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de811f14af
Signed-off-by: Volker Lendecke <vl@samba.org> Reviewed-by: Michael Adam <obnox@samba.org>
412 lines
10 KiB
C
412 lines
10 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 1999-2007
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Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003
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Copyright (C) Volker Lendecke 2007
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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, see <http://www.gnu.org/licenses/>.
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*/
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#include "includes.h"
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#include "../lib/util/memcache.h"
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#include "smbd/smbd.h"
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#include "messages.h"
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#include "smbprofile.h"
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#include <tdb.h>
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/****************************************************************************
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Stat cache code used in unix_convert.
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*****************************************************************************/
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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,
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char *translated_path,
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bool case_sensitive)
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{
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size_t translated_path_length;
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char *original_path;
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size_t original_path_length;
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char saved_char;
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TALLOC_CTX *ctx = talloc_tos();
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if (!lp_stat_cache()) {
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return;
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}
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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')
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|| ISDOT(full_orig_name) || ISDOTDOT(full_orig_name)) {
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return;
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}
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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, translated_path) == 0)) {
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return;
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}
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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_length = strlen(translated_path);
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if(translated_path[translated_path_length-1] == '/') {
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translated_path_length--;
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}
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if(case_sensitive) {
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original_path = talloc_strdup(ctx,full_orig_name);
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} else {
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original_path = talloc_strdup_upper(ctx,full_orig_name);
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}
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if (!original_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 "
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"for weird length paths [%s] %lu and [%s] %lu)!\n",
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original_path,
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(unsigned long)original_path_length,
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translated_path,
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(unsigned long)translated_path_length));
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TALLOC_FREE(original_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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/* Ensure we're null terminated. */
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saved_char = translated_path[translated_path_length];
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translated_path[translated_path_length] = '\0';
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/*
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* New entry or replace old entry.
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*/
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memcache_add(
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smbd_memcache(), STAT_CACHE,
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data_blob_const(original_path, original_path_length),
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data_blob_const(translated_path, translated_path_length + 1));
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DEBUG(5,("stat_cache_add: Added entry (%lx:size %x) %s -> %s\n",
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(unsigned long)translated_path,
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(unsigned int)translated_path_length,
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original_path,
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translated_path));
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translated_path[translated_path_length] = saved_char;
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TALLOC_FREE(original_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 posix_paths Whether to lookup using stat() or lstat()
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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. We assume that
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* it is a talloc'ed string from top of stack, we free it if
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* necessary.
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* @param dirpath The path as far as the stat cache told us. Also talloced
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* from top of stack.
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* @param start A pointer into name, for where to 'start' in fixing the rest
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* 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
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* name.
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*
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*/
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bool stat_cache_lookup(connection_struct *conn,
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bool posix_paths,
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char **pp_name,
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char **pp_dirpath,
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char **pp_start,
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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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DATA_BLOB data_val;
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char *name;
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TALLOC_CTX *ctx = talloc_tos();
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struct smb_filename smb_fname;
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int ret;
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*pp_dirpath = NULL;
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*pp_start = *pp_name;
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if (!lp_stat_cache()) {
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return False;
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}
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name = *pp_name;
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namelen = strlen(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') || ISDOT(name) || ISDOTDOT(name)) {
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return False;
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}
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if (conn->case_sensitive) {
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chk_name = talloc_strdup(ctx,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 = talloc_strdup_upper(ctx,name);
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if (!chk_name) {
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DEBUG(0, ("stat_cache_lookup: talloc_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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}
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while (1) {
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char *sp;
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data_val = data_blob_null;
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if (memcache_lookup(
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smbd_memcache(), STAT_CACHE,
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data_blob_const(chk_name, strlen(chk_name)),
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&data_val)) {
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break;
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}
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DEBUG(10,("stat_cache_lookup: lookup failed for name [%s]\n",
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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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TALLOC_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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}
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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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TALLOC_FREE(chk_name);
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return False;
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}
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}
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translated_path = talloc_strdup(ctx,(char *)data_val.data);
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if (!translated_path) {
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smb_panic("talloc failed");
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}
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translated_path_length = data_val.length - 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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ZERO_STRUCT(smb_fname);
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smb_fname.base_name = translated_path;
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if (posix_paths) {
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ret = SMB_VFS_LSTAT(conn, &smb_fname);
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} else {
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ret = SMB_VFS_STAT(conn, &smb_fname);
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}
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if (ret != 0) {
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/* Discard this entry - it doesn't exist in the filesystem. */
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memcache_delete(smbd_memcache(), STAT_CACHE,
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data_blob_const(chk_name, strlen(chk_name)));
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TALLOC_FREE(chk_name);
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TALLOC_FREE(translated_path);
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return False;
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}
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*pst = smb_fname.st;
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if (!sizechanged) {
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memcpy(*pp_name, translated_path,
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MIN(namelen, translated_path_length));
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} else {
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if (num_components == 0) {
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name = talloc_strndup(ctx, translated_path,
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translated_path_length);
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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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name = talloc_asprintf(ctx,"%.*s%s",
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(int)translated_path_length,
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translated_path, sp);
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} else {
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name = talloc_strndup(ctx,
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translated_path,
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translated_path_length);
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}
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}
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if (name == NULL) {
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/*
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* TODO: Get us out of here with a real error message
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*/
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smb_panic("talloc failed");
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}
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TALLOC_FREE(*pp_name);
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*pp_name = name;
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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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*pp_start = &name[translated_path_length];
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if (**pp_start == '/') {
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++*pp_start;
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}
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*pp_dirpath = translated_path;
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TALLOC_FREE(chk_name);
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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 smbd_send_stat_cache_delete_message(struct messaging_context *msg_ctx,
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const char *name)
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{
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#ifdef DEVELOPER
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message_send_all(msg_ctx,
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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 = talloc_strdup_upper(talloc_tos(), 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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memcache_delete(smbd_memcache(), STAT_CACHE,
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data_blob_const(lname, talloc_get_size(lname)-1));
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TALLOC_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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memcache_flush(smbd_memcache(), STAT_CACHE);
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return True;
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}
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