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 /*
  42  * Indirection for file fd's. Needed as POSIX locking
  43  * is based on file/process, not fd/process.
  44  */
  45 static file_fd_struct *FileFd;
  46
  47 static int files_used, fd_ptr_used;
  48
  49 /****************************************************************************
  50   find first available file slot
  51 ****************************************************************************/
  52 files_struct *file_new(void )
  53 {
  54         int i;
  55         static int first_file;
  56         files_struct *fsp, *next;
  57
  58         /* we want to give out file handles differently on each new
  59            connection because of a common bug in MS clients where they try to
  60            reuse a file descriptor from an earlier smb connection. This code
  61            increases the chance that the errant client will get an error rather
  62            than causing corruption */
  63         if (first_file == 0) {
  64                 first_file = (getpid() ^ (int)time(NULL)) % real_max_open_files;
  65         }
  66
  67         i = bitmap_find(file_bmap, first_file);
  68         if (i == -1) {
  69                 /*
  70                  * Before we give up, go through the open files
  71                  * and see if there are any files opened with a
  72                  * batch oplock. If so break the oplock and then
  73                  * re-use that entry (if it becomes closed).
  74                  * This may help as NT/95 clients tend to keep
  75                  * files batch oplocked for quite a long time
  76                  * after they have finished with them.
  77                  */
  78                 for (fsp=Files;fsp;fsp=next) {
  79                         next=fsp->next;
  80                         if (attempt_close_oplocked_file(fsp)) {
  81                                 return file_new();
  82                         }
  83                 }
  84
  85                 DEBUG(0,("ERROR! Out of file structures\n"));
  86                 return NULL;
  87         }
  88
  89         fsp = (files_struct *)malloc(sizeof(*fsp));
  90         if (!fsp) return NULL;
  91
  92         ZERO_STRUCTP(fsp);
  93
  94         first_file = (i+1) % real_max_open_files;
  95
  96         bitmap_set(file_bmap, i);
  97         files_used++;
  98
  99         fsp->fnum = i + FILE_HANDLE_OFFSET;
 100         string_init(&fsp->fsp_name,"");
 101
 102         DLIST_ADD(Files, fsp);
 103
 104         DEBUG(5,("allocated file structure %d, fnum = %d (%d used)\n",
 105                  i, fsp->fnum, files_used));
 106
 107         chain_fsp = fsp;
 108
 109         return fsp;
 110 }
 111
 112
 113
 114 /****************************************************************************
 115 fd support routines - attempt to find an already open file by dev
 116 and inode - increments the ref_count of the returned file_fd_struct *.
 117 ****************************************************************************/
 118 file_fd_struct *fd_get_already_open(SMB_STRUCT_STAT *sbuf)
 119 {
 120         file_fd_struct *fd_ptr;
 121
 122         if(!sbuf) return NULL;
 123
 124         for (fd_ptr=FileFd;fd_ptr;fd_ptr=fd_ptr->next) {
 125                 if ((fd_ptr->ref_count > 0) &&
 126                     (sbuf->st_dev == fd_ptr->dev) &&
 127                     (sbuf->st_ino == fd_ptr->inode)) {
 128                         fd_ptr->ref_count++;
 129
 130                         DEBUG(3,("Re-used file_fd_struct dev = %x, inode = %.0f, ref_count = %d\n",
 131                                  (unsigned int)fd_ptr->dev, (double)fd_ptr->inode,
 132                                  fd_ptr->ref_count));
 133
 134                         return fd_ptr;
 135                 }
 136         }
 137
 138         return NULL;
 139 }
 140
 141
 142
 143 /****************************************************************************
 144 fd support routines - attempt to find a empty slot in the FileFd array.
