source/smbd/files.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    Files[] structure handling
   5    Copyright (C) Andrew Tridgell 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
  24 static int real_max_open_files;
  25
  26 #define VALID_FNUM(fnum)   (((fnum) >= 0) && ((fnum) < real_max_open_files))
  27
  28 #define FILE_HANDLE_OFFSET 0x1000
  29
  30 static struct bitmap *file_bmap;
  31
  32 static files_struct *Files;
  33
  34 /* a fsp to use when chaining */
  35 static files_struct *chain_fsp = NULL;
  36 /* a fsp to use to save when breaking an oplock. */
  37 static files_struct *oplock_save_chain_fsp = NULL;
  38
  39 static int files_used;
  40
  41 /****************************************************************************
  42  Return a unique number identifying this fsp over the life of this pid.
  43 ****************************************************************************/
  44
  45 static unsigned long get_gen_count(void)
  46 {
  47         static unsigned long file_gen_counter;
  48
  49         if ((++file_gen_counter) == 0)
  50                 return ++file_gen_counter;
  51         return file_gen_counter;
  52 }
  53
  54 /****************************************************************************
  55  Find first available file slot.
  56 ****************************************************************************/
  57
  58 files_struct *file_new(connection_struct *conn)
  59 {
  60         int i;
  61         static int first_file;
  62         files_struct *fsp, *next;
  63
  64         /* we want to give out file handles differently on each new
  65            connection because of a common bug in MS clients where they try to
  66            reuse a file descriptor from an earlier smb connection. This code
  67            increases the chance that the errant client will get an error rather
  68            than causing corruption */
  69         if (first_file == 0) {
  70                 first_file = (sys_getpid() ^ (int)time(NULL)) % real_max_open_files;
  71         }
  72
  73         i = bitmap_find(file_bmap, first_file);
  74         if (i == -1) {
  75                 /*
  76                  * Before we give up, go through the open files
  77                  * and see if there are any files opened with a
  78                  * batch oplock. If so break the oplock and then
  79                  * re-use that entry (if it becomes closed).
  80                  * This may help as NT/95 clients tend to keep
  81                  * files batch oplocked for quite a long time
  82                  * after they have finished with them.
  83                  */
  84                 for (fsp=Files;fsp;fsp=next) {
  85                         next=fsp->next;
  86                         if (attempt_close_oplocked_file(fsp)) {
  87                                 return file_new(conn);
  88                         }
  89                 }
  90
  91                 DEBUG(0,("ERROR! Out of file structures\n"));
  92                 unix_ERR_class = ERRSRV;
  93                 unix_ERR_code = ERRnofids;
  94                 return NULL;
  95         }
  96
  97         fsp = (files_struct *)malloc(sizeof(*fsp));
  98         if (!fsp) {
  99                 unix_ERR_class = ERRSRV;
 100                 unix_ERR_code = ERRnofids;
 101                 return NULL;
 102         }
 103
 104         ZERO_STRUCTP(fsp);
 105         fsp->fd = -1;
 106         fsp->conn = conn;
 107         fsp->file_id = get_gen_count();
 108         GetTimeOfDay(&fsp->open_time);
 109
 110         first_file = (i+1) % real_max_open_files;
 111
 112         bitmap_set(file_bmap, i);
 113         files_used++;
 114
 115         fsp->fnum = i + FILE_HANDLE_OFFSET;
 116         string_set(&fsp->fsp_name,"");
 117
 118         DLIST_ADD(Files, fsp);
 119
 120         DEBUG(5,("allocated file structure %d, fnum = %d (%d used)\n",
 121                  i, fsp->fnum, files_used));
 122
 123         chain_fsp = fsp;
 124
 125         return fsp;
 126 }
 127
 128 /****************************************************************************
