r23743: Simplify stat_cache_lookup() logic. For the history of this, see
[ira/wip.git] / source3 / smbd / statcache.c
index 948173687d9ebcb9516a738ab1a4210bb04ea164..92c845ce2e8c59fb50c4ac397d2959ab33dd214f 100644 (file)
@@ -2,7 +2,7 @@
    Unix SMB/CIFS implementation.
    stat cache code
    Copyright (C) Andrew Tridgell 1992-2000
-   Copyright (C) Jeremy Allison 1999-2000
+   Copyright (C) Jeremy Allison 1999-2004
    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003
    
    This program is free software; you can redistribute it and/or modify
 
 #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;
+static TDB_CONTEXT *tdb_stat_cache;
 
 /**
  * Add an entry into the stat cache.
@@ -50,28 +40,31 @@ static hash_table stat_cache;
  *
  */
 
-void stat_cache_add( const char *full_orig_name, const char *orig_translated_path)
+void stat_cache_add( const char *full_orig_name, const char *orig_translated_path, BOOL case_sensitive)
 {
-       stat_cache_entry *scp;
-       stat_cache_entry *found_scp;
        char *translated_path;
        size_t translated_path_length;
-
+       TDB_DATA data_val;
        char *original_path;
        size_t original_path_length;
-
-       hash_element *hash_elem;
+       size_t sc_size = lp_max_stat_cache_size();
 
        if (!lp_stat_cache())
                return;
 
+       if (sc_size && (tdb_map_size(tdb_stat_cache) > sc_size*1024)) {
+               reset_stat_cache();
+       }
+
+       ZERO_STRUCT(data_val);
+
        /*
         * Don't cache trivial valid directory entries such as . and ..
         */
 
        if((*full_orig_name == '\0') || (full_orig_name[0] == '.' && 
                                ((full_orig_name[1] == '\0') ||
-                                (full_orig_name[1] == '.' && full_orig_name[1] == '\0'))))
+                                (full_orig_name[1] == '.' && full_orig_name[2] == '\0'))))
                return;
 
        /*
@@ -88,7 +81,7 @@ void stat_cache_add( const char *full_orig_name, const char *orig_translated_pat
         * translated path.
         */
 
-       translated_path = strdup(orig_translated_path);
+       translated_path = SMB_STRDUP(orig_translated_path);
        if (!translated_path)
                return;
 
@@ -100,7 +93,7 @@ void stat_cache_add( const char *full_orig_name, const char *orig_translated_pat
        }
 
        if(case_sensitive) {
-               original_path = strdup(full_orig_name);
+               original_path = SMB_STRDUP(full_orig_name);
        } else {
                original_path = strdup_upper(full_orig_name);
        }
@@ -119,14 +112,14 @@ void stat_cache_add( const char *full_orig_name, const char *orig_translated_pat
 
        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));
+                       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));
                        SAFE_FREE(original_path);
                        SAFE_FREE(translated_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';
@@ -134,55 +127,26 @@ void stat_cache_add( const char *full_orig_name, const char *orig_translated_pat
        }
 
        /*
-        * Check this name doesn't exist in the cache before we 
-        * add it.
+        * New entry or replace old entry.
         */
-
-       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.
-        */
-  
-       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;
-       /* pointer into the structure... */
-       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;
+       data_val.dsize = translated_path_length + 1;
+       data_val.dptr = (uint8 *)translated_path;
 
-       hash_insert(&stat_cache, (char *)scp, original_path);
+       if (tdb_store_bystring(tdb_stat_cache, original_path, data_val, TDB_REPLACE) != 0) {
+               DEBUG(0,("stat_cache_add: Error storing entry %s -> %s\n", original_path, translated_path));
+       } else {
+               DEBUG(5,("stat_cache_add: Added entry (%lx:size%x) %s -> %s\n",
+                       (unsigned long)data_val.dptr, (unsigned int)data_val.dsize, original_path, translated_path));
+       }
 
        SAFE_FREE(original_path);
        SAFE_FREE(translated_path);
-
-       DEBUG(5,("stat_cache_add: Added entry %s -> %s\n", scp->original_path, scp->translated_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
@@ -197,13 +161,13 @@ void stat_cache_add( const char *full_orig_name, const char *orig_translated_pat
 BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath, 
                       char **start, SMB_STRUCT_STAT *pst)
 {
-       stat_cache_entry *scp;
        char *chk_name;
        size_t namelen;
-       hash_element *hash_elem;
-       char *sp;
        BOOL sizechanged = False;
        unsigned int num_components = 0;
+       char *translated_path;
+       size_t translated_path_length;
+       TDB_DATA data_val;
 
        if (!lp_stat_cache())
                return False;
@@ -222,8 +186,8 @@ BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath,
                                 (name[1] == '.' && name[1] == '\0'))))
                return False;
 