 145 Increments the ref_count of the returned entry.
 146 ****************************************************************************/
 147 file_fd_struct *fd_get_new(void)
 148 {
 149         extern struct current_user current_user;
 150         file_fd_struct *fd_ptr;
 151
 152         fd_ptr = (file_fd_struct *)malloc(sizeof(*fd_ptr));
 153         if (!fd_ptr) {
 154           DEBUG(0,("ERROR! malloc fail for file_fd struct.\n"));
 155           return NULL;
 156         }
 157
 158         ZERO_STRUCTP(fd_ptr);
 159
 160         fd_ptr->dev = (SMB_DEV_T)-1;
 161         fd_ptr->inode = (SMB_INO_T)-1;
 162         fd_ptr->fd = -1;
 163         fd_ptr->fd_readonly = -1;
 164         fd_ptr->fd_writeonly = -1;
 165         fd_ptr->real_open_flags = -1;
 166         fd_add_to_uid_cache(fd_ptr, (uid_t)current_user.uid);
 167         fd_ptr->ref_count++;
 168
 169         fd_ptr_used++;
 170
 171         DLIST_ADD(FileFd, fd_ptr);
 172
 173         DEBUG(5,("allocated fd_ptr structure (%d used)\n", fd_ptr_used));
 174
 175         return fd_ptr;
 176 }
 177
 178
 179 /****************************************************************************
 180 close all open files for a connection
 181 ****************************************************************************/
 182 void file_close_conn(connection_struct *conn)
 183 {
 184         files_struct *fsp, *next;
 185
 186         for (fsp=Files;fsp;fsp=next) {
 187                 next = fsp->next;
 188                 if (fsp->conn == conn && fsp->open) {
 189                         if (fsp->is_directory)
 190                                 close_directory(fsp,False);
 191                         else
 192                                 close_file(fsp,False);
 193                 }
 194         }
 195 }
 196
 197 /****************************************************************************
 198 initialise file structures
 199 ****************************************************************************/
 200
 201 #define MAX_OPEN_FUDGEFACTOR 10
 202
 203 void file_init(void)
 204 {
 205         int request_max_open_files = lp_max_open_files();
 206         int real_lim;
 207
 208         /*
 209          * Set the max_open files to be the requested
 210          * max plus a fudgefactor to allow for the extra
 211          * fd's we need such as log files etc...
 212          */
 213         real_lim = set_maxfiles(request_max_open_files + MAX_OPEN_FUDGEFACTOR);
 214
 215         real_max_open_files = real_lim - MAX_OPEN_FUDGEFACTOR;
 216
 217         if(real_max_open_files != request_max_open_files) {
 218                 DEBUG(1,("file_init: Information only: requested %d \
 219 open files, %d are available.\n", request_max_open_files, real_max_open_files));
 220         }
 221
 222         file_bmap = bitmap_allocate(real_max_open_files);
 223
 224         if (!file_bmap) {
 225                 exit_server("out of memory in file_init");
 226         }
 227
 228         /*
 229          * Ensure that pipe_handle_oppset is set correctly.
 230          */
 231         set_pipe_handle_offset(real_max_open_files);
 232 }
 233
 234
 235 /****************************************************************************
 236 close files open by a specified vuid
 237 ****************************************************************************/
 238 void file_close_user(int vuid)
 239 {
 240         files_struct *fsp, *next;
 241
 242         for (fsp=Files;fsp;fsp=next) {
 243                 next=fsp->next;
 244                 if ((fsp->vuid == vuid) && fsp->open) {
 245                         if(!fsp->is_directory)
 246                                 close_file(fsp,False);
 247                         else
 248                                 close_directory(fsp,False);
 249                 }
 250         }
 251 }
 252
 253
 254 /****************************************************************************
 255  Find a fsp given a device, inode and timevalue
 256  If this is from a kernel oplock break request then tval may be NULL.
 257 ****************************************************************************/
 258
 259 files_struct *file_find_dit(SMB_DEV_T dev, SMB_INO_T inode, struct timeval *tval)
 260 {
 261         int count=0;
 262         files_struct *fsp;
 263
 264         for (fsp=Files;fsp;fsp=fsp->next,count++) {
 265                 if (fsp->open &&
 266                         fsp->fd_ptr != NULL &&
 267                     fsp->fd_ptr->dev == dev &&
 268                     fsp->fd_ptr->inode == inode &&
 269                     (tval ? (fsp->open_time.tv_sec == tval->tv_sec) : True ) &&
 270                     (tval ? (fsp->open_time.tv_usec == tval->tv_usec) : True )) {
 271                         if (count > 10) {
 272                                 DLIST_PROMOTE(Files, fsp);
 273                         }
 274                         return fsp;
 275                 }
 276         }
 277
 278         return NULL;
 279 }
 280
 281 /****************************************************************************
