
+  // themselves. In this case, they can install a handler callback which is
+  // called when a crash has occurred. If this function returns true, no other
+  // processing of occurs and the process will shortly be crashed. If this
+  // returns false, the normal processing continues.
+  typedef bool (*HandlerCallback)(const void* crash_context,
+                                  size_t crash_context_size,
+                                  void* context);
+
+  // Creates a new ExceptionHandler instance to handle writing minidumps.
+  // Before writing a minidump, the optional |filter| callback will be called.
+  // Its return value determines whether or not Breakpad should write a
+  // minidump.  The minidump content will be written to the file path or file
+  // descriptor from |descriptor|, and the optional |callback| is called after
+  // writing the dump file, as described above.
+  // If install_handler is true, then a minidump will be written whenever
+  // an unhandled exception occurs.  If it is false, minidumps will only
+  // be written when WriteMinidump is called.
+  // If |server_fd| is valid, the minidump is generated out-of-process.  If it
+  // is -1, in-process generation will always be used.
+  ExceptionHandler(const MinidumpDescriptor& descriptor,
+                   FilterCallback filter,
+                   MinidumpCallback callback,
+                   void* callback_context,
+                   bool install_handler,
+                   const int server_fd);
+  ~ExceptionHandler();
+
+  const MinidumpDescriptor& minidump_descriptor() const {
+    return minidump_descriptor_;
+  }
+
+  void set_minidump_descriptor(const MinidumpDescriptor& descriptor) {
+    minidump_descriptor_ = descriptor;
+  }
+
+  void set_crash_handler(HandlerCallback callback) {
+    crash_handler_ = callback;
+  }
+
+  void set_crash_generation_client(CrashGenerationClient* client) {
+    crash_generation_client_.reset(client);
+  }
+
+  // Writes a minidump immediately.  This can be used to capture the execution
+  // state independently of a crash.
+  // Returns true on success.
+  // If the ExceptionHandler has been created with a path, a new file is
+  // generated for each minidump.  The file path can be retrieved in the
+  // MinidumpDescriptor passed to the MinidumpCallback or by accessing the
+  // MinidumpDescriptor directly from the ExceptionHandler (with
+  // minidump_descriptor()).
+  // If the ExceptionHandler has been created with a file descriptor, the file
+  // descriptor is repositioned to its beginning and the previous generated
+  // minidump is overwritten.
+  // Note that this method is not supposed to be called from a compromised
+  // context as it uses the heap.
+  bool WriteMinidump();
+
+  // Convenience form of WriteMinidump which does not require an
+  // ExceptionHandler instance.
+  static bool WriteMinidump(const string& dump_path,
+                            MinidumpCallback callback,
+                            void* callback_context);
+
+  // Write a minidump of |child| immediately.  This can be used to
+  // capture the execution state of |child| independently of a crash.
+  // Pass a meaningful |child_blamed_thread| to make that thread in
+  // the child process the one from which a crash signature is
+  // extracted.
+  //
+  // WARNING: the return of this function *must* happen before
+  // the code that will eventually reap |child| executes.
+  // Otherwise there's a pernicious race condition in which |child|
+  // exits, is reaped, another process created with its pid, then that
+  // new process dumped.
+  static bool WriteMinidumpForChild(pid_t child,
+                                    pid_t child_blamed_thread,
+                                    const string& dump_path,
+                                    MinidumpCallback callback,
+                                    void* callback_context);
+
+  // This structure is passed to minidump_writer.h:WriteMinidump via an opaque
+  // blob. It shouldn't be needed in any user code.
+  struct CrashContext {
+    siginfo_t siginfo;
+    pid_t tid;  // the crashing thread.
+    ucontext_t context;
+#if !defined(__ARM_EABI__) && !defined(__mips__)
+    // #ifdef this out because FP state is not part of user ABI for Linux ARM.
+    // In case of MIPS Linux FP state is already part of ucontext_t so
+    // 'float_state' is not required.
+    fpstate_t float_state;
+#endif
+  };
+
+  // Returns whether out-of-process dump generation is used or not.
+  bool IsOutOfProcess() const {
+    return crash_generation_client_.get() != NULL;
+  }
+
+  // Add information about a memory mapping. This can be used if
+  // a custom library loader is used that maps things in a way
+  // that the linux dumper can't handle by reading the maps file.
+  void AddMappingInfo(const string& name,
+                      const wasteful_vector<uint8_t>& identifier,
+                      uintptr_t start_address,
+                      size_t mapping_size,
+                      size_t file_offset);
+
+  // Register a block of memory of length bytes starting at address ptr
+  // to be copied to the minidump when a crash happens.
+  void RegisterAppMemory(void* ptr, size_t length);
+
+  // Unregister a block of memory that was registered with RegisterAppMemory.
+  void UnregisterAppMemory(void* ptr);
+
+  // Force signal handling for the specified signal.
+  bool SimulateSignalDelivery(int sig);
+
+  // Report a crash signal from an SA_SIGINFO signal handler.
+  bool HandleSignal(int sig, siginfo_t* info, void* uc);
+
+ private:
+  // Save the old signal handlers and install new ones.
+  static bool InstallHandlersLocked();
+  // Restore the old signal handlers.
+  static void RestoreHandlersLocked();
+
+  void PreresolveSymbols();
+  bool GenerateDump(CrashContext *context,
+                    const mozilla::phc::AddrInfo* addr_info);
+  void SendContinueSignalToChild();
+  void WaitForContinueSignal();
+
+  static void SignalHandler(int sig, siginfo_t* info, void* uc);
+  static int ThreadEntry(void* arg);
+  bool DoDump(pid_t crashing_process, const void* context,
+              size_t context_size);
+
+  const FilterCallback filter_;
+  const MinidumpCallback callback_;
+  void* const callback_context_;
+
+  scoped_ptr<CrashGenerationClient> crash_generation_client_;
+
+  MinidumpDescriptor minidump_descriptor_;
+
+  // Must be volatile. The compiler is unaware of the code which runs in
+  // the signal handler which reads this variable. Without volatile the
+  // compiler is free to optimise away writes to this variable which it
+  // believes are never read.
+  volatile HandlerCallback crash_handler_;
+
+  // We need to explicitly enable ptrace of parent processes on some
+  // kernels, but we need to know the PID of the cloned process before we
+  // can do this. We create a pipe which we can use to block the
+  // cloned process after creating it, until we have explicitly enabled
+  // ptrace. This is used to store the file descriptors for the pipe
+  int fdes[2] = {-1, -1};
+
+  // Callers can add extra info about mappings for cases where the
+  // dumper code cannot extract enough information from /proc/<pid>/maps.
+  MappingList mapping_list_;
+
+  // Callers can request additional memory regions to be included in
+  // the dump.
+  AppMemoryList app_memory_list_;
+};
+
+typedef bool (*FirstChanceHandler)(int, siginfo_t*, void*);
+void SetFirstChanceExceptionHandler(FirstChanceHandler callback);
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_HANDLER_EXCEPTION_HANDLER_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/handler/exception_handler_unittest.cc b/toolkit/crashreporter/breakpad-client/linux/handler/exception_handler_unittest.cc
new file mode 100644
index 0000000000..8fa59456c9
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/handler/exception_handler_unittest.cc
@@ -0,0 +1,1290 @@
+// Copyright (c) 2010 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <poll.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <signal.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <sys/uio.h>
+#include <sys/wait.h>
+#if defined(__mips__)
+#include <sys/cachectl.h>
+#endif
+
+#include <string>
+
+#include "breakpad_googletest_includes.h"
+#include "linux/handler/exception_handler.h"
+#include "linux/minidump_writer/minidump_writer.h"
+#include "common/linux/eintr_wrapper.h"
+#include "common/linux/ignore_ret.h"
+#include "common/linux/linux_libc_support.h"
+#include "common/tests/auto_tempdir.h"
+#include "common/using_std_string.h"
+#include "third_party/lss/linux_syscall_support.h"
+#include "google_breakpad/processor/minidump.h"
+
+using namespace google_breakpad;
+
+namespace {
+
+// Flush the instruction cache for a given memory range.
+// Only required on ARM and mips.
+void FlushInstructionCache(const char* memory, uint32_t memory_size) {
+#if defined(__arm__)
+  long begin = reinterpret_cast<long>(memory);
+  long end = begin + static_cast<long>(memory_size);
+# if defined(__ANDROID__)
+  // Provided by Android's <unistd.h>
+  cacheflush(begin, end, 0);
+# elif defined(__linux__)
+  // GLibc/ARM doesn't provide a wrapper for it, do a direct syscall.
+#  ifndef __ARM_NR_cacheflush
+#  define __ARM_NR_cacheflush 0xf0002
+#  endif
+  syscall(__ARM_NR_cacheflush, begin, end, 0);
+# else
+#   error "Your operating system is not supported yet"
+# endif
+#elif defined(__mips__)
+# if defined(__ANDROID__)
+  // Provided by Android's <unistd.h>
+  long begin = reinterpret_cast<long>(memory);
+  long end = begin + static_cast<long>(memory_size);
+#if _MIPS_SIM == _ABIO32
+  cacheflush(begin, end, 0);
+#else
+  syscall(__NR_cacheflush, begin, end, ICACHE);
+#endif
+# elif defined(__linux__)
+  // See http://www.linux-mips.org/wiki/Cacheflush_Syscall.
