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