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
it under the terms of the GNU General Public License as published by
#include "includes.h"
-extern BOOL case_sensitive;
-
-
/****************************************************************************
Stat cache code used in unix_convert.
*****************************************************************************/
-typedef struct {
- int name_len;
- 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.
-*****************************************************************************/
+/**
+ * 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
+ * into the cache. This means that full_orig_name will be internally
+ * truncated.
+ *
+ */
-void stat_cache_add( char *full_orig_name, 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;
- pstring orig_name;
- pstring translated_path;
- int namelen;
- hash_element *hash_elem;
-
- if (!lp_stat_cache()) return;
-
- namelen = strlen(orig_translated_path);
-
- /*
- * Don't cache trivial valid directory entries.
- */
- if((*full_orig_name == '\0') || (strcmp(full_orig_name, ".") == 0) ||
- (strcmp(full_orig_name, "..") == 0))
- return;
-
- /*
- * If we are in case insentive mode, we need to
- * store names that need no translation - else, it
- * would be a waste.
- */
-
- if(case_sensitive && (strcmp(full_orig_name, orig_translated_path) == 0))
- return;
-
- /*
- * Remove any trailing '/' characters from the
- * translated path.
- */
-
- pstrcpy(translated_path, orig_translated_path);
- if(translated_path[namelen-1] == '/') {
- translated_path[namelen-1] = '\0';
- namelen--;
- }
-
- /*
- * We will only replace namelen characters
- * of full_orig_name.
- * StrnCpy always null terminates.
- */
-
- StrnCpy(orig_name, full_orig_name, namelen);
- if(!case_sensitive)
- strupper( orig_name );
-
- /*
- * Check this name doesn't exist in the cache before we
- * add it.
- */
-
- if ((hash_elem = hash_lookup(&stat_cache, orig_name))) {
- found_scp = (stat_cache_entry *)(hash_elem->value);
- if (strcmp((found_scp->names+found_scp->name_len+1), translated_path) == 0) {
- return;
- } else {
- hash_remove(&stat_cache, hash_elem);
- if((scp = (stat_cache_entry *)malloc(sizeof(stat_cache_entry)+2*namelen)) == NULL) {
- DEBUG(0,("stat_cache_add: Out of memory !\n"));
- return;
- }
- pstrcpy(scp->names, orig_name);
- pstrcpy((scp->names+namelen+1), translated_path);
- scp->name_len = namelen;
- hash_insert(&stat_cache, (char *)scp, orig_name);
- }
- return;
- } else {
-
- /*
- * New entry.
- */
-
- if((scp = (stat_cache_entry *)malloc(sizeof(stat_cache_entry)+2*namelen)) == NULL) {
- DEBUG(0,("stat_cache_add: Out of memory !\n"));
- return;
- }
- pstrcpy(scp->names, orig_name);
- pstrcpy(scp->names+namelen+1, translated_path);
- scp->name_len = namelen;
- hash_insert(&stat_cache, (char *)scp, orig_name);
- }
-
- DEBUG(5,("stat_cache_add: Added entry %s -> %s\n", scp->names, (scp->names+scp->name_len+1)));
+ char *translated_path;
+ size_t translated_path_length;
+ TDB_DATA data_val;
+ char *original_path;
+ size_t original_path_length;
+ 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[2] == '\0'))))
+ return;
+
+ /*
+ * If we are in case insentive mode, we don't need to
+ * store names that need no translation - else, it
+ * would be a waste.
+ */
+
+ if(case_sensitive && (strcmp(full_orig_name, orig_translated_path) == 0))
+ return;
+
+ /*
+ * Remove any trailing '/' characters from the
+ * translated path.
+ */
+
+ translated_path = SMB_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--;
+ }
+
+ if(case_sensitive) {
+ original_path = SMB_STRDUP(full_orig_name);
+ } else {
+ original_path = strdup_upper(full_orig_name);
+ }
+
+ if (!original_path) {
+ SAFE_FREE(translated_path);
+ return;
+ }
+
+ original_path_length = strlen(original_path);
+
+ if(original_path[original_path_length-1] == '/') {
+ original_path[original_path_length-1] = '\0';
+ original_path_length--;
+ }
+
+ if (original_path_length != translated_path_length) {
+ if (original_path_length < 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 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;
+ }
+
+ /*
+ * New entry or replace old entry.
