Add a in-memory cache
[nivanova/samba-autobuild/.git] / source3 / smbd / statcache.c
index 5d54a5c4ffe9d69c83d735b53547899c8d999bd1..72fed008a2a5ba0dda09e7137a808b6a2d3e68e6 100644 (file)
@@ -1,77 +1,65 @@
-/* 
+/*
    Unix SMB/CIFS implementation.
    stat cache code
    Copyright (C) Andrew Tridgell 1992-2000
-   Copyright (C) Jeremy Allison 1999-2000
+   Copyright (C) Jeremy Allison 1999-2007
    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003
-   
+   Copyright (C) Volker Lendecke 2007
+
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2 of the License, or
+   the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.
-   
+
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
-   
+
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
 #include "includes.h"
 
-extern BOOL case_sensitive;
-
 /****************************************************************************
  Stat cache code used in unix_convert.
 *****************************************************************************/
 
-typedef struct {
-       char *original_path;
-       char *translated_path;
-       size_t translated_path_length;
-       char names[2]; /* This is extended via malloc... */
-} stat_cache_entry;
-
-#define INIT_STAT_CACHE_SIZE 512
-static hash_table stat_cache;
-
 /**
  * Add an entry into the stat cache.
  *
  * @param full_orig_name       The original name as specified by the client
  * @param orig_translated_path The name on our filesystem.
- * 
- * @note Only the first strlen(orig_translated_path) characters are stored 
+ *
+ * @note Only the first strlen(orig_translated_path) characters are stored
  *       into the cache.  This means that full_orig_name will be internally
  *       truncated.
  *
  */
 
-void stat_cache_add( const char *full_orig_name, const char *orig_translated_path)
+void stat_cache_add( const char *full_orig_name,
+               char *translated_path,
+               bool case_sensitive)
 {
-       stat_cache_entry *scp;
-       stat_cache_entry *found_scp;
-       char *translated_path;
        size_t translated_path_length;
-
        char *original_path;
        size_t original_path_length;
+       char saved_char;
+       TALLOC_CTX *ctx = talloc_tos();
 
-       hash_element *hash_elem;
-
-       if (!lp_stat_cache())
+       if (!lp_stat_cache()) {
                return;
+       }
 
        /*
-        * Don't cache trivial valid directory entries.
+        * Don't cache trivial valid directory entries such as . and ..
         */
 
-       if((*full_orig_name == '\0') || (strcmp(full_orig_name, ".") == 0) ||
-                       (strcmp(full_orig_name, "..") == 0))
+       if ((*full_orig_name == '\0')
+           || ISDOT(full_orig_name) || ISDOTDOT(full_orig_name)) {
                return;
+       }
 
        /*
         * If we are in case insentive mode, we don't need to
@@ -79,28 +67,28 @@ void stat_cache_add( const char *full_orig_name, const char *orig_translated_pat
         * would be a waste.
         */
 
-       if(case_sensitive && (strcmp(full_orig_name, orig_translated_path) == 0))
+       if (case_sensitive && (strcmp(full_orig_name, translated_path) == 0)) {
                return;
+       }
 
        /*
         * Remove any trailing '/' characters from the
         * translated path.
         */
 
-       translated_path = strdup(orig_translated_path);
-       if (!translated_path)
-               return;
-
        translated_path_length = strlen(translated_path);
 
        if(translated_path[translated_path_length-1] == '/') {
-               translated_path[translated_path_length-1] = '\0';
                translated_path_length--;
        }
 
-       original_path = strdup(full_orig_name);
+       if(case_sensitive) {
+               original_path = talloc_strdup(ctx,full_orig_name);
+       } else {
+               original_path = talloc_strdup_upper(ctx,full_orig_name);
+       }
+
        if (!original_path) {
-               SAFE_FREE(translated_path);
                return;
        }
 
@@ -111,207 +99,293 @@ void stat_cache_add( const char *full_orig_name, const char *orig_translated_pat
                original_path_length--;
        }
 
-       if(!case_sensitive)
-               strupper_m(original_path);
-
        if (original_path_length != translated_path_length) {
                if (original_path_length < translated_path_length) {
-                       DEBUG(0, ("OOPS - tried to store stat cache entry for werid length paths [%s] %u and [%s] %u)!\n",
-                                               original_path, original_path_length, translated_path, translated_path_length));
-                       SAFE_FREE(original_path);
-                       SAFE_FREE(translated_path);
+                       DEBUG(0, ("OOPS - tried to store stat cache entry "
+                       "for weird length paths [%s] %lu and [%s] %lu)!\n",
+                                 original_path,
+                                 (unsigned long)original_path_length,
+                                 translated_path,
+                                 (unsigned long)translated_path_length));
+                       TALLOC_FREE(original_path);
                        return;
                }
 
