source3/smbd/fileio.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    read/write to a files_struct
   5    Copyright (C) Andrew Tridgell 1992-1998
   6    Copyright (C) Jeremy Allison 2000-2002. - write cache.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "printing.h"
  24 #include "smbd/smbd.h"
  25 #include "smbd/globals.h"
  26 #include "smbprofile.h"
  27
  28 /****************************************************************************
  29  Read from a file.
  30 ****************************************************************************/
  31
  32 ssize_t read_file(files_struct *fsp,char *data,off_t pos,size_t n)
  33 {
  34         off_t new_pos;
  35         ssize_t ret = 0;
  36         bool ok;
  37
  38         /* you can't read from print files */
  39         if (fsp->print_file) {
  40                 errno = EBADF;
  41                 return -1;
  42         }
  43
  44         ok = vfs_valid_pread_range(pos, n);
  45         if (!ok) {
  46                 errno = EINVAL;
  47                 return -1;
  48         }
  49
  50         fh_set_pos(fsp->fh, pos);
  51
  52         if (n > 0) {
  53                 ret = SMB_VFS_PREAD(fsp,data,n,pos);
  54
  55                 if (ret == -1) {
  56                         return -1;
  57                 }
  58         }
  59
  60         DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
  61                   fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
  62
  63         new_pos = fh_get_pos(fsp->fh) + ret;
  64         fh_set_pos(fsp->fh, new_pos);
  65         fh_set_position_information(fsp->fh, new_pos);
  66
  67         return(ret);
  68 }
  69
  70 /****************************************************************************
  71  *Really* write to a file.
  72 ****************************************************************************/
  73
  74 static ssize_t real_write_file(struct smb_request *req,
  75                                 files_struct *fsp,
  76                                 const char *data,
  77                                 off_t pos,
  78                                 size_t n)
  79 {
  80         ssize_t ret;
  81         bool ok;
  82
  83         ok = vfs_valid_pwrite_range(pos, n);
  84         if (!ok) {
  85                 errno = EINVAL;
  86                 return -1;
  87         }
  88
  89         if (n == 0) {
  90                 return 0;
  91         }
  92
  93         fh_set_pos(fsp->fh, pos);
  94         if (pos &&
  95             lp_strict_allocate(SNUM(fsp->conn)) &&
  96             !fsp->fsp_flags.is_sparse)
  97         {
  98                 if (vfs_fill_sparse(fsp, pos) == -1) {
  99                         return -1;
 100                 }
 101         }
 102         ret = vfs_pwrite_data(req, fsp, data, n, pos);
 103
 104         DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
 105                   fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret));
 106
 107         if (ret != -1) {
 108                 off_t new_pos = fh_get_pos(fsp->fh) + ret;
 109                 fh_set_pos(fsp->fh, new_pos);
 110
 111 /* Yes - this is correct - writes don't update this. JRA. */
 112 /* Found by Samba4 tests. */
 113 #if 0
 114                 fsp->position_information = fsp->pos;
 115 #endif
 116         }
 117
 118         return ret;
 119 }
 120
 121 void fsp_flush_write_time_update(struct files_struct *fsp)
 122 {
 123         /*
 124          * Note this won't expect any impersonation!
 125          * So don't call any SMB_VFS operations here!
 126          */
 127
 128         DEBUG(5, ("Update write time on %s\n", fsp_str_dbg(fsp)));
 129
 130         trigger_write_time_update_immediate(fsp);
 131 }
 132
 133 static void update_write_time_handler(struct tevent_context *ctx,
 134                                       struct tevent_timer *te,
 135                                       struct timeval now,
 136                                       void *private_data)
 137 {
 138         files_struct *fsp = (files_struct *)private_data;
 139         fsp_flush_write_time_update(fsp);
 140 }
 141
 142 /*********************************************************
 143  Schedule a write time update for WRITE_TIME_UPDATE_USEC_DELAY
 144  in the future.
 145 *********************************************************/
 146
 147 void trigger_write_time_update(struct files_struct *fsp)
 148 {
 149         int delay;
 150
 151         if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
 152                 /* Don't use delayed writes on POSIX files. */
 153                 return;
 154         }
 155
 156         if (fsp->fsp_flags.write_time_forced) {
 157                 /* No point - "sticky" write times
 158                  * in effect.
 159                  */
 160                 return;
 161         }
 162
 163         /* We need to remember someone did a write
 164          * and update to current time on close. */
 165
 166         fsp->fsp_flags.update_write_time_on_close = true;
 167
 168         if (fsp->fsp_flags.update_write_time_triggered) {
 169                 /*
 170                  * We only update the write time after 2 seconds
 171                  * on the first normal write. After that
 172                  * no other writes affect this until close.
