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 /****************************************************************************
  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  Initialise file structures.
 147 ****************************************************************************/
 148
 149 #define MAX_OPEN_FUDGEFACTOR 20
 150
 151 void file_init(void)
 152 {
 153         int request_max_open_files = lp_max_open_files();
 154         int real_lim;
 155
 156         /*
 157          * Set the max_open files to be the requested
 158          * max plus a fudgefactor to allow for the extra
 159          * fd's we need such as log files etc...
 160          */
 161         real_lim = set_maxfiles(request_max_open_files + MAX_OPEN_FUDGEFACTOR);
 162
 163         real_max_open_files = real_lim - MAX_OPEN_FUDGEFACTOR;
 164
 165         if (real_max_open_files + FILE_HANDLE_OFFSET + MAX_OPEN_PIPES > 65536)
 166                 real_max_open_files = 65536 - FILE_HANDLE_OFFSET - MAX_OPEN_PIPES;
 167
 168         if(real_max_open_files != request_max_open_files) {
 169                 DEBUG(1,("file_init: Information only: requested %d \
 170 open files, %d are available.\n", request_max_open_files, real_max_open_files));
 171         }
 172
 173         SMB_ASSERT(real_max_open_files > 100);
 174
 175         file_bmap = bitmap_allocate(real_max_open_files);
 176
 177         if (!file_bmap) {
 178                 exit_server("out of memory in file_init");
 179         }
 180
 181         /*
 182          * Ensure that pipe_handle_oppset is set correctly.
 183          */
 184         set_pipe_handle_offset(real_max_open_files);
 185 }
 186
 187 /****************************************************************************
 188  Close files open by a specified vuid.
 189 ****************************************************************************/
 190
 191 void file_close_user(int vuid)
 192 {
 193         files_struct *fsp, *next;
 194
 195         for (fsp=Files;fsp;fsp=next) {
 196                 next=fsp->next;
 197                 if (fsp->vuid == vuid) {
 198                         close_file(fsp,False);
 199                 }
 200         }
 201 }
 202
 203 /****************************************************************************
 204  Find a fsp given a file descriptor.
 205 ****************************************************************************/
 206
 207 files_struct *file_find_fd(int fd)
 208 {
 209         int count=0;
 210         files_struct *fsp;
 211
 212         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 213                 if (fsp->fd == fd) {
 214                         if (count > 10) {
 215                                 DLIST_PROMOTE(Files, fsp);
 216                         }
 217                         return fsp;
 218                 }
 219         }
 220
 221         return NULL;
 222 }
 223
 224 /****************************************************************************
 225  Find a fsp given a device, inode and file_id.
 226 ****************************************************************************/
 227
 228 files_struct *file_find_dif(SMB_DEV_T dev, SMB_INO_T inode, unsigned long file_id)
 229 {
 230         int count=0;
 231         files_struct *fsp;
 232
 233         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 234                 if (fsp->fd != -1 &&
 235                     fsp->dev == dev &&
 236                     fsp->inode == inode &&
 237                     fsp->file_id == file_id ) {
 238                         if (count > 10) {
 239                                 DLIST_PROMOTE(Files, fsp);
 240                         }
 241                         return fsp;
 242                 }
 243         }
 244
 245         return NULL;
 246 }
 247
 248 /****************************************************************************
 249  Check if an fsp still exists.
 250 ****************************************************************************/
 251
 252 files_struct *file_find_fsp(files_struct *orig_fsp)
 253 {
 254         files_struct *fsp;
 255
 256     for (fsp=Files;fsp;fsp=fsp->next) {
 257         if (fsp == orig_fsp)
 258             return fsp;
 259     }
 260
 261     return NULL;
 262 }
 263
 264 /****************************************************************************