+  cacheflush(const_cast<char*>(memory), memory_size, ICACHE);
+# else
+#   error "Your operating system is not supported yet"
+# endif
+#endif
+}
+
+void sigchld_handler(int signo) { }
+
+int CreateTMPFile(const string& dir, string* path) {
+  string file = dir + "/exception-handler-unittest.XXXXXX";
+  const char* c_file = file.c_str();
+  // Copy that string, mkstemp needs a C string it can modify.
+  char* c_path = strdup(c_file);
+  const int fd = mkstemp(c_path);
+  if (fd >= 0)
+    *path = c_path;
+  free(c_path);
+  return fd;
+}
+
+class ExceptionHandlerTest : public ::testing::Test {
+ protected:
+  void SetUp() {
+    // We need to be able to wait for children, so SIGCHLD cannot be SIG_IGN.
+    struct sigaction sa;
+    memset(&sa, 0, sizeof(sa));
+    sa.sa_handler = sigchld_handler;
+    ASSERT_NE(sigaction(SIGCHLD, &sa, &old_action), -1);
+  }
+
+  void TearDown() {
+    sigaction(SIGCHLD, &old_action, NULL);
+  }
+
+  struct sigaction old_action;
+};
+
+
+void WaitForProcessToTerminate(pid_t process_id, int expected_status) {
+  int status;
+  ASSERT_NE(HANDLE_EINTR(waitpid(process_id, &status, 0)), -1);
+  ASSERT_TRUE(WIFSIGNALED(status));
+  ASSERT_EQ(expected_status, WTERMSIG(status));
+}
+
+// Reads the minidump path sent over the pipe |fd| and sets it in |path|.
+void ReadMinidumpPathFromPipe(int fd, string* path) {
+  struct pollfd pfd;
+  memset(&pfd, 0, sizeof(pfd));
+  pfd.fd = fd;
+  pfd.events = POLLIN | POLLERR;
+
+  const int r = HANDLE_EINTR(poll(&pfd, 1, 0));
+  ASSERT_EQ(1, r);
+  ASSERT_TRUE(pfd.revents & POLLIN);
+
+  int32_t len;
+  ASSERT_EQ(static_cast<ssize_t>(sizeof(len)), read(fd, &len, sizeof(len)));
+  ASSERT_LT(len, 2048);
+  char* filename = static_cast<char*>(malloc(len + 1));
+  ASSERT_EQ(len, read(fd, filename, len));
+  filename[len] = 0;
+  close(fd);
+  *path = filename;
+  free(filename);
+}
+
+}  // namespace
+
+TEST(ExceptionHandlerTest, SimpleWithPath) {
+  AutoTempDir temp_dir;
+  ExceptionHandler handler(
+      MinidumpDescriptor(temp_dir.path()), NULL, NULL, NULL, true, -1);
+  EXPECT_EQ(temp_dir.path(), handler.minidump_descriptor().directory());
+  string temp_subdir = temp_dir.path() + "/subdir";
+  handler.set_minidump_descriptor(MinidumpDescriptor(temp_subdir));
+  EXPECT_EQ(temp_subdir, handler.minidump_descriptor().directory());
+}
+
+TEST(ExceptionHandlerTest, SimpleWithFD) {
+  AutoTempDir temp_dir;
+  string path;
+  const int fd = CreateTMPFile(temp_dir.path(), &path);
+  ExceptionHandler handler(MinidumpDescriptor(fd), NULL, NULL, NULL, true, -1);
+  close(fd);
+}
+
+static bool DoneCallback(const MinidumpDescriptor& descriptor,
+                         void* context,
+                         bool succeeded) {
+  if (!succeeded)
+    return false;
+
+  if (!descriptor.IsFD()) {
+    int fd = reinterpret_cast<intptr_t>(context);
+    uint32_t len = 0;
+    len = my_strlen(descriptor.path());
+    IGNORE_RET(HANDLE_EINTR(sys_write(fd, &len, sizeof(len))));
+    IGNORE_RET(HANDLE_EINTR(sys_write(fd, descriptor.path(), len)));
+  }
+  return true;
+}
+
+#ifndef ADDRESS_SANITIZER
+
+// This is a replacement for "*reinterpret_cast<volatile int*>(NULL) = 0;"
+// It is needed because GCC is allowed to assume that the program will
+// not execute any undefined behavior (UB) operation. Further, when GCC
+// observes that UB statement is reached, it can assume that all statements
+// leading to the UB one are never executed either, and can completely
+// optimize them out. In the case of ExceptionHandlerTest::ExternalDumper,
+// GCC-4.9 optimized out the entire set up of ExceptionHandler, causing
+// test failure.
+volatile int *p_null;  // external linkage, so GCC can't tell that it
+                       // remains NULL. Volatile just for a good measure.
+static void DoNullPointerDereference() {
+  *p_null = 1;
+}
+
+void ChildCrash(bool use_fd) {
+  AutoTempDir temp_dir;
+  int fds[2] = {0};
+  int minidump_fd = -1;
+  string minidump_path;
+  if (use_fd) {
+    minidump_fd = CreateTMPFile(temp_dir.path(), &minidump_path);
+  } else {
+    ASSERT_NE(pipe(fds), -1);
+  }
+
+  const pid_t child = fork();
+  if (child == 0) {
+    {
+      google_breakpad::scoped_ptr<ExceptionHandler> handler;
+      if (use_fd) {
+        handler.reset(new ExceptionHandler(MinidumpDescriptor(minidump_fd),
+                                           NULL, NULL, NULL, true, -1));
+      } else {
+        close(fds[0]);  // Close the reading end.
+        void* fd_param = reinterpret_cast<void*>(fds[1]);
+        handler.reset(new ExceptionHandler(MinidumpDescriptor(temp_dir.path()),
+                                           NULL, DoneCallback, fd_param,
+                                           true, -1));
+      }
+      // Crash with the exception handler in scope.
+      DoNullPointerDereference();
+    }
+  }
+  if (!use_fd)
+    close(fds[1]);  // Close the writting end.
+
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGSEGV));
+
+  if (!use_fd)
+    ASSERT_NO_FATAL_FAILURE(ReadMinidumpPathFromPipe(fds[0], &minidump_path));
+
+  struct stat st;
+  ASSERT_EQ(0, stat(minidump_path.c_str(), &st));
+  ASSERT_GT(st.st_size, 0);
+  unlink(minidump_path.c_str());
+}
+
+TEST(ExceptionHandlerTest, ChildCrashWithPath) {
+  ASSERT_NO_FATAL_FAILURE(ChildCrash(false));
+}
+
+TEST(ExceptionHandlerTest, ChildCrashWithFD) {
+  ASSERT_NO_FATAL_FAILURE(ChildCrash(true));
+}
+
+#if !defined(__ANDROID_API__) || __ANDROID_API__ >= __ANDROID_API_N__
+static void* SleepFunction(void* unused) {
+  while (true) usleep(1000000);
+  return NULL;
+}
+
+static void* CrashFunction(void* b_ptr) {
+  pthread_barrier_t* b = reinterpret_cast<pthread_barrier_t*>(b_ptr);
+  pthread_barrier_wait(b);
+  DoNullPointerDereference();
+  return NULL;
+}
+
+// Tests that concurrent crashes do not enter a loop by alternately triggering
+// the signal handler.
+TEST(ExceptionHandlerTest, ParallelChildCrashesDontHang) {
+  AutoTempDir temp_dir;
+  const pid_t child = fork();
+  if (child == 0) {
+    google_breakpad::scoped_ptr<ExceptionHandler> handler(
+      new ExceptionHandler(MinidumpDescriptor(temp_dir.path()), NULL, NULL,
+                            NULL, true, -1));
+
+    // We start a number of threads to make sure handling the signal takes
+    // enough time for the second thread to enter the signal handler.
+    int num_sleep_threads = 100;
+    google_breakpad::scoped_array<pthread_t> sleep_threads(
+        new pthread_t[num_sleep_threads]);
+    for (int i = 0; i < num_sleep_threads; ++i) {
+      ASSERT_EQ(0, pthread_create(&sleep_threads[i], NULL, SleepFunction,
+                                  NULL));
+    }
+
+    int num_crash_threads = 2;
+    google_breakpad::scoped_array<pthread_t> crash_threads(
+        new pthread_t[num_crash_threads]);
+    // Barrier to synchronize crashing both threads at the same time.
