src/modules/extra/m_mysql.cpp

   1 /*       +------------------------------------+
   2  *       | Inspire Internet Relay Chat Daemon |
   3  *       +------------------------------------+
   4  *
   5  *  InspIRCd: (C) 2002-2010 InspIRCd Development Team
   6  * See: http://wiki.inspircd.org/Credits
   7  *
   8  * This program is free but copyrighted software; see
   9  *          the file COPYING for details.
  10  *
  11  * ---------------------------------------------------
  12  */
  13
  14 /* Stop mysql wanting to use long long */
  15 #define NO_CLIENT_LONG_LONG
  16
  17 #include "inspircd.h"
  18 #include <mysql.h>
  19 #include "sql.h"
  20
  21 #ifdef WINDOWS
  22 #pragma comment(lib, "mysqlclient.lib")
  23 #endif
  24
  25 /* VERSION 3 API: With nonblocking (threaded) requests */
  26
  27 /* $ModDesc: SQL Service Provider module for all other m_sql* modules */
  28 /* $CompileFlags: exec("mysql_config --include") */
  29 /* $LinkerFlags: exec("mysql_config --libs_r") rpath("mysql_config --libs_r") */
  30 /* $ModDep: m_sqlv2.h */
  31
  32 /* THE NONBLOCKING MYSQL API!
  33  *
  34  * MySQL provides no nonblocking (asyncronous) API of its own, and its developers recommend
  35  * that instead, you should thread your program. This is what i've done here to allow for
  36  * asyncronous SQL requests via mysql. The way this works is as follows:
  37  *
  38  * The module spawns a thread via class Thread, and performs its mysql queries in this thread,
  39  * using a queue with priorities. There is a mutex on either end which prevents two threads
  40  * adjusting the queue at the same time, and crashing the ircd. Every 50 milliseconds, the
  41  * worker thread wakes up, and checks if there is a request at the head of its queue.
  42  * If there is, it processes this request, blocking the worker thread but leaving the ircd
  43  * thread to go about its business as usual. During this period, the ircd thread is able
  44  * to insert futher pending requests into the queue.
  45  *
  46  * Once the processing of a request is complete, it is removed from the incoming queue to
  47  * an outgoing queue, and initialized as a 'response'. The worker thread then signals the
  48  * ircd thread (via a loopback socket) of the fact a result is available, by sending the
  49  * connection ID through the connection.
  50  *
  51  * The ircd thread then mutexes the queue once more, reads the outbound response off the head
  52  * of the queue, and sends it on its way to the original calling module.
  53  *
  54  * XXX: You might be asking "why doesnt he just send the response from within the worker thread?"
  55  * The answer to this is simple. The majority of InspIRCd, and in fact most ircd's are not
  56  * threadsafe. This module is designed to be threadsafe and is careful with its use of threads,
  57  * however, if we were to call a module's OnRequest even from within a thread which was not the
  58  * one the module was originally instantiated upon, there is a chance of all hell breaking loose
  59  * if a module is ever put in a re-enterant state (stack corruption could occur, crashes, data
  60  * corruption, and worse, so DONT think about it until the day comes when InspIRCd is 100%
  61  * gauranteed threadsafe!)
  62  *
  63  * For a diagram of this system please see http://wiki.inspircd.org/Mysql2
  64  */
  65
  66 class SQLConnection;
  67 class MySQLresult;
  68 class DispatcherThread;
  69
  70 struct QQueueItem
  71 {
  72         SQLQuery* q;
  73         SQLConnection* c;
  74         QQueueItem(SQLQuery* Q, SQLConnection* C) : q(Q), c(C) {}
  75 };
  76
  77 struct RQueueItem
  78 {
  79         SQLQuery* q;
  80         MySQLresult* r;
  81         RQueueItem(SQLQuery* Q, MySQLresult* R) : q(Q), r(R) {}
  82 };
  83
  84 typedef std::map<std::string, SQLConnection*> ConnMap;
  85 typedef std::deque<QQueueItem> QueryQueue;
  86 typedef std::deque<RQueueItem> ResultQueue;
  87
  88 /** MySQL module
  89  *  */
  90 class ModuleSQL : public Module
  91 {
  92  public:
  93         DispatcherThread* Dispatcher;
  94         QueryQueue qq;       // MUST HOLD MUTEX
  95         ResultQueue rq;      // MUST HOLD MUTEX
  96         ConnMap connections; // main thread only
  97
  98         ModuleSQL();
  99         void init();
 100         ~ModuleSQL();
 101         void OnRehash(User* user);
 102         void OnUnloadModule(Module* mod);
 103         Version GetVersion();
 104 };
 105
 106 class DispatcherThread : public SocketThread
 107 {
 108  private:
 109         ModuleSQL* const Parent;
 110  public:
 111         DispatcherThread(ModuleSQL* CreatorModule) : Parent(CreatorModule) { }
 112         ~DispatcherThread() { }
 113         virtual void Run();
 114         virtual void OnNotify();
 115 };
 116
 117 #if !defined(MYSQL_VERSION_ID) || MYSQL_VERSION_ID<32224
 118 #define mysql_field_count mysql_num_fields
 119 #endif
 120
 121 /** Represents a mysql result set
 122  */
 123 class MySQLresult : public SQLResult
 124 {
 125  public:
 126         SQLerror err;
 127         int currentrow;
 128         int rows;
 129         std::vector<std::string> colnames;
 130         std::vector<SQLEntries> fieldlists;
 131
 132         MySQLresult(MYSQL_RES* res, int affected_rows) : err(SQL_NO_ERROR), currentrow(0), rows(0)
 133         {
 134                 if (affected_rows >= 1)
 135                 {
 136                         rows = affected_rows;
 137                         fieldlists.resize(rows);
 138                 }
