Add catch_exception_tool

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,
+// 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 <getopt.h>
+#include <libgen.h>
+#include <servers/bootstrap.h>
+#include <stdio.h>
+#include <string.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/mach_extensions.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 {
+
+using namespace crashpad;
+
+struct Options {
+  std::string file_path;
+  std::string mach_service;
+  FILE* file;
+  int timeout_secs;
+  MachMessageServer::Nonblocking nonblocking;
+  MachMessageServer::Persistent persistent;
+};
+
+class ExceptionServer : public UniversalMachExcServer {
+ public:
+  ExceptionServer(const Options& options,
+                  const std::string& me,
+                  int* exceptions_handled)
+      : UniversalMachExcServer(),
+        options_(options),
+        me_(me),
+        exceptions_handled_(exceptions_handled) {}
+
+  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,
+      const natural_t* old_state,
+      mach_msg_type_number_t old_state_count,
+      thread_state_t new_state,
+      mach_msg_type_number_t* new_state_count,
+      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());
+
+    pid_t pid;
+    kern_return_t kr;
+    if (ExceptionBehaviorHasIdentity(behavior)) {
+      kr = pid_for_task(task, &pid);
+      if (kr != KERN_SUCCESS) {
+        MACH_LOG(ERROR, kr) << "pid_for_task";
+        return KERN_FAILURE;
+      }
+      fprintf(options_.file, "pid %d, ", pid);
+    } else {
+      pid = -1;
+    }
+
+    if (ExceptionBehaviorHasState(behavior)) {
+      // If this is a state-carrying exception, make new_state something valid.
+      memcpy(
+          new_state,
+          old_state,
+          std::min(old_state_count, *new_state_count) * sizeof(old_state[0]));
+      *new_state_count = old_state_count;
+    }
+
+    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,
+              "%#llx%s",
+              code[index],
+              index != code_count - 1 ? ", " : "");
+    }
+
+    if (exception == EXC_CRASH) {
+      // 10.9.4 xnu-2422.110.17/bsd/kern/kern_exit.c proc_prepareexit() sets
+      // code[0] based on the signal value, original exception type, and low 20
+      // bits of the original code[0] before calling
+      // xnu-2422.110.17/osfmk/kern/exception.c task_exception_notify() to raise
+      // an EXC_CRASH.
+      int sig = (code[0] >> 24) & 0xff;

[Robert Sesek, 2014/09/17 16:28:03]

You've masked the code this way before. Would it be good to create a new
function to get these three values from a code instead of doing it inline, in
case this packing logic changes in the future?

+      int orig_exception = (code[0] >> 20) & 0xf;
+      int orig_code_0 = code[0] & 0xfffff;
+      fprintf(options_.file,
+              ", original exception %s, original code0 %d, signal %s",
+              ExceptionToString(orig_exception,
+                                kUseFullName | kUnknownIsNumeric).c_str(),
+              orig_code_0,
+              SignalToString(sig, kUseFullName | kUnknownIsNumeric).c_str());
+    }
+
+    fprintf(options_.file, "\n");
+    fflush(options_.file);
+
+    if (exception != EXC_CRASH && exception != kMachExceptionSimulated) {
+      // Find another handler.
+      return KERN_FAILURE;
+    }
+
+    return ExcServerSuccessfulReturnValue(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"
+"  -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);
+}
+
+}  // namespace
+
+int main(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, NULL, kOptionFile},
+      {"mach_service", required_argument, NULL, kOptionMachService},
+      {"nonblocking", no_argument, NULL, kOptionNonblocking},
+      {"persistent", no_argument, NULL, kOptionPersistent},
+      {"timeout", required_argument, NULL, kOptionTimeout},
+      {"help", no_argument, NULL, kOptionHelp},
+      {"version", no_argument, NULL, kOptionVersion},
+      {NULL, 0, NULL, 0},
+  };
+
+  int opt;
+  while ((opt = getopt_long(argc, argv, "f:m:npt:", long_options, NULL)) !=
+         -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");
+          return EXIT_FAILURE;
+        }
+        break;
+      case kOptionHelp:
+        Usage(me);
+        return EXIT_SUCCESS;
+      case kOptionVersion:
+        ToolSupport::Version(me);
+        return EXIT_SUCCESS;
+      default:
+        ToolSupport::UsageHint(me, NULL);
+        return EXIT_FAILURE;
+    }
+  }
+  argc -= optind;
+  argv += optind;
+
+  if (options.mach_service.empty()) {
+    ToolSupport::UsageHint(me, "-m is required");
+    return EXIT_FAILURE;
+  }
+
+  mach_port_t service_port;
+  kern_return_t kr = bootstrap_check_in(
+      bootstrap_port, options.mach_service.c_str(), &service_port);
+  if (kr != BOOTSTRAP_SUCCESS) {
+    BOOTSTRAP_LOG(ERROR, kr) << "bootstrap_check_in " << options.mach_service;
+    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();
+  }
+
+  int exceptions_handled = 0;
+  ExceptionServer exception_server(options, me, &exceptions_handled);
+
+  mach_msg_timeout_t timeout_ms = options.timeout_secs
+                                      ? options.timeout_secs * 1000
+                                      : MACH_MSG_TIMEOUT_NONE;
+
+  mach_msg_return_t mr = MachMessageServer::Run(&exception_server,
+                                                service_port,
+                                                MACH_MSG_OPTION_NONE,
+                                                options.persistent,
+                                                options.nonblocking,
+                                                timeout_ms);
+  if (mr == MACH_RCV_TIMED_OUT && options.timeout_secs && 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;
+}