debuggerd/tombstoned/tombstoned.cpp - 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 <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>

 #include <array>
 #include <deque>
 #include <unordered_map>

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

 #include <android-base/logging.h>
 #include <android-base/stringprintf.h>
 #include <android-base/unique_fd.h>
 #include <cutils/sockets.h>

 #include "debuggerd/protocol.h"
 #include "debuggerd/util.h"

 #include "intercept_manager.h"

 using android::base::StringPrintf;
 using android::base::unique_fd;

 static InterceptManager* intercept_manager;

 enum CrashStatus {
   kCrashStatusRunning,
   kCrashStatusQueued,
 };

 // Ownership of Crash is a bit messy.
 // It's either owned by an active event that must have a timeout, or owned by
 // queued_requests, in the case that multiple crashes come in at the same time.
 struct Crash {
   ~Crash() {
     event_free(crash_event);
   }

   unique_fd crash_fd;
   pid_t crash_pid;
   event* crash_event = nullptr;
 };

 static constexpr char kTombstoneDirectory[] = "/data/tombstones/";
 static constexpr size_t kTombstoneCount = 10;
 static int tombstone_directory_fd = -1;
 static int next_tombstone = 0;

 static constexpr size_t kMaxConcurrentDumps = 1;
 static size_t num_concurrent_dumps = 0;

 static std::deque<Crash*> queued_requests;

 // Forward declare the callbacks so they can be placed in a sensible order.
 static void crash_accept_cb(evconnlistener* listener, evutil_socket_t sockfd, sockaddr*, int, void*);
 static void crash_request_cb(evutil_socket_t sockfd, short ev, void* arg);
 static void crash_completed_cb(evutil_socket_t sockfd, short ev, void* arg);

 static void find_oldest_tombstone() {
   size_t oldest_tombstone = 0;
   time_t oldest_time = std::numeric_limits<time_t>::max();

   for (size_t i = 0; i < kTombstoneCount; ++i) {
     std::string path = android::base::StringPrintf("%stombstone_%02zu", kTombstoneDirectory, i);
     struct stat st;
     if (stat(path.c_str(), &st) != 0) {
       if (errno == ENOENT) {
         oldest_tombstone = i;
         break;
       } else {
         PLOG(ERROR) << "failed to stat " << path;
         continue;
       }
     }

     if (st.st_mtime < oldest_time) {
       oldest_tombstone = i;
       oldest_time = st.st_mtime;
     }
   }

   next_tombstone = oldest_tombstone;
 }

 static unique_fd get_tombstone_fd() {
   // If kMaxConcurrentDumps is greater than 1, then theoretically the same
   // filename could be handed out to multiple processes. Unlink and create the
   // file, instead of using O_TRUNC, to avoid two processes interleaving their
   // output.
   unique_fd result;
   char buf[PATH_MAX];
   snprintf(buf, sizeof(buf), "tombstone_%02d", next_tombstone);
   if (unlinkat(tombstone_directory_fd, buf, 0) != 0 && errno != ENOENT) {
     PLOG(FATAL) << "failed to unlink tombstone at " << kTombstoneDirectory << buf;
   }

   result.reset(
     openat(tombstone_directory_fd, buf, O_CREAT | O_EXCL | O_WRONLY | O_APPEND | O_CLOEXEC, 0700));
   if (result == -1) {
     PLOG(FATAL) << "failed to create tombstone at " << kTombstoneDirectory << buf;
   }

   next_tombstone = (next_tombstone + 1) % kTombstoneCount;
   return result;
 }

 static void dequeue_request(Crash* crash) {
   ++num_concurrent_dumps;

   unique_fd output_fd;
   if (!intercept_manager->GetIntercept(crash->crash_pid, &output_fd)) {
     output_fd = get_tombstone_fd();
   }

   TombstonedCrashPacket response = {
     .packet_type = CrashPacketType::kPerformDump
   };
   ssize_t rc = send_fd(crash->crash_fd, &response, sizeof(response), std::move(output_fd));
   if (rc == -1) {
     PLOG(WARNING) << "failed to send response to CrashRequest";
     goto fail;
   } else if (rc != sizeof(response)) {
     PLOG(WARNING) << "crash socket write returned short";
     goto fail;
   } else {
     // TODO: Make this configurable by the interceptor?
     struct timeval timeout = { 10, 0 };

     event_base* base = event_get_base(crash->crash_event);
     event_assign(crash->crash_event, base, crash->crash_fd, EV_TIMEOUT | EV_READ,
                  crash_completed_cb, crash);
     event_add(crash->crash_event, &timeout);
   }
   return;

