text: // Copyright 2014 The Crashpad Authors. All rights reserved.
  //
  // Licensed under the Apache License, Version 2.0 (the "License");
  // you may not use this file except in compliance with the License.
  // You may obtain a copy of the License at
  //
  //     http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing, software
  // distributed under the License is distributed on an "AS IS" BASIS,
  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  // See the License for the specific language governing permissions and
  // limitations under the License.
  
  #include <fcntl.h>
  #include <getopt.h>
  #include <libgen.h>
  #include <stdio.h>
  #include <string.h>
  #include <sys/types.h>
  #include <unistd.h>
  
  #include <algorithm>
  #include <string>
  #include <vector>
  
  #include "base/files/scoped_file.h"
  #include "base/logging.h"
  #include "base/mac/mach_logging.h"
  #include "tools/tool_support.h"
  #include "util/mach/exc_server_variants.h"
  #include "util/mach/exception_behaviors.h"
  #include "util/mach/exception_types.h"
  #include "util/mach/mach_extensions.h"
  #include "util/mach/mach_message.h"
  #include "util/mach/mach_message_server.h"
  #include "util/mach/symbolic_constants_mach.h"
  #include "util/posix/symbolic_constants_posix.h"
  #include "util/stdlib/string_number_conversion.h"
  
  namespace crashpad {
  namespace {
  
  struct Options {
    std::string file_path;
    std::string mach_service;
    FILE* file;
    int timeout_secs;
    bool has_timeout;
    MachMessageServer::Persistent persistent;
  };
  
  class ExceptionServer : public UniversalMachExcServer::Interface {
   public:
    ExceptionServer(const Options& options,
                    const std::string& me,
                    int* exceptions_handled)
        : UniversalMachExcServer::Interface(),
          options_(options),
          me_(me),
          exceptions_handled_(exceptions_handled) {}
  
    // UniversalMachExcServer::Interface:
    virtual kern_return_t CatchMachException(
        exception_behavior_t behavior,
        exception_handler_t exception_port,
        thread_t thread,
        task_t task,
        exception_type_t exception,
        const mach_exception_data_type_t* code,
        mach_msg_type_number_t code_count,
        thread_state_flavor_t* flavor,
        ConstThreadState old_state,
        mach_msg_type_number_t old_state_count,
        thread_state_t new_state,
        mach_msg_type_number_t* new_state_count,
        const mach_msg_trailer_t* trailer,
        bool* destroy_complex_request) override {
      *destroy_complex_request = true;
      ++*exceptions_handled_;
  
      fprintf(options_.file,
              "%s: behavior %s",
              me_.c_str(),
              ExceptionBehaviorToString(
                  behavior, kUseFullName | kUnknownIsNumeric | kUseOr).c_str());
  
      kern_return_t kr;
      if (ExceptionBehaviorHasIdentity(behavior)) {
        // It’s not possible to call pid_for_task() once EXC_CORPSE_NOTIFY has
        // been generated. It is possible to obtain the process ID by mapping the
        // corpse kcdata area from the task’s address space at code[0] (size
        // code[1]) and locating TASK_CRASHINFO_PID within that area. This area
        // also includes TASK_CRASHINFO_CRASHED_THREADID which could be used
        // instead of thread_info() below, and TASK_CRASHINFO_EXCEPTION_CODES
        // which could be used to recover the exception codes passed to the
        // EXC_CRASH handler. None of this is currently done because corpses are a
        // new 10.11-only feature. See 10.11 <corpses/task_corpse.h> and
        // <kern/kern_cdata.h>.
        if (exception != EXC_CORPSE_NOTIFY) {
          pid_t pid;
          kr = pid_for_task(task, &pid);
          if (kr != KERN_SUCCESS) {
            fprintf(options_.file, "\n");
            fflush(options_.file);
            MACH_LOG(ERROR, kr) << "pid_for_task";
            return KERN_FAILURE;
          }
          fprintf(options_.file, ", pid %d", pid);
        }
  
