/**
 *    Copyright (C) 2009-2016 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::kCommand

#include "mongo/platform/basic.h"

#include "mongo/db/commands.h"

#include <string>
#include <vector>

#include "mongo/bson/mutable/document.h"
#include "mongo/bson/timestamp.h"
#include "mongo/db/audit.h"
#include "mongo/db/auth/action_set.h"
#include "mongo/db/auth/action_type.h"
#include "mongo/db/auth/authorization_manager.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/auth/privilege.h"
#include "mongo/db/client.h"
#include "mongo/db/curop.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/server_parameters.h"
#include "mongo/rpc/metadata.h"
#include "mongo/rpc/write_concern_error_detail.h"
#include "mongo/s/stale_exception.h"
#include "mongo/util/log.h"

namespace mongo {

using std::string;
using std::stringstream;

using logger::LogComponent;

Command::CommandMap* Command::_commandsByBestName;
Command::CommandMap* Command::_commands;

Counter64 Command::unknownCommands;
static ServerStatusMetricField<Counter64> displayUnknownCommands("commands.<UNKNOWN>",
                                                                 &Command::unknownCommands);

namespace {

ExportedServerParameter<bool, ServerParameterType::kStartupOnly> testCommandsParameter(
    ServerParameterSet::getGlobal(), "enableTestCommands", &Command::testCommandsEnabled);

}  // namespace

Command::~Command() = default;

string Command::parseNsFullyQualified(const string& dbname, const BSONObj& cmdObj) {
    BSONElement first = cmdObj.firstElement();
    uassert(ErrorCodes::BadValue,
            str::stream() << "collection name has invalid type " << typeName(first.type()),
            first.canonicalType() == canonicalizeBSONType(mongo::String));
    const NamespaceString nss(first.valueStringData());
    uassert(ErrorCodes::InvalidNamespace,
            str::stream() << "Invalid namespace specified '" << nss.ns() << "'",
            nss.isValid());
    return nss.ns();
}

NamespaceString Command::parseNsCollectionRequired(const string& dbname, const BSONObj& cmdObj) {
    // Accepts both BSON String and Symbol for collection name per SERVER-16260
    // TODO(kangas) remove Symbol support in MongoDB 3.0 after Ruby driver audit
    BSONElement first = cmdObj.firstElement();
    uassert(ErrorCodes::BadValue,
            str::stream() << "collection name has invalid type " << typeName(first.type()),
            first.canonicalType() == canonicalizeBSONType(mongo::String));
    const NamespaceString nss(dbname, first.valueStringData());
    uassert(ErrorCodes::InvalidNamespace,
            str::stream() << "Invalid namespace specified '" << nss.ns() << "'",
            nss.isValid());
    return nss;
}

string Command::parseNs(const string& dbname, const BSONObj& cmdObj) const {
    BSONElement first = cmdObj.firstElement();
    if (first.type() != mongo::String)
        return dbname;

    return str::stream() << dbname << '.' << cmdObj.firstElement().valueStringData();
}

ResourcePattern Command::parseResourcePattern(const std::string& dbname,
                                              const BSONObj& cmdObj) const {
    const std::string ns = parseNs(dbname, cmdObj);
    if (!NamespaceString::validCollectionComponent(ns)) {
        return ResourcePattern::forDatabaseName(ns);
    }
    return ResourcePattern::forExactNamespace(NamespaceString(ns));
}

Command::Command(StringData name, bool webUI, StringData oldName)
    : _name(name.toString()),
      _webUI(webUI),
      _commandsExecutedMetric("commands." + _name + ".total", &_commandsExecuted),
      _commandsFailedMetric("commands." + _name + ".failed", &_commandsFailed) {
    // register ourself.
    if (_commands == 0)
        _commands = new CommandMap();
    if (_commandsByBestName == 0)
        _commandsByBestName = new CommandMap();
    Command*& c = (*_commands)[name];
    if (c)
        log() << "warning: 2 commands with name: " << _name;
    c = this;
    (*_commandsByBestName)[name] = this;

    if (!oldName.empty())
        (*_commands)[oldName.toString()] = this;
}

void Command::help(stringstream& help) const {
    help << "no help defined";
}

Status Command::explain(OperationContext* opCtx,
                        const string& dbname,
                        const BSONObj& cmdObj,
                        ExplainOptions::Verbosity verbosity,
                        const rpc::ServerSelectionMetadata& serverSelectionMetadata,
                        BSONObjBuilder* out) const {
    return {ErrorCodes::IllegalOperation, str::stream() << "Cannot explain cmd: " << getName()};
}

