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/**
* Copyright (C) 2017 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/db/update/path_creating_node.h"
#include "mongo/db/bson/dotted_path_support.h"
#include "mongo/db/update/path_support.h"
#include "mongo/db/update/storage_validation.h"
namespace mongo {
namespace {
/**
* Checks that no immutable paths were modified in the case where we are modifying an existing path
* in the document. 'element' should be the modified element. 'pathTaken' is the path to the
* modified element. If 'pathTaken' is a strict prefix of any immutable path, 'original' should be
* provided as the preimage of the whole document. We assume that we have already checked the update
* is not a noop.
*/
void checkImmutablePathsNotModified(mutablebson::Element element,
FieldRef* pathTaken,
const FieldRefSet& immutablePaths,
BSONObj original) {
for (auto immutablePath = immutablePaths.begin(); immutablePath != immutablePaths.end();
++immutablePath) {
auto prefixSize = pathTaken->commonPrefixSize(**immutablePath);
// If 'immutablePath' is a (strict or non-strict) prefix of 'pathTaken', and the update is
// not a noop, then we have modified 'immutablePath', which is immutable.
if (prefixSize == (*immutablePath)->numParts()) {
uasserted(ErrorCodes::ImmutableField,
str::stream() << "Updating the path '" << pathTaken->dottedField() << "' to "
<< element.toString()
<< " would modify the immutable field '"
<< (*immutablePath)->dottedField()
<< "'");
}
// If 'pathTaken' is a strict prefix of 'immutablePath', then we may have modified
// 'immutablePath'. We already know that 'pathTaken' is not equal to 'immutablePath', or we
// would have uasserted.
if (prefixSize == pathTaken->numParts()) {
auto oldElem = dotted_path_support::extractElementAtPath(
original, (*immutablePath)->dottedField());
// We are allowed to modify immutable paths that do not yet exist.
if (!oldElem.ok()) {
continue;
}
auto newElem = element;
for (size_t i = pathTaken->numParts(); i < (*immutablePath)->numParts(); ++i) {
uassert(ErrorCodes::NotSingleValueField,
str::stream()
<< "After applying the update to the document, the immutable field '"
<< (*immutablePath)->dottedField()
<< "' was found to be an array or array descendant.",
newElem.getType() != BSONType::Array);
newElem = newElem[(*immutablePath)->getPart(i)];
if (!newElem.ok()) {
break;
}
}
uassert(ErrorCodes::ImmutableField,
str::stream() << "After applying the update, the immutable field '"
<< (*immutablePath)->dottedField()
<< "' was found to have been removed.",
newElem.ok());
uassert(ErrorCodes::ImmutableField,
str::stream() << "After applying the update, the immutable field '"
<< (*immutablePath)->dottedField()
<< "' was found to have been altered to "
<< newElem.toString(),
newElem.compareWithBSONElement(oldElem, nullptr, false) == 0);
}
}
}
} // namespace
UpdateNode::ApplyResult PathCreatingNode::apply(ApplyParams applyParams) const {
if (context == Context::kInsertOnly && !applyParams.insert) {
return ApplyResult::noopResult();
}
// The value in this Element gets used to create a logging entry (if we have a LogBuilder).
mutablebson::Element valueToLog = applyParams.element.getDocument().end();
if (applyParams.pathToCreate->empty()) {
// If 'pathTaken' is a strict prefix of any immutable path, store the original document to
// ensure the immutable path does not change.
BSONObj original;
for (auto immutablePath = applyParams.immutablePaths.begin();
immutablePath != applyParams.immutablePaths.end();
++immutablePath) {
if (applyParams.pathTaken->isPrefixOf(**immutablePath)) {
original = applyParams.element.getDocument().getObject();
break;
}
}
// We found an existing element at the update path.
auto updateResult = updateExistingElement(
&applyParams.element, applyParams.pathTaken, applyParams.logBuilder);
if (updateResult == UpdateExistingElementResult::kNoOp) {
return ApplyResult::noopResult(); // Successful no-op update.
