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/**
* Copyright (C) 2015 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.
*/
#include "mongo/platform/basic.h"
#include "mongo/base/disallow_copying.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/cursor_manager.h"
#include "mongo/db/commands/killcursors_common.h"
#include "mongo/db/curop.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/query/killcursors_request.h"
#include "mongo/db/stats/top.h"
#include "mongo/util/scopeguard.h"
namespace mongo {
class KillCursorsCmd final : public KillCursorsCmdBase {
MONGO_DISALLOW_COPYING(KillCursorsCmd);
public:
KillCursorsCmd() = default;
private:
Status _killCursor(OperationContext* opCtx,
const NamespaceString& nss,
CursorId cursorId) final {
// Cursors come in one of two flavors:
// - Cursors owned by the collection cursor manager, such as those generated via the find
// command. For these cursors, we hold the appropriate collection lock for the duration of
// the getMore using AutoGetCollectionForRead. This will automatically update the CurOp
// object appropriately and record execution time via Top upon completion.
// - Cursors owned by the global cursor manager, such as those generated via the aggregate
// command. These cursors either hold no collection state or manage their collection state
// internally, so we acquire no locks. In this case we use the AutoStatsTracker object to
// update the CurOp object appropriately and record execution time via Top upon
// completion.
//
// Thus, exactly one of 'readLock' and 'statsTracker' will be populated as we populate
// 'cursorManager'.
boost::optional<AutoGetCollectionForReadCommand> readLock;
boost::optional<AutoStatsTracker> statsTracker;
CursorManager* cursorManager;
if (CursorManager::isGloballyManagedCursor(cursorId)) {
cursorManager = CursorManager::getGlobalCursorManager();
if (auto nssForCurOp = nss.isGloballyManagedNamespace()
? nss.getTargetNSForGloballyManagedNamespace()
: nss) {
const boost::optional<int> dbProfilingLevel = boost::none;
statsTracker.emplace(
opCtx, *nssForCurOp, Top::LockType::NotLocked, dbProfilingLevel);
}
// Make sure the namespace of the cursor matches the namespace passed to the killCursors
// command so we can be sure we checked the correct privileges.
auto ccPin = cursorManager->pinCursor(opCtx, cursorId);
if (ccPin.isOK()) {
auto cursorNs = ccPin.getValue().getCursor()->nss();
if (cursorNs != nss) {
return Status{ErrorCodes::Unauthorized,
str::stream() << "issued killCursors on namespace '" << nss.ns()
<< "', but cursor with id "
<< cursorId
<< " belongs to a different namespace: "
<< cursorNs.ns()};
}
}
} else {
readLock.emplace(opCtx, nss);
Collection* collection = readLock->getCollection();
if (!collection) {
return {ErrorCodes::CursorNotFound,
str::stream() << "collection does not exist: " << nss.ns()};
}
cursorManager = collection->getCursorManager();
}
invariant(cursorManager);
return cursorManager->eraseCursor(opCtx, cursorId, true /*shouldAudit*/);
}
} killCursorsCmd;
} // namespace mongo
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