Command* Command::findCommand(StringData name) {
    CommandMap::const_iterator i = _commands->find(name);
    if (i == _commands->end())
        return 0;
    return i->second;
}

bool Command::appendCommandStatus(BSONObjBuilder& result, const Status& status) {
    appendCommandStatus(result, status.isOK(), status.reason());
    BSONObj tmp = result.asTempObj();
    if (!status.isOK() && !tmp.hasField("code")) {
        result.append("code", status.code());
        result.append("codeName", ErrorCodes::errorString(status.code()));
    }
    return status.isOK();
}

void Command::appendCommandStatus(BSONObjBuilder& result, bool ok, const std::string& errmsg) {
    BSONObj tmp = result.asTempObj();
    bool have_ok = tmp.hasField("ok");
    bool need_errmsg = !ok && !tmp.hasField("errmsg");

    if (!have_ok)
        result.append("ok", ok ? 1.0 : 0.0);

    if (need_errmsg) {
        result.append("errmsg", errmsg);
    }
}

void Command::appendCommandWCStatus(BSONObjBuilder& result,
                                    const Status& awaitReplicationStatus,
                                    const WriteConcernResult& wcResult) {
    if (!awaitReplicationStatus.isOK() && !result.hasField("writeConcernError")) {
        WriteConcernErrorDetail wcError;
        wcError.setErrCode(awaitReplicationStatus.code());
        wcError.setErrMessage(awaitReplicationStatus.reason());
        if (wcResult.wTimedOut) {
            wcError.setErrInfo(BSON("wtimeout" << true));
        }
        result.append("writeConcernError", wcError.toBSON());
    }
}

void Command::appendOperationTime(BSONObjBuilder& result, LogicalTime operationTime) {
    result.append("operationTime", operationTime.asTimestamp());
}

Status Command::checkAuthForOperation(OperationContext* opCtx,
                                      const std::string& dbname,
                                      const BSONObj& cmdObj) {
    return checkAuthForCommand(opCtx->getClient(), dbname, cmdObj);
}

Status Command::checkAuthForCommand(Client* client,
                                    const std::string& dbname,
                                    const BSONObj& cmdObj) {
    std::vector<Privilege> privileges;
    this->addRequiredPrivileges(dbname, cmdObj, &privileges);
    if (AuthorizationSession::get(client)->isAuthorizedForPrivileges(privileges))
        return Status::OK();
    return Status(ErrorCodes::Unauthorized, "unauthorized");
}

void Command::redactForLogging(mutablebson::Document* cmdObj) {}

BSONObj Command::getRedactedCopyForLogging(const BSONObj& cmdObj) {
    namespace mmb = mutablebson;
    mmb::Document cmdToLog(cmdObj, mmb::Document::kInPlaceDisabled);
    redactForLogging(&cmdToLog);
    BSONObjBuilder bob;
    cmdToLog.writeTo(&bob);
    return bob.obj();
}

static Status _checkAuthorizationImpl(Command* c,
                                      OperationContext* opCtx,
                                      const std::string& dbname,
                                      const BSONObj& cmdObj) {
    namespace mmb = mutablebson;
    auto client = opCtx->getClient();
    if (c->adminOnly() && dbname != "admin") {
        return Status(ErrorCodes::Unauthorized,
                      str::stream() << c->getName()
                                    << " may only be run against the admin database.");
    }
    if (AuthorizationSession::get(client)->getAuthorizationManager().isAuthEnabled()) {
        Status status = c->checkAuthForOperation(opCtx, dbname, cmdObj);
        if (status == ErrorCodes::Unauthorized) {
            mmb::Document cmdToLog(cmdObj, mmb::Document::kInPlaceDisabled);
            c->redactForLogging(&cmdToLog);
            return Status(ErrorCodes::Unauthorized,
                          str::stream() << "not authorized on " << dbname << " to execute command "
                                        << cmdToLog.toString());
        }
        if (!status.isOK()) {
            return status;
        }
    } else if (c->adminOnly() && c->localHostOnlyIfNoAuth(cmdObj) &&
               !client->getIsLocalHostConnection()) {
        return Status(ErrorCodes::Unauthorized,
                      str::stream() << c->getName()
                                    << " must run from localhost when running db without auth");
    }
    return Status::OK();
}