 fail:
   delete crash;
 }

 static void crash_accept_cb(evconnlistener* listener, evutil_socket_t sockfd, sockaddr*, int,
                             void*) {
   event_base* base = evconnlistener_get_base(listener);
   Crash* crash = new Crash();

   struct timeval timeout = { 1, 0 };
   event* crash_event = event_new(base, sockfd, EV_TIMEOUT | EV_READ, crash_request_cb, crash);
   crash->crash_fd.reset(sockfd);
   crash->crash_event = crash_event;
   event_add(crash_event, &timeout);
 }

 static void crash_request_cb(evutil_socket_t sockfd, short ev, void* arg) {
   ssize_t rc;
   Crash* crash = static_cast<Crash*>(arg);
   TombstonedCrashPacket request = {};

   if ((ev & EV_TIMEOUT) != 0) {
     LOG(WARNING) << "crash request timed out";
     goto fail;
   } else if ((ev & EV_READ) == 0) {
     LOG(WARNING) << "tombstoned received unexpected event from crash socket";
     goto fail;
   }

   rc = TEMP_FAILURE_RETRY(read(sockfd, &request, sizeof(request)));
   if (rc == -1) {
     PLOG(WARNING) << "failed to read from crash socket";
     goto fail;
   } else if (rc != sizeof(request)) {
     LOG(WARNING) << "crash socket received short read of length " << rc << " (expected "
                  << sizeof(request) << ")";
     goto fail;
   }

   if (request.packet_type != CrashPacketType::kDumpRequest) {
     LOG(WARNING) << "unexpected crash packet type, expected kDumpRequest, received  "
                  << StringPrintf("%#2hhX", request.packet_type);
     goto fail;
   }

   crash->crash_pid = request.packet.dump_request.pid;
   LOG(INFO) << "received crash request for pid " << crash->crash_pid;

   if (num_concurrent_dumps == kMaxConcurrentDumps) {
     LOG(INFO) << "enqueueing crash request for pid " << crash->crash_pid;
     queued_requests.push_back(crash);
   } else {
     dequeue_request(crash);
   }

   return;

 fail:
   delete crash;
 }

 static void crash_completed_cb(evutil_socket_t sockfd, short ev, void* arg) {
   ssize_t rc;
   Crash* crash = static_cast<Crash*>(arg);
   TombstonedCrashPacket request = {};

   --num_concurrent_dumps;

   if ((ev & EV_READ) == 0) {
     goto fail;
   }

   rc = TEMP_FAILURE_RETRY(read(sockfd, &request, sizeof(request)));
   if (rc == -1) {
     PLOG(WARNING) << "failed to read from crash socket";
     goto fail;
   } else if (rc != sizeof(request)) {
     LOG(WARNING) << "crash socket received short read of length " << rc << " (expected "
                  << sizeof(request) << ")";
     goto fail;
   }

   if (request.packet_type != CrashPacketType::kCompletedDump) {
     LOG(WARNING) << "unexpected crash packet type, expected kCompletedDump, received "
                  << uint32_t(request.packet_type);
     goto fail;
   }

 fail:
   delete crash;

   // If there's something queued up, let them proceed.
   if (!queued_requests.empty()) {
     Crash* next_crash = queued_requests.front();
     queued_requests.pop_front();
     dequeue_request(next_crash);
   }
 }

 int main(int, char* []) {
   tombstone_directory_fd = open(kTombstoneDirectory, O_DIRECTORY | O_RDONLY | O_CLOEXEC);
   if (tombstone_directory_fd == -1) {
     PLOG(FATAL) << "failed to open tombstone directory";
   }

   find_oldest_tombstone();

   int intercept_socket = android_get_control_socket(kTombstonedInterceptSocketName);
   int crash_socket = android_get_control_socket(kTombstonedCrashSocketName);

   if (intercept_socket == -1 || crash_socket == -1) {
     PLOG(FATAL) << "failed to get socket from init";
   }

   evutil_make_socket_nonblocking(intercept_socket);
   evutil_make_socket_nonblocking(crash_socket);

   event_base* base = event_base_new();
   if (!base) {
     LOG(FATAL) << "failed to create event_base";
   }

   intercept_manager = new InterceptManager(base, intercept_socket);

   evconnlistener* listener =
     evconnlistener_new(base, crash_accept_cb, nullptr, -1, LEV_OPT_CLOSE_ON_FREE, crash_socket);
   if (!listener) {
     LOG(FATAL) << "failed to create evconnlistener";
   }

   LOG(INFO) << "tombstoned successfully initialized";
   event_base_dispatch(base);
 }
	/*
	* 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 <fcntl.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <unistd.h>