+ */
+
+ data_val.dsize = translated_path_length + 1;
+ data_val.dptr = (uint8 *)translated_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);
}
-/****************************************************************************
- Look through the stat cache for an entry - promote it to the top if found.
- Return True if we translated (and did a scuccessful stat on) the entire name.
-*****************************************************************************/
+/**
+ * Look through the stat cache for an entry
+ *
+ * @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.
+ * @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.
+ *
+ */
-BOOL stat_cache_lookup(connection_struct *conn, char *name, char *dirpath,
+BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath,
char **start, SMB_STRUCT_STAT *pst)
{
- stat_cache_entry *scp;
- char *trans_name;
- pstring chk_name;
- int namelen;
- hash_element *hash_elem;
- char *sp;
-
- if (!lp_stat_cache())
- return False;
+ char *chk_name;
+ size_t namelen;
+ BOOL sizechanged = False;
+ unsigned int num_components = 0;
+
+ if (!lp_stat_cache())
+ return False;
- namelen = strlen(name);
-
- *start = 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);
- return False;
- }
-
- pstrcpy(chk_name, name);
- if(!case_sensitive)
- strupper( chk_name );
-
- while (1) {
- hash_elem = hash_lookup(&stat_cache, chk_name);
- if(hash_elem == NULL) {
- /*
- * Didn't find it - remove last component for next try.
- */
- sp = strrchr_m(chk_name, '/');
- if (sp) {
- *sp = '\0';
- } 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;
- }
- } else {
- scp = (stat_cache_entry *)(hash_elem->value);
- DO_PROFILE_INC(statcache_hits);
- trans_name = scp->names+scp->name_len+1;
- if(vfs_stat(conn,trans_name, pst) != 0) {
- /* Discard this entry - it doesn't exist in the filesystem. */
- hash_remove(&stat_cache, hash_elem);
- return False;
- }
- memcpy(name, trans_name, scp->name_len);
- *start = &name[scp->name_len];
- if(**start == '/')
- ++*start;
- StrnCpy( dirpath, trans_name, name - (*start));
- return (namelen == scp->name_len);
- }
- }
+ namelen = strlen(name);
+
+ *start = name;
+
+ DO_PROFILE_INC(statcache_lookups);
+
+ /*
+ * Don't lookup trivial valid directory entries.
+ */
+ if((*name == '\0') || (name[0] == '.' &&
+ ((name[1] == '\0') ||
+ (name[1] == '.' && name[1] == '\0'))))
+ return False;
+
+ if (conn->case_sensitive) {
+ chk_name = SMB_STRDUP(name);
+ if (!chk_name) {
+ DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
+ return False;
+ }
+
+ } else {
+ chk_name = strdup_upper(name);
+ if (!chk_name) {
+ DEBUG(0, ("stat_cache_lookup: strdup_upper failed!\n"));
+ return False;
+ }
+
+ /*
+ * In some language encodings the length changes
+ * if we uppercase. We need to treat this differently
+ * below.
+ */
+ if (strlen(chk_name) != namelen)
+ sizechanged = True;
+ }
+
+ while (1) {
+ TDB_DATA data_val;
+ char *sp;
+
+ data_val = tdb_fetch_bystring(tdb_stat_cache, chk_name);
+ if(data_val.dptr == NULL || data_val.dsize == 0) {
+ DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n", chk_name ));
+ /*
+ * Didn't find it - remove last component for next try.
+ */
+ 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 {
+ BOOL retval;
+ char *translated_path = (char *)data_val.dptr;
+ size_t 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 {
+ 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);
+ retval = (namelen == translated_path_length) ? True : False;
+ SAFE_FREE(chk_name);
+ SAFE_FREE(data_val.dptr);
+ return retval;
+ }
+ }
}
-/*************************************************************************** **
- * 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 (!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;
-} /* reset_stat_cache */
+ /* 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;
+}
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