mirror of
https://github.com/samba-team/samba.git
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d824b98f80
Jeremy.
(This used to be commit 407e6e695b
)
366 lines
9.8 KiB
C
366 lines
9.8 KiB
C
/*
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Unix SMB/CIFS implementation.
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stat cache code
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Copyright (C) Andrew Tridgell 1992-2000
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Copyright (C) Jeremy Allison 1999-2004
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Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "includes.h"
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/****************************************************************************
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Stat cache code used in unix_convert.
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*****************************************************************************/
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static TDB_CONTEXT *tdb_stat_cache;
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/**
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* Add an entry into the stat cache.
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*
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* @param full_orig_name The original name as specified by the client
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* @param orig_translated_path The name on our filesystem.
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*
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* @note Only the first strlen(orig_translated_path) characters are stored
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* into the cache. This means that full_orig_name will be internally
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* truncated.
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*
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*/
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void stat_cache_add( const char *full_orig_name, const char *orig_translated_path, BOOL case_sensitive)
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{
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char *translated_path;
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size_t translated_path_length;
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TDB_DATA data_val;
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char *original_path;
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size_t original_path_length;
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size_t sc_size = lp_max_stat_cache_size();
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if (!lp_stat_cache())
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return;
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if (sc_size && (tdb_map_size(tdb_stat_cache) > sc_size*1024)) {
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reset_stat_cache();
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}
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ZERO_STRUCT(data_val);
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/*
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* Don't cache trivial valid directory entries such as . and ..
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*/
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if((*full_orig_name == '\0') || (full_orig_name[0] == '.' &&
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((full_orig_name[1] == '\0') ||
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(full_orig_name[1] == '.' && full_orig_name[2] == '\0'))))
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return;
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/*
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* If we are in case insentive mode, we don't need to
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* store names that need no translation - else, it
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* would be a waste.
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*/
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if(case_sensitive && (strcmp(full_orig_name, orig_translated_path) == 0))
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return;
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/*
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* Remove any trailing '/' characters from the
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* translated path.
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*/
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translated_path = SMB_STRDUP(orig_translated_path);
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if (!translated_path)
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return;
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translated_path_length = strlen(translated_path);
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if(translated_path[translated_path_length-1] == '/') {
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translated_path[translated_path_length-1] = '\0';
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translated_path_length--;
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}
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if(case_sensitive) {
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original_path = SMB_STRDUP(full_orig_name);
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} else {
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original_path = strdup_upper(full_orig_name);
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}
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if (!original_path) {
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SAFE_FREE(translated_path);
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return;
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}
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original_path_length = strlen(original_path);
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if(original_path[original_path_length-1] == '/') {
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original_path[original_path_length-1] = '\0';
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original_path_length--;
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}
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if (original_path_length != translated_path_length) {
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if (original_path_length < translated_path_length) {
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DEBUG(0, ("OOPS - tried to store stat cache entry for weird length paths [%s] %lu and [%s] %lu)!\n",
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original_path, (unsigned long)original_path_length, translated_path, (unsigned long)translated_path_length));
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SAFE_FREE(original_path);
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SAFE_FREE(translated_path);
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return;
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}
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/* we only want to index by the first part of original_path,
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up to the length of translated_path */
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original_path[translated_path_length] = '\0';
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original_path_length = translated_path_length;
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}
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/*
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* New entry or replace old entry.
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*/
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data_val.dsize = translated_path_length + 1;
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data_val.dptr = (uint8 *)translated_path;
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if (tdb_store_bystring(tdb_stat_cache, original_path, data_val, TDB_REPLACE) != 0) {
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DEBUG(0,("stat_cache_add: Error storing entry %s -> %s\n", original_path, translated_path));
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} else {
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DEBUG(5,("stat_cache_add: Added entry (%lx:size%x) %s -> %s\n",
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(unsigned long)data_val.dptr, (unsigned int)data_val.dsize, original_path, translated_path));
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}
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SAFE_FREE(original_path);
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SAFE_FREE(translated_path);
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}
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/**
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* Look through the stat cache for an entry
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*
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* @param conn A connection struct to do the stat() with.
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* @param name The path we are attempting to cache, modified by this routine
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* to be correct as far as the cache can tell us
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* @param dirpath The path as far as the stat cache told us.
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* @param start A pointer into name, for where to 'start' in fixing the rest of the name up.
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* @param psd A stat buffer, NOT from the cache, but just a side-effect.
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*
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* @return True if we translated (and did a scuccessful stat on) the entire name.
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*
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*/
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BOOL stat_cache_lookup(connection_struct *conn, pstring name, pstring dirpath,
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char **start, SMB_STRUCT_STAT *pst)
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{
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char *chk_name;
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size_t namelen;
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BOOL sizechanged = False;
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unsigned int num_components = 0;
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char *translated_path;
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size_t translated_path_length;
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TDB_DATA data_val;
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if (!lp_stat_cache())
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return False;
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namelen = strlen(name);
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*start = name;
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DO_PROFILE_INC(statcache_lookups);
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/*
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* Don't lookup trivial valid directory entries.