}
if (applyParams.validateForStorage) {
const bool doRecursiveCheck = true;
const uint32_t recursionLevel = applyParams.pathTaken->numParts();
storage_validation::storageValid(applyParams.element, doRecursiveCheck, recursionLevel);
}
checkImmutablePathsNotModified(
applyParams.element, applyParams.pathTaken.get(), applyParams.immutablePaths, original);
if (updateResult == UpdateExistingElementResult::kUpdated) {
valueToLog = applyParams.element;
} else {
// updateExistingElement() has already performed logging, so we don't set a log value.
}
} else {
// We did not find an element at the update path. Create one.
auto newElementFieldName =
applyParams.pathToCreate->getPart(applyParams.pathToCreate->numParts() - 1);
auto newElement = applyParams.element.getDocument().makeElementNull(newElementFieldName);
setValueForNewElement(&newElement);
invariant(newElement.ok());
auto statusWithFirstCreatedElem = pathsupport::createPathAt(
*(applyParams.pathToCreate), 0, applyParams.element, newElement);
if (!statusWithFirstCreatedElem.isOK()) {
// $sets on non-viable paths are ignored when the update came from replication. We do
// not error because idempotency requires that any other update modifiers must still be
// applied. For example, consider applying the following updates twice to an initially
// empty document:
// {$set: {c: 0}}
// {$set: {'a.b': 0, c: 1}}
// {$set: {a: 0}}
// Setting 'a.b' will fail the second time, but we must still set 'c'.
// (There are modifiers besides $set that use this code path, but they are not used for
// replication, so we are not concerned with their behavior when "fromReplication" is
// true.)
if (statusWithFirstCreatedElem.getStatus().code() == ErrorCodes::PathNotViable &&
applyParams.fromReplication) {
return ApplyResult::noopResult();
}
uassertStatusOK(statusWithFirstCreatedElem);
MONGO_UNREACHABLE; // The previous uassertStatusOK should always throw.
}
if (applyParams.validateForStorage) {
const bool doRecursiveCheck = true;
const uint32_t recursionLevel = applyParams.pathTaken->numParts() + 1;
storage_validation::storageValid(
statusWithFirstCreatedElem.getValue(), doRecursiveCheck, recursionLevel);
}
for (auto immutablePath = applyParams.immutablePaths.begin();
immutablePath != applyParams.immutablePaths.end();
++immutablePath) {
// If 'immutablePath' is a (strict or non-strict) prefix of 'pathTaken', then we are
// modifying 'immutablePath'. For example, adding '_id.x' will illegally modify '_id'.
uassert(ErrorCodes::ImmutableField,
str::stream() << "Updating the path '" << applyParams.pathTaken->dottedField()
<< "' to "
<< applyParams.element.toString()
<< " would modify the immutable field '"
<< (*immutablePath)->dottedField()
<< "'",
applyParams.pathTaken->commonPrefixSize(**immutablePath) !=
(*immutablePath)->numParts());
}
valueToLog = newElement;
}
// Create full field path of set element.
StringBuilder builder;
builder << applyParams.pathTaken->dottedField();
if (!applyParams.pathTaken->empty() && !applyParams.pathToCreate->empty()) {
builder << ".";
}
builder << applyParams.pathToCreate->dottedField();
auto fullPath = builder.str();
ApplyResult applyResult;
// Determine if indexes are affected.
if (!applyParams.indexData || !applyParams.indexData->mightBeIndexed(fullPath)) {
applyResult.indexesAffected = false;
}
// Log the operation.
if (applyParams.logBuilder && valueToLog.ok()) {
auto logElement =
applyParams.logBuilder->getDocument().makeElementWithNewFieldName(fullPath, valueToLog);
invariant(logElement.ok());
uassertStatusOK(applyParams.logBuilder->addToSets(logElement));
}
return applyResult;
}
} // namespace mongo
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