Revert 266968 "NonSFI NaCl: Plumb Exception IRT enough for break..."

trunk/src/components/nacl/loader/nonsfi/irt_exception_handling.cc

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <errno.h>
-#include <pthread.h>
-#include <signal.h>
-
-#include "components/nacl/loader/nonsfi/irt_interfaces.h"
-#include "native_client/src/include/nacl_macros.h"
-#include "native_client/src/trusted/service_runtime/nacl_exception.h"
-#include "native_client/src/trusted/service_runtime/nacl_signal.h"
-
-namespace nacl {
-namespace nonsfi {
-namespace {
-
-// This is NonSFI version of exception handling codebase, NaCl side of
-// things resides in:
-// native_client/src/trusted/service_runtime/linux/nacl_signal.c
-// native_client/src/trusted/service_runtime/sys_exception.c
-
-// Crash signals to handle.  The differences from SFI NaCl are that
-// NonSFI NaCl does not use NACL_THREAD_SUSPEND_SIGNAL (==SIGUSR1),
-// and SIGSYS is reserved for seccomp-bpf.
-const int kSignals[] = {
-  SIGSTKFLT,
-  SIGINT, SIGQUIT, SIGILL, SIGTRAP, SIGBUS, SIGFPE, SIGSEGV,
-  // Handle SIGABRT in case someone sends it asynchronously using kill().
-  SIGABRT
-};
-
-pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
-NaClExceptionHandler signal_handler_function_pointer = NULL;
-
-// Signal handler, responsible for calling the registered handler.
-void SignalCatch(int sig, siginfo_t* info, void* uc) {
-  if (signal_handler_function_pointer) {
-    NaClSignalContext signal_context;
-    NaClSignalContextFromHandler(&signal_context, uc);
-    NaClExceptionFrame exception_frame;
-    NaClSignalSetUpExceptionFrame(&exception_frame,
-                                  &signal_context,
-                                  0 /* context_user_addr,
-                                       not useful for NonSFI NaCl. */);
-    signal_handler_function_pointer(&exception_frame.context);
-  }
-  _exit(-1);
-}
-
-int IrtExceptionHandler(NaClExceptionHandler handler,
-                               NaClExceptionHandler* old_handler) {
-  pthread_mutex_lock(&mutex);
-  if (old_handler)
-    *old_handler = signal_handler_function_pointer;
-  signal_handler_function_pointer = handler;
-  pthread_mutex_unlock(&mutex);
-  return 0;
-}
-
-int IrtExceptionStack(void* stack, size_t size) {
-  // TODO(uekawa): Implement this function so that the exception stack
-  // actually gets used for running an exception handler.  Currently
-  // we don't switch stack, which means we can't handle stack overflow
-  // exceptions.
-  return 0;
-}
-
-int IrtExceptionClearFlag(void) {
-  // TODO(uekawa): Implement clear_flag() to behave like SFI NaCl's
-  // implementation, so that a thread can handle a second exception
-  // after handling a first exception
-  return ENOSYS;
-}
-
-}  // namespace
-
-const struct nacl_irt_exception_handling kIrtExceptionHandling = {
-  IrtExceptionHandler,
-  IrtExceptionStack,
-  IrtExceptionClearFlag,
-};
-
-void InitializeSignalHandler() {
-  struct sigaction sa;
-  unsigned int a;
-
-  memset(&sa, 0, sizeof(sa));
-  sigemptyset(&sa.sa_mask);
-  sa.sa_sigaction = SignalCatch;
-  sa.sa_flags = SA_ONSTACK | SA_SIGINFO;
-
-  // Mask all signals we catch to prevent re-entry.
-  for (a = 0; a < NACL_ARRAY_SIZE(kSignals); a++) {
-    sigaddset(&sa.sa_mask, kSignals[a]);
-  }
-
-  // Install all handlers.
-  for (a = 0; a < NACL_ARRAY_SIZE(kSignals); a++) {
-    if (sigaction(kSignals[a], &sa, NULL) != 0)
-      NaClLog(LOG_FATAL, "sigaction to register signals failed.\n");
-  }
-}
-
-}  // namespace nonsfi
-}  // namespace nacl