+    pthread_barrier_t b;
+    ASSERT_EQ(0, pthread_barrier_init(&b, NULL, num_crash_threads + 1));
+    for (int i = 0; i < num_crash_threads; ++i) {
+      ASSERT_EQ(0, pthread_create(&crash_threads[i], NULL, CrashFunction, &b));
+    }
+    pthread_barrier_wait(&b);
+    for (int i = 0; i < num_crash_threads; ++i) {
+      ASSERT_EQ(0, pthread_join(crash_threads[i], NULL));
+    }
+  }
+
+  // Wait a while until the child should have crashed.
+  usleep(1000000);
+  // Kill the child if it is still running.
+  kill(child, SIGKILL);
+
+  // If the child process terminated by itself, it will have returned SIGSEGV.
+  // If however it got stuck in a loop, it will have been killed by the
+  // SIGKILL.
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGSEGV));
+}
+#endif  // !defined(__ANDROID_API__) || __ANDROID_API__ >= __ANDROID_API_N__
+
+static bool DoneCallbackReturnFalse(const MinidumpDescriptor& descriptor,
+                                    void* context,
+                                    bool succeeded) {
+  return false;
+}
+
+static bool DoneCallbackReturnTrue(const MinidumpDescriptor& descriptor,
+                                   void* context,
+                                   bool succeeded) {
+  return true;
+}
+
+static bool DoneCallbackRaiseSIGKILL(const MinidumpDescriptor& descriptor,
+                                     void* context,
+                                     bool succeeded) {
+  raise(SIGKILL);
+  return true;
+}
+
+static bool FilterCallbackReturnFalse(void* context) {
+  return false;
+}
+
+static bool FilterCallbackReturnTrue(void* context) {
+  return true;
+}
+
+// SIGKILL cannot be blocked and a handler cannot be installed for it. In the
+// following tests, if the child dies with signal SIGKILL, then the signal was
+// redelivered to this handler. If the child dies with SIGSEGV then it wasn't.
+static void RaiseSIGKILL(int sig) {
+  raise(SIGKILL);
+}
+
+static bool InstallRaiseSIGKILL() {
+  struct sigaction sa;
+  memset(&sa, 0, sizeof(sa));
+  sa.sa_handler = RaiseSIGKILL;
+  return sigaction(SIGSEGV, &sa, NULL) != -1;
+}
+
+static void CrashWithCallbacks(ExceptionHandler::FilterCallback filter,
+                               ExceptionHandler::MinidumpCallback done,
+                               string path) {
+  ExceptionHandler handler(
+      MinidumpDescriptor(path), filter, done, NULL, true, -1);
+  // Crash with the exception handler in scope.
+  DoNullPointerDereference();
+}
+
+TEST(ExceptionHandlerTest, RedeliveryOnFilterCallbackFalse) {
+  AutoTempDir temp_dir;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    ASSERT_TRUE(InstallRaiseSIGKILL());
+    CrashWithCallbacks(FilterCallbackReturnFalse, NULL, temp_dir.path());
+  }
+
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGKILL));
+}
+
+TEST(ExceptionHandlerTest, RedeliveryOnDoneCallbackFalse) {
+  AutoTempDir temp_dir;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    ASSERT_TRUE(InstallRaiseSIGKILL());
+    CrashWithCallbacks(NULL, DoneCallbackReturnFalse, temp_dir.path());
+  }
+
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGKILL));
+}
+
+TEST(ExceptionHandlerTest, NoRedeliveryOnDoneCallbackTrue) {
+  AutoTempDir temp_dir;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    ASSERT_TRUE(InstallRaiseSIGKILL());
+    CrashWithCallbacks(NULL, DoneCallbackReturnTrue, temp_dir.path());
+  }
+
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGSEGV));
+}
+
+TEST(ExceptionHandlerTest, NoRedeliveryOnFilterCallbackTrue) {
+  AutoTempDir temp_dir;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    ASSERT_TRUE(InstallRaiseSIGKILL());
+    CrashWithCallbacks(FilterCallbackReturnTrue, NULL, temp_dir.path());
+  }
+
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGSEGV));
+}
+
+TEST(ExceptionHandlerTest, RedeliveryToDefaultHandler) {
+  AutoTempDir temp_dir;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    // Custom signal handlers, which may have been installed by a test launcher,
+    // are undesirable in this child.
+    signal(SIGSEGV, SIG_DFL);
+
+    CrashWithCallbacks(FilterCallbackReturnFalse, NULL, temp_dir.path());
+  }
+
+  // As RaiseSIGKILL wasn't installed, the redelivery should just kill the child
+  // with SIGSEGV.
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGSEGV));
+}
+
+// Check that saving and restoring the signal handler with 'signal'
+// instead of 'sigaction' doesn't make the Breakpad signal handler
+// crash. See comments in ExceptionHandler::SignalHandler for full
+// details.
+TEST(ExceptionHandlerTest, RedeliveryOnBadSignalHandlerFlag) {
+  AutoTempDir temp_dir;
+  const pid_t child = fork();
+  if (child == 0) {
+    // Install the RaiseSIGKILL handler for SIGSEGV.
+    ASSERT_TRUE(InstallRaiseSIGKILL());
+
+    // Create a new exception handler, this installs a new SIGSEGV
+    // handler, after saving the old one.
+    ExceptionHandler handler(
+        MinidumpDescriptor(temp_dir.path()), NULL,
+        DoneCallbackReturnFalse, NULL, true, -1);
+
+    // Install the default SIGSEGV handler, saving the current one.
+    // Then re-install the current one with 'signal', this loses the
+    // SA_SIGINFO flag associated with the Breakpad handler.
+    sighandler_t old_handler = signal(SIGSEGV, SIG_DFL);
+    ASSERT_NE(reinterpret_cast<void*>(old_handler),
+              reinterpret_cast<void*>(SIG_ERR));
+    ASSERT_NE(reinterpret_cast<void*>(signal(SIGSEGV, old_handler)),
+              reinterpret_cast<void*>(SIG_ERR));
+
+    // Crash with the exception handler in scope.
+    DoNullPointerDereference();
+  }
+  // SIGKILL means Breakpad's signal handler didn't crash.
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGKILL));
+}
+
+TEST(ExceptionHandlerTest, StackedHandlersDeliveredToTop) {
+  AutoTempDir temp_dir;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    ExceptionHandler bottom(MinidumpDescriptor(temp_dir.path()),
+                            NULL,
+                            NULL,
+                            NULL,
+                            true,
+                            -1);
+    CrashWithCallbacks(NULL, DoneCallbackRaiseSIGKILL, temp_dir.path());
+  }
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGKILL));
+}
+
+TEST(ExceptionHandlerTest, StackedHandlersNotDeliveredToBottom) {
+  AutoTempDir temp_dir;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    ExceptionHandler bottom(MinidumpDescriptor(temp_dir.path()),
+                            NULL,
+                            DoneCallbackRaiseSIGKILL,
+                            NULL,
+                            true,
+                            -1);
+    CrashWithCallbacks(NULL, NULL, temp_dir.path());
+  }
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGSEGV));
+}
+
+TEST(ExceptionHandlerTest, StackedHandlersFilteredToBottom) {
+  AutoTempDir temp_dir;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    ExceptionHandler bottom(MinidumpDescriptor(temp_dir.path()),
+                            NULL,
+                            DoneCallbackRaiseSIGKILL,
+                            NULL,
+                            true,
+                            -1);
+    CrashWithCallbacks(FilterCallbackReturnFalse, NULL, temp_dir.path());
+  }
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGKILL));
+}
+
+TEST(ExceptionHandlerTest, StackedHandlersUnhandledToBottom) {
+  AutoTempDir temp_dir;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    ExceptionHandler bottom(MinidumpDescriptor(temp_dir.path()),
+                            NULL,
+                            DoneCallbackRaiseSIGKILL,
+                            NULL,
+                            true,
+                            -1);
+    CrashWithCallbacks(NULL, DoneCallbackReturnFalse, temp_dir.path());
+  }
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGKILL));
+}
+
+namespace {
+const int kSimpleFirstChanceReturnStatus = 42;
+bool SimpleFirstChanceHandler(int, siginfo_t*, void*) {
+  _exit(kSimpleFirstChanceReturnStatus);
+}
+}
+
+TEST(ExceptionHandlerTest, FirstChanceHandlerRuns) {
+  AutoTempDir temp_dir;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    ExceptionHandler handler(
+        MinidumpDescriptor(temp_dir.path()), NULL, NULL, NULL, true, -1);
+    google_breakpad::SetFirstChanceExceptionHandler(SimpleFirstChanceHandler);
+    DoNullPointerDereference();
+  }
+  int status;
+  ASSERT_NE(HANDLE_EINTR(waitpid(child, &status, 0)), -1);
+  ASSERT_TRUE(WIFEXITED(status));
+  ASSERT_EQ(kSimpleFirstChanceReturnStatus, WEXITSTATUS(status));
+}
+
+#endif  // !ADDRESS_SANITIZER
+
+const unsigned char kIllegalInstruction[] = {
+#if defined(__mips__)
+  // mfc2 zero,Impl - usually illegal in userspace.