-               /* we only want to store the first part of original_path,
+               /* we only want to index by the first part of original_path,
                        up to the length of translated_path */
 
                original_path[translated_path_length] = '\0';
                original_path_length = translated_path_length;
        }
 
-       /*
-        * Check this name doesn't exist in the cache before we 
-        * add it.
-        */
+       /* Ensure we're null terminated. */
+       saved_char = translated_path[translated_path_length];
+       translated_path[translated_path_length] = '\0';
 
-       if ((hash_elem = hash_lookup(&stat_cache, original_path))) {
-               found_scp = (stat_cache_entry *)(hash_elem->value);
-               if (strcmp((found_scp->translated_path), orig_translated_path) == 0) {
-                       /* already in hash table */
-                       SAFE_FREE(original_path);
-                       SAFE_FREE(translated_path);
-                       return;
-               }
-               /* hash collision - remove before we re-add */
-               hash_remove(&stat_cache, hash_elem);
-       }  
-  
        /*
-        * New entry.
+        * New entry or replace old entry.
         */
-  
-       if((scp = (stat_cache_entry *)malloc(sizeof(stat_cache_entry)
-                                               +original_path_length
-                                               +translated_path_length)) == NULL) {
-               DEBUG(0,("stat_cache_add: Out of memory !\n"));
-               SAFE_FREE(original_path);
-               SAFE_FREE(translated_path);
-               return;
-       }
-
-       scp->original_path = scp->names;
-       scp->translated_path = scp->names + original_path_length + 1;
-       safe_strcpy(scp->original_path, original_path, original_path_length);
-       safe_strcpy(scp->translated_path, translated_path, translated_path_length);
-       scp->translated_path_length = translated_path_length;
 
-       hash_insert(&stat_cache, (char *)scp, original_path);
+       memcache_add(
+               smbd_memcache(), STAT_CACHE,
+               data_blob_const(original_path, original_path_length),
+               data_blob_const(translated_path, translated_path_length + 1));
 
-       SAFE_FREE(original_path);
-       SAFE_FREE(translated_path);
+       DEBUG(5,("stat_cache_add: Added entry (%lx:size %x) %s -> %s\n",
+                (unsigned long)translated_path,
+                (unsigned int)translated_path_length,
+                original_path,
+                translated_path));
 
-       DEBUG(5,("stat_cache_add: Added entry %s -> %s\n", scp->original_path, scp->translated_path));
+       translated_path[translated_path_length] = saved_char;
+       TALLOC_FREE(original_path);
 }
 
 /**
  * Look through the stat cache for an entry
  *
- * The hash-table's internals will promote it to the top if found.
- *
  * @param conn    A connection struct to do the stat() with.
  * @param name    The path we are attempting to cache, modified by this routine
- *                to be correct as far as the cache can tell us
- * @param dirpath The path as far as the stat cache told us.
- * @param start   A pointer into name, for where to 'start' in fixing the rest of the name up.
+ *                to be correct as far as the cache can tell us. We assume that
+ *               it is a talloc'ed string from top of stack, we free it if
+ *               necessary.
+ * @param dirpath The path as far as the stat cache told us. Also talloced
+ *               from top of stack.
+ * @param start   A pointer into name, for where to 'start' in fixing the rest
+ *               of the name up.
  * @param psd     A stat buffer, NOT from the cache, but just a side-effect.
  *
- * @return True if we translated (and did a scuccessful stat on) the entire name.
+ * @return True if we translated (and did a scuccessful stat on) the entire
+ *               name.
  *
  */
 
-BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath, 
-                      char **start, SMB_STRUCT_STAT *pst)
+bool stat_cache_lookup(connection_struct *conn,
+                       char **pp_name,
+                       char **pp_dirpath,
+                       char **pp_start,
+                       SMB_STRUCT_STAT *pst)
 {
-       stat_cache_entry *scp;
-       pstring chk_name;
+       char *chk_name;
        size_t namelen;
-       hash_element *hash_elem;
-       char *sp;
-       BOOL sizechanged = False;
+       bool sizechanged = False;
        unsigned int num_components = 0;
+       char *translated_path;
+       size_t translated_path_length;
+       DATA_BLOB data_val;
+       char *name;
+       TALLOC_CTX *ctx = talloc_tos();
 
