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Unix SMB/CIFS implementation.
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Copyright (C) Andrew Tridgell 2006
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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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this is the change notify database. It implements mechanisms for
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storing current change notify waiters in a tdb, and checking if a
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given event matches any of the stored notify waiiters.
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#include "system/filesys.h"
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#include "../tdb/include/tdb.h"
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#include "../lib/util/util_tdb.h"
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#include "messaging/messaging.h"
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#include "lib/messaging/irpc.h"
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#include "librpc/gen_ndr/ndr_notify.h"
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#include "../lib/util/dlinklist.h"
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#include "ntvfs/common/ntvfs_common.h"
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#include "ntvfs/sysdep/sys_notify.h"
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#include "cluster/cluster.h"
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#include "param/param.h"
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struct notify_context {
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struct server_id server;
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struct messaging_context *messaging_ctx;
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struct notify_list *list;
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struct notify_array *array;
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struct sys_notify_context *sys_notify_ctx;
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struct smb_iconv_convenience *iconv_convenience;
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struct notify_list *next, *prev;
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void (*callback)(void *, const struct notify_event *);
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void *sys_notify_handle;
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#define NOTIFY_KEY "notify array"
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#define NOTIFY_ENABLE "notify:enable"
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#define NOTIFY_ENABLE_DEFAULT true
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static NTSTATUS notify_remove_all(struct notify_context *notify);
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static void notify_handler(struct messaging_context *msg_ctx, void *private_data,
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uint32_t msg_type, struct server_id server_id, DATA_BLOB *data);
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destroy the notify context
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static int notify_destructor(struct notify_context *notify)
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messaging_deregister(notify->messaging_ctx, MSG_PVFS_NOTIFY, notify);
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notify_remove_all(notify);
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Open up the notify.tdb database. You should close it down using
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talloc_free(). We need the messaging_ctx to allow for notifications
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struct notify_context *notify_init(TALLOC_CTX *mem_ctx, struct server_id server,
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struct messaging_context *messaging_ctx,
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struct loadparm_context *lp_ctx,
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struct tevent_context *ev,
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struct share_config *scfg)
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struct notify_context *notify;
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if (share_bool_option(scfg, NOTIFY_ENABLE, NOTIFY_ENABLE_DEFAULT) != true) {
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notify = talloc(mem_ctx, struct notify_context);
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if (notify == NULL) {
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notify->w = cluster_tdb_tmp_open(notify, lp_ctx, "notify.tdb", TDB_SEQNUM);
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if (notify->w == NULL) {
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notify->server = server;
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notify->messaging_ctx = messaging_ctx;
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notify->array = NULL;
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notify->iconv_convenience = lp_iconv_convenience(lp_ctx);
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notify->seqnum = tdb_get_seqnum(notify->w->tdb);
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talloc_set_destructor(notify, notify_destructor);
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/* register with the messaging subsystem for the notify
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messaging_register(notify->messaging_ctx, notify,
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MSG_PVFS_NOTIFY, notify_handler);
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notify->sys_notify_ctx = sys_notify_context_create(scfg, notify, ev);
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static NTSTATUS notify_lock(struct notify_context *notify)
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if (tdb_lock_bystring(notify->w->tdb, NOTIFY_KEY) != 0) {
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return NT_STATUS_INTERNAL_DB_CORRUPTION;
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static void notify_unlock(struct notify_context *notify)
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tdb_unlock_bystring(notify->w->tdb, NOTIFY_KEY);
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load the notify array
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static NTSTATUS notify_load(struct notify_context *notify)
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enum ndr_err_code ndr_err;
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seqnum = tdb_get_seqnum(notify->w->tdb);
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if (seqnum == notify->seqnum && notify->array != NULL) {
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notify->seqnum = seqnum;
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talloc_free(notify->array);
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notify->array = talloc_zero(notify, struct notify_array);
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NT_STATUS_HAVE_NO_MEMORY(notify->array);
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dbuf = tdb_fetch_bystring(notify->w->tdb, NOTIFY_KEY);
