MachMessageServer: eliminate argument redundancy

tools/catch_exception_tool.cc

 // 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,
@@ skipping 12 matching lines @@
 #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/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;
-  MachMessageServer::Nonblocking nonblocking;
+  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),
@@ skipping 107 matching lines @@
   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"
-"  -n, --nonblocking           don't block waiting for an exception to occur\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',
-    kOptionNonblocking = 'n',
     kOptionPersistent = 'p',
     kOptionTimeout = 't',
 
     // Long options without short equivalents.
     kOptionLastChar = 255,
 
     // Standard options.
     kOptionHelp = -2,
     kOptionVersion = -3,
   };
 
   Options options = {};
 
   const struct option long_options[] = {
       {"file", required_argument, nullptr, kOptionFile},
       {"mach-service", required_argument, nullptr, kOptionMachService},
-      {"nonblocking", no_argument, nullptr, kOptionNonblocking},
       {"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:npt:", long_options, nullptr)) !=
+  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 kOptionNonblocking:
-        options.nonblocking = MachMessageServer::kNonblocking;
-        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 positive TIMEOUT");
+            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;
@@ skipping 31 matching lines @@
   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 = options.timeout_secs
-                                      ? options.timeout_secs * 1000
-                                      : MACH_MSG_TIMEOUT_NONE;
+  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,
                                                 MACH_MSG_OPTION_NONE,
                                                 options.persistent,
-                                                options.nonblocking,
                                                 receive_large,
                                                 timeout_ms);
-  if (mr == MACH_RCV_TIMED_OUT && options.timeout_secs && options.persistent &&
+  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);
 }