 129  Close all open files for a connection.
 130 ****************************************************************************/
 131
 132 void file_close_conn(connection_struct *conn)
 133 {
 134         files_struct *fsp, *next;
 135
 136         for (fsp=Files;fsp;fsp=next) {
 137                 next = fsp->next;
 138                 if (fsp->conn == conn) {
 139                         close_file(fsp,False);
 140                 }
 141         }
 142 }
 143
 144 /****************************************************************************
 145  Initialise file structures.
 146 ****************************************************************************/
 147
 148 #define MAX_OPEN_FUDGEFACTOR 10
 149
 150 void file_init(void)
 151 {
 152         int request_max_open_files = lp_max_open_files();
 153         int real_lim;
 154
 155         /*
 156          * Set the max_open files to be the requested
 157          * max plus a fudgefactor to allow for the extra
 158          * fd's we need such as log files etc...
 159          */
 160         real_lim = set_maxfiles(request_max_open_files + MAX_OPEN_FUDGEFACTOR);
 161
 162         real_max_open_files = real_lim - MAX_OPEN_FUDGEFACTOR;
 163
 164         if(real_max_open_files != request_max_open_files) {
 165                 DEBUG(1,("file_init: Information only: requested %d \
 166 open files, %d are available.\n", request_max_open_files, real_max_open_files));
 167         }
 168
 169         file_bmap = bitmap_allocate(real_max_open_files);
 170
 171         if (!file_bmap) {
 172                 exit_server("out of memory in file_init");
 173         }
 174
 175         /*
 176          * Ensure that pipe_handle_oppset is set correctly.
 177          */
 178         set_pipe_handle_offset(real_max_open_files);
 179 }
 180
 181 /****************************************************************************
 182  Close files open by a specified vuid.
 183 ****************************************************************************/
 184
 185 void file_close_user(int vuid)
 186 {
 187         files_struct *fsp, *next;
 188
 189         for (fsp=Files;fsp;fsp=next) {
 190                 next=fsp->next;
 191                 if (fsp->vuid == vuid) {
 192                         close_file(fsp,False);
 193                 }
 194         }
 195 }
 196
 197 /****************************************************************************
 198  Find a fsp given a file descriptor.
 199 ****************************************************************************/
 200
 201 files_struct *file_find_fd(int fd)
 202 {
 203         int count=0;
 204         files_struct *fsp;
 205
 206         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 207                 if (fsp->fd == fd) {
 208                         if (count > 10) {
 209                                 DLIST_PROMOTE(Files, fsp);
 210                         }
 211                         return fsp;
 212                 }
 213         }
 214
 215         return NULL;
 216 }
 217
 218 /****************************************************************************
 219  Find a fsp given a device, inode and file_id.
 220 ****************************************************************************/
 221
 222 files_struct *file_find_dif(SMB_DEV_T dev, SMB_INO_T inode, unsigned long file_id)
 223 {
 224         int count=0;
 225         files_struct *fsp;
 226
 227         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 228                 if (fsp->fd != -1 &&
 229                     fsp->dev == dev &&
 230                     fsp->inode == inode &&
 231                     fsp->file_id == file_id ) {
 232                         if (count > 10) {
 233                                 DLIST_PROMOTE(Files, fsp);
 234                         }
 235                         return fsp;
 236                 }
 237         }
 238
 239         return NULL;
 240 }
 241
 242 /****************************************************************************
 243  Check if an fsp still exists.
 244 ****************************************************************************/
 245
 246 files_struct *file_find_fsp(files_struct *orig_fsp)
 247 {
 248         files_struct *fsp;
 249
 250     for (fsp=Files;fsp;fsp=fsp->next) {
 251         if (fsp == orig_fsp)
 252             return fsp;
 253     }
 254
 255     return NULL;
 256 }
 257
 258 /****************************************************************************
 259  Find the first fsp given a device and inode.
 260 ****************************************************************************/
 261
 262 files_struct *file_find_di_first(SMB_DEV_T dev, SMB_INO_T inode)
 263 {
 264     files_struct *fsp;
 265
 266     for (fsp=Files;fsp;fsp=fsp->next) {
 267         if ( fsp->fd != -1 &&
 268             fsp->dev == dev &&
 269             fsp->inode == inode )
 270             return fsp;
 271     }
 272
 273     return NULL;
 274 }
 275
 276 /****************************************************************************
