source/smbd/blocking.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    Blocking Locking functions
   5    Copyright (C) Jeremy Allison 1998
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23 extern int DEBUGLEVEL;
  24 extern char *OutBuffer;
  25
  26 /****************************************************************************
  27  This is the structure to queue to implement blocking locks.
  28  notify. It consists of the requesting SMB and the expiry time.
  29 *****************************************************************************/
  30
  31 typedef struct {
  32   ubi_slNode msg_next;
  33   int com_type;
  34   files_struct *fsp;
  35   time_t expire_time;
  36   int lock_num;
  37   char *inbuf;
  38   int length;
  39 } blocking_lock_record;
  40
  41 static ubi_slList blocking_lock_queue = { NULL, (ubi_slNodePtr)&blocking_lock_queue, 0};
  42
  43 /****************************************************************************
  44  Destructor for the above structure.
  45 ****************************************************************************/
  46
  47 static void free_blocking_lock_record(blocking_lock_record *blr)
  48 {
  49   free(blr->inbuf);
  50   free((char *)blr);
  51 }
  52
  53 /****************************************************************************
  54  Get the files_struct given a particular queued SMB.
  55 *****************************************************************************/
  56
  57 static files_struct *get_fsp_from_pkt(char *inbuf)
  58 {
  59   switch(CVAL(inbuf,smb_com)) {
  60   case SMBlock:
  61   case SMBlockread:
  62     return file_fsp(inbuf,smb_vwv0);
  63   case SMBlockingX:
  64     return file_fsp(inbuf,smb_vwv2);
  65   default:
  66     DEBUG(0,("get_fsp_from_pkt: PANIC - unknown type on blocking lock queue - exiting.!\n"));
  67     exit_server("PANIC - unknown type on blocking lock queue");
  68   }
  69   return NULL; /* Keep compiler happy. */
  70 }
  71
  72 /****************************************************************************
  73  Determine if this is a secondary element of a chained SMB.
  74   **************************************************************************/
  75
  76 static BOOL in_chained_smb(void)
  77 {
  78   return (chain_size != 0);
  79 }
  80
  81 /****************************************************************************
  82  Function to push a blocking lock request onto the lock queue.
  83 ****************************************************************************/
  84
  85 BOOL push_blocking_lock_request( char *inbuf, int length, int lock_timeout, int lock_num)
  86 {
  87   blocking_lock_record *blr;
  88
  89   if(in_chained_smb() ) {
  90     DEBUG(0,("push_blocking_lock_request: cannot queue a chained request (currently).\n"));
  91     return False;
  92   }
  93
  94   /*
  95    * Now queue an entry on the blocking lock queue. We setup
  96    * the expiration time here.
  97    */
  98
  99   if((blr = (blocking_lock_record *)malloc(sizeof(blocking_lock_record))) == NULL) {
 100     DEBUG(0,("push_blocking_lock_request: Malloc fail !\n" ));
 101     return False;
 102   }
 103
 104   if((blr->inbuf = (char *)malloc(length)) == NULL) {
 105     DEBUG(0,("push_blocking_lock_request: Malloc fail (2)!\n" ));
 106     free((char *)blr);
 107     return False;
 108   }
 109
 110   blr->com_type = CVAL(inbuf,smb_com);
 111   blr->fsp = get_fsp_from_pkt(inbuf);
 112   blr->expire_time = (lock_timeout == -1) ? (time_t)-1 : time(NULL) + (time_t)lock_timeout;
 113   blr->lock_num = lock_num;
 114   memcpy(blr->inbuf, inbuf, length);
 115   blr->length = length;
 116
 117   ubi_slAddTail(&blocking_lock_queue, blr);
 118
 119
 120   DEBUG(3,("push_blocking_lock_request: lock request length=%d blocked with expiry time %d (+%d) \
 121 for fnum = %d, name = %s\n", length, (int)blr->expire_time, lock_timeout,
 122         blr->fsp->fnum, blr->fsp->fsp_name ));
 123
 124   return True;
 125 }
 126
 127 /****************************************************************************
