/* commands.cpp
   db "commands" (sent via db.$cmd.findOne(...))
 */

/*    Copyright 2009 10gen 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/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/get_status_from_command_result.h"
#include "mongo/rpc/metadata.h"
#include "mongo/s/stale_exception.h"
#include "mongo/s/write_ops/wc_error_detail.h"
#include "mongo/util/log.h"

namespace mongo {

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

using logger::LogComponent;

Command::CommandMap* Command::_commandsByBestName;
Command::CommandMap* Command::_webCommands;
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);
}

Command::~Command() = default;

string Command::parseNsFullyQualified(const string& dbname, const BSONObj& cmdObj) const {
    BSONElement first = cmdObj.firstElement();
    uassert(17005,
            mongoutils::str::stream()
                << "Main argument to " << first.fieldNameStringData()
                << " must be a fully qualified namespace string.  Found: " << first.toString(false),
            first.type() == mongo::String &&
                NamespaceString::validCollectionComponent(first.valuestr()));
    return first.String();
}

string Command::parseNsCollectionRequired(const string& dbname, const BSONObj& cmdObj) const {
    // 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(17009,
            "no collection name specified",
            first.canonicalType() == canonicalizeBSONType(mongo::String) &&
                first.valuestrsize() > 0);
    std::string coll = first.valuestr();
    return dbname + '.' + coll;
}

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

    string coll = cmdObj.firstElement().valuestr();
#if defined(CLC)
    DEV if (mongoutils::str::startsWith(coll, dbname + '.')) {
        log() << "DEBUG parseNs Command's collection name looks like it includes the db name\n"
              << dbname << '\n' << coll << '\n' << cmdObj.toString() << endl;
        dassert(false);
    }
#endif
    return dbname + '.' + coll;
}

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

void Command::htmlHelp(stringstream& ss) const {
    string helpStr;
    {
        stringstream h;
        help(h);
        helpStr = h.str();
    }
    ss << "\n<tr><td>";
    bool web = _webCommands->find(name) != _webCommands->end();
    if (web)
        ss << "<a href=\"/" << name << "?text=1\">";
    ss << name;
    if (web)
        ss << "</a>";
    ss << "</td>\n";
    ss << "<td>";
    if (isWriteCommandForConfigServer()) {
        ss << "W ";
    } else {
        ss << "R ";
    }
    if (slaveOk())
        ss << "S ";
    if (adminOnly())
        ss << "A";
    ss << "</td>";
    ss << "<td>";
    if (helpStr != "no help defined") {
        const char* p = helpStr.c_str();
        while (*p) {
            if (*p == '<') {
                ss << "&lt;";
                p++;
                continue;
            } else if (*p == '{')
                ss << "<code>";
            else if (*p == '}') {
                ss << "}</code>";
                p++;
                continue;
            }
            if (strncmp(p, "http:", 5) == 0) {
                ss << "<a href=\"";
                const char* q = p;
                while (*q && *q != ' ' && *q != '\n')
                    ss << *q++;
                ss << "\">";
                q = p;
                if (str::startsWith(q, "http://www.mongodb.org/display/"))
                    q += 31;
                while (*q && *q != ' ' && *q != '\n') {
                    ss << (*q == '+' ? ' ' : *q);
                    q++;
                    if (*q == '#')
                        while (*q && *q != ' ' && *q != '\n')
                            q++;
                }
                ss << "</a>";
                p = q;
                continue;
            }
            if (*p == '\n')
                ss << "<br>";
            else
                ss << *p;
            p++;
        }
    }
    ss << "</td>";
    ss << "</tr>\n";
}

Command::Command(StringData _name, bool web, StringData oldName)
    : name(_name.toString()),
      _commandsExecutedMetric("commands." + _name.toString() + ".total", &_commandsExecuted),
      _commandsFailedMetric("commands." + _name.toString() + ".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 << endl;
    c = this;
    (*_commandsByBestName)[name] = this;

    if (web) {
        if (_webCommands == 0)
            _webCommands = new CommandMap();
        (*_webCommands)[name] = this;
    }

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

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

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());
    }
    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 have_errmsg = tmp.hasField("errmsg");

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

    if (!ok && !have_errmsg) {
        result.append("errmsg", errmsg);
    }
}

void Command::appendCommandWCStatus(BSONObjBuilder& result, const Status& status) {
    if (!status.isOK()) {
        WCErrorDetail wcError;
        wcError.setErrCode(status.code());
        wcError.setErrMessage(status.reason());
        result.append("writeConcernError", wcError.toBSON());
    }
}

Status Command::getStatusFromCommandResult(const BSONObj& result) {
    return mongo::getStatusFromCommandResult(result);
}

Status Command::parseCommandCursorOptions(const BSONObj& cmdObj,
                                          long long defaultBatchSize,
                                          long long* batchSize) {
    invariant(batchSize);
    *batchSize = defaultBatchSize;

