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samba-mirror/source4/ntvfs/common/notify.c

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/*
Unix SMB/CIFS implementation.
Copyright (C) Andrew Tridgell 2006
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.
*/
/*
this is the change notify database. It implements mechanisms for
storing current change notify waiters in a tdb, and checking if a
given event matches any of the stored notify waiiters.
*/
#include "includes.h"
#include "system/filesys.h"
#include "lib/tdb/include/tdb.h"
#include "lib/tdb/include/tdbutil.h"
#include "messaging/messaging.h"
#include "db_wrap.h"
#include "lib/messaging/irpc.h"
#include "librpc/gen_ndr/ndr_notify.h"
#include "dlinklist.h"
struct notify_context {
struct tdb_wrap *w;
uint32_t server;
struct messaging_context *messaging_ctx;
struct notify_list *list;
struct notify_array *array;
int seqnum;
};
struct notify_list {
struct notify_list *next, *prev;
void *private;
void (*callback)(void *, const struct notify_event *);
};
#define NOTIFY_KEY "notify array"
static NTSTATUS notify_remove_all(struct notify_context *notify);
static void notify_handler(struct messaging_context *msg_ctx, void *private,
uint32_t msg_type, uint32_t server_id, DATA_BLOB *data);
/*
destroy the notify context
*/
static int notify_destructor(void *p)
{
struct notify_context *notify = talloc_get_type(p, struct notify_context);
messaging_deregister(notify->messaging_ctx, MSG_PVFS_NOTIFY, notify);
notify_remove_all(notify);
return 0;
}
/*
Open up the notify.tdb database. You should close it down using
talloc_free(). We need the messaging_ctx to allow for notifications
via internal messages
*/
struct notify_context *notify_init(TALLOC_CTX *mem_ctx, uint32_t server,
struct messaging_context *messaging_ctx)
{
char *path;
struct notify_context *notify;
notify = talloc(mem_ctx, struct notify_context);
if (notify == NULL) {
return NULL;
}
path = smbd_tmp_path(notify, "notify.tdb");
notify->w = tdb_wrap_open(notify, path, 0,
TDB_SEQNUM,
O_RDWR|O_CREAT, 0600);
talloc_free(path);
if (notify->w == NULL) {
talloc_free(notify);
return NULL;
}
notify->server = server;
notify->messaging_ctx = messaging_ctx;
notify->list = NULL;
notify->array = NULL;
notify->seqnum = tdb_get_seqnum(notify->w->tdb);
talloc_set_destructor(notify, notify_destructor);
/* register with the messaging subsystem for the notify
message type */
messaging_register(notify->messaging_ctx, notify,
MSG_PVFS_NOTIFY, notify_handler);
return notify;
}
/*
load the notify array
*/
static NTSTATUS notify_load(struct notify_context *notify)
{
TDB_DATA dbuf;
DATA_BLOB blob;
NTSTATUS status;
int seqnum;
seqnum = tdb_get_seqnum(notify->w->tdb);
if (seqnum == notify->seqnum && notify->array != NULL) {
return NT_STATUS_OK;
}
notify->seqnum = seqnum;
talloc_free(notify->array);
notify->array = talloc_zero(notify, struct notify_array);
NT_STATUS_HAVE_NO_MEMORY(notify->array);
dbuf = tdb_fetch_bystring(notify->w->tdb, NOTIFY_KEY);
if (dbuf.dptr == NULL) {
return NT_STATUS_OK;
}
blob.data = dbuf.dptr;
blob.length = dbuf.dsize;
status = ndr_pull_struct_blob(&blob, notify->array, notify->array,
(ndr_pull_flags_fn_t)ndr_pull_notify_array);
free(dbuf.dptr);
return status;
}
/*
save the notify array
*/
static NTSTATUS notify_save(struct notify_context *notify)
{
TDB_DATA dbuf;
DATA_BLOB blob;
NTSTATUS status;
int ret;
TALLOC_CTX *tmp_ctx;
if (notify->array->num_entries == 0) {
ret = tdb_delete_bystring(notify->w->tdb, NOTIFY_KEY);
if (ret != 0) {
return NT_STATUS_INTERNAL_DB_CORRUPTION;
}
return NT_STATUS_OK;
}
tmp_ctx = talloc_new(notify);
status = ndr_push_struct_blob(&blob, tmp_ctx, notify->array,
(ndr_push_flags_fn_t)ndr_push_notify_array);
if (!NT_STATUS_IS_OK(status)) {
talloc_free(tmp_ctx);
return status;
}
dbuf.dptr = blob.data;
dbuf.dsize = blob.length;
ret = tdb_store_bystring(notify->w->tdb, NOTIFY_KEY, dbuf, TDB_REPLACE);
talloc_free(tmp_ctx);
if (ret != 0) {
return NT_STATUS_INTERNAL_DB_CORRUPTION;
}
return NT_STATUS_OK;
}
/*
handle incoming notify messages
*/
static void notify_handler(struct messaging_context *msg_ctx, void *private,
uint32_t msg_type, uint32_t server_id, DATA_BLOB *data)
{
struct notify_context *notify = talloc_get_type(private, struct notify_context);
NTSTATUS status;
struct notify_event ev;
TALLOC_CTX *tmp_ctx = talloc_new(notify);
struct notify_list *listel;
status = ndr_pull_struct_blob(data, tmp_ctx, &ev,
(ndr_pull_flags_fn_t)ndr_pull_notify_event);
if (!NT_STATUS_IS_OK(status)) {
talloc_free(tmp_ctx);
return;
}
for (listel=notify->list;listel;listel=listel->next) {
if (listel->private == ev.private) {
listel->callback(listel->private, &ev);
break;
}
}
talloc_free(tmp_ctx);
}
/*
add a notify watch. This is called when a notify is first setup on a open
directory handle.
