/*
* InspIRCd -- Internet Relay Chat Daemon
*
* Copyright (C) 2019 linuxdaemon <linuxdaemon.irc@gmail.com>
* Copyright (C) 2016 Adam <Adam@anope.org>
* Copyright (C) 2015 Daniel Vassdal <shutter@canternet.org>
* Copyright (C) 2013-2014 Attila Molnar <attilamolnar@hush.com>
* Copyright (C) 2013, 2016-2021 Sadie Powell <sadie@witchery.services>
* Copyright (C) 2012 Robby <robby@chatbelgie.be>
* Copyright (C) 2012 ChrisTX <xpipe@hotmail.de>
* Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
* Copyright (C) 2009 Uli Schlachter <psychon@inspircd.org>
* Copyright (C) 2007, 2009 Dennis Friis <peavey@inspircd.org>
* Copyright (C) 2005, 2008-2010 Craig Edwards <brain@inspircd.org>
*
* This file is part of InspIRCd. InspIRCd is free software: you can
* redistribute it and/or modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation, version 2.
*
* 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 General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/// $CompilerFlags: execute("mysql_config --include" "MYSQL_CXXFLAGS")
/// $LinkerFlags: execute("mysql_config --libs_r" "MYSQL_LDFLAGS" "-lmysqlclient")
/// $PackageInfo: require_system("arch") mariadb-libs
/// $PackageInfo: require_system("centos" "6.0" "6.99") mysql-devel
/// $PackageInfo: require_system("centos" "7.0") mariadb-devel
/// $PackageInfo: require_system("darwin") mysql-connector-c
/// $PackageInfo: require_system("debian") libmysqlclient-dev
/// $PackageInfo: require_system("ubuntu") libmysqlclient-dev
#include "inspircd.h"
#include "threadsocket.h"
#include "modules/sql.h"
// Needs to be included after inspircd.h to avoid reincluding winsock.
#include <mysql.h>
#ifdef _WIN32
# pragma comment(lib, "mysqlclient.lib")
#endif
/* VERSION 3 API: With nonblocking (threaded) requests */
/* THE NONBLOCKING MYSQL API!
*
* MySQL provides no nonblocking (asynchronous) API of its own, and its developers recommend
* that instead, you should thread your program. This is what i've done here to allow for
* asynchronous SQL requests via mysql. The way this works is as follows:
*
* The module spawns a thread via class Thread, and performs its mysql queries in this thread,
* using a queue with priorities. There is a mutex on either end which prevents two threads
* adjusting the queue at the same time, and crashing the ircd. Every 50 milliseconds, the
* worker thread wakes up, and checks if there is a request at the head of its queue.
* If there is, it processes this request, blocking the worker thread but leaving the ircd
* thread to go about its business as usual. During this period, the ircd thread is able
* to insert further pending requests into the queue.
*
* Once the processing of a request is complete, it is removed from the incoming queue to
* an outgoing queue, and initialized as a 'response'. The worker thread then signals the
* ircd thread (via a loopback socket) of the fact a result is available, by sending the
* connection ID through the connection.
*
* The ircd thread then mutexes the queue once more, reads the outbound response off the head
* of the queue, and sends it on its way to the original calling module.
*
* XXX: You might be asking "why doesnt it just send the response from within the worker thread?"
* The answer to this is simple. The majority of InspIRCd, and in fact most ircd's are not
* threadsafe. This module is designed to be threadsafe and is careful with its use of threads,
* however, if we were to call a module's OnRequest even from within a thread which was not the
* one the module was originally instantiated upon, there is a chance of all hell breaking loose
* if a module is ever put in a reentrant state (stack corruption could occur, crashes, data
* corruption, and worse, so DONT think about it until the day comes when InspIRCd is 100%
* guaranteed threadsafe!)
*/
class SQLConnection;
class MySQLresult;
class DispatcherThread;
struct QueryQueueItem final
{
// An SQL database which this query is executed on.
SQLConnection* connection;
// An object which handles the result of the query.
SQL::Query* query;
// The SQL query which is to be executed.
std::string querystr;
QueryQueueItem(SQL::Query* q, const std::string& s, SQLConnection* c)
: connection(c)
, query(q)
, querystr(s)
{
}
};
struct ResultQueueItem final
{
// An object which handles the result of the query.
