source/smbd/files.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Files[] structure handling
   4    Copyright (C) Andrew Tridgell 1998
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include "includes.h"
  22
  23 static int real_max_open_files;
  24
  25 #define VALID_FNUM(fnum)   (((fnum) >= 0) && ((fnum) < real_max_open_files))
  26
  27 #define FILE_HANDLE_OFFSET 0x1000
  28
  29 static struct bitmap *file_bmap;
  30
  31 static files_struct *Files;
  32
  33 /* a fsp to use when chaining */
  34 static files_struct *chain_fsp = NULL;
  35 /* a fsp to use to save when breaking an oplock. */
  36 static files_struct *oplock_save_chain_fsp = NULL;
  37
  38 static int files_used;
  39
  40 /* A singleton cache to speed up searching by dev/inode. */
  41 static struct fsp_singleton_cache {
  42         files_struct *fsp;
  43         SMB_DEV_T dev;
  44         SMB_INO_T inode;
  45 } fsp_fi_cache;
  46
  47 /****************************************************************************
  48  Return a unique number identifying this fsp over the life of this pid.
  49 ****************************************************************************/
  50
  51 static unsigned long get_gen_count(void)
  52 {
  53         static unsigned long file_gen_counter;
  54
  55         if ((++file_gen_counter) == 0)
  56                 return ++file_gen_counter;
  57         return file_gen_counter;
  58 }
  59
  60 /****************************************************************************
  61  Find first available file slot.
  62 ****************************************************************************/
  63
  64 files_struct *file_new(connection_struct *conn)
  65 {
  66         int i;
  67         static int first_file;
  68         files_struct *fsp, *next;
  69
  70         /* we want to give out file handles differently on each new
  71            connection because of a common bug in MS clients where they try to
  72            reuse a file descriptor from an earlier smb connection. This code
  73            increases the chance that the errant client will get an error rather
  74            than causing corruption */
  75         if (first_file == 0) {
  76                 first_file = (sys_getpid() ^ (int)time(NULL)) % real_max_open_files;
  77         }
  78
  79         i = bitmap_find(file_bmap, first_file);
  80         if (i == -1) {
  81                 /*
  82                  * Before we give up, go through the open files
  83                  * and see if there are any files opened with a
  84                  * batch oplock. If so break the oplock and then
  85                  * re-use that entry (if it becomes closed).
  86                  * This may help as NT/95 clients tend to keep
  87                  * files batch oplocked for quite a long time
  88                  * after they have finished with them.
  89                  */
  90                 for (fsp=Files;fsp;fsp=next) {
  91                         next=fsp->next;
  92                         if (attempt_close_oplocked_file(fsp)) {
  93                                 return file_new(conn);
  94                         }
  95                 }
  96
  97                 DEBUG(0,("ERROR! Out of file structures\n"));
  98                 set_saved_error_triple(ERRSRV, ERRnofids, NT_STATUS_TOO_MANY_OPENED_FILES);
  99                 return NULL;
 100         }
 101
 102         fsp = SMB_MALLOC_P(files_struct);
 103         if (!fsp) {
 104                 set_saved_error_triple(ERRDOS, ERRnomem, NT_STATUS_NO_MEMORY);
 105                 return NULL;
 106         }
 107
 108         ZERO_STRUCTP(fsp);
 109         fsp->fd = -1;
 110         fsp->conn = conn;
 111         fsp->file_id = get_gen_count();
 112         GetTimeOfDay(&fsp->open_time);
 113
 114         first_file = (i+1) % real_max_open_files;
 115
 116         bitmap_set(file_bmap, i);
 117         files_used++;
 118
 119         fsp->fnum = i + FILE_HANDLE_OFFSET;
 120         SMB_ASSERT(fsp->fnum < 65536);
 121
 122         string_set(&fsp->fsp_name,"");
 123
 124         DLIST_ADD(Files, fsp);
 125
 126         DEBUG(5,("allocated file structure %d, fnum = %d (%d used)\n",
 127                  i, fsp->fnum, files_used));
 128
 129         chain_fsp = fsp;
 130
 131         /* A new fsp invalidates a negative fsp_fi_cache. */
 132         if (fsp_fi_cache.fsp == NULL) {
 133                 ZERO_STRUCT(fsp_fi_cache);
 134         }
 135
 136         return fsp;
 137 }
 138
 139 /****************************************************************************