-       if (case_sensitive) {
-               chk_name = strdup(name);
+       if (conn->case_sensitive) {
+               chk_name = SMB_STRDUP(name);
                if (!chk_name) {
                        DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
                        return False;
@@ -246,94 +210,156 @@ BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath,
        }
 
        while (1) {
-               hash_elem = hash_lookup(&stat_cache, chk_name);
-               if(hash_elem == NULL) {
-                       DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n", chk_name ));
+               char *sp;
+
+               data_val = tdb_fetch_bystring(tdb_stat_cache, chk_name);
+
+               if (data_val.dptr != NULL && data_val.dsize != 0) {
+                       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++;
-
-                       } else {
-                               /*
-                                * We reached the end of the name - no match.
-                                */
-                               DO_PROFILE_INC(statcache_misses);
-                               SAFE_FREE(chk_name);
-                               return False;
-                       }
-                       if((*chk_name == '\0') || (strcmp(chk_name, ".") == 0)
-                                       || (strcmp(chk_name, "..") == 0)) {
-                               DO_PROFILE_INC(statcache_misses);
-                               SAFE_FREE(chk_name);
-                               return False;
-                       }
-               } else {
-                       scp = (stat_cache_entry *)(hash_elem->value);
-                       DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] -> [%s]\n", chk_name, scp->translated_path ));
-                       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);
-                               SAFE_FREE(chk_name);
-                               return False;
-                       }
-
-                       if (!sizechanged) {
-                               memcpy(name, scp->translated_path, MIN(sizeof(pstring)-1, scp->translated_path_length));
-                       } else if (num_components == 0) {
-                               pstrcpy(name, scp->translated_path);
-                       } else {
-                               sp = strnrchr_m(name, '/', num_components);
-                               if (sp) {
-                                       pstring last_component;
-                                       pstrcpy(last_component, sp);
-                                       pstrcpy(name, scp->translated_path);
-                                       pstrcat(name, last_component);
-                               } else {
-                                       pstrcpy(name, scp->translated_path);
-                               }
-                       }
-
-                       /* 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);
+                       DO_PROFILE_INC(statcache_misses);
                        SAFE_FREE(chk_name);
-                       return (namelen == scp->translated_path_length);
+                       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);
+                       SAFE_FREE(chk_name);
+                       return False;
+               }
+       }
+
+       translated_path = (char *)data_val.dptr;
+       translated_path_length = data_val.dsize - 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. */
+               tdb_delete_bystring(tdb_stat_cache, chk_name);
+               SAFE_FREE(chk_name);
+               SAFE_FREE(data_val.dptr);
+               return False;
        }
+
+       if (!sizechanged) {
+               memcpy(name, translated_path,
+                      MIN(sizeof(pstring)-1, translated_path_length));
+       } else if (num_components == 0) {
+               pstrcpy(name, translated_path);
+       } else {
+               char *sp;
+
+               sp = strnrchr_m(name, '/', num_components);
+               if (sp) {
+                       pstring last_component;
+                       pstrcpy(last_component, sp);
+                       pstrcpy(name, translated_path);
+                       pstrcat(name, last_component);
+               } else {
+                       pstrcpy(name, translated_path);
+               }
+       }
+
+       /* set pointer for 'where to start' on fixing the rest of the name */
+       *start = &name[translated_path_length];
+       if (**start == '/')
+               ++*start;
+
+       pstrcpy(dirpath, translated_path);
+       SAFE_FREE(chk_name);
+       SAFE_FREE(data_val.dptr);
+       return (namelen == translated_path_length);
 }
 
-/*************************************************************************** **
- * Initializes or clears the stat cache.
- *
- *  Input:  none.
- *  Output: none.
- *
- * ************************************************************************** **
- */
+/***************************************************************************
+ 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 = strdup_upper(name);
+
+       if (!lname) {
+               return;
+       }
+       DEBUG(10,("stat_cache_delete: deleting name [%s] -> %s\n",
+                       lname, name ));
+
+       tdb_delete_bystring(tdb_stat_cache, lname);
+       SAFE_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);
+       if (tdb_stat_cache) {
+               tdb_close(tdb_stat_cache);
        }
 
-       initialised = hash_table_init( &stat_cache, INIT_STAT_CACHE_SIZE, 
-                                      (compare_function)(strcmp));
-       return initialised;
+       /* Create the in-memory tdb using our custom hash function. */
+       tdb_stat_cache = tdb_open_ex("statcache", 1031, TDB_INTERNAL,
+                                    (O_RDWR|O_CREAT), 0644, NULL, fast_string_hash);
+
+       if (!tdb_stat_cache)
+               return False;
+       return True;
 }