-       if (!lp_stat_cache())
+       *pp_dirpath = NULL;
+       *pp_start = *pp_name;
+
+       if (!lp_stat_cache()) {
                return False;
-       namelen = strlen(name);
+       }
 
-       *start = name;
+       name = *pp_name;
+       namelen = strlen(name);
 
        DO_PROFILE_INC(statcache_lookups);
 
        /*
         * Don't lookup trivial valid directory entries.
         */
-       if((*name == '\0') || (strcmp(name, ".") == 0) || (strcmp(name, "..") == 0)) {
-               DO_PROFILE_INC(statcache_misses);
+       if ((*name == '\0') || ISDOT(name) || ISDOTDOT(name)) {
                return False;
        }
 
-       pstrcpy(chk_name, name);
+       if (conn->case_sensitive) {
+               chk_name = talloc_strdup(ctx,name);
+               if (!chk_name) {
+                       DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
+                       return False;
+               }
+
+       } else {
+               chk_name = talloc_strdup_upper(ctx,name);
+               if (!chk_name) {
+                       DEBUG(0, ("stat_cache_lookup: strdup_upper failed!\n"));
+                       return False;
+               }
 
-       if(!case_sensitive) {
-               strupper_m( chk_name );
                /*
                 * In some language encodings the length changes
                 * if we uppercase. We need to treat this differently
                 * below.
                 */
-               if (strlen(chk_name) != namelen)
+               if (strlen(chk_name) != namelen) {
                        sizechanged = True;
+               }
        }
 
        while (1) {
-               hash_elem = hash_lookup(&stat_cache, chk_name);
-               if(hash_elem == NULL) {
+               char *sp;
+
+               data_val = data_blob_null;
+
+               if (memcache_lookup(
+                           smbd_memcache(), STAT_CACHE,
+                           data_blob_const(chk_name, strlen(chk_name)),
+                           &data_val)) {
+                       break;
+               }
+
+               DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n",
+                               chk_name ));
+               /*
+                * Didn't find it - remove last component for next try.
+                */
+               if (!(sp = strrchr_m(chk_name, '/'))) {
                        /*
-                        * Didn't find it - remove last component for next try.
+                        * We reached the end of the name - no match.
                         */
-                       sp = strrchr_m(chk_name, '/');
-                       if (sp) {
-                               *sp = '\0';
-                               /*
-                                * Count the number of times we have done this,
-                                * we'll need it when reconstructing the string.
-                                */
-                               if (sizechanged)
-                                       num_components++;
+                       DO_PROFILE_INC(statcache_misses);
+                       TALLOC_FREE(chk_name);
+                       return False;
+               }
 
-                       } else {
-                               /*
-                                * We reached the end of the name - no match.
-                                */
-                               DO_PROFILE_INC(statcache_misses);
-                               return False;
-                       }
-                       if((*chk_name == '\0') || (strcmp(chk_name, ".") == 0)
-                                       || (strcmp(chk_name, "..") == 0)) {
-                               DO_PROFILE_INC(statcache_misses);
-                               return False;
-                       }
+               *sp = '\0';
+
+               /*
+                * Count the number of times we have done this, we'll
+                * need it when reconstructing the string.
+                */
+
+               if (sizechanged) {
+                       num_components++;
+               }
+
+               if ((*chk_name == '\0')
+                   || ISDOT(chk_name) || ISDOTDOT(chk_name)) {
+                       DO_PROFILE_INC(statcache_misses);
+                       TALLOC_FREE(chk_name);
+                       return False;
+               }
+       }
+
+       translated_path = talloc_strdup(ctx,(char *)data_val.data);
+       if (!translated_path) {
+               smb_panic("talloc failed");
+       }
+       translated_path_length = data_val.length - 1;
+
+       DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] "
+                 "-> [%s]\n", chk_name, translated_path ));
+       DO_PROFILE_INC(statcache_hits);
+
+       if (SMB_VFS_STAT(conn, translated_path, pst) != 0) {
+               /* Discard this entry - it doesn't exist in the filesystem. */
+               memcache_delete(smbd_memcache(), STAT_CACHE,
+                               data_blob_const(chk_name, strlen(chk_name)));
+               TALLOC_FREE(chk_name);
+               TALLOC_FREE(translated_path);
+               return False;
+       }
+
+       if (!sizechanged) {
+               memcpy(*pp_name, translated_path,
+                      MIN(namelen, translated_path_length));
+       } else {
+               if (num_components == 0) {
+                       name = talloc_strndup(ctx, translated_path,
+                                          translated_path_length);
                } else {
-                       scp = (stat_cache_entry *)(hash_elem->value);
-                       DO_PROFILE_INC(statcache_hits);
-                       if(SMB_VFS_STAT(conn,scp->translated_path, pst) != 0) {
-                               /* Discard this entry - it doesn't exist in the filesystem.  */
-                               hash_remove(&stat_cache, hash_elem);
-                               return False;
-                       }
+                       char *sp;
 