        thread_identifier_info identifier_info;
        mach_msg_type_number_t count = THREAD_IDENTIFIER_INFO_COUNT;
        kr = thread_info(thread,
                         THREAD_IDENTIFIER_INFO,
                         reinterpret_cast<thread_info_t>(&identifier_info),
                         &count);
        if (kr != KERN_SUCCESS) {
          fprintf(options_.file, "\n");
          fflush(options_.file);
          MACH_LOG(ERROR, kr) << "thread_info";
          return KERN_FAILURE;
        }
        fprintf(options_.file, ", thread %lld", identifier_info.thread_id);
      }
  
      fprintf(
          options_.file,
          ", exception %s, codes[%d]",
          ExceptionToString(exception, kUseFullName | kUnknownIsNumeric).c_str(),
          code_count);
  
      for (size_t index = 0; index < code_count; ++index) {
        fprintf(options_.file,
                "%s %#llx",
                index != 0 ? "," : "",
                code[index]);
      }
  
      if (exception == EXC_CRASH) {
        mach_exception_code_t original_code_0;
        int signal;
        exception_type_t original_exception =
            ExcCrashRecoverOriginalException(code[0], &original_code_0, &signal);
        fprintf(options_.file,
                ", original exception %s, original code[0] %lld, signal %s",
                ExceptionToString(original_exception,
                                  kUseFullName | kUnknownIsNumeric).c_str(),
                original_code_0,
                SignalToString(signal, kUseFullName | kUnknownIsNumeric).c_str());
      }
  
      if (ExceptionBehaviorHasState(behavior)) {
        std::string flavor_string =
            ThreadStateFlavorToString(*flavor, kUseFullName | kUnknownIsNumeric);
        fprintf(options_.file,
                ", flavor %s, old_state_count %d",
                flavor_string.c_str(),
                old_state_count);
      }
  
      fprintf(options_.file, "\n");
      fflush(options_.file);
  
      if (exception != EXC_CRASH && exception != kMachExceptionSimulated) {
        // Find another handler.
        return KERN_FAILURE;
      }
  
      ExcServerCopyState(
          behavior, old_state, old_state_count, new_state, new_state_count);
  
      return ExcServerSuccessfulReturnValue(exception, behavior, false);
    }
  
   private:
    const Options& options_;
    const std::string& me_;
    int* exceptions_handled_;
  };
  
  void Usage(const std::string& me) {
    fprintf(stderr,
  "Usage: %s -m SERVICE [OPTION]...\n"
  "Catch Mach exceptions and display information about them.\n"
  "\n"
  "  -f, --file=FILE             append information to FILE instead of stdout\n"
  "  -m, --mach-service=SERVICE  register SERVICE with the bootstrap server\n"
  "  -p, --persistent            continue processing exceptions after the first\n"
  "  -t, --timeout=TIMEOUT       run for a maximum of TIMEOUT seconds\n"
  "      --help                  display this help and exit\n"
  "      --version               output version information and exit\n",
            me.c_str());
    ToolSupport::UsageTail(me);
  }
  
  int CatchExceptionToolMain(int argc, char* argv[]) {
    const std::string me(basename(argv[0]));
  
    enum OptionFlags {
      // “Short” (single-character) options.
      kOptionFile = 'f',
      kOptionMachService = 'm',
      kOptionPersistent = 'p',
      kOptionTimeout = 't',
  
      // Long options without short equivalents.
      kOptionLastChar = 255,
  
      // Standard options.
      kOptionHelp = -2,
      kOptionVersion = -3,
    };
  