 140  Close all open files for a connection.
 141 ****************************************************************************/
 142
 143 void file_close_conn(connection_struct *conn)
 144 {
 145         files_struct *fsp, *next;
 146
 147         for (fsp=Files;fsp;fsp=next) {
 148                 next = fsp->next;
 149                 if (fsp->conn == conn) {
 150                         close_file(fsp,False);
 151                 }
 152         }
 153 }
 154
 155 /****************************************************************************
 156  Close all open files for a pid.
 157 ****************************************************************************/
 158
 159 void file_close_pid(uint16 smbpid)
 160 {
 161         files_struct *fsp, *next;
 162
 163         for (fsp=Files;fsp;fsp=next) {
 164                 next = fsp->next;
 165                 if (fsp->file_pid == smbpid) {
 166                         close_file(fsp,False);
 167                 }
 168         }
 169 }
 170
 171 /****************************************************************************
 172  Initialise file structures.
 173 ****************************************************************************/
 174
 175 #define MAX_OPEN_FUDGEFACTOR 20
 176
 177 void file_init(void)
 178 {
 179         int request_max_open_files = lp_max_open_files();
 180         int real_lim;
 181
 182         /*
 183          * Set the max_open files to be the requested
 184          * max plus a fudgefactor to allow for the extra
 185          * fd's we need such as log files etc...
 186          */
 187         real_lim = set_maxfiles(request_max_open_files + MAX_OPEN_FUDGEFACTOR);
 188
 189         real_max_open_files = real_lim - MAX_OPEN_FUDGEFACTOR;
 190
 191         if (real_max_open_files + FILE_HANDLE_OFFSET + MAX_OPEN_PIPES > 65536)
 192                 real_max_open_files = 65536 - FILE_HANDLE_OFFSET - MAX_OPEN_PIPES;
 193
 194         if(real_max_open_files != request_max_open_files) {
 195                 DEBUG(1,("file_init: Information only: requested %d \
 196 open files, %d are available.\n", request_max_open_files, real_max_open_files));
 197         }
 198
 199         SMB_ASSERT(real_max_open_files > 100);
 200
 201         file_bmap = bitmap_allocate(real_max_open_files);
 202
 203         if (!file_bmap) {
 204                 exit_server("out of memory in file_init");
 205         }
 206
 207         /*
 208          * Ensure that pipe_handle_oppset is set correctly.
 209          */
 210         set_pipe_handle_offset(real_max_open_files);
 211 }
 212
 213 /****************************************************************************
 214  Close files open by a specified vuid.
 215 ****************************************************************************/
 216
 217 void file_close_user(int vuid)
 218 {
 219         files_struct *fsp, *next;
 220
 221         for (fsp=Files;fsp;fsp=next) {
 222                 next=fsp->next;
 223                 if (fsp->vuid == vuid) {
 224                         close_file(fsp,False);
 225                 }
 226         }
 227 }
 228
 229 void file_dump_open_table(void)
 230 {
 231         int count=0;
 232         files_struct *fsp;
 233
 234         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 235                 DEBUG(10,("Files[%d], fnum = %d, name %s, fd = %d, fileid = %lu, dev = %x, inode = %.0f\n",
 236                         count, fsp->fnum, fsp->fsp_name, fsp->fd, (unsigned long)fsp->file_id,
 237                         (unsigned int)fsp->dev, (double)fsp->inode ));
 238         }
 239 }
 240
 241 /****************************************************************************
 242  Find a fsp given a file descriptor.
 243 ****************************************************************************/
 244
 245 files_struct *file_find_fd(int fd)
 246 {
 247         int count=0;
 248         files_struct *fsp;
 249
 250         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 251                 if (fsp->fd == fd) {
 252                         if (count > 10) {
 253                                 DLIST_PROMOTE(Files, fsp);
 254                         }
 255                         return fsp;
 256                 }
 257         }
 258
 259         return NULL;
 260 }
 261
 262 /****************************************************************************