SQL::Query* query;
// The result returned from executing the MySQL query.
MySQLresult* result;
ResultQueueItem(SQL::Query* q, MySQLresult* r)
: query(q)
, result(r)
{
}
};
typedef insp::flat_map<std::string, SQLConnection*> ConnMap;
typedef std::deque<QueryQueueItem> QueryQueue;
typedef std::deque<ResultQueueItem> ResultQueue;
/** MySQL module
* */
class ModuleSQL final
: public Module
{
public:
DispatcherThread* Dispatcher = nullptr;
QueryQueue qq; // MUST HOLD MUTEX
ResultQueue rq; // MUST HOLD MUTEX
ConnMap connections; // main thread only
void init() override;
ModuleSQL();
~ModuleSQL() override;
void ReadConfig(ConfigStatus& status) override;
void OnUnloadModule(Module* mod) override;
};
class DispatcherThread final
: public SocketThread
{
private:
ModuleSQL* const Parent;
public:
DispatcherThread(ModuleSQL* CreatorModule) : Parent(CreatorModule) { }
void OnStart() override;
void OnNotify() override;
};
/** Represents a mysql result set
*/
class MySQLresult final
: public SQL::Result
{
public:
SQL::Error err;
int currentrow = 0;
int rows = 0;
std::vector<std::string> colnames;
std::vector<SQL::Row> fieldlists;
MySQLresult(MYSQL_RES* res, unsigned long affected_rows)
: err(SQL::SUCCESS)
{
if (affected_rows >= 1)
{
rows = int(affected_rows);
fieldlists.resize(rows);
}
unsigned int field_count = 0;
if (res)
{
MYSQL_ROW row;
int n = 0;
while ((row = mysql_fetch_row(res)))
{
if (fieldlists.size() < (size_t)rows+1)
{
fieldlists.resize(fieldlists.size()+1);
}
field_count = 0;
MYSQL_FIELD *fields = mysql_fetch_fields(res);
if(mysql_num_fields(res) == 0)
break;
if (fields && mysql_num_fields(res))
{
colnames.clear();
while (field_count < mysql_num_fields(res))
{
std::string a = (fields[field_count].name ? fields[field_count].name : "");
if (row[field_count])
fieldlists[n].emplace_back(row[field_count]);
else
fieldlists[n].emplace_back();
colnames.push_back(a);
field_count++;
}
n++;
}
rows++;
}
mysql_free_result(res);
}
}
MySQLresult(SQL::Error& e)
: err(e)
{
}
int Rows() override
{
return rows;
}
void GetCols(std::vector<std::string>& result) override
{
result.assign(colnames.begin(), colnames.end());
}
bool HasColumn(const std::string& column, size_t& index) override
{
for (size_t i = 0; i < colnames.size(); ++i)
{
if (colnames[i] == column)
{
index = i;
return true;
}
}
return false;
}
SQL::Field GetValue(int row, int column)
{
if ((row >= 0) && (row < rows) && (column >= 0) && (column < (int)fieldlists[row].size()))
{
return fieldlists[row][column];
}
return std::nullopt;
}
bool GetRow(SQL::Row& result) override
{
if (currentrow < rows)
{
result.assign(fieldlists[currentrow].begin(), fieldlists[currentrow].end());
currentrow++;
return true;
}
else
{
result.clear();
return false;
}
}
};
/** Represents a connection to a mysql database
*/
class SQLConnection final
: public SQL::Provider
{
private:
bool EscapeString(SQL::Query* query, const std::string& in, std::string& out)
{
// In the worst case each character may need to be encoded as using two bytes and one
// byte is the NUL terminator.
std::vector<char> buffer(in.length() * 2 + 1);
// The return value of mysql_escape_string() is either an error or the length of the
// encoded string not including the NUL terminator.
//
// Unfortunately, someone genius decided that mysql_escape_string should return an
// unsigned type even though -1 is returned on error so checking whether an error
// happened is a bit cursed.
unsigned long escapedsize = mysql_escape_string(&buffer[0], in.c_str(), in.length());
if (escapedsize == static_cast<unsigned long>(-1))
{
SQL::Error err(SQL::QSEND_FAIL, InspIRCd::Format("%u: %s", mysql_errno(connection), mysql_error(connection)));
query->OnError(err);
return false;
}
out.append(&buffer[0], escapedsize);
return true;
}
public:
std::shared_ptr<ConfigTag> config;
MYSQL* connection = nullptr;
std::mutex lock;
// This constructor creates an SQLConnection object with the given credentials, but does not connect yet.
