Linux: Use upstream google-breakpad instead of our fork....

breakpad/linux/exception_handler.cc

Index: breakpad/linux/exception_handler.cc
===================================================================
--- breakpad/linux/exception_handler.cc	(revision 32662)
+++ breakpad/linux/exception_handler.cc	(working copy)
@@ -1,322 +0,0 @@
-// Copyright (c) 2009, 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 "breakpad/linux/exception_handler.h"
-
-#include <errno.h>
-#include <fcntl.h>
-#include <linux/limits.h>
-#include <sched.h>
-#include <signal.h>
-#include <stdio.h>
-#include <sys/mman.h>
-#include <sys/signal.h>
-#include <sys/syscall.h>
-#include <sys/ucontext.h>
-#include <sys/user.h>
-#include <sys/wait.h>
-#include <unistd.h>
-
-#include "breakpad/linux/linux_libc_support.h"
-#include "breakpad/linux/linux_syscall_support.h"
-#include "breakpad/linux/memory.h"
-#include "breakpad/linux/minidump_writer.h"
-#include "common/linux/guid_creator.h"
-
-// A wrapper for the tgkill syscall: send a signal to a specific thread.
-static int tgkill(pid_t tgid, pid_t tid, int sig) {
-  syscall(__NR_tgkill, tgid, tid, sig);
-}
-
-namespace google_breakpad {
-
-// 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.
-static const int kExceptionSignals[] = {
-  SIGSEGV, SIGABRT, SIGFPE, SIGILL, SIGBUS, -1
-};
-
-// We can stack multiple exception handlers. In that case, this is the global
-// which holds the stack.
-std::vector<ExceptionHandler*>* ExceptionHandler::handler_stack_ = NULL;
-unsigned ExceptionHandler::handler_stack_index_ = 0;
-pthread_mutex_t ExceptionHandler::handler_stack_mutex_ =
-    PTHREAD_MUTEX_INITIALIZER;
-
-// Runs before crashing: normal context.
-ExceptionHandler::ExceptionHandler(const std::string &dump_path,
-                                   FilterCallback filter,
-                                   MinidumpCallback callback,
-                                   void *callback_context,
-                                   bool install_handler)
-    : filter_(filter),
-      callback_(callback),
-      callback_context_(callback_context),
-      dump_path_(),
-      handler_installed_(install_handler),
-      crash_handler_(NULL) {
-  set_dump_path(dump_path);
-
-  if (install_handler) {
-    InstallHandlers();
-
-    pthread_mutex_lock(&handler_stack_mutex_);
-      if (handler_stack_ == NULL)
-        handler_stack_ = new std::vector<ExceptionHandler *>;
-      handler_stack_->push_back(this);
-    pthread_mutex_unlock(&handler_stack_mutex_);
-  }
-}
-
-// Runs before crashing: normal context.
-ExceptionHandler::~ExceptionHandler() {
-  UninstallHandlers();
-}
-
-// Runs before crashing: normal context.
-bool ExceptionHandler::InstallHandlers() {
-  // We run the signal handlers on an alternative stack because we might have
-  // crashed because of a stack overflow.
-
-  // We use this value rather than SIGSTKSZ because we would end up overrunning
-  // such a small stack.
-  static const unsigned kSigStackSize = 8192;
-
-  signal_stack = malloc(kSigStackSize);
-  stack_t stack;
-  memset(&stack, 0, sizeof(stack));
-  stack.ss_sp = signal_stack;
-  stack.ss_size = kSigStackSize;
-
-  if (sigaltstack(&stack, NULL) == -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 (unsigned i = 0; kExceptionSignals[i] != -1; ++i)
-    sigaddset(&sa.sa_mask, kExceptionSignals[i]);
-
-  sa.sa_sigaction = SignalHandler;
-  sa.sa_flags = SA_ONSTACK | SA_SIGINFO;
-
-  for (unsigned i = 0; kExceptionSignals[i] != -1; ++i) {
-    struct sigaction* old = new struct sigaction;
-    if (sigaction(kExceptionSignals[i], &sa, old) == -1)
-      return false;
-    old_handlers_.push_back(std::make_pair(kExceptionSignals[i], old));
-  }
-}
-
-// Runs before crashing: normal context.
