debuggerd/tombstoned/intercept_manager.cpp - LeafOS-Project/android_system_core - Gitiles

 /*
  * Copyright 2016, The Android Open Source Project
  *
  * 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 "intercept_manager.h"

 #include <inttypes.h>
 #include <sys/types.h>

 #include <limits>
 #include <memory>
 #include <unordered_map>
 #include <utility>

 #include <event2/event.h>
 #include <event2/listener.h>

 #include <android-base/cmsg.h>
 #include <android-base/logging.h>
 #include <android-base/properties.h>
 #include <android-base/unique_fd.h>

 #include "protocol.h"
 #include "util.h"

 using android::base::ReceiveFileDescriptors;
 using android::base::unique_fd;

 static void intercept_close_cb(evutil_socket_t sockfd, short event, void* arg) {
   std::unique_ptr<Intercept> intercept(reinterpret_cast<Intercept*>(arg));

   CHECK_EQ(sockfd, intercept->sockfd.get());

   // If we can read, either we received unexpected data from the other side, or the other side
   // closed their end of the socket. Either way, kill the intercept.

   // Ownership of intercept differs based on whether we've registered it with InterceptManager.
   if (!intercept->registered) {
     LOG(WARNING) << "intercept for pid " << intercept->pid << " and type " << intercept->dump_type
                  << " closed before being registered.";
     return;
   }

   const char* reason = (event & EV_TIMEOUT) ? "due to timeout" : "due to input";
   LOG(INFO) << "intercept for pid " << intercept->pid << " and type " << intercept->dump_type
             << " terminated: " << reason;
 }

 void InterceptManager::Unregister(Intercept* intercept) {
   CHECK(intercept->registered);
   auto pid_entry = intercepts.find(intercept->pid);
   if (pid_entry == intercepts.end()) {
     LOG(FATAL) << "No intercepts found for pid " << intercept->pid;
   }
   auto& dump_type_hash = pid_entry->second;
   auto dump_type_entry = dump_type_hash.find(intercept->dump_type);
   if (dump_type_entry == dump_type_hash.end()) {
     LOG(FATAL) << "Unknown intercept " << intercept->pid << " " << intercept->dump_type;
   }
   if (intercept != dump_type_entry->second) {
     LOG(FATAL) << "Mismatch pointer trying to unregister intercept " << intercept->pid << " "
                << intercept->dump_type;
   }

   dump_type_hash.erase(dump_type_entry);
   if (dump_type_hash.empty()) {
     intercepts.erase(pid_entry);
   }
 }

 static void intercept_request_cb(evutil_socket_t sockfd, short ev, void* arg) {
   std::unique_ptr<Intercept> intercept(reinterpret_cast<Intercept*>(arg));
   InterceptManager* intercept_manager = intercept->intercept_manager;

   CHECK_EQ(sockfd, intercept->sockfd.get());

   if ((ev & EV_TIMEOUT) != 0) {
     LOG(WARNING) << "tombstoned didn't receive InterceptRequest before timeout";
     return;
   } else if ((ev & EV_READ) == 0) {
     LOG(WARNING) << "tombstoned received unexpected event on intercept socket";
     return;
   }

   unique_fd rcv_fd;
   InterceptRequest intercept_request;
   ssize_t result =
       ReceiveFileDescriptors(sockfd, &intercept_request, sizeof(intercept_request), &rcv_fd);

   if (result == -1) {
     PLOG(WARNING) << "failed to read from intercept socket";
     return;
   }
   if (result != sizeof(intercept_request)) {
     LOG(WARNING) << "intercept socket received short read of length " << result << " (expected "
                  << sizeof(intercept_request) << ")";
     return;
   }

   // Move the received FD to the upper half, in order to more easily notice FD leaks.
   int moved_fd = fcntl(rcv_fd.get(), F_DUPFD, 512);
   if (moved_fd == -1) {
     LOG(WARNING) << "failed to move received fd (" << rcv_fd.get() << ")";
     return;
   }
   rcv_fd.reset(moved_fd);