Status Command::checkAuthorization(Command* c,
                                   OperationContext* opCtx,
                                   const std::string& dbname,
                                   const BSONObj& cmdObj) {
    namespace mmb = mutablebson;
    Status status = _checkAuthorizationImpl(c, opCtx, dbname, cmdObj);
    if (!status.isOK()) {
        log(LogComponent::kAccessControl) << status;
    }
    audit::logCommandAuthzCheck(opCtx->getClient(), dbname, cmdObj, c, status.code());
    return status;
}

bool Command::isHelpRequest(const BSONElement& helpElem) {
    return !helpElem.eoo() && helpElem.trueValue();
}

const char Command::kHelpFieldName[] = "help";

void Command::generateHelpResponse(OperationContext* opCtx,
                                   const rpc::RequestInterface& request,
                                   rpc::ReplyBuilderInterface* replyBuilder,
                                   const Command& command) {
    std::stringstream ss;
    BSONObjBuilder helpBuilder;
    ss << "help for: " << command.getName() << " ";
    command.help(ss);
    helpBuilder.append("help", ss.str());

    replyBuilder->setCommandReply(helpBuilder.done());
    replyBuilder->setMetadata(rpc::makeEmptyMetadata());
}

namespace {

void _generateErrorResponse(OperationContext* opCtx,
                            rpc::ReplyBuilderInterface* replyBuilder,
                            const DBException& exception,
                            const BSONObj& metadata) {
    Command::registerError(opCtx, exception);

    // We could have thrown an exception after setting fields in the builder,
    // so we need to reset it to a clean state just to be sure.
    replyBuilder->reset();

    // We need to include some extra information for SendStaleConfig.
    if (exception.getCode() == ErrorCodes::SendStaleConfig) {
        const SendStaleConfigException& scex =
            static_cast<const SendStaleConfigException&>(exception);
        replyBuilder->setCommandReply(scex.toStatus(),
                                      BSON("ns" << scex.getns() << "vReceived"
                                                << BSONArray(scex.getVersionReceived().toBSON())
                                                << "vWanted"
                                                << BSONArray(scex.getVersionWanted().toBSON())));
    } else {
        replyBuilder->setCommandReply(exception.toStatus());
    }

    replyBuilder->setMetadata(metadata);
}

void _generateErrorResponse(OperationContext* opCtx,
                            rpc::ReplyBuilderInterface* replyBuilder,
                            const DBException& exception,
                            const BSONObj& metadata,
                            LogicalTime operationTime) {
    Command::registerError(opCtx, exception);

    // We could have thrown an exception after setting fields in the builder,
    // so we need to reset it to a clean state just to be sure.
    replyBuilder->reset();

    // We need to include some extra information for SendStaleConfig.
    if (exception.getCode() == ErrorCodes::SendStaleConfig) {
        const SendStaleConfigException& scex =
            static_cast<const SendStaleConfigException&>(exception);
        replyBuilder->setCommandReply(scex.toStatus(),
                                      BSON("ns" << scex.getns() << "vReceived"
                                                << BSONArray(scex.getVersionReceived().toBSON())
                                                << "vWanted"
                                                << BSONArray(scex.getVersionWanted().toBSON())
                                                << "operationTime"
                                                << operationTime.asTimestamp()));
    } else {
        replyBuilder->setCommandReply(exception.toStatus(),
                                      BSON("operationTime" << operationTime.asTimestamp()));
    }

    replyBuilder->setMetadata(metadata);
}

}  // namespace

void Command::generateErrorResponse(OperationContext* opCtx,
                                    rpc::ReplyBuilderInterface* replyBuilder,
                                    const DBException& exception,
                                    const rpc::RequestInterface& request,
                                    Command* command,
                                    const BSONObj& metadata,
                                    LogicalTime operationTime) {
    LOG(1) << "assertion while executing command '" << request.getCommandName() << "' "
           << "on database '" << request.getDatabase() << "' "
           << "with arguments '" << command->getRedactedCopyForLogging(request.getCommandArgs())
           << "' metadata '" << request.getMetadata() << "' and operationTime '"
           << operationTime.toString() << "': " << exception.toString();

