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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 3 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, see <http://www.gnu.org/licenses/>.
*/
/*
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/util/util_tdb.h"
#include "messaging/messaging.h"
#include "tdb_wrap.h"
#include "lib/messaging/irpc.h"
#include "librpc/gen_ndr/ndr_notify.h"
#include "lib/util/dlinklist.h"
#include "ntvfs/common/ntvfs_common.h"
#include "ntvfs/sysdep/sys_notify.h"
#include "cluster/cluster.h"
#include "param/param.h"
struct notify_context {
struct tdb_wrap *w;
struct server_id server;
struct messaging_context *messaging_ctx;
struct notify_list *list;
struct notify_array *array;
int seqnum;
struct sys_notify_context *sys_notify_ctx;
struct smb_iconv_convenience *iconv_convenience;
};
struct notify_list {
struct notify_list *next, *prev;
void *private_data;
void (*callback)(void *, const struct notify_event *);
void *sys_notify_handle;
int depth;
};
#define NOTIFY_KEY "notify array"
#define NOTIFY_ENABLE "notify:enable"
#define NOTIFY_ENABLE_DEFAULT true
static NTSTATUS notify_remove_all(struct notify_context *notify);
static void notify_handler(struct messaging_context *msg_ctx, void *private_data,
uint32_t msg_type, struct server_id server_id, DATA_BLOB *data);
/*
destroy the notify context
*/
static int notify_destructor(struct notify_context *notify)
{
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, struct server_id server,
struct messaging_context *messaging_ctx,
struct loadparm_context *lp_ctx,
struct event_context *ev,
struct share_config *scfg)
{
struct notify_context *notify;
if (share_bool_option(scfg, NOTIFY_ENABLE, NOTIFY_ENABLE_DEFAULT) != true) {
return NULL;
}
if (ev == NULL) {
return NULL;
}
notify = talloc(mem_ctx, struct notify_context);
if (notify == NULL) {
return NULL;
}
notify->w = cluster_tdb_tmp_open(notify, lp_ctx, "notify.tdb", TDB_SEQNUM);
if (notify->w == NULL) {
talloc_free(notify);
return NULL;
}
notify->server = server;
notify->messaging_ctx = messaging_ctx;
notify->list = NULL;
notify->array = NULL;
notify->iconv_convenience = lp_iconv_convenience(lp_ctx);
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);
notify->sys_notify_ctx = sys_notify_context_create(scfg, notify, ev);
return notify;
}
/*
lock the notify db
*/
static NTSTATUS notify_lock(struct notify_context *notify)
{
if (tdb_lock_bystring(notify->w->tdb, NOTIFY_KEY) != 0) {
return NT_STATUS_INTERNAL_DB_CORRUPTION;
}
return NT_STATUS_OK;
}
/*
unlock the notify db
*/
static void notify_unlock(struct notify_context *notify)
{
tdb_unlock_bystring(notify->w->tdb, NOTIFY_KEY);
}
/*
load the notify array
*/
static NTSTATUS notify_load(struct notify_context *notify)
{
TDB_DATA dbuf;
DATA_BLOB blob;
enum ndr_err_code ndr_err;
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;
ndr_err = ndr_pull_struct_blob(&blob, notify->array, notify->iconv_convenience,
notify->array,
(ndr_pull_flags_fn_t)ndr_pull_notify_array);
free(dbuf.dptr);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
return ndr_map_error2ntstatus(ndr_err);
}
return NT_STATUS_OK;
}
/*
compare notify entries for sorting
*/
static int notify_compare(const void *p1, const void *p2)
{
const struct notify_entry *e1 = p1, *e2 = p2;
return strcmp(e1->path, e2->path);
}
/*
save the notify array
*/
static NTSTATUS notify_save(struct notify_context *notify)
{
TDB_DATA dbuf;
DATA_BLOB blob;
enum ndr_err_code ndr_err;
int ret;
TALLOC_CTX *tmp_ctx;
/* if possible, remove some depth arrays */
while (notify->array->num_depths > 0 &&
notify->array->depth[notify->array->num_depths-1].num_entries == 0) {
notify->array->num_depths--;
}
/* we might just be able to delete the record */
if (notify->array->num_depths == 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);
NT_STATUS_HAVE_NO_MEMORY(tmp_ctx);
ndr_err = ndr_push_struct_blob(&blob, tmp_ctx, notify->iconv_convenience, notify->array,
(ndr_push_flags_fn_t)ndr_push_notify_array);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
talloc_free(tmp_ctx);
return ndr_map_error2ntstatus(ndr_err);
}
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_data,
uint32_t msg_type, struct server_id server_id, DATA_BLOB *data)
{
struct notify_context *notify = talloc_get_type(private_data, struct notify_context);
enum ndr_err_code ndr_err;
struct notify_event ev;