-                       if (!sizechanged) {
-                               memcpy(name, scp->translated_path, MIN(sizeof(pstring)-1, scp->translated_path_length));
+                       sp = strnrchr_m(name, '/', num_components);
+                       if (sp) {
+                               name = talloc_asprintf(ctx,"%.*s%s",
+                                        (int)translated_path_length,
+                                        translated_path, sp);
                        } else {
-                               pstring last_component;
-                               sp = strnrchr_m(name, '/', num_components);
-                               if (!sp) {
-                                       /* Logic error. */
-                                       smb_panic("logic error in stat_cache_lookup\n");
-                               }
-                               pstrcpy(last_component, sp);
-                               pstrcpy(name, scp->translated_path);
-                               pstrcat(name, last_component);
+                               name = talloc_strndup(ctx,
+                                               translated_path,
+                                               translated_path_length);
                        }
+               }
+               if (name == NULL) {
+                       /*
+                        * TODO: Get us out of here with a real error message
+                        */
+                       smb_panic("talloc failed");
+               }
+               TALLOC_FREE(*pp_name);
+               *pp_name = name;
+       }
 
-                       /* set pointer for 'where to start' on fixing the rest of the name */
-                       *start = &name[scp->translated_path_length];
-                       if(**start == '/')
-                               ++*start;
 
-                       pstrcpy(dirpath, scp->translated_path);
-                       return (namelen == scp->translated_path_length);
-               }
+       /* set pointer for 'where to start' on fixing the rest of the name */
+       *pp_start = &name[translated_path_length];
+       if (**pp_start == '/') {
+               ++*pp_start;
        }
+
+       *pp_dirpath = translated_path;
+       TALLOC_FREE(chk_name);
+       return (namelen == translated_path_length);
 }
 
-/*************************************************************************** **
- * Initializes or clears the stat cache.
- *
- *  Input:  none.
- *  Output: none.
- *
- * ************************************************************************** **
- */
-BOOL reset_stat_cache( void )
+/***************************************************************************
+ Tell all smbd's to delete an entry.
+**************************************************************************/
+
+void send_stat_cache_delete_message(const char *name)
+{
+#ifdef DEVELOPER
+       message_send_all(smbd_messaging_context(),
+                       MSG_SMB_STAT_CACHE_DELETE,
+                       name,
+                       strlen(name)+1,
+                       NULL);
+#endif
+}
+
+/***************************************************************************
+ Delete an entry.
+**************************************************************************/
+
+void stat_cache_delete(const char *name)
+{
+       char *lname = talloc_strdup_upper(talloc_tos(), name);
+
+       if (!lname) {
+               return;
+       }
+       DEBUG(10,("stat_cache_delete: deleting name [%s] -> %s\n",
+                       lname, name ));
+
+       memcache_delete(smbd_memcache(), STAT_CACHE,
+                       data_blob_const(lname, talloc_get_size(lname)-1));
+       TALLOC_FREE(lname);
+}
+
+/***************************************************************
+ Compute a hash value based on a string key value.
+ The function returns the bucket index number for the hashed key.
+ JRA. Use a djb-algorithm hash for speed.
+***************************************************************/
+
+unsigned int fast_string_hash(TDB_DATA *key)
+{
+        unsigned int n = 0;
+        const char *p;
+        for (p = (const char *)key->dptr; *p != '\0'; p++) {
+                n = ((n << 5) + n) ^ (unsigned int)(*p);
+        }
+        return n;
+}
+
+/***************************************************************************
+ Initializes or clears the stat cache.
+**************************************************************************/
+
+bool reset_stat_cache( void )
 {
-       static BOOL initialised;
        if (!lp_stat_cache())
                return True;
 
-       if (initialised) {
-               hash_clear(&stat_cache);
-       }
+       memcache_flush(smbd_memcache(), STAT_CACHE);
 
-       initialised = hash_table_init( &stat_cache, INIT_STAT_CACHE_SIZE, 
-                                      (compare_function)(strcmp));
-       return initialised;
+       return True;
 }