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