    Options options = {};
  
    static constexpr option long_options[] = {
        {"file", required_argument, nullptr, kOptionFile},
        {"mach-service", required_argument, nullptr, kOptionMachService},
        {"persistent", no_argument, nullptr, kOptionPersistent},
        {"timeout", required_argument, nullptr, kOptionTimeout},
        {"help", no_argument, nullptr, kOptionHelp},
        {"version", no_argument, nullptr, kOptionVersion},
        {nullptr, 0, nullptr, 0},
    };
  
    int opt;
    while ((opt = getopt_long(argc, argv, "f:m:pt:", long_options, nullptr)) !=
           -1) {
      switch (opt) {
        case kOptionFile:
          options.file_path = optarg;
          break;
        case kOptionMachService:
          options.mach_service = optarg;
          break;
        case kOptionPersistent:
          options.persistent = MachMessageServer::kPersistent;
          break;
        case kOptionTimeout:
          if (!StringToNumber(optarg, &options.timeout_secs) ||
              options.timeout_secs < 0) {
            ToolSupport::UsageHint(me, "-t requires a zero or positive TIMEOUT");
            return EXIT_FAILURE;
          }
          options.has_timeout = true;
          break;
        case kOptionHelp:
          Usage(me);
          return EXIT_SUCCESS;
        case kOptionVersion:
          ToolSupport::Version(me);
          return EXIT_SUCCESS;
        default:
          ToolSupport::UsageHint(me, nullptr);
          return EXIT_FAILURE;
      }
    }
    argc -= optind;
    argv += optind;
  
    if (options.mach_service.empty()) {
      ToolSupport::UsageHint(me, "-m is required");
      return EXIT_FAILURE;
    }
  
    base::mac::ScopedMachReceiveRight
        service_port(BootstrapCheckIn(options.mach_service));
    if (service_port == kMachPortNull) {
      return EXIT_FAILURE;
    }
  
    base::ScopedFILE file_owner;
    if (options.file_path.empty()) {
      options.file = stdout;
    } else {
      file_owner.reset(fopen(options.file_path.c_str(), "a"));
      if (!file_owner.get()) {
        PLOG(ERROR) << "fopen " << options.file_path;
        return EXIT_FAILURE;
      }
      options.file = file_owner.get();
      if (fcntl(fileno(options.file), F_SETFD, FD_CLOEXEC) == -1) {
        PLOG(ERROR) << "fcntl " << options.file_path;
        return EXIT_FAILURE;
      }
    }
  
    int exceptions_handled = 0;
    ExceptionServer exception_server(options, me, &exceptions_handled);
    UniversalMachExcServer universal_mach_exc_server(&exception_server);
  
    // Assume that if persistent mode has been requested, it’s desirable to ignore
    // large messages and keep running.
    MachMessageServer::ReceiveLarge receive_large =
        (options.persistent == MachMessageServer::kPersistent)
            ? MachMessageServer::kReceiveLargeIgnore
            : MachMessageServer::kReceiveLargeError;
  
    mach_msg_timeout_t timeout_ms;
    if (!options.has_timeout) {
      timeout_ms = kMachMessageTimeoutWaitIndefinitely;
    } else if (options.timeout_secs == 0) {
      timeout_ms = kMachMessageTimeoutNonblocking;
    } else {
      timeout_ms = options.timeout_secs * 1000;
    }
  
    mach_msg_return_t mr = MachMessageServer::Run(&universal_mach_exc_server,
                                                  service_port.get(),
                                                  MACH_MSG_OPTION_NONE,
                                                  options.persistent,
                                                  receive_large,
                                                  timeout_ms);
    if (mr == MACH_RCV_TIMED_OUT && options.has_timeout && options.persistent &&
        exceptions_handled) {
      // This is not an error: when exiting on timeout during persistent
      // processing and at least one exception was handled, it’s considered a
      // success.
    } else if (mr != MACH_MSG_SUCCESS) {
      MACH_LOG(ERROR, mr) << "MachMessageServer::Run";
      return EXIT_FAILURE;
    }
  
    return EXIT_SUCCESS;
  }
  
  }  // namespace
  }  // namespace crashpad
  
  int main(int argc, char* argv[]) {
    return crashpad::CatchExceptionToolMain(argc, argv);
  }
  