Added a caching system to smbsh. Previously access to workgroup or server

directories under /smb generated net share enum or net server enum calls.
For large networks this could result in bad performance.  We now cache these
results and only call net * enums after the cache timeout has exceeded.
(This used to be commit 1e38eef54d729aeb7fe905b344cf1480c686a348)

3 files changed, 215 insertions, 7 deletions

diff --git a/source3/Makefile.in b/source3/Makefile.in
index b3723223ee..d6a2cfed1f 100644
--- a/source3/Makefile.in
+++ b/source3/Makefile.in
@@ -275,6 +275,7 @@ PAM_WINBIND_OBJ = nsswitch/pam_winbind.po nsswitch/wb_common.po
 SMBW_OBJ = smbwrapper/smbw.o \
 		smbwrapper/smbw_dir.o smbwrapper/smbw_stat.o \
 		smbwrapper/realcalls.o smbwrapper/shared.o \
+		smbwrapper/smbw_cache.o \
 		$(LIBSMB_OBJ) $(PARAM_OBJ) \
                 $(UBIQX_OBJ) $(LIB_OBJ)
 
diff --git a/source3/smbwrapper/smbw_cache.c b/source3/smbwrapper/smbw_cache.c
new file mode 100644
index 0000000000..3213d99941
--- /dev/null
+++ b/source3/smbwrapper/smbw_cache.c
@@ -0,0 +1,208 @@
+/* 
+   Unix SMB/Netbios implementation.
+   Version 2.0
+   SMB wrapper directory functions
+   Copyright (C) Tim Potter 2000
+   
+   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"
+
+/* We cache lists of workgroups, lists of servers in workgroups, and lists
+   of shares exported by servers. */
+
+#define CACHE_TIMEOUT 30
+
+struct name_list {
+	struct name_list *prev, *next;
+	char *name;
+	uint32 stype;
+	char *comment;
+};
+
+struct cached_names {
+	struct cached_names *prev, *next;
+	char *key;
+	struct name_list *name_list;
+	time_t cache_timeout;
+	int result;
+};
+
+static struct cached_names *cached_names = NULL;
+
+/* Find a list of cached name for a workgroup, server or share list */
+
+static struct cached_names *find_cached_names(char *key)
+{
+	struct cached_names *tmp;
+
+	for (tmp = cached_names; tmp; tmp = tmp->next) {
+		if (strequal(tmp->key, key)) {
+			return tmp;
+		}
+	}
+
+	return NULL;
+}
+
+/* Add a name to a list stored in the state variable */
+
+static void add_cached_names(const char *name, uint32 stype, 
+			     const char *comment, void *state)
+{
+	struct name_list **name_list = (struct name_list **)state;
+	struct name_list *new_name;
+
+	new_name = (struct name_list *)malloc(sizeof(struct name_list));
+	if (!new_name) return;
+
+	ZERO_STRUCTP(new_name);
+
+	new_name->name = strdup(name);
+	new_name->stype = stype;
+	new_name->comment = strdup(comment);
+
+	DLIST_ADD(*name_list, new_name);
+}
+
+static void free_name_list(struct name_list *name_list)
+{
+	struct name_list *tmp = name_list;
+
+	while(tmp) {
+		struct name_list *next;
+
+		next = tmp->next;
+
+		free(tmp->name);
+		free(tmp->comment);
+		free(tmp);
+		
+		tmp = next;
+	}
+}
+
+/* Wrapper for NetServerEnum function */
+
+BOOL smbw_NetServerEnum(struct cli_state *cli, char *workgroup, uint32 stype,
+			void (*fn)(const char *, uint32, const char *, void *),
+			void *state)
+{
+	struct cached_names *names;
+	struct name_list *tmp;
+	time_t now = time(NULL);
+	char key[PATH_MAX];
+	BOOL result = True;
+
+	slprintf(key, PATH_MAX - 1, "%s/%s#%s", cli->desthost, 
+		 workgroup, (stype == SV_TYPE_DOMAIN_ENUM ? "DOM" : "SRV"));
+
+	names = find_cached_names(key);
+
+	if (names == NULL || (now - names->cache_timeout) > CACHE_TIMEOUT) {
+		struct cached_names *new_names = NULL;
+
+		/* No names cached for this workgroup */
+
+		if (names == NULL) {
+			new_names = (struct cached_names *)
+				malloc(sizeof(struct cached_names));
+
+			ZERO_STRUCTP(new_names);
+			DLIST_ADD(cached_names, new_names);
+
+		} else {
+
+			/* Dispose of out of date name list */
+
+			free_name_list(names->name_list);
+			names->name_list = NULL;
+
+			new_names = names;
+		}		
+
+		result = cli_NetServerEnum(cli, workgroup, stype, 
+					   add_cached_names, 
+					   &new_names->name_list);
+					   
+		new_names->cache_timeout = now;
+		new_names->result = result;
+		new_names->key = strdup(key);
+
+		names = new_names;
+	}
+
+	/* Return names by running callback function. */
+
+	for (tmp = names->name_list; tmp; tmp = tmp->next)
+		fn(tmp->name, stype, tmp->comment, state);
+	
+	return names->result;
+}
+
+/* Wrapper for RNetShareEnum function */
+
+int smbw_RNetShareEnum(struct cli_state *cli, 
+		       void (*fn)(const char *, uint32, const char *, void *), 
+		       void *state)
+{
+	struct cached_names *names;
+	struct name_list *tmp;
+	time_t now = time(NULL);
+	char key[PATH_MAX];
+
+	slprintf(key, PATH_MAX - 1, "SHARE/%s", cli->desthost);
+
+	names = find_cached_names(key);
+
+	if (names == NULL || (now - names->cache_timeout) > CACHE_TIMEOUT) {
+		struct cached_names *new_names = NULL;
+
+		/* No names cached for this server */
+
+		if (names == NULL) {
+			new_names = (struct cached_names *)
+				malloc(sizeof(struct cached_names));
+
+			ZERO_STRUCTP(new_names);
+			DLIST_ADD(cached_names, new_names);
+
+		} else {
+
+			/* Dispose of out of date name list */
+
+			free_name_list(names->name_list);
+			names->name_list = NULL;
+
+			new_names = names;
+		}
+
+		new_names->result = cli_RNetShareEnum(cli, add_cached_names, 
+						      &new_names->name_list);
+		
+		new_names->cache_timeout = now;
+		new_names->key = strdup(key);
+
+		names = new_names;
+	}
+
+	/* Return names by running callback function. */
+
+	for (tmp = names->name_list; tmp; tmp = tmp->next)
+		fn(tmp->name, tmp->stype, tmp->comment, state);
+	
+	return names->result;
+}
diff --git a/source3/smbwrapper/smbw_dir.c b/source3/smbwrapper/smbw_dir.c
index d94ea6ec87..4f6c18eb7f 100644
--- a/source3/smbwrapper/smbw_dir.c
+++ b/source3/smbwrapper/smbw_dir.c
@@ -72,7 +72,6 @@ static void free_dir(struct smbw_dir *dir)
 	free(dir);
 }
 