	#include <array>
	#include <deque>
	#include <unordered_map>

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

	#include <android-base/logging.h>
	#include <android-base/stringprintf.h>
	#include <android-base/unique_fd.h>
	#include <cutils/sockets.h>

	#include "debuggerd/protocol.h"
	#include "debuggerd/util.h"

	#include "intercept_manager.h"

	using android::base::StringPrintf;
	using android::base::unique_fd;

	static InterceptManager* intercept_manager;

	enum CrashStatus {
	kCrashStatusRunning,
	kCrashStatusQueued,
	};

	// Ownership of Crash is a bit messy.
	// It's either owned by an active event that must have a timeout, or owned by
	// queued_requests, in the case that multiple crashes come in at the same time.
	struct Crash {
	~Crash() {
	event_free(crash_event);
	}

	unique_fd crash_fd;
	pid_t crash_pid;
	event* crash_event = nullptr;
	};

	static constexpr char kTombstoneDirectory[] = "/data/tombstones/";
	static constexpr size_t kTombstoneCount = 10;
	static int tombstone_directory_fd = -1;
	static int next_tombstone = 0;

	static constexpr size_t kMaxConcurrentDumps = 1;
	static size_t num_concurrent_dumps = 0;

	static std::deque<Crash*> queued_requests;

	// Forward declare the callbacks so they can be placed in a sensible order.
	static void crash_accept_cb(evconnlistener* listener, evutil_socket_t sockfd, sockaddr, int, void);
	static void crash_request_cb(evutil_socket_t sockfd, short ev, void* arg);
	static void crash_completed_cb(evutil_socket_t sockfd, short ev, void* arg);

	static void find_oldest_tombstone() {
	size_t oldest_tombstone = 0;
	time_t oldest_time = std::numeric_limits<time_t>::max();

	for (size_t i = 0; i < kTombstoneCount; ++i) {
	std::string path = android::base::StringPrintf("%stombstone_%02zu", kTombstoneDirectory, i);
	struct stat st;
	if (stat(path.c_str(), &st) != 0) {
	if (errno == ENOENT) {
	oldest_tombstone = i;
	break;
	} else {
	PLOG(ERROR) << "failed to stat " << path;
	continue;
	}
	}

	if (st.st_mtime < oldest_time) {
	oldest_tombstone = i;
	oldest_time = st.st_mtime;
	}
	}

	next_tombstone = oldest_tombstone;
	}

	static unique_fd get_tombstone_fd() {
	// If kMaxConcurrentDumps is greater than 1, then theoretically the same
	// filename could be handed out to multiple processes. Unlink and create the
	// file, instead of using O_TRUNC, to avoid two processes interleaving their
	// output.
	unique_fd result;
	char buf[PATH_MAX];
	snprintf(buf, sizeof(buf), "tombstone_%02d", next_tombstone);
	if (unlinkat(tombstone_directory_fd, buf, 0) != 0 && errno != ENOENT) {
	PLOG(FATAL) << "failed to unlink tombstone at " << kTombstoneDirectory << buf;
	}

	result.reset(
	openat(tombstone_directory_fd, buf, O_CREAT \| O_EXCL \| O_WRONLY \| O_APPEND \| O_CLOEXEC, 0700));
	if (result == -1) {
	PLOG(FATAL) << "failed to create tombstone at " << kTombstoneDirectory << buf;
	}

	next_tombstone = (next_tombstone + 1) % kTombstoneCount;
	return result;
	}

	static void dequeue_request(Crash* crash) {
	++num_concurrent_dumps;

	unique_fd output_fd;
	if (!intercept_manager->GetIntercept(crash->crash_pid, &output_fd)) {
	output_fd = get_tombstone_fd();
	}

	TombstonedCrashPacket response = {
	.packet_type = CrashPacketType::kPerformDump
	};
	ssize_t rc = send_fd(crash->crash_fd, &response, sizeof(response), std::move(output_fd));
	if (rc == -1) {
	PLOG(WARNING) << "failed to send response to CrashRequest";
	goto fail;
	} else if (rc != sizeof(response)) {
	PLOG(WARNING) << "crash socket write returned short";
	goto fail;
	} else {
	// TODO: Make this configurable by the interceptor?
	struct timeval timeout = { 10, 0 };

	event_base* base = event_get_base(crash->crash_event);
	event_assign(crash->crash_event, base, crash->crash_fd, EV_TIMEOUT \| EV_READ,
	crash_completed_cb, crash);
	event_add(crash->crash_event, &timeout);
	}
	return;

