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         string_set(&fsp->fsp_name,"");
 116
 117         DLIST_ADD(Files, fsp);
 118
 119         DEBUG(5,("allocated file structure %d, fnum = %d (%d used)\n",
 120                  i, fsp->fnum, files_used));
 121
 122         chain_fsp = fsp;
 123
 124         return fsp;
 125 }
 126
 127 /****************************************************************************
 128  Close all open files for a connection.
 129 ****************************************************************************/
 130
 131 void file_close_conn(connection_struct *conn)
 132 {
 133         files_struct *fsp, *next;
 134
 135         for (fsp=Files;fsp;fsp=next) {
 136                 next = fsp->next;
 137                 if (fsp->conn == conn) {
 138                         close_file(fsp,False);
 139                 }
 140         }
 141 }
 142
 143 /****************************************************************************
 144  Initialise file structures.
 145 ****************************************************************************/
 146
 147 #define MAX_OPEN_FUDGEFACTOR 10
 148
 149 void file_init(void)
 150 {
 151         int request_max_open_files = lp_max_open_files();
 152         int real_lim;
 153
 154         /*
 155          * Set the max_open files to be the requested
 156          * max plus a fudgefactor to allow for the extra
 157          * fd's we need such as log files etc...
 158          */
 159         real_lim = set_maxfiles(request_max_open_files + MAX_OPEN_FUDGEFACTOR);
 160
 161         real_max_open_files = real_lim - MAX_OPEN_FUDGEFACTOR;
 162
 163         if(real_max_open_files != request_max_open_files) {
 164                 DEBUG(1,("file_init: Information only: requested %d \
 165 open files, %d are available.\n", request_max_open_files, real_max_open_files));
 166         }
 167
 168         file_bmap = bitmap_allocate(real_max_open_files);
 169
 170         if (!file_bmap) {
 171                 exit_server("out of memory in file_init");
 172         }
 173
 174         /*
 175          * Ensure that pipe_handle_oppset is set correctly.
 176          */
 177         set_pipe_handle_offset(real_max_open_files);
 178 }
 179
 180 /****************************************************************************
 181  Close files open by a specified vuid.
 182 ****************************************************************************/
 183
 184 void file_close_user(int vuid)
 185 {
 186         files_struct *fsp, *next;
 187
 188         for (fsp=Files;fsp;fsp=next) {
 189                 next=fsp->next;
 190                 if (fsp->vuid == vuid) {
 191                         close_file(fsp,False);
 192                 }
 193         }
 194 }
 195
 196 /****************************************************************************
 197  Find a fsp given a file descriptor.
 198 ****************************************************************************/
 199
 200 files_struct *file_find_fd(int fd)
 201 {
 202         int count=0;
 203         files_struct *fsp;
 204
 205         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 206                 if (fsp->fd == fd) {
 207                         if (count > 10) {
 208                                 DLIST_PROMOTE(Files, fsp);
 209                         }
 210                         return fsp;
 211                 }
 212         }
 213
 214         return NULL;
 215 }
 216
 217 /****************************************************************************
 218  Find a fsp given a device, inode and file_id.
 219 ****************************************************************************/
 220
 221 files_struct *file_find_dif(SMB_DEV_T dev, SMB_INO_T inode, unsigned long file_id)
 222 {
 223         int count=0;
 224         files_struct *fsp;
 225
 226         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 227                 if (fsp->fd != -1 &&
 228                     fsp->dev == dev &&
 229                     fsp->inode == inode &&
 230                     fsp->file_id == file_id ) {
 231                         if (count > 10) {
 232                                 DLIST_PROMOTE(Files, fsp);
 233                         }
 234                         return fsp;
 235                 }
 236         }
 237
 238         return NULL;
 239 }
 240
 241 /****************************************************************************
 242  Check if an fsp still exists.
 243 ****************************************************************************/
 244
 245 files_struct *file_find_fsp(files_struct *orig_fsp)
 246 {
 247         files_struct *fsp;
 248
 249     for (fsp=Files;fsp;fsp=fsp->next) {
 250         if (fsp == orig_fsp)
 251             return fsp;
 252     }
 253
 254     return NULL;
 255 }
 256
 257 /****************************************************************************