   // See if we can properly register the intercept.
   InterceptResponse response = {};
   if (!intercept_manager->CanRegister(intercept_request, response)) {
     TEMP_FAILURE_RETRY(write(sockfd, &response, sizeof(response)));
     LOG(WARNING) << response.error_message;
     return;
   }

   // Let the other side know that the intercept has been registered, now that we know we can't
   // fail. tombstoned is single threaded, so this isn't racy.
   response.status = InterceptStatus::kRegistered;
   if (TEMP_FAILURE_RETRY(write(sockfd, &response, sizeof(response))) == -1) {
     PLOG(WARNING) << "failed to notify interceptor of registration";
     return;
   }

   intercept->pid = intercept_request.pid;
   intercept->dump_type = intercept_request.dump_type;
   intercept->output_fd = std::move(rcv_fd);
   intercept_manager->Register(intercept.get());

   LOG(INFO) << "registered intercept for pid " << intercept_request.pid << " and type "
             << intercept_request.dump_type;

   // Register a different read event on the socket so that we can remove intercepts if the socket
   // closes (e.g. if a user CTRL-C's the process that requested the intercept).
   event_assign(intercept->intercept_event, intercept_manager->base, sockfd, EV_READ | EV_TIMEOUT,
                intercept_close_cb, arg);

   // If no request comes in, then this will close the intercept and free the pointer.
   struct timeval timeout = {.tv_sec = 10 * android::base::HwTimeoutMultiplier(), .tv_usec = 0};
   event_add(intercept->intercept_event, &timeout);
   intercept.release();
 }

 static void intercept_accept_cb(evconnlistener* listener, evutil_socket_t sockfd, sockaddr*, int,
                                 void* arg) {
   Intercept* intercept = new Intercept();
   intercept->intercept_manager = static_cast<InterceptManager*>(arg);
   intercept->sockfd.reset(sockfd);

   struct timeval timeout = {1 * android::base::HwTimeoutMultiplier(), 0};
   event_base* base = evconnlistener_get_base(listener);
   event* intercept_event =
     event_new(base, sockfd, EV_TIMEOUT | EV_READ, intercept_request_cb, intercept);
   intercept->intercept_event = intercept_event;
   event_add(intercept_event, &timeout);
 }

 Intercept::~Intercept() {
   event_free(intercept_event);
   if (registered) {
     CHECK(intercept_manager != nullptr);
     intercept_manager->Unregister(this);
   }
 }

 InterceptManager::InterceptManager(event_base* base, int intercept_socket) : base(base) {
   this->listener = evconnlistener_new(base, intercept_accept_cb, this, LEV_OPT_CLOSE_ON_FREE,
                                       /* backlog */ -1, intercept_socket);
 }

 static DebuggerdDumpType canonical_dump_type(const DebuggerdDumpType dump_type) {
   // kDebuggerdTombstone and kDebuggerdTombstoneProto should be treated as
   // a single dump_type for intercepts (kDebuggerdTombstone).
   if (dump_type == kDebuggerdTombstoneProto) {
     return kDebuggerdTombstone;
   }
   return dump_type;
 }

 Intercept* InterceptManager::Get(const pid_t pid, const DebuggerdDumpType dump_type) {
   auto pid_entry = intercepts.find(pid);
   if (pid_entry == intercepts.end()) {
     return nullptr;
   }

   const auto& dump_type_hash = pid_entry->second;
   auto dump_type_entry = dump_type_hash.find(canonical_dump_type(dump_type));
   if (dump_type_entry == dump_type_hash.end()) {
     if (dump_type != kDebuggerdAnyIntercept) {
       return nullptr;
     }
     // If doing a dump with an any intercept, only allow an any to match
     // a single intercept. If there are multiple dump types with intercepts
     // then there would be no way to figure out which to use.
     if (dump_type_hash.size() != 1) {
       LOG(WARNING) << "Cannot intercept using kDebuggerdAnyIntercept: there is more than one "
                       "intercept registered for pid "
                    << pid;
       return nullptr;
     }
     dump_type_entry = dump_type_hash.begin();
   }
   return dump_type_entry->second;
 }

