source3/smbd/dfree.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    functions to calculate the free disk space
   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 3 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, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "smbd/smbd.h"
  22 #include "smbd/globals.h"
  23 #include "lib/util_file.h"
  24 #include "lib/util/memcache.h"
  25
  26 /****************************************************************************
  27  Normalise for DOS usage.
  28 ****************************************************************************/
  29
  30 static void disk_norm(uint64_t *bsize, uint64_t *dfree, uint64_t *dsize)
  31 {
  32         /* check if the disk is beyond the max disk size */
  33         uint64_t maxdisksize = lp_max_disk_size();
  34         if (maxdisksize) {
  35                 /* convert to blocks - and don't overflow */
  36                 maxdisksize = ((maxdisksize*1024)/(*bsize))*1024;
  37                 if (*dsize > maxdisksize) {
  38                         *dsize = maxdisksize;
  39                 }
  40                 if (*dfree > maxdisksize) {
  41                         *dfree = maxdisksize - 1;
  42                 }
  43                 /* the -1 should stop applications getting div by 0
  44                    errors */
  45         }
  46 }
  47
  48
  49
  50 /****************************************************************************
  51  Return number of 1K blocks available on a path and total number.
  52 ****************************************************************************/
  53
  54 static uint64_t sys_disk_free(connection_struct *conn,
  55                               struct smb_filename *fname,
  56                               uint64_t *bsize,
  57                               uint64_t *dfree,
  58                               uint64_t *dsize)
  59 {
  60         const struct loadparm_substitution *lp_sub =
  61                 loadparm_s3_global_substitution();
  62         uint64_t dfree_retval;
  63         uint64_t dfree_q = 0;
  64         uint64_t bsize_q = 0;
  65         uint64_t dsize_q = 0;
  66         const char *dfree_command;
  67         static bool dfree_broken = false;
  68         char *path = fname->base_name;
  69
  70         (*dfree) = (*dsize) = 0;
  71         (*bsize) = 512;
  72
  73         /*
  74          * If external disk calculation specified, use it.
  75          */
  76
  77         dfree_command = lp_dfree_command(talloc_tos(), lp_sub, SNUM(conn));
  78         if (dfree_command && *dfree_command) {
  79                 const char *p;
  80                 char **lines = NULL;
  81                 char **argl = NULL;
  82
  83                 argl = str_list_make_empty(talloc_tos());
  84                 str_list_add_printf(&argl, "%s", dfree_command);
  85                 str_list_add_printf(&argl, "%s", path);
  86                 if (argl == NULL) {
  87                         return (uint64_t)-1;
  88                 }
  89
  90                 DBG_NOTICE("Running command '%s %s'\n",
  91                         dfree_command,
  92                         path);
  93
  94                 lines = file_lines_ploadv(talloc_tos(), argl, NULL);
  95
  96                 TALLOC_FREE(argl);
  97
  98                 if (lines != NULL) {
  99                         char *line = lines[0];
 100
 101                         DEBUG (3, ("Read input from dfree, \"%s\"\n", line));
 102
 103                         *dsize = STR_TO_SMB_BIG_UINT(line, &p);
 104                         while (p && *p && isspace(*p))
 105                                 p++;
 106                         if (p && *p)
 107                                 *dfree = STR_TO_SMB_BIG_UINT(p, &p);
 108                         while (p && *p && isspace(*p))
 109                                 p++;
 110                         if (p && *p)
 111                                 *bsize = STR_TO_SMB_BIG_UINT(p, NULL);
 112                         else
 113                                 *bsize = 1024;
 114                         TALLOC_FREE(lines);
 115                         DEBUG (3, ("Parsed output of dfree, dsize=%u, dfree=%u, bsize=%u\n",
 116                                 (unsigned int)*dsize, (unsigned int)*dfree, (unsigned int)*bsize));
 117
 118                         if (!*dsize)
 119                                 *dsize = 2048;
 120                         if (!*dfree)
 121                                 *dfree = 1024;
 122
 123                         goto dfree_done;
 124                 }
 125                 DBG_ERR("file_lines_load() failed for "
 126                            "command '%s %s'. Error was : %s\n",
 127                            dfree_command, path, strerror(errno));
 128         }
 129
 130         if (SMB_VFS_DISK_FREE(conn, fname, bsize, dfree, dsize) ==
 131             (uint64_t)-1) {
 132                 DBG_ERR("VFS disk_free failed. Error was : %s\n",
 133                         strerror(errno));
 134                 return (uint64_t)-1;
 135         }
 136
 137         if (disk_quotas(conn, fname, &bsize_q, &dfree_q, &dsize_q)) {
 138                 uint64_t min_bsize = MIN(*bsize, bsize_q);
 139
 140                 (*dfree) = (*dfree) * (*bsize) / min_bsize;
 141                 (*dsize) = (*dsize) * (*bsize) / min_bsize;
 142                 dfree_q = dfree_q * bsize_q / min_bsize;
 143                 dsize_q = dsize_q * bsize_q / min_bsize;
 144
 145                 (*bsize) = min_bsize;
 146                 (*dfree) = MIN(*dfree,dfree_q);
 147                 (*dsize) = MIN(*dsize,dsize_q);
 148         }
 149
 150         /* FIXME : Any reason for this assumption ? */
 151         if (*bsize < 256) {
 152                 DEBUG(5,("disk_free:Warning: bsize == %d < 256 . Changing to assumed correct bsize = 512\n",(int)*bsize));
 153                 *bsize = 512;
 154         }
 155
 156         if ((*dsize)<1) {
 157                 if (!dfree_broken) {
 158                         DEBUG(0,("WARNING: dfree is broken on this system\n"));
 159                         dfree_broken=true;
 160                 }
 161                 *dsize = 20*1024*1024/(*bsize);
 162                 *dfree = MAX(1,*dfree);
 163         }
 164
 165 dfree_done:
 166         disk_norm(bsize, dfree, dsize);
 167
 168         if ((*bsize) < 1024) {
 169                 dfree_retval = (*dfree)/(1024/(*bsize));
 170         } else {
 171                 dfree_retval = ((*bsize)/1024)*(*dfree);
 172         }
 173
 174         return(dfree_retval);
 175 }
 176
 177 /****************************************************************************