+  0x48, 0x00, 0x00, 0x48
+#else
+  // This crashes with SIGILL on x86/x86-64/arm.
+  0xff, 0xff, 0xff, 0xff
+#endif
+};
+
+// Test that memory around the instruction pointer is written
+// to the dump as a MinidumpMemoryRegion.
+TEST(ExceptionHandlerTest, InstructionPointerMemory) {
+  AutoTempDir temp_dir;
+  int fds[2];
+  ASSERT_NE(pipe(fds), -1);
+
+  // These are defined here so the parent can use them to check the
+  // data from the minidump afterwards.
+  const uint32_t kMemorySize = 256;  // bytes
+  const int kOffset = kMemorySize / 2;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[0]);
+    ExceptionHandler handler(MinidumpDescriptor(temp_dir.path()), NULL,
+                             DoneCallback, reinterpret_cast<void*>(fds[1]),
+                             true, -1);
+    // Get some executable memory.
+    char* memory =
+      reinterpret_cast<char*>(mmap(NULL,
+                                   kMemorySize,
+                                   PROT_READ | PROT_WRITE | PROT_EXEC,
+                                   MAP_PRIVATE | MAP_ANON,
+                                   -1,
+                                   0));
+    if (!memory)
+      exit(0);
+
+    // Write some instructions that will crash. Put them in the middle
+    // of the block of memory, because the minidump should contain 128
+    // bytes on either side of the instruction pointer.
+    memcpy(memory + kOffset, kIllegalInstruction, sizeof(kIllegalInstruction));
+    FlushInstructionCache(memory, kMemorySize);
+
+    // Now execute the instructions, which should crash.
+    typedef void (*void_function)(void);
+    void_function memory_function =
+        reinterpret_cast<void_function>(memory + kOffset);
+    memory_function();
+  }
+  close(fds[1]);
+
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGILL));
+
+  string minidump_path;
+  ASSERT_NO_FATAL_FAILURE(ReadMinidumpPathFromPipe(fds[0], &minidump_path));
+
+  struct stat st;
+  ASSERT_EQ(0, stat(minidump_path.c_str(), &st));
+  ASSERT_GT(st.st_size, 0);
+
+  // Read the minidump. Locate the exception record and the
+  // memory list, and then ensure that there is a memory region
+  // in the memory list that covers the instruction pointer from
+  // the exception record.
+  Minidump minidump(minidump_path);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpException* exception = minidump.GetException();
+  MinidumpMemoryList* memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(exception);
+  ASSERT_TRUE(memory_list);
+  ASSERT_LT(0U, memory_list->region_count());
+
+  MinidumpContext* context = exception->GetContext();
+  ASSERT_TRUE(context);
+
+  uint64_t instruction_pointer;
+  ASSERT_TRUE(context->GetInstructionPointer(&instruction_pointer));
+
+  MinidumpMemoryRegion* region =
+      memory_list->GetMemoryRegionForAddress(instruction_pointer);
+  ASSERT_TRUE(region);
+
+  EXPECT_EQ(kMemorySize, region->GetSize());
+  const uint8_t* bytes = region->GetMemory();
+  ASSERT_TRUE(bytes);
+
+  uint8_t prefix_bytes[kOffset];
+  uint8_t suffix_bytes[kMemorySize - kOffset - sizeof(kIllegalInstruction)];
+  memset(prefix_bytes, 0, sizeof(prefix_bytes));
+  memset(suffix_bytes, 0, sizeof(suffix_bytes));
+  EXPECT_TRUE(memcmp(bytes, prefix_bytes, sizeof(prefix_bytes)) == 0);
+  EXPECT_TRUE(memcmp(bytes + kOffset, kIllegalInstruction, 
+                     sizeof(kIllegalInstruction)) == 0);
+  EXPECT_TRUE(memcmp(bytes + kOffset + sizeof(kIllegalInstruction),
+                     suffix_bytes, sizeof(suffix_bytes)) == 0);
+
+  unlink(minidump_path.c_str());
+}
+
+// Test that the memory region around the instruction pointer is
+// bounded correctly on the low end.
+TEST(ExceptionHandlerTest, InstructionPointerMemoryMinBound) {
+  AutoTempDir temp_dir;
+  int fds[2];
+  ASSERT_NE(pipe(fds), -1);
+
+  // These are defined here so the parent can use them to check the
+  // data from the minidump afterwards.
+  const uint32_t kMemorySize = 256;  // bytes
+  const int kOffset = 0;
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[0]);
+    ExceptionHandler handler(MinidumpDescriptor(temp_dir.path()), NULL,
+                             DoneCallback, reinterpret_cast<void*>(fds[1]),
+                             true, -1);
+    // Get some executable memory.
+    char* memory =
+        reinterpret_cast<char*>(mmap(NULL,
+                                     kMemorySize,
+                                     PROT_READ | PROT_WRITE | PROT_EXEC,
+                                     MAP_PRIVATE | MAP_ANON,
+                                     -1,
+                                     0));
+    if (!memory)
+      exit(0);
+
+    // Write some instructions that will crash. Put them in the middle
+    // of the block of memory, because the minidump should contain 128
+    // bytes on either side of the instruction pointer.
+    memcpy(memory + kOffset, kIllegalInstruction, sizeof(kIllegalInstruction));
+    FlushInstructionCache(memory, kMemorySize);
+
+    // Now execute the instructions, which should crash.
+    typedef void (*void_function)(void);
+    void_function memory_function =
+        reinterpret_cast<void_function>(memory + kOffset);
+    memory_function();
+  }
+  close(fds[1]);
+
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGILL));
+
+  string minidump_path;
+  ASSERT_NO_FATAL_FAILURE(ReadMinidumpPathFromPipe(fds[0], &minidump_path));
+
+  struct stat st;
+  ASSERT_EQ(0, stat(minidump_path.c_str(), &st));
+  ASSERT_GT(st.st_size, 0);
+
+  // Read the minidump. Locate the exception record and the
+  // memory list, and then ensure that there is a memory region
+  // in the memory list that covers the instruction pointer from
+  // the exception record.
+  Minidump minidump(minidump_path);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpException* exception = minidump.GetException();
+  MinidumpMemoryList* memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(exception);
+  ASSERT_TRUE(memory_list);
+  ASSERT_LT(0U, memory_list->region_count());
+
+  MinidumpContext* context = exception->GetContext();
+  ASSERT_TRUE(context);
+
+  uint64_t instruction_pointer;
+  ASSERT_TRUE(context->GetInstructionPointer(&instruction_pointer));
+
+  MinidumpMemoryRegion* region =
+      memory_list->GetMemoryRegionForAddress(instruction_pointer);
+  ASSERT_TRUE(region);
+
+  EXPECT_EQ(kMemorySize / 2, region->GetSize());
+  const uint8_t* bytes = region->GetMemory();
+  ASSERT_TRUE(bytes);
+
+  uint8_t suffix_bytes[kMemorySize / 2 - sizeof(kIllegalInstruction)];
+  memset(suffix_bytes, 0, sizeof(suffix_bytes));
+  EXPECT_TRUE(memcmp(bytes + kOffset, kIllegalInstruction, 
+                     sizeof(kIllegalInstruction)) == 0);
+  EXPECT_TRUE(memcmp(bytes + kOffset + sizeof(kIllegalInstruction),
+                     suffix_bytes, sizeof(suffix_bytes)) == 0);
+  unlink(minidump_path.c_str());
+}
+
+// Test that the memory region around the instruction pointer is
+// bounded correctly on the high end.
+TEST(ExceptionHandlerTest, InstructionPointerMemoryMaxBound) {
+  AutoTempDir temp_dir;
+  int fds[2];
+  ASSERT_NE(pipe(fds), -1);
+
+  // These are defined here so the parent can use them to check the
+  // data from the minidump afterwards.
+  // Use 4k here because the OS will hand out a single page even
+  // if a smaller size is requested, and this test wants to
+  // test the upper bound of the memory range.
+  const uint32_t kMemorySize = 4096;  // bytes
+  const int kOffset = kMemorySize - sizeof(kIllegalInstruction);
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[0]);
+    ExceptionHandler handler(MinidumpDescriptor(temp_dir.path()), NULL,
+                             DoneCallback, reinterpret_cast<void*>(fds[1]),
+                             true, -1);
+    // Get some executable memory.
+    char* memory =
+        reinterpret_cast<char*>(mmap(NULL,
+                                     kMemorySize,
+                                     PROT_READ | PROT_WRITE | PROT_EXEC,
+                                     MAP_PRIVATE | MAP_ANON,
+                                     -1,
+                                     0));
+    if (!memory)
+      exit(0);
+
+    // Write some instructions that will crash. Put them in the middle
+    // of the block of memory, because the minidump should contain 128
+    // bytes on either side of the instruction pointer.
+    memcpy(memory + kOffset, kIllegalInstruction, sizeof(kIllegalInstruction));
+    FlushInstructionCache(memory, kMemorySize);
+
+    // Now execute the instructions, which should crash.