 bool InterceptManager::CanRegister(const InterceptRequest& request, InterceptResponse& response) {
   if (request.pid <= 0 || request.pid > std::numeric_limits<pid_t>::max()) {
     response.status = InterceptStatus::kFailed;
     snprintf(response.error_message, sizeof(response.error_message),
              "invalid intercept request: bad pid %" PRId32, request.pid);
     return false;
   }
   if (request.dump_type < 0 || request.dump_type > kDebuggerdJavaBacktrace) {
     response.status = InterceptStatus::kFailed;
     snprintf(response.error_message, sizeof(response.error_message),
              "invalid intercept request: bad dump type %s", get_dump_type_name(request.dump_type));
     return false;
   }

   if (Get(request.pid, request.dump_type) != nullptr) {
     response.status = InterceptStatus::kFailedAlreadyRegistered;
     snprintf(response.error_message, sizeof(response.error_message),
              "pid %" PRId32 " already registered, type %s", request.pid,
              get_dump_type_name(request.dump_type));
     return false;
   }

   return true;
 }

 void InterceptManager::Register(Intercept* intercept) {
   CHECK(!intercept->registered);
   auto& dump_type_hash = intercepts[intercept->pid];
   dump_type_hash[canonical_dump_type(intercept->dump_type)] = intercept;
   intercept->registered = true;
 }

 bool InterceptManager::FindIntercept(pid_t pid, DebuggerdDumpType dump_type,
                                      android::base::unique_fd* out_fd) {
   Intercept* intercept = Get(pid, dump_type);
   if (intercept == nullptr) {
     return false;
   }

   if (dump_type != intercept->dump_type) {
     LOG(INFO) << "found registered intercept of type " << intercept->dump_type
               << " for requested type " << dump_type;
   }

   LOG(INFO) << "found intercept fd " << intercept->output_fd.get() << " for pid " << pid
             << " and type " << intercept->dump_type;
   InterceptResponse response = {};
   response.status = InterceptStatus::kStarted;
   TEMP_FAILURE_RETRY(write(intercept->sockfd, &response, sizeof(response)));
   *out_fd = std::move(intercept->output_fd);

   // Delete the intercept data, which will unregister the intercept and remove the timeout event.
   delete intercept;

   return true;
 }
	/*
	* Copyright 2016, The Android Open Source Project
	*
	* 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 "intercept_manager.h"

	#include <inttypes.h>
	#include <sys/types.h>

	#include <limits>
	#include <memory>
	#include <unordered_map>
	#include <utility>

	#include <event2/event.h>
	#include <event2/listener.h>

	#include <android-base/cmsg.h>
	#include <android-base/logging.h>
	#include <android-base/properties.h>
	#include <android-base/unique_fd.h>

	#include "protocol.h"
	#include "util.h"

	using android::base::ReceiveFileDescriptors;
	using android::base::unique_fd;

	static void intercept_close_cb(evutil_socket_t sockfd, short event, void* arg) {
	std::unique_ptr<Intercept> intercept(reinterpret_cast<Intercept*>(arg));

	CHECK_EQ(sockfd, intercept->sockfd.get());

	// If we can read, either we received unexpected data from the other side, or the other side
	// closed their end of the socket. Either way, kill the intercept.

	// Ownership of intercept differs based on whether we've registered it with InterceptManager.
	if (!intercept->registered) {
	LOG(WARNING) << "intercept for pid " << intercept->pid << " and type " << intercept->dump_type
	<< " closed before being registered.";
	return;
	}

	const char* reason = (event & EV_TIMEOUT) ? "due to timeout" : "due to input";
	LOG(INFO) << "intercept for pid " << intercept->pid << " and type " << intercept->dump_type
	<< " terminated: " << reason;
	}

	void InterceptManager::Unregister(Intercept* intercept) {
	CHECK(intercept->registered);
	auto pid_entry = intercepts.find(intercept->pid);
	if (pid_entry == intercepts.end()) {
	LOG(FATAL) << "No intercepts found for pid " << intercept->pid;
	}
	auto& dump_type_hash = pid_entry->second;
	auto dump_type_entry = dump_type_hash.find(intercept->dump_type);
	if (dump_type_entry == dump_type_hash.end()) {
	LOG(FATAL) << "Unknown intercept " << intercept->pid << " " << intercept->dump_type;
	}
	if (intercept != dump_type_entry->second) {
	LOG(FATAL) << "Mismatch pointer trying to unregister intercept " << intercept->pid << " "
	<< intercept->dump_type;
	}