    _generateErrorResponse(opCtx, replyBuilder, exception, metadata, operationTime);
}

void Command::generateErrorResponse(OperationContext* opCtx,
                                    rpc::ReplyBuilderInterface* replyBuilder,
                                    const DBException& exception,
                                    const rpc::RequestInterface& request,
                                    Command* command,
                                    const BSONObj& metadata) {
    LOG(1) << "assertion while executing command '" << request.getCommandName() << "' "
           << "on database '" << request.getDatabase() << "' "
           << "with arguments '" << command->getRedactedCopyForLogging(request.getCommandArgs())
           << "' "
           << "and metadata '" << request.getMetadata() << "': " << exception.toString();

    _generateErrorResponse(opCtx, replyBuilder, exception, metadata);
}

void Command::generateErrorResponse(OperationContext* opCtx,
                                    rpc::ReplyBuilderInterface* replyBuilder,
                                    const DBException& exception,
                                    const rpc::RequestInterface& request) {
    LOG(1) << "assertion while executing command '" << request.getCommandName() << "' "
           << "on database '" << request.getDatabase() << "': " << exception.toString();

    _generateErrorResponse(opCtx, replyBuilder, exception, rpc::makeEmptyMetadata());
}

void Command::generateErrorResponse(OperationContext* opCtx,
                                    rpc::ReplyBuilderInterface* replyBuilder,
                                    const DBException& exception) {
    LOG(1) << "assertion while executing command: " << exception.toString();
    _generateErrorResponse(opCtx, replyBuilder, exception, rpc::makeEmptyMetadata());
}

namespace {
const stdx::unordered_set<std::string> userManagementCommands{"createUser",
                                                              "updateUser",
                                                              "dropUser",
                                                              "dropAllUsersFromDatabase",
                                                              "grantRolesToUser",
                                                              "revokeRolesFromUser",
                                                              "createRole",
                                                              "updateRole",
                                                              "dropRole",
                                                              "dropAllRolesFromDatabase",
                                                              "grantPrivilegesToRole",
                                                              "revokePrivilegesFromRole",
                                                              "grantRolesToRole",
                                                              "revokeRolesFromRole",
                                                              "_mergeAuthzCollections",
                                                              "authSchemaUpgrade"};
}  // namespace

bool Command::isUserManagementCommand(const std::string& name) {
    return userManagementCommands.count(name);
}

namespace {
stdx::function<void(OperationContext*, const DBException&)> registeredRegisterErrorHandler =
    [](OperationContext*, const DBException&) { fassertFailed(40357); };
}  // namespace

void Command::registerRegisterError(
    stdx::function<void(OperationContext*, const DBException&)> handler) {
    registeredRegisterErrorHandler = std::move(handler);
}

void Command::registerError(OperationContext* const opCtx, const DBException& exception) {
    registeredRegisterErrorHandler(opCtx, exception);
}

namespace {
stdx::function<Command::ExecCommandHandler> execCommandHandler =
    [](OperationContext* const,
       Command* const,
       const rpc::RequestInterface&,
       rpc::ReplyBuilderInterface* const) { invariant(false); };
}  // namespace

void Command::execCommand(OperationContext* const opCtx,
                          Command* const command,
                          const rpc::RequestInterface& request,
                          rpc::ReplyBuilderInterface* const replyBuilder) {
    execCommandHandler(opCtx, command, request, replyBuilder);
}

void Command::registerExecCommand(stdx::function<Command::ExecCommandHandler> handler) {
    execCommandHandler = std::move(handler);
}
}  // namespace mongo