 128  Return a smd with a given size.
 129 *****************************************************************************/
 130
 131 static void send_blocking_reply(char *outbuf, int outsize)
 132 {
 133         if(outsize > 4)
 134                 smb_setlen(outbuf,outsize - 4);
 135
 136         if (!send_smb(smbd_server_fd(),outbuf))
 137                 exit_server("send_blocking_reply: send_smb failed.\n");
 138 }
 139
 140 /****************************************************************************
 141  Return a lockingX success SMB.
 142 *****************************************************************************/
 143
 144 static void reply_lockingX_success(blocking_lock_record *blr)
 145 {
 146   char *outbuf = OutBuffer;
 147   int bufsize = BUFFER_SIZE;
 148   char *inbuf = blr->inbuf;
 149   int outsize = 0;
 150
 151   construct_reply_common(inbuf, outbuf);
 152   set_message(outbuf,2,0,True);
 153
 154   /*
 155    * As this message is a lockingX call we must handle
 156    * any following chained message correctly.
 157    * This is normally handled in construct_reply(),
 158    * but as that calls switch_message, we can't use
 159    * that here and must set up the chain info manually.
 160    */
 161
 162   outsize = chain_reply(inbuf,outbuf,blr->length,bufsize);
 163
 164   outsize += chain_size;
 165
 166   send_blocking_reply(outbuf,outsize);
 167 }
 168
 169 /****************************************************************************
 170  Return a generic lock fail error blocking call.
 171 *****************************************************************************/
 172
 173 static void generic_blocking_lock_error(blocking_lock_record *blr, int eclass, int32 ecode)
 174 {
 175         char *outbuf = OutBuffer;
 176         char *inbuf = blr->inbuf;
 177         construct_reply_common(inbuf, outbuf);
 178
 179         if(eclass == 0) /* NT Error. */
 180                 SSVAL(outbuf,smb_flg2, SVAL(outbuf,smb_flg2) | FLAGS2_32_BIT_ERROR_CODES);
 181
 182         ERROR(eclass,ecode);
 183         if (!send_smb(smbd_server_fd(),outbuf))
 184                 exit_server("generic_blocking_lock_error: send_smb failed.\n");
 185 }
 186
 187 /****************************************************************************
 188  Return a lock fail error for a lockingX call. Undo all the locks we have
 189  obtained first.
 190 *****************************************************************************/
 191
 192 static void reply_lockingX_error(blocking_lock_record *blr, int eclass, int32 ecode)
 193 {
 194   char *inbuf = blr->inbuf;
 195   files_struct *fsp = blr->fsp;
 196   connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 197   uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 198   SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT) 0;
 199   uint16 lock_pid;
 200   unsigned char locktype = CVAL(inbuf,smb_vwv3);
 201   BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 202   char *data;
 203   int i;
 204
 205   data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 206
 207   /*
 208    * Data now points at the beginning of the list
 209    * of smb_lkrng structs.
 210    */
 211
 212   /*
 213    * Ensure we don't do a remove on the lock that just failed,
 214    * as under POSIX rules, if we have a lock already there, we
 215    * will delete it (and we shouldn't) .....
 216    */
 217
 218   for(i = blr->lock_num - 1; i >= 0; i--) {
 219     int dummy1;
 220     uint32 dummy2;
 221     BOOL err;
 222
 223     lock_pid = get_lock_pid( data, i, large_file_format);
 224     count = get_lock_count( data, i, large_file_format);
 225     offset = get_lock_offset( data, i, large_file_format, &err);
 226
 227     /*
 228      * We know err cannot be set as if it was the lock
 229      * request would never have been queued. JRA.
 230      */
 231
 232     do_unlock(fsp,conn,lock_pid,count,offset,&dummy1,&dummy2);
 233   }
 234
 235   generic_blocking_lock_error(blr, eclass, ecode);
 236 }
 237
 238 /****************************************************************************
 239  Return a lock fail error.
 240 *****************************************************************************/
 241
 242 static void blocking_lock_reply_error(blocking_lock_record *blr, int eclass, int32 ecode)
 243 {
 244   switch(blr->com_type) {
 245   case SMBlock:
 246     generic_blocking_lock_error(blr, eclass, ecode);
 247     break;
 248   case SMBlockread:
 249     generic_blocking_lock_error(blr, eclass, ecode);
 250     break;
 251   case SMBlockingX:
 252     reply_lockingX_error(blr, eclass, ecode);
 253     break;
 254   default:
 255     DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 256     exit_server("PANIC - unknown type on blocking lock queue");
 257   }
 258 }
 259
 260 /****************************************************************************