 178  Potentially returned cached dfree info.
 179
 180  Depending on the file system layout and file system features, the free space
 181  information can be different for different sub directories underneath a SMB
 182  share. Store the cache information in memcache using the query path as the
 183  key to accomodate this.
 184 ****************************************************************************/
 185
 186 struct dfree_cached_info {
 187         time_t last_dfree_time;
 188         uint64_t dfree_ret;
 189         uint64_t bsize;
 190         uint64_t dfree;
 191         uint64_t dsize;
 192 };
 193
 194 uint64_t get_dfree_info(connection_struct *conn, struct smb_filename *fname,
 195                         uint64_t *bsize, uint64_t *dfree, uint64_t *dsize)
 196 {
 197         int dfree_cache_time = lp_dfree_cache_time(SNUM(conn));
 198         struct dfree_cached_info *dfc = NULL;
 199         struct dfree_cached_info dfc_new = { 0 };
 200         uint64_t dfree_ret;
 201         char tmpbuf[PATH_MAX];
 202         char *full_path = NULL;
 203         char *to_free = NULL;
 204         char *key_path = NULL;
 205         size_t len;
 206         DATA_BLOB key, value;
 207         bool found;
 208
 209         if (!dfree_cache_time) {
 210                 return sys_disk_free(conn, fname, bsize, dfree, dsize);
 211         }
 212
 213         len = full_path_tos(conn->connectpath,
 214                             fname->base_name,
 215                             tmpbuf,
 216                             sizeof(tmpbuf),
 217                             &full_path,
 218                             &to_free);
 219         if (len == -1) {
 220                 errno = ENOMEM;
 221                 return -1;
 222         }
 223
 224         if (VALID_STAT(fname->st) && S_ISREG(fname->st.st_ex_mode)) {
 225                 /*
 226                  * In case of a file use the parent directory to reduce number
 227                  * of cache entries.
 228                  */
 229                 bool ok;
 230
 231                 ok = parent_dirname(talloc_tos(),
 232                                     full_path,
 233                                     &key_path,
 234                                     NULL);
 235                 TALLOC_FREE(to_free); /* We're done with full_path */
 236
 237                 if (!ok) {
 238                         errno = ENOMEM;
 239                         return -1;
 240                 }
 241
 242                 /*
 243                  * key_path is always a talloced object.
 244                  */
 245                 to_free = key_path;
 246         } else {
 247                 /*
 248                  * key_path might not be a talloced object; rely on
 249                  * to_free set from full_path_tos.
 250                  */
 251                 key_path = full_path;
 252         }
 253
 254         key = data_blob_const(key_path, strlen(key_path));
 255         found = memcache_lookup(smbd_memcache(),
 256                                 DFREE_CACHE,
 257                                 key,
 258                                 &value);
 259         dfc = found ? (struct dfree_cached_info *)value.data : NULL;
 260
 261         if (dfc && (conn->lastused - dfc->last_dfree_time < dfree_cache_time)) {
 262                 DBG_DEBUG("Returning dfree cache entry for %s\n", key_path);
 263                 *bsize = dfc->bsize;
 264                 *dfree = dfc->dfree;
 265                 *dsize = dfc->dsize;
 266                 dfree_ret = dfc->dfree_ret;
 267                 goto out;
 268         }
 269
 270         dfree_ret = sys_disk_free(conn, fname, bsize, dfree, dsize);
 271
 272         if (dfree_ret == (uint64_t)-1) {
 273                 /* Don't cache bad data. */
 274                 goto out;
 275         }
 276
 277         DBG_DEBUG("Creating dfree cache entry for %s\n", key_path);
 278         dfc_new.bsize = *bsize;
 279         dfc_new.dfree = *dfree;
 280         dfc_new.dsize = *dsize;
 281         dfc_new.dfree_ret = dfree_ret;
 282         dfc_new.last_dfree_time = conn->lastused;
 283         memcache_add(smbd_memcache(),
 284                      DFREE_CACHE,
 285                      key,
 286                      data_blob_const(&dfc_new, sizeof(dfc_new)));
 287
 288 out:
 289         TALLOC_FREE(to_free);
 290         return dfree_ret;
 291 }
 292
 293 void flush_dfree_cache(void)
 294 {
 295         memcache_flush(smbd_memcache(), DFREE_CACHE);
 296 }