/* Unix SMB/CIFS implementation. stat cache code Copyright (C) Andrew Tridgell 1992-2000 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 the Free Software Foundation; either version 2 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. */ #include "includes.h" /**************************************************************************** Stat cache code used in unix_convert. *****************************************************************************/ static TDB_CONTEXT *tdb_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( const char *full_orig_name, const char *orig_translated_path, BOOL case_sensitive) { 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_stat_cache->map_size > 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 = 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 * * @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, pstring name, pstring dirpath, char **start, SMB_STRUCT_STAT *pst) { 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') || (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 = 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; } } } /*************************************************************** 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. ***************************************************************/ u32 fast_string_hash(TDB_DATA *key) { u32 n = 0; const char *p; for (p = key->dptr; *p != '\0'; p++) { n = ((n << 5) + n) ^ (u32)(*p); } return n; } /*************************************************************************** Initializes or clears the stat cache. **************************************************************************/ BOOL reset_stat_cache( void ) { if (!lp_stat_cache()) return True; if (tdb_stat_cache) { tdb_close(tdb_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; }