src/modules/extra/m_mysql.cpp

   1 /*
   2  * InspIRCd -- Internet Relay Chat Daemon
   3  *
   4  *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
   5  *   Copyright (C) 2006-2007, 2009 Dennis Friis <peavey@inspircd.org>
   6  *   Copyright (C) 2006-2009 Craig Edwards <craigedwards@brainbox.cc>
   7  *   Copyright (C) 2008 Robin Burchell <robin+git@viroteck.net>
   8  *
   9  * This file is part of InspIRCd.  InspIRCd is free software: you can
  10  * redistribute it and/or modify it under the terms of the GNU General Public
  11  * License as published by the Free Software Foundation, version 2.
  12  *
  13  * This program is distributed in the hope that it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  15  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  16  * details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22
  23 /* Stop mysql wanting to use long long */
  24 #define NO_CLIENT_LONG_LONG
  25
  26 #include "inspircd.h"
  27 #include <mysql.h>
  28 #include "sql.h"
  29
  30 #ifdef _WIN32
  31 # pragma comment(lib, "libmysql.lib")
  32 #endif
  33
  34 /* VERSION 3 API: With nonblocking (threaded) requests */
  35
  36 /* $ModDesc: SQL Service Provider module for all other m_sql* modules */
  37 /* $CompileFlags: exec("mysql_config --include") */
  38 /* $LinkerFlags: exec("mysql_config --libs_r") rpath("mysql_config --libs_r") */
  39
  40 /* THE NONBLOCKING MYSQL API!
  41  *
  42  * MySQL provides no nonblocking (asyncronous) API of its own, and its developers recommend
  43  * that instead, you should thread your program. This is what i've done here to allow for
  44  * asyncronous SQL requests via mysql. The way this works is as follows:
  45  *
  46  * The module spawns a thread via class Thread, and performs its mysql queries in this thread,
  47  * using a queue with priorities. There is a mutex on either end which prevents two threads
  48  * adjusting the queue at the same time, and crashing the ircd. Every 50 milliseconds, the
  49  * worker thread wakes up, and checks if there is a request at the head of its queue.
  50  * If there is, it processes this request, blocking the worker thread but leaving the ircd
  51  * thread to go about its business as usual. During this period, the ircd thread is able
  52  * to insert futher pending requests into the queue.
  53  *
  54  * Once the processing of a request is complete, it is removed from the incoming queue to
  55  * an outgoing queue, and initialized as a 'response'. The worker thread then signals the
  56  * ircd thread (via a loopback socket) of the fact a result is available, by sending the
  57  * connection ID through the connection.
  58  *
  59  * The ircd thread then mutexes the queue once more, reads the outbound response off the head
  60  * of the queue, and sends it on its way to the original calling module.
  61  *
  62  * XXX: You might be asking "why doesnt he just send the response from within the worker thread?"
  63  * The answer to this is simple. The majority of InspIRCd, and in fact most ircd's are not
  64  * threadsafe. This module is designed to be threadsafe and is careful with its use of threads,
  65  * however, if we were to call a module's OnRequest even from within a thread which was not the
  66  * one the module was originally instantiated upon, there is a chance of all hell breaking loose
  67  * if a module is ever put in a re-enterant state (stack corruption could occur, crashes, data
  68  * corruption, and worse, so DONT think about it until the day comes when InspIRCd is 100%
  69  * gauranteed threadsafe!)