-
 static struct smbw_dir *cur_dir;
 
 /***************************************************** 
@@ -102,7 +101,7 @@ static void smbw_dir_add(struct file_info *finfo, const char *mask,
 add a entry to a directory listing
 *******************************************************/
 static void smbw_share_add(const char *share, uint32 type, 
-                           const char *comment, void *state)
+			   const char *comment, void *state)
 {
 	struct file_info finfo;
 
@@ -205,22 +204,22 @@ int smbw_dir_open(const char *fname)
 		*p = 0;
 		smbw_server_add(".",0,"", NULL);
 		smbw_server_add("..",0,"", NULL);
-		cli_NetServerEnum(&srv->cli, srv->server_name, SV_TYPE_DOMAIN_ENUM,
-				  smbw_server_add, NULL);
+		smbw_NetServerEnum(&srv->cli, srv->server_name, 
+				   SV_TYPE_DOMAIN_ENUM, smbw_server_add, NULL);
 		*p = '#';
 	} else if ((p=strstr(srv->server_name,"#1D"))) {
 		DEBUG(4,("doing NetServerEnum\n"));
 		*p = 0;
 		smbw_server_add(".",0,"", NULL);
 		smbw_server_add("..",0,"", NULL);
-		cli_NetServerEnum(&srv->cli, srv->server_name, SV_TYPE_ALL,
-				  smbw_server_add, NULL);
+		smbw_NetServerEnum(&srv->cli, srv->server_name, SV_TYPE_ALL,
+				   smbw_server_add, NULL);
 		*p = '#';
 	} else if (strcmp(srv->cli.dev,"IPC") == 0) {
 		DEBUG(4,("doing NetShareEnum\n"));
 		smbw_share_add(".",0,"", NULL);
 		smbw_share_add("..",0,"", NULL);
-		if (cli_RNetShareEnum(&srv->cli, smbw_share_add, NULL) < 0) {
+		if (smbw_RNetShareEnum(&srv->cli, smbw_share_add, NULL) < 0) {
 			errno = smbw_errno(&srv->cli);
 			goto failed;
 		}