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