SQLConnection(Module* p, std::shared_ptr<ConfigTag> tag)
: SQL::Provider(p, tag->getString("id"))
, config(tag)
{
}
~SQLConnection() override
{
mysql_close(connection);
}
// This method connects to the database using the credentials supplied to the constructor, and returns
// true upon success.
bool Connect()
{
connection = mysql_init(connection);
// Set the connection timeout.
unsigned int timeout = static_cast<unsigned int>(config->getDuration("timeout", 5, 1, 30));
mysql_options(connection, MYSQL_OPT_CONNECT_TIMEOUT, &timeout);
// Attempt to connect to the database.
const std::string host = config->getString("host");
const std::string user = config->getString("user");
const std::string pass = config->getString("pass");
const std::string dbname = config->getString("name");
unsigned int port = static_cast<unsigned int>(config->getUInt("port", 3306, 1, 65535));
if (!mysql_real_connect(connection, host.c_str(), user.c_str(), pass.c_str(), dbname.c_str(), port, nullptr, CLIENT_IGNORE_SIGPIPE))
{
ServerInstance->Logs.Normal(MODNAME, "Unable to connect to the %s MySQL server: %s",
GetId().c_str(), mysql_error(connection));
return false;
}
// Set the default character set.
const std::string charset = config->getString("charset");
if (!charset.empty() && mysql_set_character_set(connection, charset.c_str()))
{
ServerInstance->Logs.Normal(MODNAME, "Could not set character set for %s to \"%s\": %s",
GetId().c_str(), charset.c_str(), mysql_error(connection));
return false;
}
// Execute the initial SQL query.
const std::string initialquery = config->getString("initialquery");
if (!initialquery.empty() && mysql_real_query(connection, initialquery.data(), initialquery.length()))
{
ServerInstance->Logs.Normal(MODNAME, "Could not execute initial query \"%s\" for %s: %s",
initialquery.c_str(), name.c_str(), mysql_error(connection));
return false;
}
return true;
}
ModuleSQL* Parent()
{
return (ModuleSQL*)(Module*)creator;
}
MySQLresult* DoBlockingQuery(const std::string& query)
{
/* Parse the command string and dispatch it to mysql */
if (CheckConnection() && !mysql_real_query(connection, query.data(), query.length()))
{
/* Successful query */
MYSQL_RES* res = mysql_use_result(connection);
unsigned long rows = mysql_affected_rows(connection);
return new MySQLresult(res, rows);
}
else
{
/* XXX: See /usr/include/mysql/mysqld_error.h for a list of
* possible error numbers and error messages */
SQL::Error e(SQL::QREPLY_FAIL, InspIRCd::Format("%u: %s", mysql_errno(connection), mysql_error(connection)));
return new MySQLresult(e);
}
}
bool CheckConnection()
{
if (!connection || mysql_ping(connection) != 0)
return Connect();
return true;
}
void Submit(SQL::Query* q, const std::string& qs) override
{
ServerInstance->Logs.Debug(MODNAME, "Executing MySQL query: " + qs);
Parent()->Dispatcher->LockQueue();
Parent()->qq.emplace_back(q, qs, this);
Parent()->Dispatcher->UnlockQueueWakeup();
}
void Submit(SQL::Query* call, const std::string& q, const SQL::ParamList& p) override
{
std::string res;
unsigned int param = 0;
for (const auto chr : q)
{
if (chr != '?')
res.push_back(chr);
else if (param < p.size() && !EscapeString(call, p[param++], res))
return;
}
Submit(call, res);
}
void Submit(SQL::Query* call, const std::string& q, const SQL::ParamMap& p) override
{
std::string res;
for(std::string::size_type i = 0; i < q.length(); i++)
{
if (q[i] != '$')
res.push_back(q[i]);
else
{
std::string field;
i++;
while (i < q.length() && isalnum(q[i]))
field.push_back(q[i++]);
i--;
SQL::ParamMap::const_iterator it = p.find(field);
if (it != p.end() && !EscapeString(call, it->second, res))
return;
}
}
Submit(call, res);
}
};
void ModuleSQL::init()
{
if (mysql_library_init(0, nullptr, nullptr))
throw ModuleException(this, "Unable to initialise the MySQL library!");
Dispatcher = new DispatcherThread(this);
Dispatcher->Start();
}
ModuleSQL::ModuleSQL()
: Module(VF_VENDOR, "Provides the ability for SQL modules to query a MySQL database.")