+    typedef void (*void_function)(void);
+    void_function memory_function =
+        reinterpret_cast<void_function>(memory + kOffset);
+    memory_function();
+  }
+  close(fds[1]);
+
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGILL));
+
+  string minidump_path;
+  ASSERT_NO_FATAL_FAILURE(ReadMinidumpPathFromPipe(fds[0], &minidump_path));
+
+  struct stat st;
+  ASSERT_EQ(0, stat(minidump_path.c_str(), &st));
+  ASSERT_GT(st.st_size, 0);
+
+  // Read the minidump. Locate the exception record and the memory list, and
+  // then ensure that there is a memory region in the memory list that covers
+  // the instruction pointer from the exception record.
+  Minidump minidump(minidump_path);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpException* exception = minidump.GetException();
+  MinidumpMemoryList* memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(exception);
+  ASSERT_TRUE(memory_list);
+  ASSERT_LT(0U, memory_list->region_count());
+
+  MinidumpContext* context = exception->GetContext();
+  ASSERT_TRUE(context);
+
+  uint64_t instruction_pointer;
+  ASSERT_TRUE(context->GetInstructionPointer(&instruction_pointer));
+
+  MinidumpMemoryRegion* region =
+      memory_list->GetMemoryRegionForAddress(instruction_pointer);
+  ASSERT_TRUE(region);
+
+  const size_t kPrefixSize = 128;  // bytes
+  EXPECT_EQ(kPrefixSize + sizeof(kIllegalInstruction), region->GetSize());
+  const uint8_t* bytes = region->GetMemory();
+  ASSERT_TRUE(bytes);
+
+  uint8_t prefix_bytes[kPrefixSize];
+  memset(prefix_bytes, 0, sizeof(prefix_bytes));
+  EXPECT_TRUE(memcmp(bytes, prefix_bytes, sizeof(prefix_bytes)) == 0);
+  EXPECT_TRUE(memcmp(bytes + kPrefixSize,
+                     kIllegalInstruction, sizeof(kIllegalInstruction)) == 0);
+
+  unlink(minidump_path.c_str());
+}
+
+#ifndef ADDRESS_SANITIZER
+
+// Ensure that an extra memory block doesn't get added when the instruction
+// pointer is not in mapped memory.
+TEST(ExceptionHandlerTest, InstructionPointerMemoryNullPointer) {
+  AutoTempDir temp_dir;
+  int fds[2];
+  ASSERT_NE(pipe(fds), -1);
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[0]);
+    ExceptionHandler handler(MinidumpDescriptor(temp_dir.path()), NULL,
+                             DoneCallback, reinterpret_cast<void*>(fds[1]),
+                             true, -1);
+    // Try calling a NULL pointer.
+    typedef void (*void_function)(void);
+    // Volatile markings are needed to keep Clang from generating invalid
+    // opcodes.  See http://crbug.com/498354 for details.
+    volatile void_function memory_function =
+      reinterpret_cast<void_function>(NULL);
+    memory_function();
+    // not reached
+    exit(1);
+  }
+  close(fds[1]);
+
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGSEGV));
+
+  string minidump_path;
+  ASSERT_NO_FATAL_FAILURE(ReadMinidumpPathFromPipe(fds[0], &minidump_path));
+
+  struct stat st;
+  ASSERT_EQ(0, stat(minidump_path.c_str(), &st));
+  ASSERT_GT(st.st_size, 0);
+
+  // Read the minidump. Locate the exception record and the
+  // memory list, and then ensure that there is no memory region
+  // in the memory list that covers the instruction pointer from
+  // the exception record.
+  Minidump minidump(minidump_path);
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpException* exception = minidump.GetException();
+  ASSERT_TRUE(exception);
+
+  MinidumpContext* exception_context = exception->GetContext();
+  ASSERT_TRUE(exception_context);
+
+  uint64_t instruction_pointer;
+  ASSERT_TRUE(exception_context->GetInstructionPointer(&instruction_pointer));
+  EXPECT_EQ(instruction_pointer, 0u);
+
+  MinidumpMemoryList* memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(memory_list);
+
+  unsigned int region_count = memory_list->region_count();
+  ASSERT_GE(region_count, 1u);
+
+  for (unsigned int region_index = 0;
+       region_index < region_count;
+       ++region_index) {
+    MinidumpMemoryRegion* region =
+        memory_list->GetMemoryRegionAtIndex(region_index);
+    uint64_t region_base = region->GetBase();
+    EXPECT_FALSE(instruction_pointer >= region_base &&
+                 instruction_pointer < region_base + region->GetSize());
+  }
+
+  unlink(minidump_path.c_str());
+}
+
+#endif  // !ADDRESS_SANITIZER
+
+// Test that anonymous memory maps can be annotated with names and IDs.
+TEST(ExceptionHandlerTest, ModuleInfo) {
+  // These are defined here so the parent can use them to check the
+  // data from the minidump afterwards.
+  const uint32_t kMemorySize = sysconf(_SC_PAGESIZE);
+  const char* kMemoryName = "a fake module";
+  const uint8_t kModuleGUID[sizeof(MDGUID)] = {
+    0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
+    0x88, 0x99, 0xAA, 0xBB, 0xCC, 0xDD, 0xEE, 0xFF
+  };
+  const string module_identifier = "33221100554477668899AABBCCDDEEFF0";
+
+  // Get some memory.
+  char* memory =
+      reinterpret_cast<char*>(mmap(NULL,
+                                   kMemorySize,
+                                   PROT_READ | PROT_WRITE,
+                                   MAP_PRIVATE | MAP_ANON,
+                                   -1,
+                                   0));
+  const uintptr_t kMemoryAddress = reinterpret_cast<uintptr_t>(memory);
+  ASSERT_TRUE(memory);
+
+  PageAllocator allocator;
+  auto_wasteful_vector<uint8_t, sizeof(MDGUID)> guid(&allocator);
+  guid.assign(std::begin(kModuleGUID), std::end(kModuleGUID));
+  AutoTempDir temp_dir;
+  ExceptionHandler handler(
+      MinidumpDescriptor(temp_dir.path()), NULL, NULL, NULL, true, -1);
+
+  // Add info about the anonymous memory mapping.
+  handler.AddMappingInfo(kMemoryName,
+                         guid,
+                         kMemoryAddress,
+                         kMemorySize,
+                         0);
+  ASSERT_TRUE(handler.WriteMinidump());
+
+  const MinidumpDescriptor& minidump_desc = handler.minidump_descriptor();
+  // Read the minidump. Load the module list, and ensure that the mmap'ed
+  // |memory| is listed with the given module name and debug ID.