 265  Find the first fsp given a device and inode.
 266 ****************************************************************************/
 267
 268 files_struct *file_find_di_first(SMB_DEV_T dev, SMB_INO_T inode)
 269 {
 270     files_struct *fsp;
 271
 272     for (fsp=Files;fsp;fsp=fsp->next) {
 273         if ( fsp->fd != -1 &&
 274             fsp->dev == dev &&
 275             fsp->inode == inode )
 276             return fsp;
 277     }
 278
 279     return NULL;
 280 }
 281
 282 /****************************************************************************
 283  Find the next fsp having the same device and inode.
 284 ****************************************************************************/
 285
 286 files_struct *file_find_di_next(files_struct *start_fsp)
 287 {
 288     files_struct *fsp;
 289
 290     for (fsp = start_fsp->next;fsp;fsp=fsp->next) {
 291         if ( fsp->fd != -1 &&
 292             fsp->dev == start_fsp->dev &&
 293             fsp->inode == start_fsp->inode )
 294             return fsp;
 295     }
 296
 297     return NULL;
 298 }
 299
 300 /****************************************************************************
 301  Find a fsp that is open for printing.
 302 ****************************************************************************/
 303
 304 files_struct *file_find_print(void)
 305 {
 306         files_struct *fsp;
 307
 308         for (fsp=Files;fsp;fsp=fsp->next) {
 309                 if (fsp->print_file) return fsp;
 310         }
 311
 312         return NULL;
 313 }
 314
 315 /****************************************************************************
 316  Sync open files on a connection.
 317 ****************************************************************************/
 318
 319 void file_sync_all(connection_struct *conn)
 320 {
 321         files_struct *fsp, *next;
 322
 323         for (fsp=Files;fsp;fsp=next) {
 324                 next=fsp->next;
 325                 if ((conn == fsp->conn) && (fsp->fd != -1)) {
 326                         sync_file(conn,fsp);
 327                 }
 328         }
 329 }
 330
 331 /****************************************************************************
 332  Free up a fsp.
 333 ****************************************************************************/
 334
 335 void file_free(files_struct *fsp)
 336 {
 337         DLIST_REMOVE(Files, fsp);
 338
 339         string_free(&fsp->fsp_name);
 340
 341         bitmap_clear(file_bmap, fsp->fnum - FILE_HANDLE_OFFSET);
 342         files_used--;
 343
 344         DEBUG(5,("freed files structure %d (%d used)\n",
 345                  fsp->fnum, files_used));
 346
 347         /* this is paranoia, just in case someone tries to reuse the
 348            information */
 349         ZERO_STRUCTP(fsp);
 350
 351         if (fsp == chain_fsp) chain_fsp = NULL;
 352
 353         SAFE_FREE(fsp);
 354 }
 355
 356 /****************************************************************************
 357  Get a fsp from a packet given the offset of a 16 bit fnum.
 358 ****************************************************************************/
 359
 360 files_struct *file_fsp(char *buf, int where)
 361 {
 362         int fnum, count=0;
 363         files_struct *fsp;
 364
 365         if (chain_fsp)
 366                 return chain_fsp;
 367
 368         fnum = SVAL(buf, where);
 369
 370         for (fsp=Files;fsp;fsp=fsp->next, count++) {
 371                 if (fsp->fnum == fnum) {
 372                         chain_fsp = fsp;
 373                         if (count > 10) {
 374                                 DLIST_PROMOTE(Files, fsp);
 375                         }
 376                         return fsp;
 377                 }
 378         }
 379         return NULL;
 380 }
 381
 382 /****************************************************************************
 383  Reset the chained fsp - done at the start of a packet reply.
 384 ****************************************************************************/
 385
 386 void file_chain_reset(void)
 387 {
 388         chain_fsp = NULL;
 389 }
 390
 391 /****************************************************************************
 392 Save the chained fsp - done when about to do an oplock break.
 393 ****************************************************************************/
 394
 395 void file_chain_save(void)
 396 {
 397         oplock_save_chain_fsp = chain_fsp;
 398 }
 399
 400 /****************************************************************************
 401 Restore the chained fsp - done after an oplock break.
 402 ****************************************************************************/
 403
 404 void file_chain_restore(void)
 405 {
 406         chain_fsp = oplock_save_chain_fsp;
 407 }