source3/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 /****************************************************************************
  41  Return a unique number identifying this fsp over the life of this pid.
  42 ****************************************************************************/
  43
  44 static unsigned long get_gen_count(void)
  45 {
  46         static unsigned long file_gen_counter;
  47
  48         if ((++file_gen_counter) == 0)
  49                 return ++file_gen_counter;
  50         return file_gen_counter;
  51 }
  52
  53 /****************************************************************************
  54  Find first available file slot.
  55 ****************************************************************************/
  56
  57 files_struct *file_new(connection_struct *conn)
  58 {
  59         int i;
  60         static int first_file;
  61         files_struct *fsp, *next;
  62
  63         /* we want to give out file handles differently on each new
  64            connection because of a common bug in MS clients where they try to
  65            reuse a file descriptor from an earlier smb connection. This code
  66            increases the chance that the errant client will get an error rather
  67            than causing corruption */
  68         if (first_file == 0) {
  69                 first_file = (sys_getpid() ^ (int)time(NULL)) % real_max_open_files;
  70         }
  71
  72         i = bitmap_find(file_bmap, first_file);
  73         if (i == -1) {
  74                 /*
  75                  * Before we give up, go through the open files
  76                  * and see if there are any files opened with a
  77                  * batch oplock. If so break the oplock and then
  78                  * re-use that entry (if it becomes closed).
  79                  * This may help as NT/95 clients tend to keep
  80                  * files batch oplocked for quite a long time
  81                  * after they have finished with them.
  82                  */
  83                 for (fsp=Files;fsp;fsp=next) {
  84                         next=fsp->next;
  85                         if (attempt_close_oplocked_file(fsp)) {
  86                                 return file_new(conn);
  87                         }
  88                 }
  89
  90                 DEBUG(0,("ERROR! Out of file structures\n"));
  91                 unix_ERR_class = ERRSRV;
  92                 unix_ERR_code = ERRnofids;
  93                 return NULL;
  94         }
  95
  96         fsp = (files_struct *)malloc(sizeof(*fsp));
  97         if (!fsp) {
  98                 unix_ERR_class = ERRSRV;
  99                 unix_ERR_code = ERRnofids;
 100                 return NULL;
 101         }
 102
 103         ZERO_STRUCTP(fsp);
 104         fsp->fd = -1;
 105         fsp->conn = conn;
 106         fsp->file_id = get_gen_count();
 107         GetTimeOfDay(&fsp->open_time);
 108
 109         first_file = (i+1) % real_max_open_files;
 110
 111         bitmap_set(file_bmap, i);
 112         files_used++;
 113
 114         fsp->fnum = i + FILE_HANDLE_OFFSET;
 115         SMB_ASSERT(fsp->fnum < 65536);
 116
 117         string_set(&fsp->fsp_name,"");
 118
 119         DLIST_ADD(Files, fsp);
 120
 121         DEBUG(5,("allocated file structure %d, fnum = %d (%d used)\n",
 122                  i, fsp->fnum, files_used));
 123
 124         chain_fsp = fsp;
 125
 126         return fsp;
 127 }
 128
 129 /****************************************************************************
 130  Close all open files for a connection.
 131 ****************************************************************************/
 132
 133 void file_close_conn(connection_struct *conn)
 134 {
 135         files_struct *fsp, *next;
 136
 137         for (fsp=Files;fsp;fsp=next) {
 138                 next = fsp->next;
 139                 if (fsp->conn == conn) {
 140                         close_file(fsp,False);
 141                 }
 142         }
 143 }
 144
 145 /****************************************************************************
 146  Close all open files for a pid.
 147 ****************************************************************************/
 148
 149 void file_close_pid(uint16 smbpid)
 150 {
 151         files_struct *fsp, *next;
 152
 153         for (fsp=Files;fsp;fsp=next) {
 154                 next = fsp->next;
 155                 if (fsp->file_pid == smbpid) {
 156                         close_file(fsp,False);
 157                 }
 158         }
 159 }
 160
 161 /****************************************************************************
 162  Initialise file structures.
 163 ****************************************************************************/
 164
 165 #define MAX_OPEN_FUDGEFACTOR 20
 166
 167 void file_init(void)
 168 {
 169         int request_max_open_files = lp_max_open_files();
 170         int real_lim;
 171
 172         /*
 173          * Set the max_open files to be the requested
 174          * max plus a fudgefactor to allow for the extra
 175          * fd's we need such as log files etc...