  70  *
  71  * For a diagram of this system please see http://wiki.inspircd.org/Mysql2
  72  */
  73
  74 class SQLConnection;
  75 class MySQLresult;
  76 class DispatcherThread;
  77
  78 struct QQueueItem
  79 {
  80         SQLQuery* q;
  81         std::string query;
  82         SQLConnection* c;
  83         QQueueItem(SQLQuery* Q, const std::string& S, SQLConnection* C) : q(Q), query(S), c(C) {}
  84 };
  85
  86 struct RQueueItem
  87 {
  88         SQLQuery* q;
  89         MySQLresult* r;
  90         RQueueItem(SQLQuery* Q, MySQLresult* R) : q(Q), r(R) {}
  91 };
  92
  93 typedef std::map<std::string, SQLConnection*> ConnMap;
  94 typedef std::deque<QQueueItem> QueryQueue;
  95 typedef std::deque<RQueueItem> ResultQueue;
  96
  97 /** MySQL module
  98  *  */
  99 class ModuleSQL : public Module
 100 {
 101  public:
 102         DispatcherThread* Dispatcher;
 103         QueryQueue qq;       // MUST HOLD MUTEX
 104         ResultQueue rq;      // MUST HOLD MUTEX
 105         ConnMap connections; // main thread only
 106
 107         ModuleSQL();
 108         void init();
 109         ~ModuleSQL();
 110         void OnRehash(User* user);
 111         void OnUnloadModule(Module* mod);
 112         Version GetVersion();
 113 };
 114
 115 class DispatcherThread : public SocketThread
 116 {
 117  private:
 118         ModuleSQL* const Parent;
 119  public:
 120         DispatcherThread(ModuleSQL* CreatorModule) : Parent(CreatorModule) { }
 121         ~DispatcherThread() { }
 122         virtual void Run();
 123         virtual void OnNotify();
 124 };
 125
 126 #if !defined(MYSQL_VERSION_ID) || MYSQL_VERSION_ID<32224
 127 #define mysql_field_count mysql_num_fields
 128 #endif
 129
 130 /** Represents a mysql result set
 131  */
 132 class MySQLresult : public SQLResult
 133 {
 134  public:
 135         SQLerror err;
 136         int currentrow;
 137         int rows;
 138         std::vector<std::string> colnames;
 139         std::vector<SQLEntries> fieldlists;
 140
 141         MySQLresult(MYSQL_RES* res, int affected_rows) : err(SQL_NO_ERROR), currentrow(0), rows(0)
 142         {
 143                 if (affected_rows >= 1)
 144                 {
 145                         rows = affected_rows;
 146                         fieldlists.resize(rows);
 147                 }
 148                 unsigned int field_count = 0;
 149                 if (res)
 150                 {
 151                         MYSQL_ROW row;
 152                         int n = 0;
 153                         while ((row = mysql_fetch_row(res)))
 154                         {
 155                                 if (fieldlists.size() < (unsigned int)rows+1)
 156                                 {
 157                                         fieldlists.resize(fieldlists.size()+1);
 158                                 }
 159                                 field_count = 0;
 160                                 MYSQL_FIELD *fields = mysql_fetch_fields(res);
 161                                 if(mysql_num_fields(res) == 0)
 162                                         break;
 163                                 if (fields && mysql_num_fields(res))
 164                                 {
 165                                         colnames.clear();
 166                                         while (field_count < mysql_num_fields(res))
 167                                         {
 168                                                 std::string a = (fields[field_count].name ? fields[field_count].name : "");
 169                                                 if (row[field_count])
 170                                                         fieldlists[n].push_back(SQLEntry(row[field_count]));
 171                                                 else
 172                                                         fieldlists[n].push_back(SQLEntry());
 173                                                 colnames.push_back(a);
 174                                                 field_count++;
 175                                         }
 176                                         n++;
 177                                 }
 178                                 rows++;
 179                         }
 180                         mysql_free_result(res);
 181                 }
 182         }
 183
 184         MySQLresult(SQLerror& e) : err(e)
 185         {
 186
 187         }
 188
 189         ~MySQLresult()
 190         {
 191         }
 192
 193         virtual int Rows()
 194         {
 195                 return rows;
 196         }
 197
 198         virtual void GetCols(std::vector<std::string>& result)
 199         {
 200                 result.assign(colnames.begin(), colnames.end());
 201         }
 202
 203         virtual SQLEntry GetValue(int row, int column)
 204         {
 205                 if ((row >= 0) && (row < rows) && (column >= 0) && (column < (int)fieldlists[row].size()))
 206                 {
 207                         return fieldlists[row][column];
 208                 }
 209                 return SQLEntry();
 210         }
 211
 212         virtual bool GetRow(SQLEntries& result)
 213         {
 214                 if (currentrow < rows)
 215                 {
 216                         result.assign(fieldlists[currentrow].begin(), fieldlists[currentrow].end());
 217                         currentrow++;
 218                         return true;
 219                 }
 220                 else
 221                 {
 222                         result.clear();
 223                         return false;
 224                 }
 225         }
 226 };
 227
 228 /** Represents a connection to a mysql database
 229  */
 230 class SQLConnection : public SQLProvider
 231 {
 232  public:
 233         reference<ConfigTag> config;
 234         MYSQL *connection;
 235         Mutex lock;
 236
 237         // This constructor creates an SQLConnection object with the given credentials, but does not connect yet.