	fail:
	delete crash;
	}

	static void crash_accept_cb(evconnlistener* listener, evutil_socket_t sockfd, sockaddr*, int,
	void*) {
	event_base* base = evconnlistener_get_base(listener);
	Crash* crash = new Crash();

	struct timeval timeout = { 1, 0 };
	event* crash_event = event_new(base, sockfd, EV_TIMEOUT \| EV_READ, crash_request_cb, crash);
	crash->crash_fd.reset(sockfd);
	crash->crash_event = crash_event;
	event_add(crash_event, &timeout);
	}

	static void crash_request_cb(evutil_socket_t sockfd, short ev, void* arg) {
	ssize_t rc;
	Crash* crash = static_cast<Crash*>(arg);
	TombstonedCrashPacket request = {};

	if ((ev & EV_TIMEOUT) != 0) {
	LOG(WARNING) << "crash request timed out";
	goto fail;
	} else if ((ev & EV_READ) == 0) {
	LOG(WARNING) << "tombstoned received unexpected event from crash socket";
	goto fail;
	}

	rc = TEMP_FAILURE_RETRY(read(sockfd, &request, sizeof(request)));
	if (rc == -1) {
	PLOG(WARNING) << "failed to read from crash socket";
	goto fail;
	} else if (rc != sizeof(request)) {
	LOG(WARNING) << "crash socket received short read of length " << rc << " (expected "
	<< sizeof(request) << ")";
	goto fail;
	}

	if (request.packet_type != CrashPacketType::kDumpRequest) {
	LOG(WARNING) << "unexpected crash packet type, expected kDumpRequest, received "
	<< StringPrintf("%#2hhX", request.packet_type);
	goto fail;
	}

	crash->crash_pid = request.packet.dump_request.pid;
	LOG(INFO) << "received crash request for pid " << crash->crash_pid;

	if (num_concurrent_dumps == kMaxConcurrentDumps) {
	LOG(INFO) << "enqueueing crash request for pid " << crash->crash_pid;
	queued_requests.push_back(crash);
	} else {
	dequeue_request(crash);
	}

	return;

	fail:
	delete crash;
	}

	static void crash_completed_cb(evutil_socket_t sockfd, short ev, void* arg) {
	ssize_t rc;
	Crash* crash = static_cast<Crash*>(arg);
	TombstonedCrashPacket request = {};

	--num_concurrent_dumps;

	if ((ev & EV_READ) == 0) {
	goto fail;
	}

	rc = TEMP_FAILURE_RETRY(read(sockfd, &request, sizeof(request)));
	if (rc == -1) {
	PLOG(WARNING) << "failed to read from crash socket";
	goto fail;
	} else if (rc != sizeof(request)) {
	LOG(WARNING) << "crash socket received short read of length " << rc << " (expected "
	<< sizeof(request) << ")";
	goto fail;
	}

	if (request.packet_type != CrashPacketType::kCompletedDump) {
	LOG(WARNING) << "unexpected crash packet type, expected kCompletedDump, received "
	<< uint32_t(request.packet_type);
	goto fail;
	}

	fail:
	delete crash;

	// If there's something queued up, let them proceed.
	if (!queued_requests.empty()) {
	Crash* next_crash = queued_requests.front();
	queued_requests.pop_front();
	dequeue_request(next_crash);
	}
	}

	int main(int, char* []) {
	tombstone_directory_fd = open(kTombstoneDirectory, O_DIRECTORY \| O_RDONLY \| O_CLOEXEC);
	if (tombstone_directory_fd == -1) {
	PLOG(FATAL) << "failed to open tombstone directory";
	}

	find_oldest_tombstone();

	int intercept_socket = android_get_control_socket(kTombstonedInterceptSocketName);
	int crash_socket = android_get_control_socket(kTombstonedCrashSocketName);

	if (intercept_socket == -1 \|\| crash_socket == -1) {
	PLOG(FATAL) << "failed to get socket from init";
	}

	evutil_make_socket_nonblocking(intercept_socket);
	evutil_make_socket_nonblocking(crash_socket);

	event_base* base = event_base_new();
	if (!base) {
	LOG(FATAL) << "failed to create event_base";
	}

	intercept_manager = new InterceptManager(base, intercept_socket);

	evconnlistener* listener =
	evconnlistener_new(base, crash_accept_cb, nullptr, -1, LEV_OPT_CLOSE_ON_FREE, crash_socket);
	if (!listener) {
	LOG(FATAL) << "failed to create evconnlistener";
	}

	LOG(INFO) << "tombstoned successfully initialized";
	event_base_dispatch(base);
	}