*/
NTSTATUS notify_add(struct notify_context *notify, struct notify_entry *e,
void (*callback)(void *, const struct notify_event *),
void *private)
{
NTSTATUS status;
struct notify_list *listel;
char *path = NULL;
size_t len;
status = notify_load(notify);
NT_STATUS_NOT_OK_RETURN(status);
notify->array->entries = talloc_realloc(notify->array, notify->array->entries,
struct notify_entry,
notify->array->num_entries+1);
if (notify->array->entries == NULL) {
return NT_STATUS_NO_MEMORY;
}
/* cope with /. on the end of the path */
len = strlen(e->path);
if (len > 1 && e->path[len-1] == '.' && e->path[len-2] == '/') {
path = talloc_strndup(notify, e->path, len-2);
}
notify->array->entries[notify->array->num_entries] = *e;
notify->array->entries[notify->array->num_entries].private = private;
notify->array->entries[notify->array->num_entries].server = notify->server;
if (path) {
notify->array->entries[notify->array->num_entries].path = path;
}
notify->array->num_entries++;
status = notify_save(notify);
NT_STATUS_NOT_OK_RETURN(status);
if (path) {
talloc_free(path);
}
listel = talloc(notify, struct notify_list);
NT_STATUS_HAVE_NO_MEMORY(listel);
listel->private = private;
listel->callback = callback;
DLIST_ADD(notify->list, listel);
return status;
}
/*
remove a notify watch. Called when the directory handle is closed
*/
NTSTATUS notify_remove(struct notify_context *notify, void *private)
{
NTSTATUS status;
struct notify_list *listel;
int i;
for (listel=notify->list;listel;listel=listel->next) {
if (listel->private == private) {
DLIST_REMOVE(notify->list, listel);
break;
}
}
if (listel == NULL) {
return NT_STATUS_OBJECT_NAME_NOT_FOUND;
}
status = notify_load(notify);
NT_STATUS_NOT_OK_RETURN(status);
for (i=0;i<notify->array->num_entries;i++) {
if (notify->server == notify->array->entries[i].server &&
private == notify->array->entries[i].private) {
break;
}
}
if (i == notify->array->num_entries) {
return NT_STATUS_OBJECT_NAME_NOT_FOUND;
}
if (i < notify->array->num_entries-1) {
memmove(&notify->array->entries[i], &notify->array->entries[i+1],
sizeof(notify->array->entries[i])*(notify->array->num_entries-(i+1)));
}
notify->array->num_entries--;
return notify_save(notify);
}
/*
remove all notify watches for this messaging server
*/
static NTSTATUS notify_remove_all(struct notify_context *notify)
{
NTSTATUS status;
int i;
if (notify->list == NULL) {
return NT_STATUS_OK;
}
status = notify_load(notify);
NT_STATUS_NOT_OK_RETURN(status);
for (i=0;i<notify->array->num_entries;i++) {
if (notify->server == notify->array->entries[i].server) {
if (i < notify->array->num_entries-1) {
memmove(&notify->array->entries[i], &notify->array->entries[i+1],
sizeof(notify->array->entries[i])*(notify->array->num_entries-(i+1)));
}
i--;
notify->array->num_entries--;
}
}
return notify_save(notify);
}
/*
see if a notify event matches
*/
static BOOL notify_match(struct notify_context *notify, struct notify_entry *e,
const char *path, uint32_t filter)
{
size_t len;
if (!(filter & e->filter)) {
return False;
}
len = strlen(e->path);
if (strncmp(path, e->path, len) != 0) {
return False;
}
if (path[len] != '/') {
return False;
}
if (!e->recursive) {
if (strchr(&path[len+1], '/') != NULL) {
return False;
}
}
return True;
}
/*
send a notify message to another messaging server
*/
static void notify_send(struct notify_context *notify, struct notify_entry *e,
const char *path, uint32_t action)
{
struct notify_event ev;
DATA_BLOB data;
NTSTATUS status;
TALLOC_CTX *tmp_ctx;
ev.action = action;
ev.path = path;
ev.private = e->private;
tmp_ctx = talloc_new(notify);
status = ndr_push_struct_blob(&data, tmp_ctx, &ev,
(ndr_push_flags_fn_t)ndr_push_notify_event);
if (!NT_STATUS_IS_OK(status)) {
talloc_free(tmp_ctx);
return;
}
status = messaging_send(notify->messaging_ctx, e->server,
MSG_PVFS_NOTIFY, &data);
talloc_free(tmp_ctx);
}
/*
trigger a notify message for anyone waiting on a matching event
*/
void notify_trigger(struct notify_context *notify,
uint32_t action, uint32_t filter, const char *path)
{
NTSTATUS status;
int i;
status = notify_load(notify);
if (!NT_STATUS_IS_OK(status)) {
return;
}
/* this needs to be changed to a log(n) search */
for (i=0;i<notify->array->num_entries;i++) {
if (notify_match(notify, &notify->array->entries[i], path, filter)) {
notify_send(notify, &notify->array->entries[i],
path + strlen(notify->array->entries[i].path) + 1,
action);
}
}
}