 258  Find the first fsp given a device and inode.
 259 ****************************************************************************/
 260
 261 files_struct *file_find_di_first(SMB_DEV_T dev, SMB_INO_T inode)
 262 {
 263     files_struct *fsp;
 264
 265     for (fsp=Files;fsp;fsp=fsp->next) {
 266         if ( fsp->fd != -1 &&
 267             fsp->dev == dev &&
 268             fsp->inode == inode )
 269             return fsp;
 270     }
 271
 272     return NULL;
 273 }
 274
 275 /****************************************************************************
 276  Find the next fsp having the same device and inode.
 277 ****************************************************************************/
 278
 279 files_struct *file_find_di_next(files_struct *start_fsp)
 280 {
 281     files_struct *fsp;
 282
 283     for (fsp = start_fsp->next;fsp;fsp=fsp->next) {
 284         if ( fsp->fd != -1 &&
 285             fsp->dev == start_fsp->dev &&
 286             fsp->inode == start_fsp->inode )
 287             return fsp;
 288     }
 289
 290     return NULL;
 291 }
 292
 293 /****************************************************************************
 294  Find a fsp that is open for printing.
 295 ****************************************************************************/
 296
 297 files_struct *file_find_print(void)
 298 {
 299         files_struct *fsp;
 300
 301         for (fsp=Files;fsp;fsp=fsp->next) {
 302                 if (fsp->print_file) return fsp;
 303         }
 304
 305         return NULL;
 306 }
 307
 308 /****************************************************************************
 309  Sync open files on a connection.
 310 ****************************************************************************/
 311
 312 void file_sync_all(connection_struct *conn)
 313 {
 314         files_struct *fsp, *next;
 315
 316         for (fsp=Files;fsp;fsp=next) {
 317                 next=fsp->next;
 318                 if ((conn == fsp->conn) && (fsp->fd != -1)) {
 319                         sync_file(conn,fsp);
 320                 }
 321         }
 322 }
 323
 324 /****************************************************************************
 325  Free up a fsp.
 326 ****************************************************************************/
 327
 328 void file_free(files_struct *fsp)
 329 {
 330         DLIST_REMOVE(Files, fsp);
 331
 332         string_free(&fsp->fsp_name);
 333
 334         bitmap_clear(file_bmap, fsp->fnum - FILE_HANDLE_OFFSET);
 335         files_used--;
 336
 337         DEBUG(5,("freed files structure %d (%d used)\n",
 338                  fsp->fnum, files_used));
 339
 340         /* this is paranoia, just in case someone tries to reuse the
 341            information */
 342         ZERO_STRUCTP(fsp);
 343
 344         if (fsp == chain_fsp) chain_fsp = NULL;
 345
 346         SAFE_FREE(fsp);
 347 }
 348
 349 /****************************************************************************
 350  Get a fsp from a packet given the offset of a 16 bit fnum.
 351 ****************************************************************************/
 352
 353 files_struct *file_fsp(char *buf, int where)
 354 {
 355         int fnum, count=0;
 356         files_struct *fsp;
 357
 358         if (chain_fsp)
 359                 return chain_fsp;
 360
 361         fnum = SVAL(buf, where);
 362
 363         for (fsp=Files;fsp;fsp=fsp->next, count++) {
 364                 if (fsp->fnum == fnum) {
 365                         chain_fsp = fsp;
 366                         if (count > 10) {
 367                                 DLIST_PROMOTE(Files, fsp);
 368                         }
 369                         return fsp;
 370                 }
 371         }
 372         return NULL;
 373 }
 374
 375 /****************************************************************************
 376  Reset the chained fsp - done at the start of a packet reply.
 377 ****************************************************************************/
 378
 379 void file_chain_reset(void)
 380 {
 381         chain_fsp = NULL;
 382 }
 383
 384 /****************************************************************************
 385 Save the chained fsp - done when about to do an oplock break.
 386 ****************************************************************************/
 387
 388 void file_chain_save(void)
 389 {
 390         oplock_save_chain_fsp = chain_fsp;
 391 }
 392
 393 /****************************************************************************
 394 Restore the chained fsp - done after an oplock break.
 395 ****************************************************************************/
 396
 397 void file_chain_restore(void)
 398 {
 399         chain_fsp = oplock_save_chain_fsp;
 400 }