 176          */
 177         real_lim = set_maxfiles(request_max_open_files + MAX_OPEN_FUDGEFACTOR);
 178
 179         real_max_open_files = real_lim - MAX_OPEN_FUDGEFACTOR;
 180
 181         if (real_max_open_files + FILE_HANDLE_OFFSET + MAX_OPEN_PIPES > 65536)
 182                 real_max_open_files = 65536 - FILE_HANDLE_OFFSET - MAX_OPEN_PIPES;
 183
 184         if(real_max_open_files != request_max_open_files) {
 185                 DEBUG(1,("file_init: Information only: requested %d \
 186 open files, %d are available.\n", request_max_open_files, real_max_open_files));
 187         }
 188
 189         SMB_ASSERT(real_max_open_files > 100);
 190
 191         file_bmap = bitmap_allocate(real_max_open_files);
 192
 193         if (!file_bmap) {
 194                 exit_server("out of memory in file_init");
 195         }
 196
 197         /*
 198          * Ensure that pipe_handle_oppset is set correctly.
 199          */
 200         set_pipe_handle_offset(real_max_open_files);
 201 }
 202
 203 /****************************************************************************
 204  Close files open by a specified vuid.
 205 ****************************************************************************/
 206
 207 void file_close_user(int vuid)
 208 {
 209         files_struct *fsp, *next;
 210
 211         for (fsp=Files;fsp;fsp=next) {
 212                 next=fsp->next;
 213                 if (fsp->vuid == vuid) {
 214                         close_file(fsp,False);
 215                 }
 216         }
 217 }
 218
 219 void file_dump_open_table(void)
 220 {
 221         int count=0;
 222         files_struct *fsp;
 223
 224         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 225                 DEBUG(10,("Files[%d], fnum = %d, name %s, fd = %d, fileid = %lu, dev = %x, inode = %.0f\n",
 226                         count, fsp->fnum, fsp->fsp_name, fsp->fd, (unsigned long)fsp->file_id,
 227                         (unsigned int)fsp->dev, (double)fsp->inode ));
 228         }
 229 }
 230
 231 /****************************************************************************
 232  Find a fsp given a file descriptor.
 233 ****************************************************************************/
 234
 235 files_struct *file_find_fd(int fd)
 236 {
 237         int count=0;
 238         files_struct *fsp;
 239
 240         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 241                 if (fsp->fd == fd) {
 242                         if (count > 10) {
 243                                 DLIST_PROMOTE(Files, fsp);
 244                         }
 245                         return fsp;
 246                 }
 247         }
 248
 249         return NULL;
 250 }
 251
 252 /****************************************************************************
 253  Find a fsp given a device, inode and file_id.
 254 ****************************************************************************/
 255
 256 files_struct *file_find_dif(SMB_DEV_T dev, SMB_INO_T inode, unsigned long file_id)
 257 {
 258         int count=0;
 259         files_struct *fsp;
 260
 261         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 262                 /* We can have a fsp->fd == -1 here as it could be a stat open. */
 263                 if (fsp->dev == dev &&
 264                     fsp->inode == inode &&
 265                     fsp->file_id == file_id ) {
 266                         if (count > 10) {
 267                                 DLIST_PROMOTE(Files, fsp);
 268                         }
 269                         /* Paranoia check. */
 270                         if (fsp->fd == -1 && fsp->oplock_type != NO_OPLOCK) {
 271                                 DEBUG(0,("file_find_dif: file %s dev = %x, inode = %.0f, file_id = %u \
 272 oplock_type = %u is a stat open with oplock type !\n", fsp->fsp_name, (unsigned int)fsp->dev,
 273                                                 (double)fsp->inode, (unsigned int)fsp->file_id,
 274                                                 (unsigned int)fsp->oplock_type ));
 275                                 smb_panic("file_find_dif\n");
 276                         }
 277                         return fsp;
 278                 }
 279         }
 280
 281         return NULL;
 282 }
 283
 284 /****************************************************************************
 285  Check if an fsp still exists.
 286 ****************************************************************************/
 287
 288 files_struct *file_find_fsp(files_struct *orig_fsp)
 289 {
 290         files_struct *fsp;
 291
 292     for (fsp=Files;fsp;fsp=fsp->next) {
 293         if (fsp == orig_fsp)
 294             return fsp;
 295     }
 296
 297     return NULL;
 298 }
 299
 300 /****************************************************************************