TALLOC_CTX *tmp_ctx = talloc_new(notify);
struct notify_list *listel;
if (tmp_ctx == NULL) {
return;
}
ndr_err = ndr_pull_struct_blob(data, tmp_ctx, notify->iconv_convenience, &ev,
(ndr_pull_flags_fn_t)ndr_pull_notify_event);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
talloc_free(tmp_ctx);
return;
}
for (listel=notify->list;listel;listel=listel->next) {
if (listel->private_data == ev.private_data) {
listel->callback(listel->private_data, &ev);
break;
}
}
talloc_free(tmp_ctx);
}
/*
callback from sys_notify telling us about changes from the OS
*/
static void sys_notify_callback(struct sys_notify_context *ctx,
void *ptr, struct notify_event *ev)
{
struct notify_list *listel = talloc_get_type(ptr, struct notify_list);
ev->private_data = listel;
listel->callback(listel->private_data, ev);
}
/*
add an entry to the notify array
*/
static NTSTATUS notify_add_array(struct notify_context *notify, struct notify_entry *e,
void *private_data, int depth)
{
int i;
struct notify_depth *d;
struct notify_entry *ee;
/* possibly expand the depths array */
if (depth >= notify->array->num_depths) {
d = talloc_realloc(notify->array, notify->array->depth,
struct notify_depth, depth+1);
NT_STATUS_HAVE_NO_MEMORY(d);
for (i=notify->array->num_depths;i<=depth;i++) {
ZERO_STRUCT(d[i]);
}
notify->array->depth = d;
notify->array->num_depths = depth+1;
}
d = &notify->array->depth[depth];
/* expand the entries array */
ee = talloc_realloc(notify->array->depth, d->entries, struct notify_entry,
d->num_entries+1);
NT_STATUS_HAVE_NO_MEMORY(ee);
d->entries = ee;
d->entries[d->num_entries] = *e;
d->entries[d->num_entries].private_data = private_data;
d->entries[d->num_entries].server = notify->server;
d->entries[d->num_entries].path_len = strlen(e->path);
d->num_entries++;
d->max_mask |= e->filter;
d->max_mask_subdir |= e->subdir_filter;
if (d->num_entries > 1) {
qsort(d->entries, d->num_entries, sizeof(d->entries[0]), notify_compare);
}
/* recalculate the maximum masks */
d->max_mask = 0;
d->max_mask_subdir = 0;
for (i=0;i<d->num_entries;i++) {
d->max_mask |= d->entries[i].filter;
d->max_mask_subdir |= d->entries[i].subdir_filter;
}
return notify_save(notify);
}
/*
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 *e0,
void (*callback)(void *, const struct notify_event *),
void *private_data)
{
struct notify_entry e = *e0;
NTSTATUS status;
char *tmp_path = NULL;
struct notify_list *listel;
size_t len;
int depth;
/* see if change notify is enabled at all */
if (notify == NULL) {
return NT_STATUS_NOT_IMPLEMENTED;
}
status = notify_lock(notify);
NT_STATUS_NOT_OK_RETURN(status);
status = notify_load(notify);
if (!NT_STATUS_IS_OK(status)) {
goto done;
}
/* cope with /. on the end of the path */
len = strlen(e.path);
if (len > 1 && e.path[len-1] == '.' && e.path[len-2] == '/') {
tmp_path = talloc_strndup(notify, e.path, len-2);
if (tmp_path == NULL) {
status = NT_STATUS_NO_MEMORY;
goto done;
}
e.path = tmp_path;
}
depth = count_chars(e.path, '/');
listel = talloc_zero(notify, struct notify_list);
if (listel == NULL) {
status = NT_STATUS_NO_MEMORY;
goto done;
}
listel->private_data = private_data;
listel->callback = callback;
listel->depth = depth;
DLIST_ADD(notify->list, listel);
/* ignore failures from sys_notify */
if (notify->sys_notify_ctx != NULL) {
/*
this call will modify e.filter and e.subdir_filter
to remove bits handled by the backend
*/
status = sys_notify_watch(notify->sys_notify_ctx, &e,
sys_notify_callback, listel,
&listel->sys_notify_handle);
if (NT_STATUS_IS_OK(status)) {
talloc_steal(listel, listel->sys_notify_handle);
}
}
/* if the system notify handler couldn't handle some of the
filter bits, or couldn't handle a request for recursion
then we need to install it in the array used for the
intra-samba notify handling */
if (e.filter != 0 || e.subdir_filter != 0) {
status = notify_add_array(notify, &e, private_data, depth);
}
done:
notify_unlock(notify);
talloc_free(tmp_path);
return status;
}
/*
remove a notify watch. Called when the directory handle is closed
*/
NTSTATUS notify_remove(struct notify_context *notify, void *private_data)
{
NTSTATUS status;
struct notify_list *listel;
int i, depth;
struct notify_depth *d;
/* see if change notify is enabled at all */
if (notify == NULL) {
return NT_STATUS_NOT_IMPLEMENTED;
}
for (listel=notify->list;listel;listel=listel->next) {
if (listel->private_data == private_data) {