+  Minidump minidump(minidump_desc.path());
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpModuleList* module_list = minidump.GetModuleList();
+  ASSERT_TRUE(module_list);
+  const MinidumpModule* module =
+      module_list->GetModuleForAddress(kMemoryAddress);
+  ASSERT_TRUE(module);
+
+  EXPECT_EQ(kMemoryAddress, module->base_address());
+  EXPECT_EQ(kMemorySize, module->size());
+  EXPECT_EQ(kMemoryName, module->code_file());
+  EXPECT_EQ(module_identifier, module->debug_identifier());
+
+  unlink(minidump_desc.path());
+}
+
+#ifndef ADDRESS_SANITIZER
+
+static const unsigned kControlMsgSize =
+    CMSG_SPACE(sizeof(int)) + CMSG_SPACE(sizeof(struct ucred));
+
+static bool
+CrashHandler(const void* crash_context, size_t crash_context_size,
+             void* context) {
+  const int fd = (intptr_t) context;
+  int fds[2];
+  if (pipe(fds) == -1) {
+    // There doesn't seem to be any way to reliably handle
+    // this failure without the parent process hanging
+    // At least make sure that this process doesn't access
+    // unexpected file descriptors
+    fds[0] = -1;
+    fds[1] = -1;
+  }
+  struct kernel_msghdr msg = {0};
+  struct kernel_iovec iov;
+  iov.iov_base = const_cast<void*>(crash_context);
+  iov.iov_len = crash_context_size;
+  msg.msg_iov = &iov;
+  msg.msg_iovlen = 1;
+  char cmsg[kControlMsgSize];
+  memset(cmsg, 0, kControlMsgSize);
+  msg.msg_control = cmsg;
+  msg.msg_controllen = sizeof(cmsg);
+
+  struct cmsghdr *hdr = CMSG_FIRSTHDR(&msg);
+  hdr->cmsg_level = SOL_SOCKET;
+  hdr->cmsg_type = SCM_RIGHTS;
+  hdr->cmsg_len = CMSG_LEN(sizeof(int));
+  *((int*) CMSG_DATA(hdr)) = fds[1];
+  hdr = CMSG_NXTHDR((struct msghdr*) &msg, hdr);
+  hdr->cmsg_level = SOL_SOCKET;
+  hdr->cmsg_type = SCM_CREDENTIALS;
+  hdr->cmsg_len = CMSG_LEN(sizeof(struct ucred));
+  struct ucred *cred = reinterpret_cast<struct ucred*>(CMSG_DATA(hdr));
+  cred->uid = getuid();
+  cred->gid = getgid();
+  cred->pid = getpid();
+
+  ssize_t ret = HANDLE_EINTR(sys_sendmsg(fd, &msg, 0));
+  sys_close(fds[1]);
+  if (ret <= 0)
+    return false;
+
+  char b;
+  IGNORE_RET(HANDLE_EINTR(sys_read(fds[0], &b, 1)));
+
+  return true;
+}
+
+TEST(ExceptionHandlerTest, ExternalDumper) {
+  int fds[2];
+  ASSERT_NE(socketpair(AF_UNIX, SOCK_DGRAM, 0, fds), -1);
+  static const int on = 1;
+  setsockopt(fds[0], SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
+  setsockopt(fds[1], SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[0]);
+    ExceptionHandler handler(MinidumpDescriptor("/tmp1"), NULL, NULL,
+                             reinterpret_cast<void*>(fds[1]), true, -1);
+    handler.set_crash_handler(CrashHandler);
+    DoNullPointerDereference();
+  }
+  close(fds[1]);
+  struct msghdr msg = {0};
+  struct iovec iov;
+  static const unsigned kCrashContextSize =
+      sizeof(ExceptionHandler::CrashContext);
+  char context[kCrashContextSize];
+  char control[kControlMsgSize];
+  iov.iov_base = context;
+  iov.iov_len = kCrashContextSize;
+  msg.msg_iov = &iov;
+  msg.msg_iovlen = 1;
+  msg.msg_control = control;
+  msg.msg_controllen = kControlMsgSize;
+
+  const ssize_t n = HANDLE_EINTR(recvmsg(fds[0], &msg, 0));
+  ASSERT_EQ(static_cast<ssize_t>(kCrashContextSize), n);
+  ASSERT_EQ(kControlMsgSize, msg.msg_controllen);
+  ASSERT_EQ(static_cast<__typeof__(msg.msg_flags)>(0), msg.msg_flags);
+  ASSERT_EQ(0, close(fds[0]));
+
+  pid_t crashing_pid = -1;
+  int signal_fd = -1;
+  for (struct cmsghdr *hdr = CMSG_FIRSTHDR(&msg); hdr;
+       hdr = CMSG_NXTHDR(&msg, hdr)) {
+    if (hdr->cmsg_level != SOL_SOCKET)
+      continue;
+    if (hdr->cmsg_type == SCM_RIGHTS) {
+      const unsigned len = hdr->cmsg_len -
+          (((uint8_t*)CMSG_DATA(hdr)) - (uint8_t*)hdr);
+      ASSERT_EQ(sizeof(int), len);
+      signal_fd = *(reinterpret_cast<int*>(CMSG_DATA(hdr)));
+    } else if (hdr->cmsg_type == SCM_CREDENTIALS) {
+      const struct ucred *cred =
+          reinterpret_cast<struct ucred*>(CMSG_DATA(hdr));
+      crashing_pid = cred->pid;
+    }
+  }
+
+  ASSERT_NE(crashing_pid, -1);
+  ASSERT_NE(signal_fd, -1);
+
+  AutoTempDir temp_dir;
+  string templ = temp_dir.path() + "/exception-handler-unittest";
+  ASSERT_TRUE(WriteMinidump(templ.c_str(), crashing_pid, context,
+                            kCrashContextSize));
+  static const char b = 0;
+  ASSERT_EQ(1, (HANDLE_EINTR(write(signal_fd, &b, 1))));
+  ASSERT_EQ(0, close(signal_fd));
+
+  ASSERT_NO_FATAL_FAILURE(WaitForProcessToTerminate(child, SIGSEGV));
+
+  struct stat st;
+  ASSERT_EQ(0, stat(templ.c_str(), &st));
+  ASSERT_GT(st.st_size, 0);
+  unlink(templ.c_str());
+}
+
+#endif  // !ADDRESS_SANITIZER
+
+TEST(ExceptionHandlerTest, WriteMinidumpExceptionStream) {
+  AutoTempDir temp_dir;
+  ExceptionHandler handler(MinidumpDescriptor(temp_dir.path()), NULL, NULL,
+                           NULL, false, -1);
+  ASSERT_TRUE(handler.WriteMinidump());
+
+  string minidump_path = handler.minidump_descriptor().path();
+
+  // Read the minidump and check the exception stream.
+  Minidump minidump(minidump_path);
+  ASSERT_TRUE(minidump.Read());
+  MinidumpException* exception = minidump.GetException();
+  ASSERT_TRUE(exception);
+  const MDRawExceptionStream* raw = exception->exception();
+  ASSERT_TRUE(raw);
+  EXPECT_EQ(MD_EXCEPTION_CODE_LIN_DUMP_REQUESTED,
+            raw->exception_record.exception_code);
+}
+
+TEST(ExceptionHandlerTest, GenerateMultipleDumpsWithFD) {
+  AutoTempDir temp_dir;
+  string path;
+  const int fd = CreateTMPFile(temp_dir.path(), &path);
+  ExceptionHandler handler(MinidumpDescriptor(fd), NULL, NULL, NULL, false, -1);
+  ASSERT_TRUE(handler.WriteMinidump());
+  // Check by the size of the data written to the FD that a minidump was
+  // generated.
+  off_t size = lseek(fd, 0, SEEK_CUR);
+  ASSERT_GT(size, 0);
+
+  // Generate another minidump.
+  ASSERT_TRUE(handler.WriteMinidump());
+  size = lseek(fd, 0, SEEK_CUR);
+  ASSERT_GT(size, 0);
+}
+
+TEST(ExceptionHandlerTest, GenerateMultipleDumpsWithPath) {
+  AutoTempDir temp_dir;
+  ExceptionHandler handler(MinidumpDescriptor(temp_dir.path()), NULL, NULL,
+                           NULL, false, -1);
+  ASSERT_TRUE(handler.WriteMinidump());
+
+  const MinidumpDescriptor& minidump_1 = handler.minidump_descriptor();
+  struct stat st;
+  ASSERT_EQ(0, stat(minidump_1.path(), &st));
+  ASSERT_GT(st.st_size, 0);
+  string minidump_1_path(minidump_1.path());
+  // Check it is a valid minidump.
+  Minidump minidump1(minidump_1_path);
+  ASSERT_TRUE(minidump1.Read());
+  unlink(minidump_1.path());
+
+  // Generate another minidump, it should go to a different file.
+  ASSERT_TRUE(handler.WriteMinidump());
+  const MinidumpDescriptor& minidump_2 = handler.minidump_descriptor();
+  ASSERT_EQ(0, stat(minidump_2.path(), &st));
+  ASSERT_GT(st.st_size, 0);
+  string minidump_2_path(minidump_2.path());
+  // Check it is a valid minidump.
+  Minidump minidump2(minidump_2_path);
+  ASSERT_TRUE(minidump2.Read());
+  unlink(minidump_2.path());
+
+  // 2 distinct files should be produced.
+  ASSERT_STRNE(minidump_1_path.c_str(), minidump_2_path.c_str());
+}
+
+// Test that an additional memory region can be added to the minidump.
+TEST(ExceptionHandlerTest, AdditionalMemory) {
+  const uint32_t kMemorySize = sysconf(_SC_PAGESIZE);
+
+  // Get some heap memory.
+  uint8_t* memory = new uint8_t[kMemorySize];
+  const uintptr_t kMemoryAddress = reinterpret_cast<uintptr_t>(memory);
+  ASSERT_TRUE(memory);
+
+  // Stick some data into the memory so the contents can be verified.
+  for (uint32_t i = 0; i < kMemorySize; ++i) {
+    memory[i] = i % 255;
+  }
+
+  AutoTempDir temp_dir;
+  ExceptionHandler handler(
+      MinidumpDescriptor(temp_dir.path()), NULL, NULL, NULL, true, -1);
+
+  // Add the memory region to the list of memory to be included.
+  handler.RegisterAppMemory(memory, kMemorySize);
+  handler.WriteMinidump();
+
+  const MinidumpDescriptor& minidump_desc = handler.minidump_descriptor();
+
+  // Read the minidump. Ensure that the memory region is present
+  Minidump minidump(minidump_desc.path());
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpMemoryList* dump_memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(dump_memory_list);
+  const MinidumpMemoryRegion* region =
+    dump_memory_list->GetMemoryRegionForAddress(kMemoryAddress);
+  ASSERT_TRUE(region);
+
+  EXPECT_EQ(kMemoryAddress, region->GetBase());
+  EXPECT_EQ(kMemorySize, region->GetSize());
+
+  // Verify memory contents.
+  EXPECT_EQ(0, memcmp(region->GetMemory(), memory, kMemorySize));
+
+  delete[] memory;
+}
+
+// Test that a memory region that was previously registered
+// can be unregistered.
+TEST(ExceptionHandlerTest, AdditionalMemoryRemove) {
+  const uint32_t kMemorySize = sysconf(_SC_PAGESIZE);
+
+  // Get some heap memory.