{
}
ModuleSQL::~ModuleSQL()
{
if (Dispatcher)
{
Dispatcher->Stop();
Dispatcher->OnNotify();
delete Dispatcher;
}
for (const auto& [_, connection] : connections)
delete connection;
mysql_library_end();
}
void ModuleSQL::ReadConfig(ConfigStatus& status)
{
ConnMap conns;
for (const auto& [_, tag] : ServerInstance->Config->ConfTags("database"))
{
if (!stdalgo::string::equalsci(tag->getString("module"), "mysql"))
continue;
std::string id = tag->getString("id");
ConnMap::iterator curr = connections.find(id);
if (curr == connections.end())
{
SQLConnection* conn = new SQLConnection(this, tag);
conns.emplace(id, conn);
ServerInstance->Modules.AddService(*conn);
}
else
{
conns.insert(*curr);
connections.erase(curr);
}
}
// now clean up the deleted databases
Dispatcher->LockQueue();
SQL::Error err(SQL::BAD_DBID);
for (const auto& [_, connection] : connections)
{
ServerInstance->Modules.DelService(*connection);
// it might be running a query on this database. Wait for that to complete
connection->lock.lock();
connection->lock.unlock();
// now remove all active queries to this DB
for (size_t j = qq.size(); j > 0; j--)
{
size_t k = j - 1;
if (qq[k].connection == connection)
{
qq[k].query->OnError(err);
delete qq[k].query;
qq.erase(qq.begin() + k);
}
}
// finally, nuke the connection
delete connection;
}
Dispatcher->UnlockQueue();
connections.swap(conns);
}
void ModuleSQL::OnUnloadModule(Module* mod)
{
SQL::Error err(SQL::BAD_DBID);
Dispatcher->LockQueue();
size_t i = qq.size();
while (i > 0)
{
i--;
if (qq[i].query->creator == mod)
{
if (i == 0)
{
// need to wait until the query is done
// (the result will be discarded)
qq[i].connection->lock.lock();
}
qq[i].query->OnError(err);
delete qq[i].query;
qq.erase(qq.begin() + i);
}
}
Dispatcher->UnlockQueue();
// clean up any result queue entries
Dispatcher->OnNotify();
}
void DispatcherThread::OnStart()
{
this->LockQueue();
while (!this->IsStopping())
{
if (!Parent->qq.empty())
{
QueryQueueItem i = Parent->qq.front();
i.connection->lock.lock();
this->UnlockQueue();
MySQLresult* res = i.connection->DoBlockingQuery(i.querystr);
i.connection->lock.unlock();
/*
* At this point, the main thread could be working on:
* Rehash - delete i.connection out from under us. We don't care about that.
* UnloadModule - delete i.query and the qq item. Need to avoid reporting results.
*/
this->LockQueue();
if (!Parent->qq.empty() && Parent->qq.front().query == i.query)
{
Parent->qq.pop_front();
Parent->rq.emplace_back(i.query, res);
NotifyParent();
}
else
{
// UnloadModule ate the query
delete res;
}
}
else
{
/* We know the queue is empty, we can safely hang this thread until
* something happens
*/
this->WaitForQueue();
}
}
this->UnlockQueue();
}
void DispatcherThread::OnNotify()
{
// this could unlock during the dispatch, but OnResult isn't expected to take that long
this->LockQueue();
for (const auto& item : Parent->rq)
{
MySQLresult* res = item.result;
if (res->err.code == SQL::SUCCESS)
item.query->OnResult(*res);
else
item.query->OnError(res->err);
delete item.query;
delete item.result;
}
Parent->rq.clear();
this->UnlockQueue();
}
MODULE_INIT(ModuleSQL)