DLIST_REMOVE(notify->list, listel);
break;
}
}
if (listel == NULL) {
return NT_STATUS_OBJECT_NAME_NOT_FOUND;
}
depth = listel->depth;
talloc_free(listel);
status = notify_lock(notify);
NT_STATUS_NOT_OK_RETURN(status);
status = notify_load(notify);
if (!NT_STATUS_IS_OK(status)) {
notify_unlock(notify);
return status;
}
if (depth >= notify->array->num_depths) {
notify_unlock(notify);
return NT_STATUS_OBJECT_NAME_NOT_FOUND;
}
/* we only have to search at the depth of this element */
d = &notify->array->depth[depth];
for (i=0;i<d->num_entries;i++) {
if (private_data == d->entries[i].private_data &&
cluster_id_equal(&notify->server, &d->entries[i].server)) {
break;
}
}
if (i == d->num_entries) {
notify_unlock(notify);
return NT_STATUS_OBJECT_NAME_NOT_FOUND;
}
if (i < d->num_entries-1) {
memmove(&d->entries[i], &d->entries[i+1],
sizeof(d->entries[i])*(d->num_entries-(i+1)));
}
d->num_entries--;
status = notify_save(notify);
notify_unlock(notify);
return status;
}
/*
remove all notify watches for this messaging server
*/
static NTSTATUS notify_remove_all(struct notify_context *notify)
{
NTSTATUS status;
int i, depth, del_count=0;
if (notify->list == NULL) {
return NT_STATUS_OK;
}
status = notify_lock(notify);
NT_STATUS_NOT_OK_RETURN(status);
status = notify_load(notify);
if (!NT_STATUS_IS_OK(status)) {
notify_unlock(notify);
return status;
}
/* we have to search for all entries across all depths, looking for matches
for our server id */
for (depth=0;depth<notify->array->num_depths;depth++) {
struct notify_depth *d = &notify->array->depth[depth];
for (i=0;i<d->num_entries;i++) {
if (cluster_id_equal(&notify->server, &d->entries[i].server)) {
if (i < d->num_entries-1) {
memmove(&d->entries[i], &d->entries[i+1],
sizeof(d->entries[i])*(d->num_entries-(i+1)));
}
i--;
d->num_entries--;
del_count++;
}
}
}
if (del_count > 0) {
status = notify_save(notify);
}
notify_unlock(notify);
return status;
}
/*
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;
enum ndr_err_code ndr_err;
TALLOC_CTX *tmp_ctx;
ev.action = action;
ev.path = path;
ev.private_data = e->private_data;
tmp_ctx = talloc_new(notify);
ndr_err = ndr_push_struct_blob(&data, tmp_ctx, notify->iconv_convenience, &ev, (ndr_push_flags_fn_t)ndr_push_notify_event);
if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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
This function is called a lot, and needs to be very fast. The unusual data structure
and traversal is designed to be fast in the average case, even for large numbers of
notifies
*/
void notify_trigger(struct notify_context *notify,
uint32_t action, uint32_t filter, const char *path)
{
NTSTATUS status;
int depth;
const char *p, *next_p;
/* see if change notify is enabled at all */
if (notify == NULL) {
return;
}
status = notify_load(notify);
if (!NT_STATUS_IS_OK(status)) {
return;
}
/* loop along the given path, working with each directory depth separately */
for (depth=0,p=path;
p && depth < notify->array->num_depths;
p=next_p,depth++) {
int p_len = p - path;
int min_i, max_i, i;
struct notify_depth *d = &notify->array->depth[depth];
next_p = strchr(p+1, '/');
/* see if there are any entries at this depth */
if (d->num_entries == 0) continue;
/* try to skip based on the maximum mask. If next_p is
NULL then we know it will be a 'this directory'
match, otherwise it must be a subdir match */
if (next_p != NULL) {
if (0 == (filter & d->max_mask_subdir)) {
continue;
}
} else {
if (0 == (filter & d->max_mask)) {
continue;
}
}
/* we know there is an entry here worth looking
for. Use a bisection search to find the first entry
with a matching path */
min_i = 0;
max_i = d->num_entries-1;
while (min_i < max_i) {
struct notify_entry *e;
int cmp;
i = (min_i+max_i)/2;
e = &d->entries[i];
cmp = strncmp(path, e->path, p_len);
if (cmp == 0) {
if (p_len == e->path_len) {
max_i = i;
} else {
max_i = i-1;
}
} else if (cmp < 0) {
max_i = i-1;
} else {
min_i = i+1;
}
}
if (min_i != max_i) {
/* none match */
continue;
}
/* we now know that the entries start at min_i */
for (i=min_i;i<d->num_entries;i++) {
struct notify_entry *e = &d->entries[i];
if (p_len != e->path_len ||
strncmp(path, e->path, p_len) != 0) break;
if (next_p != NULL) {
if (0 == (filter & e->subdir_filter)) {
continue;
}
} else {
if (0 == (filter & e->filter)) {
continue;
}
}
notify_send(notify, e, path + e->path_len + 1, action);
}
}
}