 173                  */
 174                 return;
 175         }
 176         fsp->fsp_flags.update_write_time_triggered = true;
 177
 178         delay = lp_parm_int(SNUM(fsp->conn),
 179                             "smbd", "writetimeupdatedelay",
 180                             WRITE_TIME_UPDATE_USEC_DELAY);
 181
 182         DEBUG(5, ("Update write time %d usec later on %s\n",
 183                   delay, fsp_str_dbg(fsp)));
 184
 185         /* trigger the update 2 seconds later */
 186         fsp->update_write_time_event =
 187                 tevent_add_timer(fsp->conn->sconn->ev_ctx, NULL,
 188                                  timeval_current_ofs_usec(delay),
 189                                  update_write_time_handler, fsp);
 190 }
 191
 192 void trigger_write_time_update_immediate(struct files_struct *fsp)
 193 {
 194         struct smb_file_time ft;
 195
 196         init_smb_file_time(&ft);
 197
 198         if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
 199                 /* Don't use delayed writes on POSIX files. */
 200                 return;
 201         }
 202
 203         if (fsp->fsp_flags.write_time_forced) {
 204                 /*
 205                  * No point - "sticky" write times
 206                  * in effect.
 207                  */
 208                 return;
 209         }
 210
 211         TALLOC_FREE(fsp->update_write_time_event);
 212         DEBUG(5, ("Update write time immediate on %s\n",
 213                   fsp_str_dbg(fsp)));
 214
 215         /* After an immediate update, reset the trigger. */
 216         fsp->fsp_flags.update_write_time_triggered = true;
 217         fsp->fsp_flags.update_write_time_on_close = false;
 218
 219         ft.mtime = timespec_current();
 220
 221         /* Update the time in the open file db. */
 222         (void)set_write_time(fsp->file_id, ft.mtime);
 223
 224         /* Now set on disk - takes care of notify. */
 225         (void)smb_set_file_time(fsp->conn, fsp, fsp->fsp_name, &ft, false);
 226 }
 227
 228 void mark_file_modified(files_struct *fsp)
 229 {
 230         int dosmode;
 231
 232         trigger_write_time_update(fsp);
 233
 234         if (fsp->fsp_flags.modified) {
 235                 return;
 236         }
 237
 238         fsp->fsp_flags.modified = true;
 239
 240         if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) {
 241                 return;
 242         }
 243         if (!(lp_store_dos_attributes(SNUM(fsp->conn)) ||
 244               MAP_ARCHIVE(fsp->conn))) {
 245                 return;
 246         }
 247
 248         dosmode = fdos_mode(fsp);
 249         if (IS_DOS_ARCHIVE(dosmode)) {
 250                 return;
 251         }
 252         file_set_dosmode(fsp->conn, fsp->fsp_name,
 253                          dosmode | FILE_ATTRIBUTE_ARCHIVE, NULL, false);
 254 }
 255
 256 /****************************************************************************
 257  Write to a file.
 258 ****************************************************************************/
 259
 260 ssize_t write_file(struct smb_request *req,
 261                         files_struct *fsp,
 262                         const char *data,
 263                         off_t pos,
 264                         size_t n)
 265 {
 266         ssize_t total_written = 0;
 267
 268         if (fsp->print_file) {
 269                 uint32_t t;
 270                 int ret;
 271
 272                 ret = print_spool_write(fsp, data, n, pos, &t);
 273                 if (ret) {
 274                         errno = ret;
 275                         return -1;
 276                 }
 277                 return t;
 278         }
 279
 280         if (!fsp->fsp_flags.can_write) {
 281                 errno = EPERM;
 282                 return -1;
 283         }
 284
 285         mark_file_modified(fsp);
 286
 287         /*
 288          * If this file is level II oplocked then we need
 289          * to grab the shared memory lock and inform all
 290          * other files with a level II lock that they need
 291          * to flush their read caches. We keep the lock over
 292          * the shared memory area whilst doing this.
 293          */
 294
 295         /* This should actually be improved to span the write. */
 296         contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_WRITE);
 297         contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_WRITE);
 298
 299         total_written = real_write_file(req, fsp, data, pos, n);
 300         return total_written;
 301 }
 302
 303 /*******************************************************************
 304 sync a file
 305 ********************************************************************/
 306
 307 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
 308 {
 309         if (fsp_get_io_fd(fsp) == -1)
 310                 return NT_STATUS_INVALID_HANDLE;
 311
 312         if (lp_strict_sync(SNUM(conn)) &&
 313             (lp_sync_always(SNUM(conn)) || write_through)) {
 314                 int ret;
 315                 ret = smb_vfs_fsync_sync(fsp);
 316                 if (ret == -1) {
 317                         return map_nt_error_from_unix(errno);
 318                 }
 319         }
 320         return NT_STATUS_OK;
 321 }