 263  Find a fsp given a device, inode and file_id.
 264 ****************************************************************************/
 265
 266 files_struct *file_find_dif(SMB_DEV_T dev, SMB_INO_T inode, unsigned long file_id)
 267 {
 268         int count=0;
 269         files_struct *fsp;
 270
 271         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 272                 /* We can have a fsp->fd == -1 here as it could be a stat open. */
 273                 if (fsp->dev == dev &&
 274                     fsp->inode == inode &&
 275                     fsp->file_id == file_id ) {
 276                         if (count > 10) {
 277                                 DLIST_PROMOTE(Files, fsp);
 278                         }
 279                         /* Paranoia check. */
 280                         if (fsp->fd == -1 && fsp->oplock_type != NO_OPLOCK) {
 281                                 DEBUG(0,("file_find_dif: file %s dev = %x, inode = %.0f, file_id = %u \
 282 oplock_type = %u is a stat open with oplock type !\n", fsp->fsp_name, (unsigned int)fsp->dev,
 283                                                 (double)fsp->inode, (unsigned int)fsp->file_id,
 284                                                 (unsigned int)fsp->oplock_type ));
 285                                 smb_panic("file_find_dif\n");
 286                         }
 287                         return fsp;
 288                 }
 289         }
 290
 291         return NULL;
 292 }
 293
 294 /****************************************************************************
 295  Check if an fsp still exists.
 296 ****************************************************************************/
 297
 298 files_struct *file_find_fsp(files_struct *orig_fsp)
 299 {
 300         files_struct *fsp;
 301
 302         for (fsp=Files;fsp;fsp=fsp->next) {
 303                 if (fsp == orig_fsp)
 304                         return fsp;
 305         }
 306
 307         return NULL;
 308 }
 309
 310 /****************************************************************************
 311  Find the first fsp given a device and inode.
 312  We use a singleton cache here to speed up searching from getfilepathinfo
 313  calls.
 314 ****************************************************************************/
 315
 316 files_struct *file_find_di_first(SMB_DEV_T dev, SMB_INO_T inode)
 317 {
 318         files_struct *fsp;
 319
 320         if (fsp_fi_cache.dev == dev && fsp_fi_cache.inode == inode) {
 321                 /* Positive or negative cache hit. */
 322                 return fsp_fi_cache.fsp;
 323         }
 324
 325         fsp_fi_cache.dev = dev;
 326         fsp_fi_cache.inode = inode;
 327
 328         for (fsp=Files;fsp;fsp=fsp->next) {
 329                 if ( fsp->fd != -1 &&
 330                                 fsp->dev == dev &&
 331                                 fsp->inode == inode ) {
 332                         /* Setup positive cache. */
 333                         fsp_fi_cache.fsp = fsp;
 334                         return fsp;
 335                 }
 336         }
 337
 338         /* Setup negative cache. */
 339         fsp_fi_cache.fsp = NULL;
 340         return NULL;
 341 }
 342
 343 /****************************************************************************
 344  Find the next fsp having the same device and inode.
 345 ****************************************************************************/
 346
 347 files_struct *file_find_di_next(files_struct *start_fsp)
 348 {
 349         files_struct *fsp;
 350
 351         for (fsp = start_fsp->next;fsp;fsp=fsp->next) {
 352                 if ( fsp->fd != -1 &&
 353                                 fsp->dev == start_fsp->dev &&
 354                                 fsp->inode == start_fsp->inode )
 355                         return fsp;
 356         }
 357
 358         return NULL;
 359 }
 360
 361 /****************************************************************************
 362  Find a fsp that is open for printing.
 363 ****************************************************************************/
 364
 365 files_struct *file_find_print(void)
 366 {
 367         files_struct *fsp;
 368
 369         for (fsp=Files;fsp;fsp=fsp->next) {
 370                 if (fsp->print_file) {
 371                         return fsp;
 372                 }
 373         }
 374
 375         return NULL;
 376 }
 377
 378 /****************************************************************************