 238         SQLConnection(Module* p, ConfigTag* tag) : SQLProvider(p, "SQL/" + tag->getString("id")),
 239                 config(tag), connection(NULL)
 240         {
 241         }
 242
 243         ~SQLConnection()
 244         {
 245                 Close();
 246         }
 247
 248         // This method connects to the database using the credentials supplied to the constructor, and returns
 249         // true upon success.
 250         bool Connect()
 251         {
 252                 unsigned int timeout = 1;
 253                 connection = mysql_init(connection);
 254                 mysql_options(connection,MYSQL_OPT_CONNECT_TIMEOUT,(char*)&timeout);
 255                 std::string host = config->getString("host");
 256                 std::string user = config->getString("user");
 257                 std::string pass = config->getString("pass");
 258                 std::string dbname = config->getString("name");
 259                 int port = config->getInt("port");
 260                 bool rv = mysql_real_connect(connection, host.c_str(), user.c_str(), pass.c_str(), dbname.c_str(), port, NULL, 0);
 261                 if (!rv)
 262                         return rv;
 263                 std::string initquery;
 264                 if (config->readString("initialquery", initquery))
 265                 {
 266                         mysql_query(connection,initquery.c_str());
 267                 }
 268                 return true;
 269         }
 270
 271         ModuleSQL* Parent()
 272         {
 273                 return (ModuleSQL*)(Module*)creator;
 274         }
 275
 276         MySQLresult* DoBlockingQuery(const std::string& query)
 277         {
 278
 279                 /* Parse the command string and dispatch it to mysql */
 280                 if (CheckConnection() && !mysql_real_query(connection, query.data(), query.length()))
 281                 {
 282                         /* Successfull query */
 283                         MYSQL_RES* res = mysql_use_result(connection);
 284                         unsigned long rows = mysql_affected_rows(connection);
 285                         return new MySQLresult(res, rows);
 286                 }
 287                 else
 288                 {
 289                         /* XXX: See /usr/include/mysql/mysqld_error.h for a list of
 290                          * possible error numbers and error messages */
 291                         SQLerror e(SQL_QREPLY_FAIL, ConvToStr(mysql_errno(connection)) + ": " + mysql_error(connection));
 292                         return new MySQLresult(e);
 293                 }
 294         }
 295
 296         bool CheckConnection()
 297         {
 298                 if (!connection || mysql_ping(connection) != 0)
 299                         return Connect();
 300                 return true;
 301         }
 302
 303         std::string GetError()
 304         {
 305                 return mysql_error(connection);
 306         }
 307
 308         void Close()
 309         {
 310                 mysql_close(connection);
 311         }
 312
 313         void submit(SQLQuery* q, const std::string& qs)
 314         {
 315                 Parent()->Dispatcher->LockQueue();
 316                 Parent()->qq.push_back(QQueueItem(q, qs, this));
 317                 Parent()->Dispatcher->UnlockQueueWakeup();
 318         }
 319
 320         void submit(SQLQuery* call, const std::string& q, const ParamL& p)
 321         {
 322                 std::string res;
 323                 unsigned int param = 0;
 324                 for(std::string::size_type i = 0; i < q.length(); i++)
 325                 {
 326                         if (q[i] != '?')