 277  Find the next fsp having the same device and inode.
 278 ****************************************************************************/
 279
 280 files_struct *file_find_di_next(files_struct *start_fsp)
 281 {
 282     files_struct *fsp;
 283
 284     for (fsp = start_fsp->next;fsp;fsp=fsp->next) {
 285         if ( fsp->fd != -1 &&
 286             fsp->dev == start_fsp->dev &&
 287             fsp->inode == start_fsp->inode )
 288             return fsp;
 289     }
 290
 291     return NULL;
 292 }
 293
 294 /****************************************************************************
 295  Find a fsp that is open for printing.
 296 ****************************************************************************/
 297
 298 files_struct *file_find_print(void)
 299 {
 300         files_struct *fsp;
 301
 302         for (fsp=Files;fsp;fsp=fsp->next) {
 303                 if (fsp->print_file) return fsp;
 304         }
 305
 306         return NULL;
 307 }
 308
 309 /****************************************************************************
 310  Sync open files on a connection.
 311 ****************************************************************************/
 312
 313 void file_sync_all(connection_struct *conn)
 314 {
 315         files_struct *fsp, *next;
 316
 317         for (fsp=Files;fsp;fsp=next) {
 318                 next=fsp->next;
 319                 if ((conn == fsp->conn) && (fsp->fd != -1)) {
 320                         sync_file(conn,fsp);
 321                 }
 322         }
 323 }
 324
 325 /****************************************************************************
 326  Free up a fsp.
 327 ****************************************************************************/
 328
 329 void file_free(files_struct *fsp)
 330 {
 331         DLIST_REMOVE(Files, fsp);
 332
 333         string_free(&fsp->fsp_name);
 334
 335         bitmap_clear(file_bmap, fsp->fnum - FILE_HANDLE_OFFSET);
 336         files_used--;
 337
 338         DEBUG(5,("freed files structure %d (%d used)\n",
 339                  fsp->fnum, files_used));
 340
 341         /* this is paranoia, just in case someone tries to reuse the
 342            information */
 343         ZERO_STRUCTP(fsp);
 344
 345         if (fsp == chain_fsp) chain_fsp = NULL;
 346
 347         SAFE_FREE(fsp);
 348 }
 349
 350 /****************************************************************************
 351  Get a fsp from a packet given the offset of a 16 bit fnum.
 352 ****************************************************************************/
 353
 354 files_struct *file_fsp(char *buf, int where)
 355 {
 356         int fnum, count=0;
 357         files_struct *fsp;
 358
 359         if (chain_fsp)
 360                 return chain_fsp;
 361
 362         fnum = SVAL(buf, where);
 363
 364         for (fsp=Files;fsp;fsp=fsp->next, count++) {
 365                 if (fsp->fnum == fnum) {
 366                         chain_fsp = fsp;
 367                         if (count > 10) {
 368                                 DLIST_PROMOTE(Files, fsp);
 369                         }
 370                         return fsp;
 371                 }
 372         }
 373         return NULL;
 374 }
 375
 376 /****************************************************************************
 377  Reset the chained fsp - done at the start of a packet reply.
 378 ****************************************************************************/
 379
 380 void file_chain_reset(void)
 381 {
 382         chain_fsp = NULL;
 383 }
 384
 385 /****************************************************************************
 386 Save the chained fsp - done when about to do an oplock break.
 387 ****************************************************************************/
 388
 389 void file_chain_save(void)
 390 {
 391         oplock_save_chain_fsp = chain_fsp;
 392 }
 393
 394 /****************************************************************************
 395 Restore the chained fsp - done after an oplock break.
 396 ****************************************************************************/
 397
 398 void file_chain_restore(void)
 399 {
 400         chain_fsp = oplock_save_chain_fsp;
 401 }