 139                 unsigned int field_count = 0;
 140                 if (res)
 141                 {
 142                         MYSQL_ROW row;
 143                         int n = 0;
 144                         while ((row = mysql_fetch_row(res)))
 145                         {
 146                                 if (fieldlists.size() < (unsigned int)rows+1)
 147                                 {
 148                                         fieldlists.resize(fieldlists.size()+1);
 149                                 }
 150                                 field_count = 0;
 151                                 MYSQL_FIELD *fields = mysql_fetch_fields(res);
 152                                 if(mysql_num_fields(res) == 0)
 153                                         break;
 154                                 if (fields && mysql_num_fields(res))
 155                                 {
 156                                         colnames.clear();
 157                                         while (field_count < mysql_num_fields(res))
 158                                         {
 159                                                 std::string a = (fields[field_count].name ? fields[field_count].name : "");
 160                                                 if (row[field_count])
 161                                                         fieldlists[n].push_back(SQLEntry(row[field_count]));
 162                                                 else
 163                                                         fieldlists[n].push_back(SQLEntry());
 164                                                 colnames.push_back(a);
 165                                                 field_count++;
 166                                         }
 167                                         n++;
 168                                 }
 169                                 rows++;
 170                         }
 171                         mysql_free_result(res);
 172                         res = NULL;
 173                 }
 174         }
 175
 176         MySQLresult(SQLerror& e) : err(e)
 177         {
 178
 179         }
 180
 181         ~MySQLresult()
 182         {
 183         }
 184
 185         virtual int Rows()
 186         {
 187                 return rows;
 188         }
 189
 190         virtual void GetCols(std::vector<std::string>& result)
 191         {
 192                 result.assign(colnames.begin(), colnames.end());
 193         }
 194
 195         virtual SQLEntry GetValue(int row, int column)
 196         {
 197                 if ((row >= 0) && (row < rows) && (column >= 0) && (column < (int)fieldlists[row].size()))
 198                 {
 199                         return fieldlists[row][column];
 200                 }
 201                 return SQLEntry();
 202         }
 203
 204         virtual bool GetRow(SQLEntries& result)
 205         {
 206                 if (currentrow < rows)
 207                 {
 208                         result.assign(fieldlists[currentrow].begin(), fieldlists[currentrow].end());
 209                         currentrow++;
 210                         return true;
 211                 }
 212                 else
 213                 {
 214                         result.clear();
 215                         return false;
 216                 }
 217         }
 218 };
 219
 220 /** Represents a connection to a mysql database
 221  */
 222 class SQLConnection : public SQLProvider
 223 {
 224  public:
 225         reference<ConfigTag> config;
 226         MYSQL *connection;
 227         Mutex lock;
 228
 229         // This constructor creates an SQLConnection object with the given credentials, but does not connect yet.
 230         SQLConnection(Module* p, ConfigTag* tag) : SQLProvider(p, "SQL/" + tag->getString("id")),
 231                 config(tag)
 232         {
 233         }
 234
 235         ~SQLConnection()
 236         {
 237                 Close();
 238         }
 239
 240         // This method connects to the database using the credentials supplied to the constructor, and returns
 241         // true upon success.
 242         bool Connect()
 243         {
 244                 unsigned int timeout = 1;
 245                 connection = mysql_init(connection);
 246                 mysql_options(connection,MYSQL_OPT_CONNECT_TIMEOUT,(char*)&timeout);
 247                 std::string host = config->getString("host");
 248                 std::string user = config->getString("user");
 249                 std::string pass = config->getString("pass");
 250                 std::string dbname = config->getString("name");
 251                 int port = config->getInt("port");
 252                 bool rv = mysql_real_connect(connection, host.c_str(), user.c_str(), pass.c_str(), dbname.c_str(), port, NULL, 0);
 253                 if (!rv)
 254                         return rv;
 255                 std::string initquery;
 256                 if (config->readString("initialquery", initquery))
 257                 {
 258                         mysql_query(connection,initquery.c_str());
 259                 }
 260                 return true;
 261         }
 262
 263         virtual std::string FormatQuery(const std::string& q, const ParamL& p)
 264         {
 265                 std::string res;
 266                 unsigned int param = 0;
 267                 for(std::string::size_type i = 0; i < q.length(); i++)
 268                 {
 269                         if (q[i] != '?')