 327                                 res.push_back(q[i]);
 328                         else
 329                         {
 330                                 if (param < p.size())
 331                                 {
 332                                         std::string parm = p[param++];
 333                                         // In the worst case, each character may need to be encoded as using two bytes,
 334                                         // and one byte is the terminating null
 335                                         std::vector<char> buffer(parm.length() * 2 + 1);
 336
 337                                         // The return value of mysql_escape_string() is the length of the encoded string,
 338                                         // not including the terminating null
 339                                         unsigned long escapedsize = mysql_escape_string(&buffer[0], parm.c_str(), parm.length());
 340 //                                      mysql_real_escape_string(connection, queryend, paramscopy[paramnum].c_str(), paramscopy[paramnum].length());
 341                                         res.append(&buffer[0], escapedsize);
 342                                 }
 343                         }
 344                 }
 345                 submit(call, res);
 346         }
 347
 348         void submit(SQLQuery* call, const std::string& q, const ParamM& p)
 349         {
 350                 std::string res;
 351                 for(std::string::size_type i = 0; i < q.length(); i++)
 352                 {
 353                         if (q[i] != '$')
 354                                 res.push_back(q[i]);
 355                         else
 356                         {
 357                                 std::string field;
 358                                 i++;
 359                                 while (i < q.length() && isalnum(q[i]))
 360                                         field.push_back(q[i++]);
 361                                 i--;
 362
 363                                 ParamM::const_iterator it = p.find(field);
 364                                 if (it != p.end())
 365                                 {
 366                                         std::string parm = it->second;
 367                                         // NOTE: See above
 368                                         std::vector<char> buffer(parm.length() * 2 + 1);
 369                                         unsigned long escapedsize = mysql_escape_string(&buffer[0], parm.c_str(), parm.length());
 370                                         res.append(&buffer[0], escapedsize);
 371                                 }
 372                         }
 373                 }
 374                 submit(call, res);
 375         }
 376 };
 377
 378 ModuleSQL::ModuleSQL()
 379 {
 380         Dispatcher = NULL;
 381 }
 382
 383 void ModuleSQL::init()
 384 {
 385         Dispatcher = new DispatcherThread(this);
 386         ServerInstance->Threads->Start(Dispatcher);
 387
 388         Implementation eventlist[] = { I_OnRehash, I_OnUnloadModule };
 389         ServerInstance->Modules->Attach(eventlist, this, sizeof(eventlist)/sizeof(Implementation));
 390
 391         OnRehash(NULL);
 392 }
 393
 394 ModuleSQL::~ModuleSQL()
 395 {
 396         if (Dispatcher)
 397         {
 398                 Dispatcher->join();
 399                 Dispatcher->OnNotify();
 400                 delete Dispatcher;
 401         }
 402         for(ConnMap::iterator i = connections.begin(); i != connections.end(); i++)
 403         {
 404                 delete i->second;
 405         }
 406 }
 407
 408 void ModuleSQL::OnRehash(User* user)
 409 {
 410         ConnMap conns;
 411         ConfigTagList tags = ServerInstance->Config->ConfTags("database");
 412         for(ConfigIter i = tags.first; i != tags.second; i++)
 413         {
 414                 if (i->second->getString("module", "mysql") != "mysql")
 415                         continue;
 416                 std::string id = i->second->getString("id");
 417                 ConnMap::iterator curr = connections.find(id);
 418                 if (curr == connections.end())
 419                 {
 420                         SQLConnection* conn = new SQLConnection(this, i->second);
 421                         conns.insert(std::make_pair(id, conn));
 422                         ServerInstance->Modules->AddService(*conn);
 423                 }
 424                 else
 425                 {
 426                         conns.insert(*curr);
 427                         connections.erase(curr);
 428                 }
 429         }
 430
 431         // now clean up the deleted databases
 432         Dispatcher->LockQueue();