    BSONElement cursorElem = cmdObj["cursor"];
    if (cursorElem.eoo()) {
        return Status::OK();
    }

    if (cursorElem.type() != mongo::Object) {
        return Status(ErrorCodes::TypeMismatch, "cursor field must be missing or an object");
    }

    BSONObj cursor = cursorElem.embeddedObject();
    BSONElement batchSizeElem = cursor["batchSize"];

    const int expectedNumberOfCursorFields = batchSizeElem.eoo() ? 0 : 1;
    if (cursor.nFields() != expectedNumberOfCursorFields) {
        return Status(ErrorCodes::BadValue,
                      "cursor object can't contain fields other than batchSize");
    }

    if (batchSizeElem.eoo()) {
        return Status::OK();
    }

    if (!batchSizeElem.isNumber()) {
        return Status(ErrorCodes::TypeMismatch, "cursor.batchSize must be a number");
    }

    // This can change in the future, but for now all negatives are reserved.
    if (batchSizeElem.numberLong() < 0) {
        return Status(ErrorCodes::BadValue, "cursor.batchSize must not be negative");
    }

    *batchSize = batchSizeElem.numberLong();

    return Status::OK();
}

Status Command::checkAuthForCommand(ClientBasic* 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();
}

void Command::logIfSlow(const Timer& timer, const string& msg) {
    int ms = timer.millis();
    if (ms > serverGlobalParams.slowMS) {
        log() << msg << " took " << ms << " ms." << endl;
    }
}

static Status _checkAuthorizationImpl(Command* c,
                                      ClientBasic* client,
                                      const std::string& dbname,
                                      const BSONObj& cmdObj) {
    namespace mmb = mutablebson;
    if (c->adminOnly() && dbname != "admin") {
        return Status(ErrorCodes::Unauthorized,
                      str::stream() << c->name << " may only be run against the admin database.");
    }
    if (AuthorizationSession::get(client)->getAuthorizationManager().isAuthEnabled()) {
        Status status = c->checkAuthForCommand(client, 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->name
                                    << " must run from localhost when running db without auth");
    }
    return Status::OK();
}

Status Command::_checkAuthorization(Command* c,
                                    ClientBasic* client,
                                    const std::string& dbname,
                                    const BSONObj& cmdObj) {
    namespace mmb = mutablebson;
    Status status = _checkAuthorizationImpl(c, client, dbname, cmdObj);
    if (!status.isOK()) {
        log(LogComponent::kAccessControl) << status << std::endl;
    }
    audit::logCommandAuthzCheck(client, 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* txn,
                                   const rpc::RequestInterface& request,
                                   rpc::ReplyBuilderInterface* replyBuilder,
                                   const Command& command) {
    std::stringstream ss;
    BSONObjBuilder helpBuilder;
    ss << "help for: " << command.name << " ";
    command.help(ss);
    helpBuilder.append("help", ss.str());
    helpBuilder.append("lockType", command.isWriteCommandForConfigServer() ? 1 : 0);

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

namespace {

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

}  // namespace

void Command::generateErrorResponse(OperationContext* txn,
                                    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(txn, replyBuilder, exception, metadata);
}

void Command::generateErrorResponse(OperationContext* txn,
                                    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(txn, replyBuilder, exception, rpc::makeEmptyMetadata());
}

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

void runCommands(OperationContext* txn,
                 const rpc::RequestInterface& request,
                 rpc::ReplyBuilderInterface* replyBuilder) {
    try {
        dassert(replyBuilder->getState() == rpc::ReplyBuilderInterface::State::kCommandReply);

        Command* c = nullptr;
        // In the absence of a Command object, no redaction is possible. Therefore
        // to avoid displaying potentially sensitive information in the logs,
        // we restrict the log message to the name of the unrecognized command.
        // However, the complete command object will still be echoed to the client.
        if (!(c = Command::findCommand(request.getCommandName()))) {
            Command::unknownCommands.increment();
            std::string msg = str::stream() << "no such command: '" << request.getCommandName()
                                            << "'";
            LOG(2) << msg;
            uasserted(ErrorCodes::CommandNotFound,
                      str::stream() << msg << ", bad cmd: '" << request.getCommandArgs() << "'");
        }

        LOG(2) << "run command " << request.getDatabase() << ".$cmd" << ' '
               << c->getRedactedCopyForLogging(request.getCommandArgs());

        {
            // Try to set this as early as possible, as soon as we have figured out the command.
            stdx::lock_guard<Client> lk(*txn->getClient());
            CurOp::get(txn)->setLogicalOp_inlock(c->getLogicalOp());
        }

        Command::execCommand(txn, c, request, replyBuilder);
    }

    catch (const DBException& ex) {
        Command::generateErrorResponse(txn, replyBuilder, ex, request);
    }
}

}  // namespace mongo