 270                                 res.push_back(q[i]);
 271                         else
 272                         {
 273                                 // TODO numbered parameter support ('?1')
 274                                 if (param < p.size())
 275                                 {
 276                                         std::string parm = p[param++];
 277                                         char buffer[MAXBUF];
 278                                         mysql_escape_string(buffer, parm.c_str(), parm.length());
 279 //                                      mysql_real_escape_string(connection, queryend, paramscopy[paramnum].c_str(), paramscopy[paramnum].length());
 280                                         res.append(buffer);
 281                                 }
 282                         }
 283                 }
 284                 return res;
 285         }
 286
 287         std::string FormatQuery(const std::string& q, const ParamM& p)
 288         {
 289                 std::string res;
 290                 for(std::string::size_type i = 0; i < q.length(); i++)
 291                 {
 292                         if (q[i] != '$')
 293                                 res.push_back(q[i]);
 294                         else
 295                         {
 296                                 std::string field;
 297                                 i++;
 298                                 while (i < q.length() && isalpha(q[i]))
 299                                         field.push_back(q[i++]);
 300                                 i--;
 301
 302                                 ParamM::const_iterator it = p.find(field);
 303                                 if (it != p.end())
 304                                 {
 305                                         std::string parm = it->second;
 306                                         char buffer[MAXBUF];
 307                                         mysql_escape_string(buffer, parm.c_str(), parm.length());
 308                                         res.append(buffer);
 309                                 }
 310                         }
 311                 }
 312                 return res;
 313         }
 314
 315         ModuleSQL* Parent()
 316         {
 317                 return (ModuleSQL*)(Module*)creator;
 318         }
 319
 320         MySQLresult* DoBlockingQuery(SQLQuery* req)
 321         {
 322
 323                 /* Parse the command string and dispatch it to mysql */
 324                 if (CheckConnection() && !mysql_real_query(connection, req->query.data(), req->query.length()))
 325                 {
 326                         /* Successfull query */
 327                         MYSQL_RES* res = mysql_use_result(connection);
 328                         unsigned long rows = mysql_affected_rows(connection);
 329                         return new MySQLresult(res, rows);
 330                 }
 331                 else
 332                 {
 333                         /* XXX: See /usr/include/mysql/mysqld_error.h for a list of
 334                          * possible error numbers and error messages */
 335                         SQLerror e(SQL_QREPLY_FAIL, ConvToStr(mysql_errno(connection)) + std::string(": ") + mysql_error(connection));
 336                         return new MySQLresult(e);
 337                 }
 338         }
 339
 340         bool CheckConnection()
 341         {
 342                 if (mysql_ping(connection) != 0)
 343                 {
 344                         return Connect();
 345                 }
 346                 else return true;
 347         }
 348
 349         std::string GetError()
 350         {
 351                 return mysql_error(connection);
 352         }
 353
 354         void Close()
 355         {
 356                 mysql_close(connection);
 357         }
 358
 359         void submit(SQLQuery* q)
 360         {
 361                 Parent()->Dispatcher->LockQueue();
 362                 Parent()->qq.push_back(QQueueItem(q, this));
 363                 Parent()->Dispatcher->UnlockQueueWakeup();
 364         }
 365 };
 366
 367 ModuleSQL::ModuleSQL()
 368 {
 369         Dispatcher = NULL;
 370 }
 371
 372 void ModuleSQL::init()
 373 {
 374         Dispatcher = new DispatcherThread(this);
 375         ServerInstance->Threads->Start(Dispatcher);
 376
 377         Implementation eventlist[] = { I_OnRehash, I_OnUnloadModule };
 378         ServerInstance->Modules->Attach(eventlist, this, 2);
 379 }
 380
 381 ModuleSQL::~ModuleSQL()
 382 {
 383         if (Dispatcher)
 384         {
 385                 Dispatcher->join();
 386                 Dispatcher->OnNotify();
 387                 delete Dispatcher;
 388         }
 389         for(ConnMap::iterator i = connections.begin(); i != connections.end(); i++)
 390         {
 391                 delete i->second;
 392         }
 393 }
 394
 395 void ModuleSQL::OnRehash(User* user)
 396 {
 397         ConnMap conns;
 398         ConfigTagList tags = ServerInstance->Config->ConfTags("database");
 399         for(ConfigIter i = tags.first; i != tags.second; i++)
 400         {
 401                 if (i->second->getString("module", "mysql") != "mysql")
 402                         continue;
 403                 std::string id = i->second->getString("id");