 261  Attempt to finish off getting all pending blocking locks for a lockread call.
 262  Returns True if we want to be removed from the list.
 263 *****************************************************************************/
 264
 265 static BOOL process_lockread(blocking_lock_record *blr)
 266 {
 267   char *outbuf = OutBuffer;
 268   char *inbuf = blr->inbuf;
 269   ssize_t nread = -1;
 270   char *data;
 271   int outsize = 0;
 272   SMB_OFF_T startpos;
 273   size_t numtoread;
 274   int eclass;
 275   uint32 ecode;
 276   connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 277   files_struct *fsp = blr->fsp;
 278
 279   numtoread = SVAL(inbuf,smb_vwv1);
 280   startpos = IVAL(inbuf,smb_vwv2);
 281
 282   numtoread = MIN(BUFFER_SIZE-outsize,numtoread);
 283   data = smb_buf(outbuf) + 3;
 284
 285   if(!do_lock( fsp, conn, SVAL(inbuf,smb_pid), (SMB_BIG_UINT)numtoread, (SMB_BIG_UINT)startpos, READ_LOCK, &eclass, &ecode)) {
 286     if((errno != EACCES) && (errno != EAGAIN)) {
 287       /*
 288        * We have other than a "can't get lock" POSIX
 289        * error. Send an error.
 290        * Return True so we get dequeued.
 291        */
 292
 293       generic_blocking_lock_error(blr, eclass, ecode);
 294       return True;
 295     }
 296
 297     /*
 298      * Still waiting for lock....
 299      */
 300
 301     DEBUG(10,("process_lockread: failed to get lock for file = %s. Still waiting....\n",
 302           fsp->fsp_name));
 303     return False;
 304   }
 305
 306   nread = read_file(fsp,data,startpos,numtoread);
 307
 308   if (nread < 0) {
 309     generic_blocking_lock_error(blr,ERRDOS,ERRnoaccess);
 310     return True;
 311   }
 312
 313   construct_reply_common(inbuf, outbuf);
 314   outsize = set_message(outbuf,5,3,True);
 315
 316   outsize += nread;
 317   SSVAL(outbuf,smb_vwv0,nread);
 318   SSVAL(outbuf,smb_vwv5,nread+3);
 319   SSVAL(smb_buf(outbuf),1,nread);
 320
 321   DEBUG(3, ( "process_lockread file = %s, fnum=%d num=%d nread=%d\n",
 322         fsp->fsp_name, fsp->fnum, (int)numtoread, (int)nread ) );
 323
 324   send_blocking_reply(outbuf,outsize);
 325   return True;
 326 }
 327
 328 /****************************************************************************
 329  Attempt to finish off getting all pending blocking locks for a lock call.
 330  Returns True if we want to be removed from the list.
 331 *****************************************************************************/
 332
 333 static BOOL process_lock(blocking_lock_record *blr)
 334 {
 335   char *outbuf = OutBuffer;
 336   char *inbuf = blr->inbuf;
 337   int outsize;
 338   SMB_OFF_T count = 0, offset = 0;
 339   int eclass;
 340   uint32 ecode;
 341   connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 342   files_struct *fsp = blr->fsp;
 343
 344   count = IVAL(inbuf,smb_vwv1);
 345   offset = IVAL(inbuf,smb_vwv3);
 346
 347   errno = 0;
 348   if (!do_lock(fsp, conn, SVAL(inbuf,smb_pid), (SMB_BIG_UINT)count, (SMB_BIG_UINT)offset, WRITE_LOCK, &eclass, &ecode)) {
 349     if((errno != EACCES) && (errno != EAGAIN)) {
 350
 351       /*
 352        * We have other than a "can't get lock" POSIX
 353        * error. Send an error.
 354        * Return True so we get dequeued.
 355        */
 356
 357       blocking_lock_reply_error(blr, eclass, ecode);
 358       return True;
 359     }
 360
 361     /*
 362      * Still can't get the lock - keep waiting.