	dump_type_hash.erase(dump_type_entry);
	if (dump_type_hash.empty()) {
	intercepts.erase(pid_entry);
	}
	}

	static void intercept_request_cb(evutil_socket_t sockfd, short ev, void* arg) {
	std::unique_ptr<Intercept> intercept(reinterpret_cast<Intercept*>(arg));
	InterceptManager* intercept_manager = intercept->intercept_manager;

	CHECK_EQ(sockfd, intercept->sockfd.get());

	if ((ev & EV_TIMEOUT) != 0) {
	LOG(WARNING) << "tombstoned didn't receive InterceptRequest before timeout";
	return;
	} else if ((ev & EV_READ) == 0) {
	LOG(WARNING) << "tombstoned received unexpected event on intercept socket";
	return;
	}

	unique_fd rcv_fd;
	InterceptRequest intercept_request;
	ssize_t result =
	ReceiveFileDescriptors(sockfd, &intercept_request, sizeof(intercept_request), &rcv_fd);

	if (result == -1) {
	PLOG(WARNING) << "failed to read from intercept socket";
	return;
	}
	if (result != sizeof(intercept_request)) {
	LOG(WARNING) << "intercept socket received short read of length " << result << " (expected "
	<< sizeof(intercept_request) << ")";
	return;
	}

	// Move the received FD to the upper half, in order to more easily notice FD leaks.
	int moved_fd = fcntl(rcv_fd.get(), F_DUPFD, 512);
	if (moved_fd == -1) {
	LOG(WARNING) << "failed to move received fd (" << rcv_fd.get() << ")";
	return;
	}
	rcv_fd.reset(moved_fd);

	// See if we can properly register the intercept.
	InterceptResponse response = {};
	if (!intercept_manager->CanRegister(intercept_request, response)) {
	TEMP_FAILURE_RETRY(write(sockfd, &response, sizeof(response)));
	LOG(WARNING) << response.error_message;
	return;
	}

	// Let the other side know that the intercept has been registered, now that we know we can't
	// fail. tombstoned is single threaded, so this isn't racy.
	response.status = InterceptStatus::kRegistered;
	if (TEMP_FAILURE_RETRY(write(sockfd, &response, sizeof(response))) == -1) {
	PLOG(WARNING) << "failed to notify interceptor of registration";
	return;
	}

	intercept->pid = intercept_request.pid;
	intercept->dump_type = intercept_request.dump_type;
	intercept->output_fd = std::move(rcv_fd);
	intercept_manager->Register(intercept.get());

	LOG(INFO) << "registered intercept for pid " << intercept_request.pid << " and type "
	<< intercept_request.dump_type;

	// Register a different read event on the socket so that we can remove intercepts if the socket
	// closes (e.g. if a user CTRL-C's the process that requested the intercept).
	event_assign(intercept->intercept_event, intercept_manager->base, sockfd, EV_READ \| EV_TIMEOUT,
	intercept_close_cb, arg);

	// If no request comes in, then this will close the intercept and free the pointer.
	struct timeval timeout = {.tv_sec = 10 * android::base::HwTimeoutMultiplier(), .tv_usec = 0};
	event_add(intercept->intercept_event, &timeout);
	intercept.release();
	}

	static void intercept_accept_cb(evconnlistener* listener, evutil_socket_t sockfd, sockaddr*, int,
	void* arg) {
	Intercept* intercept = new Intercept();
	intercept->intercept_manager = static_cast<InterceptManager*>(arg);
	intercept->sockfd.reset(sockfd);

	struct timeval timeout = {1 * android::base::HwTimeoutMultiplier(), 0};
	event_base* base = evconnlistener_get_base(listener);
	event* intercept_event =
	event_new(base, sockfd, EV_TIMEOUT \| EV_READ, intercept_request_cb, intercept);
	intercept->intercept_event = intercept_event;
	event_add(intercept_event, &timeout);
	}