 433         SQLerror err(SQL_BAD_DBID);
 434         for(ConnMap::iterator i = connections.begin(); i != connections.end(); i++)
 435         {
 436                 ServerInstance->Modules->DelService(*i->second);
 437                 // it might be running a query on this database. Wait for that to complete
 438                 i->second->lock.Lock();
 439                 i->second->lock.Unlock();
 440                 // now remove all active queries to this DB
 441                 for (size_t j = qq.size(); j > 0; j--)
 442                 {
 443                         size_t k = j - 1;
 444                         if (qq[k].c == i->second)
 445                         {
 446                                 qq[k].q->OnError(err);
 447                                 delete qq[k].q;
 448                                 qq.erase(qq.begin() + k);
 449                         }
 450                 }
 451                 // finally, nuke the connection
 452                 delete i->second;
 453         }
 454         Dispatcher->UnlockQueue();
 455         connections.swap(conns);
 456 }
 457
 458 void ModuleSQL::OnUnloadModule(Module* mod)
 459 {
 460         SQLerror err(SQL_BAD_DBID);
 461         Dispatcher->LockQueue();
 462         unsigned int i = qq.size();
 463         while (i > 0)
 464         {
 465                 i--;
 466                 if (qq[i].q->creator == mod)
 467                 {
 468                         if (i == 0)
 469                         {
 470                                 // need to wait until the query is done
 471                                 // (the result will be discarded)
 472                                 qq[i].c->lock.Lock();
 473                                 qq[i].c->lock.Unlock();
 474                         }
 475                         qq[i].q->OnError(err);
 476                         delete qq[i].q;
 477                         qq.erase(qq.begin() + i);
 478                 }
 479         }
 480         Dispatcher->UnlockQueue();
 481         // clean up any result queue entries
 482         Dispatcher->OnNotify();
 483 }
 484
 485 Version ModuleSQL::GetVersion()
 486 {
 487         return Version("MySQL support", VF_VENDOR);
 488 }
 489
 490 void DispatcherThread::Run()
 491 {
 492         this->LockQueue();
 493         while (!this->GetExitFlag())
 494         {
 495                 if (!Parent->qq.empty())
 496                 {
 497                         QQueueItem i = Parent->qq.front();
 498                         i.c->lock.Lock();
 499                         this->UnlockQueue();
 500                         MySQLresult* res = i.c->DoBlockingQuery(i.query);
 501                         i.c->lock.Unlock();
 502
 503                         /*
 504                          * At this point, the main thread could be working on:
 505                          *  Rehash - delete i.c out from under us. We don't care about that.
 506                          *  UnloadModule - delete i.q and the qq item. Need to avoid reporting results.
 507                          */
 508
 509                         this->LockQueue();
 510                         if (!Parent->qq.empty() && Parent->qq.front().q == i.q)
 511                         {
 512                                 Parent->qq.pop_front();
 513                                 Parent->rq.push_back(RQueueItem(i.q, res));
 514                                 NotifyParent();
 515                         }
 516                         else
 517                         {
 518                                 // UnloadModule ate the query
 519                                 delete res;
 520                         }
 521                 }
 522                 else
 523                 {
 524                         /* We know the queue is empty, we can safely hang this thread until
 525                          * something happens
 526                          */
 527                         this->WaitForQueue();
 528                 }
 529         }
 530         this->UnlockQueue();
 531 }
 532
 533 void DispatcherThread::OnNotify()
 534 {
 535         // this could unlock during the dispatch, but OnResult isn't expected to take that long
 536         this->LockQueue();
 537         for(ResultQueue::iterator i = Parent->rq.begin(); i != Parent->rq.end(); i++)
 538         {
 539                 MySQLresult* res = i->r;
 540                 if (res->err.id == SQL_NO_ERROR)
 541                         i->q->OnResult(*res);
 542                 else
 543                         i->q->OnError(res->err);
 544                 delete i->q;
 545                 delete i->r;
 546         }
 547         Parent->rq.clear();
 548         this->UnlockQueue();
 549 }
 550
 551 MODULE_INIT(ModuleSQL)