source/smbd/statcache.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 3.0
   4    stat cache code
   5    Copyright (C) Andrew Tridgell 1992-2000
   6    Copyright (C) Jeremy Allison 1999-200
   7
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "includes.h"
  25
  26 extern BOOL case_sensitive;
  27
  28
  29 /****************************************************************************
  30  Stat cache code used in unix_convert.
  31 *****************************************************************************/
  32
  33 typedef struct {
  34   int name_len;
  35   char names[2]; /* This is extended via malloc... */
  36 } stat_cache_entry;
  37
  38 #define INIT_STAT_CACHE_SIZE 512
  39 static hash_table stat_cache;
  40
  41 /****************************************************************************
  42  Add an entry into the stat cache.
  43 *****************************************************************************/
  44
  45 void stat_cache_add( char *full_orig_name, char *orig_translated_path)
  46 {
  47   stat_cache_entry *scp;
  48   stat_cache_entry *found_scp;
  49   pstring orig_name;
  50   pstring translated_path;
  51   int namelen;
  52   hash_element *hash_elem;
  53
  54   if (!lp_stat_cache()) return;
  55
  56   namelen = strlen(orig_translated_path);
  57
  58   /*
  59    * Don't cache trivial valid directory entries.
  60    */
  61   if((*full_orig_name == '\0') || (strcmp(full_orig_name, ".") == 0) ||
  62      (strcmp(full_orig_name, "..") == 0))
  63     return;
  64
  65   /*
  66    * If we are in case insentive mode, we need to
  67    * store names that need no translation - else, it
  68    * would be a waste.
  69    */
  70
  71   if(case_sensitive && (strcmp(full_orig_name, orig_translated_path) == 0))
  72     return;
  73
  74   /*
  75    * Remove any trailing '/' characters from the
  76    * translated path.
  77    */
  78
  79   pstrcpy(translated_path, orig_translated_path);
  80   if(translated_path[namelen-1] == '/') {
  81     translated_path[namelen-1] = '\0';
  82     namelen--;
  83   }
  84
  85   /*
  86    * We will only replace namelen characters
  87    * of full_orig_name.
  88    * StrnCpy always null terminates.
  89    */
  90
  91   StrnCpy(orig_name, full_orig_name, namelen);
  92   if(!case_sensitive)
  93     strupper( orig_name );
  94
  95   /*
  96    * Check this name doesn't exist in the cache before we
  97    * add it.
  98    */
  99
 100   if ((hash_elem = hash_lookup(&stat_cache, orig_name))) {
 101     found_scp = (stat_cache_entry *)(hash_elem->value);
 102     if (strcmp((found_scp->names+found_scp->name_len+1), translated_path) == 0) {
 103       return;
 104     } else {
 105       hash_remove(&stat_cache, hash_elem);
 106       if((scp = (stat_cache_entry *)malloc(sizeof(stat_cache_entry)+2*namelen)) == NULL) {
 107         DEBUG(0,("stat_cache_add: Out of memory !\n"));
 108         return;
 109       }
 110       pstrcpy(scp->names, orig_name);
 111       pstrcpy((scp->names+namelen+1), translated_path);
 112       scp->name_len = namelen;
 113       hash_insert(&stat_cache, (char *)scp, orig_name);
 114     }
 115     return;
 116   } else {
 117
 118     /*
 119      * New entry.
 120      */
 121
 122     if((scp = (stat_cache_entry *)malloc(sizeof(stat_cache_entry)+2*namelen)) == NULL) {
 123       DEBUG(0,("stat_cache_add: Out of memory !\n"));
 124       return;
 125     }
 126     pstrcpy(scp->names, orig_name);
 127     pstrcpy(scp->names+namelen+1, translated_path);
 128     scp->name_len = namelen;
 129     hash_insert(&stat_cache, (char *)scp, orig_name);
 130   }
 131
 132   DEBUG(5,("stat_cache_add: Added entry %s -> %s\n", scp->names, (scp->names+scp->name_len+1)));
 133 }
 134
 135 /****************************************************************************
 136  Look through the stat cache for an entry - promote it to the top if found.
 137  Return True if we translated (and did a scuccessful stat on) the entire name.
 138 *****************************************************************************/
 139
 140 BOOL stat_cache_lookup(connection_struct *conn, char *name, char *dirpath,
 141                        char **start, SMB_STRUCT_STAT *pst)
 142 {
 143   stat_cache_entry *scp;
 144   char *trans_name;
 145   pstring chk_name;
 146   int namelen;
 147   hash_element *hash_elem;
 148   char *sp;
 149
 150   if (!lp_stat_cache())
 151     return False;
 152
 153   namelen = strlen(name);
 154
 155   *start = name;
 156
 157   DO_PROFILE_INC(statcache_lookups);
 158
 159   /*
 160    * Don't lookup trivial valid directory entries.
 161    */
 162   if((*name == '\0') || (strcmp(name, ".") == 0) || (strcmp(name, "..") == 0)) {
 163     DO_PROFILE_INC(statcache_misses);
 164     return False;
 165   }
 166
 167   pstrcpy(chk_name, name);
 168   if(!case_sensitive)
 169     strupper( chk_name );
 170
 171   while (1) {
 172     hash_elem = hash_lookup(&stat_cache, chk_name);
 173     if(hash_elem == NULL) {
 174       /*
 175        * Didn't find it - remove last component for next try.
 176        */
 177       sp = strrchr(chk_name, '/');
 178       if (sp) {
 179         *sp = '\0';
 180       } else {
 181         /*
 182          * We reached the end of the name - no match.
 183          */
 184         DO_PROFILE_INC(statcache_misses);
 185         return False;
 186       }
 187       if((*chk_name == '\0') || (strcmp(chk_name, ".") == 0)
 188                           || (strcmp(chk_name, "..") == 0)) {
 189         DO_PROFILE_INC(statcache_misses);
 190         return False;
 191       }
 192     } else {
 193       scp = (stat_cache_entry *)(hash_elem->value);
 194       DO_PROFILE_INC(statcache_hits);
 195       trans_name = scp->names+scp->name_len+1;
 196       if(vfs_stat(conn,trans_name, pst) != 0) {
 197         /* Discard this entry - it doesn't exist in the filesystem.  */
 198         hash_remove(&stat_cache, hash_elem);
 199         return False;
 200       }
 201       memcpy(name, trans_name, scp->name_len);
 202       *start = &name[scp->name_len];
 203       if(**start == '/')
 204         ++*start;
 205       StrnCpy( dirpath, trans_name, name - (*start));
 206       return (namelen == scp->name_len);
 207     }
 208   }
 209 }
 210
 211 /*************************************************************************** **
 212  * Initializes or clears the stat cache.
 213  *
 214  *  Input:  none.
 215  *  Output: none.
 216  *
 217  * ************************************************************************** **
 218  */
 219 BOOL reset_stat_cache( void )
 220 {
 221         static BOOL initialised;
 222         if (!lp_stat_cache()) return True;
 223
 224         if (initialised) {
 225                 hash_clear(&stat_cache);
 226         }
 227
 228         initialised = hash_table_init( &stat_cache, INIT_STAT_CACHE_SIZE,
 229                                        (compare_function)(strcmp));
 230         return initialised;
 231 } /* reset_stat_cache  */