 404                 ConnMap::iterator curr = connections.find(id);
 405                 if (curr == connections.end())
 406                 {
 407                         SQLConnection* conn = new SQLConnection(this, i->second);
 408                         conns.insert(std::make_pair(id, conn));
 409                         ServerInstance->Modules->AddService(*conn);
 410                 }
 411                 else
 412                 {
 413                         conns.insert(*curr);
 414                         connections.erase(curr);
 415                 }
 416         }
 417
 418         // now clean up the deleted databases
 419         Dispatcher->LockQueue();
 420         SQLerror err(SQL_BAD_DBID);
 421         for(ConnMap::iterator i = connections.begin(); i != connections.end(); i++)
 422         {
 423                 ServerInstance->Modules->DelService(*i->second);
 424                 // it might be running a query on this database. Wait for that to complete
 425                 i->second->lock.Lock();
 426                 i->second->lock.Unlock();
 427                 // now remove all active queries to this DB
 428                 for(unsigned int j = qq.size() - 1; j >= 0; j--)
 429                 {
 430                         if (qq[j].c == i->second)
 431                         {
 432                                 qq[j].q->OnError(err);
 433                                 delete qq[j].q;
 434                                 qq.erase(qq.begin() + j);
 435                         }
 436                 }
 437                 // finally, nuke the connection
 438                 delete i->second;
 439         }
 440         Dispatcher->UnlockQueue();
 441         connections.swap(conns);
 442 }
 443
 444 void ModuleSQL::OnUnloadModule(Module* mod)
 445 {
 446         SQLerror err(SQL_BAD_DBID);
 447         Dispatcher->LockQueue();
 448         for(unsigned int i = qq.size() - 1; i >= 0; i--)
 449         {
 450                 if (qq[i].q->creator == mod)
 451                 {
 452                         if (i == 0)
 453                         {
 454                                 // need to wait until the query is done
 455                                 // (the result will be discarded)
 456                                 qq[i].c->lock.Lock();
 457                                 qq[i].c->lock.Unlock();
 458                         }
 459                         qq[i].q->OnError(err);
 460                         delete qq[i].q;
 461                         qq.erase(qq.begin() + i);
 462                 }
 463         }
 464         Dispatcher->UnlockQueue();
 465         // clean up any result queue entries
 466         Dispatcher->OnNotify();
 467 }
 468
 469 Version ModuleSQL::GetVersion()
 470 {
 471         return Version("MySQL support", VF_VENDOR);
 472 }
 473
 474 void DispatcherThread::Run()
 475 {
 476         this->LockQueue();
 477         while (!this->GetExitFlag())
 478         {
 479                 if (!Parent->qq.empty())
 480                 {
 481                         QQueueItem i = Parent->qq.front();
 482                         i.c->lock.Lock();
 483                         this->UnlockQueue();
 484                         MySQLresult* res = i.c->DoBlockingQuery(i.q);
 485                         i.c->lock.Unlock();
 486
 487                         /*
 488                          * At this point, the main thread could be working on:
 489                          *  Rehash - delete i.c out from under us. We don't care about that.
 490                          *  UnloadModule - delete i.q and the qq item. Need to avoid reporting results.
 491                          */
 492
 493                         this->LockQueue();
 494                         if (Parent->qq.front().q == i.q)
 495                         {
 496                                 Parent->qq.pop_front();
 497                                 Parent->rq.push_back(RQueueItem(i.q, res));
 498                                 NotifyParent();
 499                         }
 500                         else
 501                         {
 502                                 // UnloadModule ate the query
 503                                 delete res;
 504                         }
 505                 }
 506                 else
 507                 {
 508                         /* We know the queue is empty, we can safely hang this thread until
 509                          * something happens
 510                          */
 511                         this->WaitForQueue();
 512                 }
 513         }
 514         this->UnlockQueue();
 515 }
 516
 517 void DispatcherThread::OnNotify()
 518 {
 519         // this could unlock during the dispatch, but OnResult isn't expected to take that long
 520         this->LockQueue();
 521         for(ResultQueue::iterator i = Parent->rq.begin(); i != Parent->rq.end(); i++)
 522         {
 523                 MySQLresult* res = i->r;
 524                 if (res->err.id == SQL_NO_ERROR)
 525                         i->q->OnResult(*res);
 526                 else
 527                         i->q->OnError(res->err);
 528                 delete i->q;
 529                 delete i->r;
 530         }
 531         Parent->rq.clear();
 532         this->UnlockQueue();
 533 }
 534
 535 MODULE_INIT(ModuleSQL)