 363      */
 364
 365     DEBUG(10,("process_lock: failed to get lock for file = %s. Still waiting....\n",
 366           fsp->fsp_name));
 367     return False;
 368   }
 369
 370   /*
 371    * Success - we got the lock.
 372    */
 373
 374   DEBUG(3,("process_lock : file=%s fnum=%d offset=%.0f count=%.0f\n",
 375        fsp->fsp_name, fsp->fnum, (double)offset, (double)count));
 376
 377   construct_reply_common(inbuf, outbuf);
 378   outsize = set_message(outbuf,0,0,True);
 379   send_blocking_reply(outbuf,outsize);
 380   return True;
 381 }
 382
 383 /****************************************************************************
 384  Attempt to finish off getting all pending blocking locks for a lockingX call.
 385  Returns True if we want to be removed from the list.
 386 *****************************************************************************/
 387
 388 static BOOL process_lockingX(blocking_lock_record *blr)
 389 {
 390   char *inbuf = blr->inbuf;
 391   unsigned char locktype = CVAL(inbuf,smb_vwv3);
 392   files_struct *fsp = blr->fsp;
 393   connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 394   uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 395   uint16 num_locks = SVAL(inbuf,smb_vwv7);
 396   SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT)0;
 397   uint16 lock_pid;
 398   BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 399   char *data;
 400   int eclass=0;
 401   uint32 ecode=0;
 402
 403   data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 404
 405   /*
 406    * Data now points at the beginning of the list
 407    * of smb_lkrng structs.
 408    */
 409
 410   for(; blr->lock_num < num_locks; blr->lock_num++) {
 411     BOOL err;
 412
 413     lock_pid = get_lock_pid( data, blr->lock_num, large_file_format);
 414     count = get_lock_count( data, blr->lock_num, large_file_format);
 415     offset = get_lock_offset( data, blr->lock_num, large_file_format, &err);
 416
 417     /*
 418      * We know err cannot be set as if it was the lock
 419      * request would never have been queued. JRA.
 420      */
 421     errno = 0;
 422     if(!do_lock(fsp,conn,count,lock_pid,offset, ((locktype & 1) ? READ_LOCK : WRITE_LOCK),
 423                 &eclass, &ecode))
 424       break;
 425   }
 426
 427   if(blr->lock_num == num_locks) {
 428
 429     /*
 430      * Success - we got all the locks.
 431      */
 432
 433     DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n",
 434           fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) );
 435
 436     reply_lockingX_success(blr);
 437     return True;
 438
 439   } else if((errno != EACCES) && (errno != EAGAIN)) {
 440
 441     /*
 442      * We have other than a "can't get lock" POSIX
 443      * error. Free any locks we had and return an error.
 444      * Return True so we get dequeued.
 445      */
 446
 447     blocking_lock_reply_error(blr, eclass, ecode);
 448     return True;
 449   }
 450
 451   /*
 452    * Still can't get all the locks - keep waiting.
 453    */
 454
 455   DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \
 456 Waiting....\n", blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum));
 457
 458   return False;
 459 }
 460
 461 /****************************************************************************
 462  Process a blocking lock SMB.
 463  Returns True if we want to be removed from the list.
 464 *****************************************************************************/
 465
 466 static BOOL blocking_lock_record_process(blocking_lock_record *blr)
 467 {
 468   switch(blr->com_type) {
 469   case SMBlock:
 470     return process_lock(blr);
 471   case SMBlockread:
 472     return process_lockread(blr);
 473   case SMBlockingX:
 474     return process_lockingX(blr);
 475   default:
 476     DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 477     exit_server("PANIC - unknown type on blocking lock queue");
 478   }
 479   return False; /* Keep compiler happy. */
 480 }
 481
 482 /****************************************************************************
 483  Delete entries by fnum from the blocking lock pending queue.
 484 *****************************************************************************/
 485
 486 void remove_pending_lock_requests_by_fid(files_struct *fsp)
 487 {
 488   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 489   blocking_lock_record *prev = NULL;
 490
 491   while(blr != NULL) {
 492     if(blr->fsp->fnum == fsp->fnum) {
 493
 494       DEBUG(10,("remove_pending_lock_requests_by_fid - removing request type %d for \
 495 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 496
 497       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 498       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 499       continue;
 500     }
 501
 502     prev = blr;
 503     blr = (blocking_lock_record *)ubi_slNext(blr);
 504   }
 505 }
 506
 507 /****************************************************************************