 301  Find the first fsp given a device and inode.
 302 ****************************************************************************/
 303
 304 files_struct *file_find_di_first(SMB_DEV_T dev, SMB_INO_T inode)
 305 {
 306     files_struct *fsp;
 307
 308     for (fsp=Files;fsp;fsp=fsp->next) {
 309         if ( fsp->fd != -1 &&
 310             fsp->dev == dev &&
 311             fsp->inode == inode )
 312             return fsp;
 313     }
 314
 315     return NULL;
 316 }
 317
 318 /****************************************************************************
 319  Find the next fsp having the same device and inode.
 320 ****************************************************************************/
 321
 322 files_struct *file_find_di_next(files_struct *start_fsp)
 323 {
 324     files_struct *fsp;
 325
 326     for (fsp = start_fsp->next;fsp;fsp=fsp->next) {
 327         if ( fsp->fd != -1 &&
 328             fsp->dev == start_fsp->dev &&
 329             fsp->inode == start_fsp->inode )
 330             return fsp;
 331     }
 332
 333     return NULL;
 334 }
 335
 336 /****************************************************************************
 337  Find a fsp that is open for printing.
 338 ****************************************************************************/
 339
 340 files_struct *file_find_print(void)
 341 {
 342         files_struct *fsp;
 343
 344         for (fsp=Files;fsp;fsp=fsp->next) {
 345                 if (fsp->print_file) return fsp;
 346         }
 347
 348         return NULL;
 349 }
 350
 351 /****************************************************************************
 352  Sync open files on a connection.
 353 ****************************************************************************/
 354
 355 void file_sync_all(connection_struct *conn)
 356 {
 357         files_struct *fsp, *next;
 358
 359         for (fsp=Files;fsp;fsp=next) {
 360                 next=fsp->next;
 361                 if ((conn == fsp->conn) && (fsp->fd != -1)) {
 362                         sync_file(conn,fsp);
 363                 }
 364         }
 365 }
 366
 367 /****************************************************************************
 368  Free up a fsp.
 369 ****************************************************************************/
 370
 371 void file_free(files_struct *fsp)
 372 {
 373         DLIST_REMOVE(Files, fsp);
 374
 375         string_free(&fsp->fsp_name);
 376
 377         if (fsp->fake_file_handle) {
 378                 destroy_fake_file_handle(&fsp->fake_file_handle);
 379         }
 380
 381         bitmap_clear(file_bmap, fsp->fnum - FILE_HANDLE_OFFSET);
 382         files_used--;
 383
 384         DEBUG(5,("freed files structure %d (%d used)\n",
 385                  fsp->fnum, files_used));
 386
 387         /* this is paranoia, just in case someone tries to reuse the
 388            information */
 389         ZERO_STRUCTP(fsp);
 390
 391         if (fsp == chain_fsp) chain_fsp = NULL;
 392
 393         SAFE_FREE(fsp);
 394 }
 395
 396 /****************************************************************************
 397  Get a fsp from a packet given the offset of a 16 bit fnum.
 398 ****************************************************************************/
 399
 400 files_struct *file_fsp(char *buf, int where)
 401 {
 402         int fnum, count=0;
 403         files_struct *fsp;
 404
 405         if (chain_fsp)
 406                 return chain_fsp;
 407
 408         if (!buf)
 409                 return NULL;
 410         fnum = SVAL(buf, where);
 411
 412         for (fsp=Files;fsp;fsp=fsp->next, count++) {
 413                 if (fsp->fnum == fnum) {
 414                         chain_fsp = fsp;
 415                         if (count > 10) {
 416                                 DLIST_PROMOTE(Files, fsp);
 417                         }
 418                         return fsp;
 419                 }
 420         }
 421         return NULL;
 422 }
 423
 424 /****************************************************************************
 425  Reset the chained fsp - done at the start of a packet reply.
 426 ****************************************************************************/
 427
 428 void file_chain_reset(void)
 429 {
 430         chain_fsp = NULL;
 431 }
 432
 433 /****************************************************************************
 434 Save the chained fsp - done when about to do an oplock break.
 435 ****************************************************************************/
 436
 437 void file_chain_save(void)
 438 {
 439         oplock_save_chain_fsp = chain_fsp;
 440 }
 441
 442 /****************************************************************************
 443 Restore the chained fsp - done after an oplock break.
 444 ****************************************************************************/
 445
 446 void file_chain_restore(void)
 447 {
 448         chain_fsp = oplock_save_chain_fsp;
 449 }