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-rw-r--r--source3/smbd/statcache.c243
1 files changed, 243 insertions, 0 deletions
diff --git a/source3/smbd/statcache.c b/source3/smbd/statcache.c
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+++ b/source3/smbd/statcache.c
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+/*
+ Unix SMB/Netbios implementation.
+ Version 3.0
+ stat cache code
+ Copyright (C) Andrew Tridgell 1992-2000
+ Copyright (C) Jeremy Allison 1999-200
+
+
+ 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"
+
+extern BOOL case_sensitive;
+
+
+/****************************************************************************
+ Stat cache code used in unix_convert.
+*****************************************************************************/
+
+static int global_stat_cache_lookups;
+static int global_stat_cache_misses;
+static int global_stat_cache_hits;
+
+/****************************************************************************
+ Stat cache statistics code.
+*****************************************************************************/
+
+void print_stat_cache_statistics(void)
+{
+ double eff;
+
+ if(global_stat_cache_lookups == 0)
+ return;
+
+ eff = (100.0* (double)global_stat_cache_hits)/(double)global_stat_cache_lookups;
+
+ DEBUG(0,("stat cache stats: lookups = %d, hits = %d, misses = %d, \
+stat cache was %f%% effective.\n", global_stat_cache_lookups,
+ global_stat_cache_hits, global_stat_cache_misses, eff ));
+}
+
+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;
+
+/****************************************************************************
+ Add an entry into the stat cache.
+*****************************************************************************/
+
+void stat_cache_add( char *full_orig_name, char *orig_translated_path)
+{
+ 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)));
+}
+
+/****************************************************************************
+ 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.
+*****************************************************************************/
+
+BOOL stat_cache_lookup(connection_struct *conn, char *name, char *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;
+
+ namelen = strlen(name);
+
+ *start = name;
+ global_stat_cache_lookups++;
+
+ /*
+ * Don't lookup trivial valid directory entries.
+ */
+ if((*name == '\0') || (strcmp(name, ".") == 0) || (strcmp(name, "..") == 0)) {
+ global_stat_cache_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(chk_name, '/');
+ if (sp) {
+ *sp = '\0';
+ } else {
+ /*
+ * We reached the end of the name - no match.
+ */
+ global_stat_cache_misses++;
+ return False;
+ }
+ if((*chk_name == '\0') || (strcmp(chk_name, ".") == 0)
+ || (strcmp(chk_name, "..") == 0)) {
+ global_stat_cache_misses++;
+ return False;
+ }
+ } else {
+ scp = (stat_cache_entry *)(hash_elem->value);
+ global_stat_cache_hits++;
+ trans_name = scp->names+scp->name_len+1;
+ if(conn->vfs_ops.stat(dos_to_unix(trans_name,False), 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);
+ }
+ }
+}
+
+/*************************************************************************** **
+ * Initializes or clears the stat cache.
+ *
+ * Input: none.
+ * Output: none.
+ *
+ * ************************************************************************** **
+ */
+BOOL reset_stat_cache( void )
+{
+ return hash_table_init( &stat_cache, INIT_STAT_CACHE_SIZE, (compare_function)(strcmp));
+} /* reset_stat_cache */
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