 508  Delete entries by mid from the blocking lock pending queue. Always send reply.
 509 *****************************************************************************/
 510
 511 void remove_pending_lock_requests_by_mid(int mid)
 512 {
 513   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 514   blocking_lock_record *prev = NULL;
 515
 516   while(blr != NULL) {
 517     if(SVAL(blr->inbuf,smb_mid) == mid) {
 518       files_struct *fsp = blr->fsp;
 519
 520       DEBUG(10,("remove_pending_lock_requests_by_mid - removing request type %d for \
 521 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 522
 523       blocking_lock_reply_error(blr,0,NT_STATUS_CANCELLED);
 524       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 525       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 526       continue;
 527     }
 528
 529     prev = blr;
 530     blr = (blocking_lock_record *)ubi_slNext(blr);
 531   }
 532 }
 533
 534 /****************************************************************************
 535  Return True if the blocking lock queue has entries.
 536 *****************************************************************************/
 537
 538 BOOL blocking_locks_pending(void)
 539 {
 540   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 541   return (blr == NULL ? False : True);
 542 }
 543
 544 /****************************************************************************
 545  Process the blocking lock queue. Note that this is only called as root.
 546 *****************************************************************************/
 547
 548 void process_blocking_lock_queue(time_t t)
 549 {
 550   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 551   blocking_lock_record *prev = NULL;
 552
 553   if(blr == NULL)
 554     return;
 555
 556   /*
 557    * Go through the queue and see if we can get any of the locks.
 558    */
 559
 560   while(blr != NULL) {
 561     connection_struct *conn = NULL;
 562     uint16 vuid;
 563     files_struct *fsp = NULL;
 564
 565     /*
 566      * Ensure we don't have any old chain_fsp values
 567      * sitting around....
 568      */
 569     chain_size = 0;
 570     file_chain_reset();
 571     fsp = blr->fsp;
 572
 573     conn = conn_find(SVAL(blr->inbuf,smb_tid));
 574     vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
 575                   SVAL(blr->inbuf,smb_uid);
 576
 577     DEBUG(5,("process_blocking_lock_queue: examining pending lock fnum = %d for file %s\n",
 578           fsp->fnum, fsp->fsp_name ));
 579
 580     if((blr->expire_time != -1) && (blr->expire_time > t)) {
 581       /*
 582        * Lock expired - throw away all previously
 583        * obtained locks and return lock error.
 584        */
 585       DEBUG(5,("process_blocking_lock_queue: pending lock fnum = %d for file %s timed out.\n",
 586           fsp->fnum, fsp->fsp_name ));
 587
 588       blocking_lock_reply_error(blr,ERRSRV,ERRaccess);
 589       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 590       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 591       continue;
 592     }
 593
 594     if(!become_user(conn,vuid)) {
 595       DEBUG(0,("process_blocking_lock_queue: Unable to become user vuid=%d.\n",
 596             vuid ));
 597       /*
 598        * Remove the entry and return an error to the client.
 599        */
 600       blocking_lock_reply_error(blr,ERRSRV,ERRaccess);
 601       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 602       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 603       continue;
 604     }
 605
 606     if(!become_service(conn,True)) {
 607       DEBUG(0,("process_blocking_lock_queue: Unable to become service Error was %s.\n", strerror(errno) ));
 608       /*
 609        * Remove the entry and return an error to the client.
 610        */
 611       blocking_lock_reply_error(blr,ERRSRV,ERRaccess);
 612       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 613       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 614       unbecome_user();
 615       continue;
 616     }
 617
 618     /*
 619      * Go through the remaining locks and try and obtain them.
 620      * The call returns True if all locks were obtained successfully
 621      * and False if we still need to wait.
 622      */
 623
 624     if(blocking_lock_record_process(blr)) {
 625       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 626       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 627       unbecome_user();
 628       continue;
 629     }
 630
 631     unbecome_user();
 632
 633     /*
 634      * Move to the next in the list.
 635      */
 636     prev = blr;
 637     blr = (blocking_lock_record *)ubi_slNext(blr);
 638   }
 639 }