 379  Set a pending modtime across all files with a given dev/ino pair.
 380  Record the owner of that modtime.
 381 ****************************************************************************/
 382
 383 void fsp_set_pending_modtime(files_struct *tfsp, time_t pmod)
 384 {
 385         files_struct *fsp;
 386
 387         if (null_mtime(pmod)) {
 388                 return;
 389         }
 390
 391         for (fsp = Files;fsp;fsp=fsp->next) {
 392                 if ( fsp->fd != -1 &&
 393                                 fsp->dev == tfsp->dev &&
 394                                 fsp->inode == tfsp->inode ) {
 395                         fsp->pending_modtime = pmod;
 396                         fsp->pending_modtime_owner = False;
 397                 }
 398         }
 399
 400         tfsp->pending_modtime_owner = True;
 401 }
 402
 403 /****************************************************************************
 404  Sync open files on a connection.
 405 ****************************************************************************/
 406
 407 void file_sync_all(connection_struct *conn)
 408 {
 409         files_struct *fsp, *next;
 410
 411         for (fsp=Files;fsp;fsp=next) {
 412                 next=fsp->next;
 413                 if ((conn == fsp->conn) && (fsp->fd != -1)) {
 414                         sync_file(conn,fsp);
 415                 }
 416         }
 417 }
 418
 419 /****************************************************************************
 420  Free up a fsp.
 421 ****************************************************************************/
 422
 423 void file_free(files_struct *fsp)
 424 {
 425         DLIST_REMOVE(Files, fsp);
 426
 427         string_free(&fsp->fsp_name);
 428
 429         if (fsp->fake_file_handle) {
 430                 destroy_fake_file_handle(&fsp->fake_file_handle);
 431         }
 432
 433         bitmap_clear(file_bmap, fsp->fnum - FILE_HANDLE_OFFSET);
 434         files_used--;
 435
 436         DEBUG(5,("freed files structure %d (%d used)\n",
 437                  fsp->fnum, files_used));
 438
 439         /* this is paranoia, just in case someone tries to reuse the
 440            information */
 441         ZERO_STRUCTP(fsp);
 442
 443         if (fsp == chain_fsp) {
 444                 chain_fsp = NULL;
 445         }
 446
 447         /* Closing a file can invalidate the positive cache. */
 448         if (fsp == fsp_fi_cache.fsp) {
 449                 ZERO_STRUCT(fsp_fi_cache);
 450         }
 451
 452         SAFE_FREE(fsp);
 453 }
 454
 455 /****************************************************************************
 456  Get a fsp from a packet given the offset of a 16 bit fnum.
 457 ****************************************************************************/
 458
 459 files_struct *file_fsp(char *buf, int where)
 460 {
 461         int fnum, count=0;
 462         files_struct *fsp;
 463
 464         if (chain_fsp)
 465                 return chain_fsp;
 466
 467         if (!buf)
 468                 return NULL;
 469         fnum = SVAL(buf, where);
 470
 471         for (fsp=Files;fsp;fsp=fsp->next, count++) {
 472                 if (fsp->fnum == fnum) {
 473                         chain_fsp = fsp;
 474                         if (count > 10) {
 475                                 DLIST_PROMOTE(Files, fsp);
 476                         }
 477                         return fsp;
 478                 }
 479         }
 480         return NULL;
 481 }
 482
 483 /****************************************************************************
 484  Reset the chained fsp - done at the start of a packet reply.
 485 ****************************************************************************/
 486
 487 void file_chain_reset(void)
 488 {
 489         chain_fsp = NULL;
 490 }
 491
 492 /****************************************************************************
 493 Save the chained fsp - done when about to do an oplock break.
 494 ****************************************************************************/
 495
 496 void file_chain_save(void)
 497 {
 498         oplock_save_chain_fsp = chain_fsp;
 499 }
 500
 501 /****************************************************************************
 502 Restore the chained fsp - done after an oplock break.
 503 ****************************************************************************/
 504
 505 void file_chain_restore(void)
 506 {
 507         chain_fsp = oplock_save_chain_fsp;
 508 }