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*/
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if((*name == '\0') || (name[0] == '.' &&
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((name[1] == '\0') ||
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(name[1] == '.' && name[1] == '\0'))))
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return False;
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if (conn->case_sensitive) {
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chk_name = SMB_STRDUP(name);
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if (!chk_name) {
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DEBUG(0, ("stat_cache_lookup: strdup failed!\n"));
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return False;
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}
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} else {
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chk_name = strdup_upper(name);
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if (!chk_name) {
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DEBUG(0, ("stat_cache_lookup: strdup_upper failed!\n"));
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return False;
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}
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/*
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* In some language encodings the length changes
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* if we uppercase. We need to treat this differently
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* below.
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*/
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if (strlen(chk_name) != namelen)
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sizechanged = True;
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}
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while (1) {
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char *sp;
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data_val = tdb_fetch_bystring(tdb_stat_cache, chk_name);
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if (data_val.dptr != NULL && data_val.dsize != 0) {
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break;
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}
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DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n", chk_name ));
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/*
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* Didn't find it - remove last component for next try.
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*/
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if (!(sp = strrchr_m(chk_name, '/'))) {
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/*
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* We reached the end of the name - no match.
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*/
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DO_PROFILE_INC(statcache_misses);
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SAFE_FREE(chk_name);
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return False;
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}
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*sp = '\0';
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/*
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* Count the number of times we have done this, we'll
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* need it when reconstructing the string.
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*/
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if (sizechanged)
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num_components++;
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if ((*chk_name == '\0')
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|| ISDOT(chk_name) || ISDOTDOT(chk_name)) {
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DO_PROFILE_INC(statcache_misses);
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SAFE_FREE(chk_name);
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return False;
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}
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}
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translated_path = (char *)data_val.dptr;
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translated_path_length = data_val.dsize - 1;
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DEBUG(10,("stat_cache_lookup: lookup succeeded for name [%s] "
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"-> [%s]\n", chk_name, translated_path ));
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DO_PROFILE_INC(statcache_hits);
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if (SMB_VFS_STAT(conn, translated_path, pst) != 0) {
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/* Discard this entry - it doesn't exist in the filesystem. */
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tdb_delete_bystring(tdb_stat_cache, chk_name);
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SAFE_FREE(chk_name);
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SAFE_FREE(data_val.dptr);
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return False;
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}
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if (!sizechanged) {
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memcpy(name, translated_path,
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MIN(sizeof(pstring)-1, translated_path_length));
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} else if (num_components == 0) {
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pstrcpy(name, translated_path);
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} else {
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char *sp;
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sp = strnrchr_m(name, '/', num_components);
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if (sp) {
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pstring last_component;
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pstrcpy(last_component, sp);
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pstrcpy(name, translated_path);
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pstrcat(name, last_component);
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} else {
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pstrcpy(name, translated_path);
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}
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}
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/* set pointer for 'where to start' on fixing the rest of the name */
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*start = &name[translated_path_length];
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if (**start == '/')
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++*start;
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pstrcpy(dirpath, translated_path);
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SAFE_FREE(chk_name);
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SAFE_FREE(data_val.dptr);
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return (namelen == translated_path_length);
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}
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/***************************************************************************
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Tell all smbd's to delete an entry.
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**************************************************************************/
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void send_stat_cache_delete_message(const char *name)
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{
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#ifdef DEVELOPER
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message_send_all(smbd_messaging_context(),
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MSG_SMB_STAT_CACHE_DELETE,
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name,
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strlen(name)+1,
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NULL);
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#endif
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}
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/***************************************************************************
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Delete an entry.
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**************************************************************************/
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void stat_cache_delete(const char *name)
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{
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char *lname = strdup_upper(name);
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if (!lname) {
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return;
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}
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DEBUG(10,("stat_cache_delete: deleting name [%s] -> %s\n",
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lname, name ));
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tdb_delete_bystring(tdb_stat_cache, lname);
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SAFE_FREE(lname);
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}
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/***************************************************************
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Compute a hash value based on a string key value.
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The function returns the bucket index number for the hashed key.
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JRA. Use a djb-algorithm hash for speed.
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***************************************************************/
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unsigned int fast_string_hash(TDB_DATA *key)
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{
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unsigned int n = 0;
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const char *p;
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for (p = (const char *)key->dptr; *p != '\0'; p++) {
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n = ((n << 5) + n) ^ (unsigned int)(*p);
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}
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return n;
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}
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/***************************************************************************
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Initializes or clears the stat cache.
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**************************************************************************/
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BOOL reset_stat_cache( void )
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{
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if (!lp_stat_cache())
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return True;
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if (tdb_stat_cache) {
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tdb_close(tdb_stat_cache);
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}
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/* Create the in-memory tdb using our custom hash function. */
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tdb_stat_cache = tdb_open_ex("statcache", 1031, TDB_INTERNAL,
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(O_RDWR|O_CREAT), 0644, NULL, fast_string_hash);
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if (!tdb_stat_cache)
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return False;
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return True;
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}
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