 282  Find the first fsp given a device and inode.
 283 ****************************************************************************/
 284
 285 files_struct *file_find_di_first(SMB_DEV_T dev, SMB_INO_T inode)
 286 {
 287     files_struct *fsp;
 288
 289     for (fsp=Files;fsp;fsp=fsp->next) {
 290         if (fsp->open &&
 291                         fsp->fd_ptr != NULL &&
 292             fsp->fd_ptr->dev == dev &&
 293             fsp->fd_ptr->inode == inode )
 294             return fsp;
 295     }
 296
 297     return NULL;
 298 }
 299
 300 /****************************************************************************
 301  Find the next fsp having the same device and inode.
 302 ****************************************************************************/
 303
 304 files_struct *file_find_di_next(files_struct *start_fsp)
 305 {
 306     files_struct *fsp;
 307
 308     for (fsp = start_fsp->next;fsp;fsp=fsp->next) {
 309         if (fsp->open &&
 310                         fsp->fd_ptr != NULL &&
 311             fsp->fd_ptr->dev == start_fsp->fd_ptr->dev &&
 312             fsp->fd_ptr->inode == start_fsp->fd_ptr->inode )
 313             return fsp;
 314     }
 315
 316     return NULL;
 317 }
 318
 319 /****************************************************************************
 320 find a fsp that is open for printing
 321 ****************************************************************************/
 322 files_struct *file_find_print(void)
 323 {
 324         files_struct *fsp;
 325
 326         for (fsp=Files;fsp;fsp=fsp->next) {
 327                 if (fsp->open && fsp->print_file) return fsp;
 328         }
 329
 330         return NULL;
 331 }
 332
 333
 334 /****************************************************************************
 335 sync open files on a connection
 336 ****************************************************************************/
 337 void file_sync_all(connection_struct *conn)
 338 {
 339         files_struct *fsp, *next;
 340
 341         for (fsp=Files;fsp;fsp=next) {
 342                 next=fsp->next;
 343                 if (fsp->open && (conn == fsp->conn) && (fsp->fd_ptr != NULL)) {
 344                         sync_file(conn,fsp);
 345                 }
 346         }
 347 }
 348
 349
 350 /****************************************************************************
 351 free up a fd_ptr
 352 ****************************************************************************/
 353 void fd_ptr_free(file_fd_struct *fd_ptr)
 354 {
 355         DLIST_REMOVE(FileFd, fd_ptr);
 356
 357         fd_ptr_used--;
 358
 359         DEBUG(5,("freed fd_ptr structure (%d used)\n", fd_ptr_used));
 360
 361         /* paranoia */
 362         ZERO_STRUCTP(fd_ptr);
 363
 364         free(fd_ptr);
 365 }
 366
 367
 368 /****************************************************************************
 369 free up a fsp
 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->fd_ptr != NULL) && fsp->fd_ptr->ref_count == 0) {
 378                 fd_ptr_free(fsp->fd_ptr);
 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         free(fsp);
 394 }
 395
 396
 397 /****************************************************************************
 398 get a fsp from a packet given the offset of a 16 bit fnum
 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) return chain_fsp;
 406
 407         fnum = SVAL(buf, where);
 408
 409         for (fsp=Files;fsp;fsp=fsp->next, count++) {
 410                 if (fsp->fnum == fnum) {
 411                         chain_fsp = fsp;
 412                         if (count > 10) {
 413                                 DLIST_PROMOTE(Files, fsp);
 414                         }
 415                         return fsp;
 416                 }
 417         }
 418         return NULL;
 419 }
 420
 421 /****************************************************************************
 422  Reset the chained fsp - done at the start of a packet reply
 423 ****************************************************************************/
 424
 425 void file_chain_reset(void)
 426 {
 427         chain_fsp = NULL;
 428 }
 429
 430 /****************************************************************************
 431 Save the chained fsp - done when about to do an oplock break.
 432 ****************************************************************************/
 433
 434 void file_chain_save(void)
 435 {
 436         oplock_save_chain_fsp = chain_fsp;
 437 }
 438
 439 /****************************************************************************
 440 Restore the chained fsp - done after an oplock break.
 441 ****************************************************************************/
 442 void file_chain_restore(void)
 443 {
 444         chain_fsp = oplock_save_chain_fsp;
 445 }