	Intercept::~Intercept() {
	event_free(intercept_event);
	if (registered) {
	CHECK(intercept_manager != nullptr);
	intercept_manager->Unregister(this);
	}
	}

	InterceptManager::InterceptManager(event_base* base, int intercept_socket) : base(base) {
	this->listener = evconnlistener_new(base, intercept_accept_cb, this, LEV_OPT_CLOSE_ON_FREE,
	/* backlog */ -1, intercept_socket);
	}

	static DebuggerdDumpType canonical_dump_type(const DebuggerdDumpType dump_type) {
	// kDebuggerdTombstone and kDebuggerdTombstoneProto should be treated as
	// a single dump_type for intercepts (kDebuggerdTombstone).
	if (dump_type == kDebuggerdTombstoneProto) {
	return kDebuggerdTombstone;
	}
	return dump_type;
	}

	Intercept* InterceptManager::Get(const pid_t pid, const DebuggerdDumpType dump_type) {
	auto pid_entry = intercepts.find(pid);
	if (pid_entry == intercepts.end()) {
	return nullptr;
	}

	const auto& dump_type_hash = pid_entry->second;
	auto dump_type_entry = dump_type_hash.find(canonical_dump_type(dump_type));
	if (dump_type_entry == dump_type_hash.end()) {
	if (dump_type != kDebuggerdAnyIntercept) {
	return nullptr;
	}
	// If doing a dump with an any intercept, only allow an any to match
	// a single intercept. If there are multiple dump types with intercepts
	// then there would be no way to figure out which to use.
	if (dump_type_hash.size() != 1) {
	LOG(WARNING) << "Cannot intercept using kDebuggerdAnyIntercept: there is more than one "
	"intercept registered for pid "
	<< pid;
	return nullptr;
	}
	dump_type_entry = dump_type_hash.begin();
	}
	return dump_type_entry->second;
	}

	bool InterceptManager::CanRegister(const InterceptRequest& request, InterceptResponse& response) {
	if (request.pid <= 0 \|\| request.pid > std::numeric_limits<pid_t>::max()) {
	response.status = InterceptStatus::kFailed;
	snprintf(response.error_message, sizeof(response.error_message),
	"invalid intercept request: bad pid %" PRId32, request.pid);
	return false;
	}
	if (request.dump_type < 0 \|\| request.dump_type > kDebuggerdJavaBacktrace) {
	response.status = InterceptStatus::kFailed;
	snprintf(response.error_message, sizeof(response.error_message),
	"invalid intercept request: bad dump type %s", get_dump_type_name(request.dump_type));
	return false;
	}

	if (Get(request.pid, request.dump_type) != nullptr) {
	response.status = InterceptStatus::kFailedAlreadyRegistered;
	snprintf(response.error_message, sizeof(response.error_message),
	"pid %" PRId32 " already registered, type %s", request.pid,
	get_dump_type_name(request.dump_type));
	return false;
	}

	return true;
	}

	void InterceptManager::Register(Intercept* intercept) {
	CHECK(!intercept->registered);
	auto& dump_type_hash = intercepts[intercept->pid];
	dump_type_hash[canonical_dump_type(intercept->dump_type)] = intercept;
	intercept->registered = true;
	}

	bool InterceptManager::FindIntercept(pid_t pid, DebuggerdDumpType dump_type,
	android::base::unique_fd* out_fd) {
	Intercept* intercept = Get(pid, dump_type);
	if (intercept == nullptr) {
	return false;
	}

	if (dump_type != intercept->dump_type) {
	LOG(INFO) << "found registered intercept of type " << intercept->dump_type
	<< " for requested type " << dump_type;
	}

	LOG(INFO) << "found intercept fd " << intercept->output_fd.get() << " for pid " << pid
	<< " and type " << intercept->dump_type;
	InterceptResponse response = {};
	response.status = InterceptStatus::kStarted;
	TEMP_FAILURE_RETRY(write(intercept->sockfd, &response, sizeof(response)));
	*out_fd = std::move(intercept->output_fd);

	// Delete the intercept data, which will unregister the intercept and remove the timeout event.
	delete intercept;

	return true;
	}