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/**
* Copyright (C) 2016 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kNetwork
#include "mongo/platform/basic.h"
#include "mongo/db/service_entry_point_mongod.h"
#include <vector>
#include "mongo/db/client.h"
#include "mongo/db/dbmessage.h"
#include "mongo/db/instance.h"
#include "mongo/stdx/thread.h"
#include "mongo/transport/service_entry_point_utils.h"
#include "mongo/transport/session.h"
#include "mongo/transport/ticket.h"
#include "mongo/transport/transport_layer.h"
#include "mongo/util/concurrency/idle_thread_block.h"
#include "mongo/util/exit.h"
#include "mongo/util/log.h"
#include "mongo/util/net/message.h"
#include "mongo/util/net/socket_exception.h"
#include "mongo/util/net/thread_idle_callback.h"
#include "mongo/util/quick_exit.h"
#include "mongo/util/scopeguard.h"
namespace mongo {
namespace {
// Set up proper headers for formatting an exhaust request, if we need to
bool setExhaustMessage(Message* m, const DbResponse& dbresponse) {
MsgData::View header = dbresponse.response.header();
QueryResult::View qr = header.view2ptr();
long long cursorid = qr.getCursorId();
if (!cursorid) {
return false;
}
verify(dbresponse.exhaustNS.size() && dbresponse.exhaustNS[0]);
auto ns = dbresponse.exhaustNS; // reset() will free this
m->reset();
BufBuilder b(512);
b.appendNum(static_cast<int>(0) /* size set later in appendData() */);
b.appendNum(header.getId());
b.appendNum(header.getResponseToMsgId());
b.appendNum(static_cast<int>(dbGetMore));
b.appendNum(static_cast<int>(0));
b.appendStr(ns);
b.appendNum(static_cast<int>(0)); // ntoreturn
b.appendNum(cursorid);
MsgData::View(b.buf()).setLen(b.len());
m->setData(b.release());
return true;
}
} // namespace
using transport::Session;
using transport::TransportLayer;
ServiceEntryPointMongod::ServiceEntryPointMongod(TransportLayer* tl) : _tl(tl) {}
void ServiceEntryPointMongod::startSession(transport::SessionHandle session) {
// Pass ownership of the transport::SessionHandle into our worker thread. When this
// thread exits, the session will end.
launchWrappedServiceEntryWorkerThread(
std::move(session), [this](const transport::SessionHandle& session) {
_nWorkers.fetchAndAdd(1);
auto guard = MakeGuard([&] { _nWorkers.fetchAndSubtract(1); });
_sessionLoop(session);
});
}
void ServiceEntryPointMongod::_sessionLoop(const transport::SessionHandle& session) {
Message inMessage;
bool inExhaust = false;
int64_t counter = 0;
while (true) {
// 1. Source a Message from the client (unless we are exhausting)
if (!inExhaust) {
inMessage.reset();
auto status = [&] {
MONGO_IDLE_THREAD_BLOCK;
return session->sourceMessage(&inMessage).wait();
}();
if (ErrorCodes::isInterruption(status.code()) ||
ErrorCodes::isNetworkError(status.code())) {
break;
}
// Our session may have been closed internally.
if (status == TransportLayer::TicketSessionClosedStatus) {
break;
}
uassertStatusOK(status);
}
// 2. Pass sourced Message up to mongod
DbResponse dbresponse;
{
auto opCtx = cc().makeOperationContext();
assembleResponse(opCtx.get(), inMessage, dbresponse, session->remote());
// opCtx must go out of scope here so that the operation cannot show
// up in currentOp results after the response reaches the client
}
// 3. Format our response, if we have one
Message& toSink = dbresponse.response;
if (!toSink.empty()) {
toSink.header().setId(nextMessageId());
toSink.header().setResponseToMsgId(inMessage.header().getId());
// If this is an exhaust cursor, don't source more Messages
if (dbresponse.exhaustNS.size() > 0 && setExhaustMessage(&inMessage, dbresponse)) {
inExhaust = true;
} else {
inExhaust = false;
}
// 4. Sink our response to the client
uassertStatusOK(session->sinkMessage(toSink).wait());
} else {
inExhaust = false;
}
if ((counter++ & 0xf) == 0) {
markThreadIdle();
}
}
}
} // namespace mongo
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