-void ExceptionHandler::UninstallHandlers() {
-  for (unsigned i = 0; i < old_handlers_.size(); ++i) {
-    struct sigaction *action =
-        reinterpret_cast<struct sigaction*>(old_handlers_[i].second);
-    sigaction(old_handlers_[i].first, action, NULL);
-    delete action;
-  }
-
-  old_handlers_.clear();
-}
-
-// Runs before crashing: normal context.
-void ExceptionHandler::UpdateNextID() {
-  GUID guid;
-  char guid_str[kGUIDStringLength + 1];
-  if (CreateGUID(&guid) && GUIDToString(&guid, guid_str, sizeof(guid_str))) {
-    next_minidump_id_ = guid_str;
-    next_minidump_id_c_ = next_minidump_id_.c_str();
-
-    char minidump_path[PATH_MAX];
-    snprintf(minidump_path, sizeof(minidump_path), "%s/%s.dmp",
-             dump_path_c_,
-             guid_str);
-
-    next_minidump_path_ = minidump_path;
-    next_minidump_path_c_ = next_minidump_path_.c_str();
-  }
-}
-
-// 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) {
-  // All the exception signals are blocked at this point.
-
-  pthread_mutex_lock(&handler_stack_mutex_);
-
-  if (!handler_stack_->size()) {
-    pthread_mutex_unlock(&handler_stack_mutex_);
-    return;
-  }
-
-  for (int i = handler_stack_->size() - 1; i >= 0; --i) {
-    if ((*handler_stack_)[i]->HandleSignal(sig, info, uc)) {
-      // successfully handled: We are in an invalid state since an exception
-      // signal has been delivered. We don't call the exit handlers because
-      // they could end up corrupting on-disk state.
-      break;
-    }
-  }
-
-  pthread_mutex_unlock(&handler_stack_mutex_);
-
-  // Terminate ourselves with the same signal so that our parent knows that we
-  // crashed. The default action for all the signals which we catch is Core, so
-  // this is the end of us.
-  signal(sig, SIG_DFL);
-  tgkill(getpid(), sys_gettid(), sig);
-
-  // not reached.
-}
-
-struct ThreadArgument {
-  pid_t pid;  // the crashing process
-  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);
-  return thread_arg->handler->DoDump(thread_arg->pid, thread_arg->context,
-                                     thread_arg->context_size) == false;
-}
-
-// 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) {
-  if (filter_ && !filter_(callback_context_))
-    return false;
-
-  // Allow ourselves to be dumped.
-  sys_prctl(PR_SET_DUMPABLE, 1);
-
-  CrashContext context;
-  memcpy(&context.siginfo, info, sizeof(siginfo_t));
-  memcpy(&context.context, uc, sizeof(struct ucontext));
-  memcpy(&context.float_state, ((struct ucontext *)uc)->uc_mcontext.fpregs,
-         sizeof(context.float_state));
-  context.tid = sys_gettid();
-
-  if (crash_handler_ && crash_handler_(&context, sizeof(context),
-                                       callback_context_))
-    return true;
-
-  static const unsigned kChildStackSize = 8000;
-  PageAllocator allocator;
-  uint8_t* stack = (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.pid = getpid();
-  thread_arg.context = &context;
-  thread_arg.context_size = sizeof(context);
-
-  const pid_t child = sys_clone(
-      ThreadEntry, stack, CLONE_FILES | CLONE_FS | CLONE_UNTRACED,
-      &thread_arg, NULL, NULL, NULL);
-  int r, status;
-  do {
-    r = sys_waitpid(child, &status, __WALL);
-  } while (r == -1 && errno == EINTR);
-
-  if (r == -1) {
-    static const char msg[] = "ExceptionHandler::HandleSignal: waitpid failed:";
-    sys_write(2, msg, sizeof(msg) - 1);
-    sys_write(2, strerror(errno), strlen(strerror(errno)));
-    sys_write(2, "\n", 1);
-  }
-
-  bool success = r != -1 && WIFEXITED(status) && WEXITSTATUS(status) == 0;
-
-  if (callback_)
-    success = callback_(dump_path_c_, next_minidump_id_c_,
-                        callback_context_, success);
-
-  return success;
-}
-
-// 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) {
-  return google_breakpad::WriteMinidump(
-      next_minidump_path_c_, crashing_process, context, context_size);
-}
-
-}  // namespace google_breakpad