+  uint8_t* memory = new uint8_t[kMemorySize];
+  const uintptr_t kMemoryAddress = reinterpret_cast<uintptr_t>(memory);
+  ASSERT_TRUE(memory);
+
+  AutoTempDir temp_dir;
+  ExceptionHandler handler(
+      MinidumpDescriptor(temp_dir.path()), NULL, NULL, NULL, true, -1);
+
+  // Add the memory region to the list of memory to be included.
+  handler.RegisterAppMemory(memory, kMemorySize);
+
+  // ...and then remove it
+  handler.UnregisterAppMemory(memory);
+  handler.WriteMinidump();
+
+  const MinidumpDescriptor& minidump_desc = handler.minidump_descriptor();
+
+  // Read the minidump. Ensure that the memory region is not present.
+  Minidump minidump(minidump_desc.path());
+  ASSERT_TRUE(minidump.Read());
+
+  MinidumpMemoryList* dump_memory_list = minidump.GetMemoryList();
+  ASSERT_TRUE(dump_memory_list);
+  const MinidumpMemoryRegion* region =
+    dump_memory_list->GetMemoryRegionForAddress(kMemoryAddress);
+  EXPECT_FALSE(region);
+
+  delete[] memory;
+}
+
+static bool SimpleCallback(const MinidumpDescriptor& descriptor,
+                           void* context,
+                           bool succeeded) {
+  string* filename = reinterpret_cast<string*>(context);
+  *filename = descriptor.path();
+  return true;
+}
+
+TEST(ExceptionHandlerTest, WriteMinidumpForChild) {
+  int fds[2];
+  ASSERT_NE(-1, pipe(fds));
+
+  const pid_t child = fork();
+  if (child == 0) {
+    close(fds[1]);
+    char b;
+    HANDLE_EINTR(read(fds[0], &b, sizeof(b)));
+    close(fds[0]);
+    syscall(__NR_exit);
+  }
+  close(fds[0]);
+
+  AutoTempDir temp_dir;
+  string minidump_filename;
+  ASSERT_TRUE(
+    ExceptionHandler::WriteMinidumpForChild(child, child,
+                                            temp_dir.path(), SimpleCallback,
+                                            (void*)&minidump_filename));
+
+  Minidump minidump(minidump_filename);
+  ASSERT_TRUE(minidump.Read());
+  // Check that the crashing thread is the main thread of |child|
+  MinidumpException* exception = minidump.GetException();
+  ASSERT_TRUE(exception);
+  uint32_t thread_id;
+  ASSERT_TRUE(exception->GetThreadID(&thread_id));
+  EXPECT_EQ(child, static_cast<int32_t>(thread_id));
+
+  const MDRawExceptionStream* raw = exception->exception();
+  ASSERT_TRUE(raw);
+  EXPECT_EQ(MD_EXCEPTION_CODE_LIN_DUMP_REQUESTED,
+            raw->exception_record.exception_code);
+
+  close(fds[1]);
+  unlink(minidump_filename.c_str());
+}
diff --git a/toolkit/crashreporter/breakpad-client/linux/handler/guid_generator.cc b/toolkit/crashreporter/breakpad-client/linux/handler/guid_generator.cc
new file mode 100644
index 0000000000..b0ef05bd9d
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/handler/guid_generator.cc
@@ -0,0 +1,108 @@
+// Copyright (c) 2006, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "linux/handler/guid_generator.h"
+
+#include <assert.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+//
+// GUIDGenerator
+//
+// This class is used to generate random GUID.
+// Currently use random number to generate a GUID since Linux has
+// no native GUID generator. This should be OK since we don't expect
+// crash to happen very offen.
+//
+class GUIDGenerator {
+ public:
+  static uint16_t BytesToUInt16(const uint8_t bytes[]) {
+    return ((uint16_t) bytes[1] << 8) | ((uint16_t) bytes[0]);
+  }
+
+  // The last field in a GUID is 48 bits long so we're converting only 6 bytes
+  static uint64_t BytesToUInt48(const uint8_t bytes[]) {
+    return ((uint64_t) bytes[0] << 40) | ((uint64_t) bytes[1] << 32) |
+           ((uint64_t) bytes[2] << 24) | ((uint64_t) bytes[3] << 16) |
+           ((uint64_t) bytes[4] << 8)  | (uint64_t) bytes[5];
+  }
+
+  static void UInt32ToBytes(uint8_t bytes[], uint32_t n) {
+    bytes[0] = n & 0xff;
+    bytes[1] = (n >> 8) & 0xff;
+    bytes[2] = (n >> 16) & 0xff;
+    bytes[3] = (n >> 24) & 0xff;
+  }
+
+  static bool CreateGUID(GUID *guid) {
+    InitOnce();
+    guid->data1 = random();
+    guid->data2 = (uint16_t)(random());
+    guid->data3 = (uint16_t)(random());
+    UInt32ToBytes(&guid->data4[0], random());
+    UInt32ToBytes(&guid->data4[4], random());
+    return true;
+  }
+
+ private:
+  static void InitOnce() {
+    pthread_once(&once_control, &InitOnceImpl);
+  }
+
+  static void InitOnceImpl() {
+    srandom(time(NULL));
+  }
+
+  static pthread_once_t once_control;
+};
+
+pthread_once_t GUIDGenerator::once_control = PTHREAD_ONCE_INIT;
+
+bool CreateGUID(GUID *guid) {
+  return GUIDGenerator::CreateGUID(guid);
+}
+
+// Parse guid to string.
+bool GUIDToString(const GUID *guid, char *buf, size_t buf_len) {
+  // Should allow more space the the max length of GUID.
+  assert(buf_len > kGUIDStringLength);
+  int num = snprintf(buf, buf_len, kGUIDFormatString,
+                     guid->data1, guid->data2, guid->data3,
+                     GUIDGenerator::BytesToUInt16(&(guid->data4[0])),
+                     GUIDGenerator::BytesToUInt48(&(guid->data4[2])));
+  if (num != kGUIDStringLength)
+    return false;
+
+  buf[num] = '\0';
+  return true;
+}
diff --git a/toolkit/crashreporter/breakpad-client/linux/handler/guid_generator.h b/toolkit/crashreporter/breakpad-client/linux/handler/guid_generator.h
new file mode 100644
index 0000000000..de97eda1cb
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/handler/guid_generator.h
@@ -0,0 +1,48 @@
+// Copyright (c) 2006, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef LINUX_HANDLER_GUID_GENERATOR_H__
+#define LINUX_HANDLER_GUID_GENERATOR_H__
+
+#include "google_breakpad/common/minidump_format.h"
+
+typedef MDGUID GUID;
+
+// Format string for parsing GUID.
+const char kGUIDFormatString[] = "%08x-%04x-%04x-%04x-%012" PRIx64;
+// Length of GUID string. Don't count the ending '\0'.
+const size_t kGUIDStringLength = 36;
+
+// Create a guid.
+bool CreateGUID(GUID *guid);
+
+// Get the string from guid.
+bool GUIDToString(const GUID *guid, char *buf, size_t buf_len);
+
+#endif
diff --git a/toolkit/crashreporter/breakpad-client/linux/handler/microdump_extra_info.h b/toolkit/crashreporter/breakpad-client/linux/handler/microdump_extra_info.h
new file mode 100644
index 0000000000..bf01f0c7b1
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/handler/microdump_extra_info.h
@@ -0,0 +1,52 @@
+// Copyright 2015 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_HANDLER_MICRODUMP_EXTRA_INFO_H_
+#define CLIENT_LINUX_HANDLER_MICRODUMP_EXTRA_INFO_H_
+
+namespace google_breakpad {
+
+struct MicrodumpExtraInfo {
+  // Strings pointed to by this struct are not copied, and are
+  // expected to remain valid for the lifetime of the process.
+  const char* build_fingerprint;
+  const char* product_info;
+  const char* gpu_fingerprint;
+  const char* process_type;
+
+  MicrodumpExtraInfo()
+      : build_fingerprint(NULL),
+        product_info(NULL),
+        gpu_fingerprint(NULL),
+        process_type(NULL) {}
+};
+
+}
+
+#endif  // CLIENT_LINUX_HANDLER_MICRODUMP_EXTRA_INFO_H_
diff --git a/toolkit/crashreporter/breakpad-client/linux/handler/minidump_descriptor.cc b/toolkit/crashreporter/breakpad-client/linux/handler/minidump_descriptor.cc
new file mode 100644
index 0000000000..21cf4b0dce
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/handler/minidump_descriptor.cc
@@ -0,0 +1,96 @@
+// Copyright (c) 2012 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <stdio.h>
+
+#include "linux/handler/guid_generator.h"
+#include "linux/handler/minidump_descriptor.h"
+
+namespace google_breakpad {
+
+//static
+const MinidumpDescriptor::MicrodumpOnConsole
+    MinidumpDescriptor::kMicrodumpOnConsole = {};
+
+MinidumpDescriptor::MinidumpDescriptor(const MinidumpDescriptor& descriptor)
+    : mode_(descriptor.mode_),
+      fd_(descriptor.fd_),
+      directory_(descriptor.directory_),
+      c_path_(NULL),
+      size_limit_(descriptor.size_limit_),
+      address_within_principal_mapping_(
+          descriptor.address_within_principal_mapping_),
+      skip_dump_if_principal_mapping_not_referenced_(
+          descriptor.skip_dump_if_principal_mapping_not_referenced_),
+      sanitize_stacks_(descriptor.sanitize_stacks_),
+      microdump_extra_info_(descriptor.microdump_extra_info_) {
+  // The copy constructor is not allowed to be called on a MinidumpDescriptor
+  // with a valid path_, as getting its c_path_ would require the heap which
+  // can cause problems in compromised environments.
+  assert(descriptor.path_.empty());
+}
+
+MinidumpDescriptor& MinidumpDescriptor::operator=(
+    const MinidumpDescriptor& descriptor) {
+  assert(descriptor.path_.empty());
+
+  mode_ = descriptor.mode_;
+  fd_ = descriptor.fd_;
+  directory_ = descriptor.directory_;
+  path_.clear();
+  if (c_path_) {
+    // This descriptor already had a path set, so generate a new one.
+    c_path_ = NULL;
+    UpdatePath();
+  }
+  size_limit_ = descriptor.size_limit_;
+  address_within_principal_mapping_ =
+      descriptor.address_within_principal_mapping_;
+  skip_dump_if_principal_mapping_not_referenced_ =
+      descriptor.skip_dump_if_principal_mapping_not_referenced_;
+  sanitize_stacks_ = descriptor.sanitize_stacks_;
+  microdump_extra_info_ = descriptor.microdump_extra_info_;
+  return *this;
+}
+
+void MinidumpDescriptor::UpdatePath() {
+  assert(mode_ == kWriteMinidumpToFile && !directory_.empty());
+
+  GUID guid;
+  char guid_str[kGUIDStringLength + 1];
+  if (!CreateGUID(&guid) || !GUIDToString(&guid, guid_str, sizeof(guid_str))) {
+    assert(false);
+  }
+
+  path_.clear();
+  path_ = directory_ + "/" + guid_str + ".dmp";
+  c_path_ = path_.c_str();
+}
+
+}  // namespace google_breakpad
diff --git a/toolkit/crashreporter/breakpad-client/linux/handler/minidump_descriptor.h b/toolkit/crashreporter/breakpad-client/linux/handler/minidump_descriptor.h
new file mode 100644
index 0000000000..c3deae8a74
--- /dev/null
+++ b/toolkit/crashreporter/breakpad-client/linux/handler/minidump_descriptor.h
@@ -0,0 +1,199 @@
+// Copyright (c) 2012 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef CLIENT_LINUX_HANDLER_MINIDUMP_DESCRIPTOR_H_
+#define CLIENT_LINUX_HANDLER_MINIDUMP_DESCRIPTOR_H_
+
+#include <assert.h>
+#include <sys/types.h>
+
+#include <string>
+
+#include "linux/handler/microdump_extra_info.h"
+#include "common/using_std_string.h"
+
+// This class describes how a crash dump should be generated, either:
+// - Writing a full minidump to a file in a given directory (the actual path,
+//   inside the directory, is determined by this class).
+// - Writing a full minidump to a given fd.
+// - Writing a reduced microdump to the console (logcat on Android).
+namespace google_breakpad {
+
+class MinidumpDescriptor {
+ public:
+  struct MicrodumpOnConsole {};
+  static const MicrodumpOnConsole kMicrodumpOnConsole;
+
+  MinidumpDescriptor()
+      : mode_(kUninitialized),
+        fd_(-1),
+        size_limit_(-1),
+        address_within_principal_mapping_(0),
+        skip_dump_if_principal_mapping_not_referenced_(false) {}
+
+  explicit MinidumpDescriptor(const string& directory)
+      : mode_(kWriteMinidumpToFile),
+        fd_(-1),
+        directory_(directory),
+        c_path_(NULL),
+        size_limit_(-1),
+        address_within_principal_mapping_(0),
+        skip_dump_if_principal_mapping_not_referenced_(false),
+        sanitize_stacks_(false) {
+    assert(!directory.empty());
+  }
+
+  explicit MinidumpDescriptor(int fd)
+      : mode_(kWriteMinidumpToFd),
+        fd_(fd),
+        c_path_(NULL),
+        size_limit_(-1),
+        address_within_principal_mapping_(0),
+        skip_dump_if_principal_mapping_not_referenced_(false),
+        sanitize_stacks_(false) {
+    assert(fd != -1);
+  }
+
+  explicit MinidumpDescriptor(const MicrodumpOnConsole&)
+      : mode_(kWriteMicrodumpToConsole),
+        fd_(-1),
+        size_limit_(-1),
+        address_within_principal_mapping_(0),
+        skip_dump_if_principal_mapping_not_referenced_(false),
+        sanitize_stacks_(false) {}
+
+  explicit MinidumpDescriptor(const MinidumpDescriptor& descriptor);
+  MinidumpDescriptor& operator=(const MinidumpDescriptor& descriptor);
+
+  static MinidumpDescriptor getMicrodumpDescriptor();
+
+  bool IsFD() const { return mode_ == kWriteMinidumpToFd; }
+
+  int fd() const { return fd_; }
+
+  string directory() const { return directory_; }
+
+  const char* path() const { return c_path_; }
+
+  bool IsMicrodumpOnConsole() const {
+    return mode_ == kWriteMicrodumpToConsole;
+  }
+
+  // Updates the path so it is unique.
+  // Should be called from a normal context: this methods uses the heap.
+  void UpdatePath();
+
+  off_t size_limit() const { return size_limit_; }
+  void set_size_limit(off_t limit) { size_limit_ = limit; }
+
+  uintptr_t address_within_principal_mapping() const {
+    return address_within_principal_mapping_;
+  }
+  void set_address_within_principal_mapping(
+      uintptr_t address_within_principal_mapping) {
+    address_within_principal_mapping_ = address_within_principal_mapping;
+  }
+
+  bool skip_dump_if_principal_mapping_not_referenced() {
+    return skip_dump_if_principal_mapping_not_referenced_;
+  }
+  void set_skip_dump_if_principal_mapping_not_referenced(
+      bool skip_dump_if_principal_mapping_not_referenced) {
+    skip_dump_if_principal_mapping_not_referenced_ =
+        skip_dump_if_principal_mapping_not_referenced;
+  }
+
+  bool sanitize_stacks() const { return sanitize_stacks_; }
+  void set_sanitize_stacks(bool sanitize_stacks) {
+    sanitize_stacks_ = sanitize_stacks;
+  }
+
+  MicrodumpExtraInfo* microdump_extra_info() {
+    assert(IsMicrodumpOnConsole());
+    return &microdump_extra_info_;
+  }
+
+ private:
+  enum DumpMode {
+    kUninitialized = 0,
+    kWriteMinidumpToFile,
+    kWriteMinidumpToFd,
+    kWriteMicrodumpToConsole
+  };
+
+  // Specifies the dump mode (see DumpMode).
+  DumpMode mode_;
+
+  // The file descriptor where the minidump is generated.
+  int fd_;
+
+  // The directory where the minidump should be generated.
+  string directory_;
+
+  // The full path to the generated minidump.
+  string path_;
+
+  // The C string of |path_|. Precomputed so it can be access from a compromised
+  // context.
+  const char* c_path_;
+
+  off_t size_limit_;
+
+  // This member points somewhere into the main module for this
+  // process (the module that is considerered interesting for the
+  // purposes of debugging crashes).
+  uintptr_t address_within_principal_mapping_;
+
+  // If set, threads that do not reference the address range
+  // associated with |address_within_principal_mapping_| will not have their
+  // stacks logged.
+  bool skip_dump_if_principal_mapping_not_referenced_;
+
+  // If set, stacks are sanitized to remove PII. This involves
+  // overwriting any pointer-aligned words that are not either
+  // pointers into a process mapping or small integers (+/-4096). This
+  // leaves enough information to unwind stacks, and preserve some
+  // register values, but elides strings and other program data.
+  bool sanitize_stacks_;
+
+  // The extra microdump data (e.g. product name/version, build
+  // fingerprint, gpu fingerprint) that should be appended to the dump
+  // (microdump only). Microdumps don't have the ability of appending
+  // extra metadata after the dump is generated (as opposite to
+  // minidumps MIME fields), therefore the extra data must be provided
+  // upfront. Any memory pointed to by members of the
+  // MicrodumpExtraInfo struct must be valid for the lifetime of the
+  // process (read: the caller has to guarantee that it is stored in
+  // global static storage.)
+  MicrodumpExtraInfo microdump_extra_info_;
+};
+
+}  // namespace google_breakpad
+
+#endif  // CLIENT_LINUX_HANDLER_MINIDUMP_DESCRIPTOR_H_