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if (dbuf.dptr == NULL) {
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blob.data = dbuf.dptr;
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blob.length = dbuf.dsize;
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ndr_err = ndr_pull_struct_blob(&blob, notify->array, notify->iconv_convenience,
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(ndr_pull_flags_fn_t)ndr_pull_notify_array);
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if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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return ndr_map_error2ntstatus(ndr_err);
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compare notify entries for sorting
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static int notify_compare(const void *p1, const void *p2)
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const struct notify_entry *e1 = p1, *e2 = p2;
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return strcmp(e1->path, e2->path);
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save the notify array
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static NTSTATUS notify_save(struct notify_context *notify)
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enum ndr_err_code ndr_err;
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/* if possible, remove some depth arrays */
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while (notify->array->num_depths > 0 &&
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notify->array->depth[notify->array->num_depths-1].num_entries == 0) {
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notify->array->num_depths--;
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/* we might just be able to delete the record */
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if (notify->array->num_depths == 0) {
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ret = tdb_delete_bystring(notify->w->tdb, NOTIFY_KEY);
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return NT_STATUS_INTERNAL_DB_CORRUPTION;
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tmp_ctx = talloc_new(notify);
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NT_STATUS_HAVE_NO_MEMORY(tmp_ctx);
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ndr_err = ndr_push_struct_blob(&blob, tmp_ctx, notify->iconv_convenience, notify->array,
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(ndr_push_flags_fn_t)ndr_push_notify_array);
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if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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talloc_free(tmp_ctx);
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return ndr_map_error2ntstatus(ndr_err);
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dbuf.dptr = blob.data;
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dbuf.dsize = blob.length;
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ret = tdb_store_bystring(notify->w->tdb, NOTIFY_KEY, dbuf, TDB_REPLACE);
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talloc_free(tmp_ctx);
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return NT_STATUS_INTERNAL_DB_CORRUPTION;
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handle incoming notify messages
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static void notify_handler(struct messaging_context *msg_ctx, void *private_data,
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uint32_t msg_type, struct server_id server_id, DATA_BLOB *data)
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struct notify_context *notify = talloc_get_type(private_data, struct notify_context);
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enum ndr_err_code ndr_err;
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struct notify_event ev;
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TALLOC_CTX *tmp_ctx = talloc_new(notify);
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struct notify_list *listel;
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if (tmp_ctx == NULL) {
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ndr_err = ndr_pull_struct_blob(data, tmp_ctx, notify->iconv_convenience, &ev,
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(ndr_pull_flags_fn_t)ndr_pull_notify_event);
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if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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talloc_free(tmp_ctx);
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for (listel=notify->list;listel;listel=listel->next) {
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if (listel->private_data == ev.private_data) {
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listel->callback(listel->private_data, &ev);
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talloc_free(tmp_ctx);
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callback from sys_notify telling us about changes from the OS
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static void sys_notify_callback(struct sys_notify_context *ctx,
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void *ptr, struct notify_event *ev)
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struct notify_list *listel = talloc_get_type(ptr, struct notify_list);
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ev->private_data = listel;
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listel->callback(listel->private_data, ev);
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add an entry to the notify array
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static NTSTATUS notify_add_array(struct notify_context *notify, struct notify_entry *e,
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void *private_data, int depth)
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struct notify_depth *d;
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struct notify_entry *ee;
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/* possibly expand the depths array */
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if (depth >= notify->array->num_depths) {
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d = talloc_realloc(notify->array, notify->array->depth,
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struct notify_depth, depth+1);
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NT_STATUS_HAVE_NO_MEMORY(d);
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for (i=notify->array->num_depths;i<=depth;i++) {
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notify->array->depth = d;
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notify->array->num_depths = depth+1;
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d = ¬ify->array->depth[depth];
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/* expand the entries array */
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ee = talloc_realloc(notify->array->depth, d->entries, struct notify_entry,
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NT_STATUS_HAVE_NO_MEMORY(ee);
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d->entries[d->num_entries] = *e;
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d->entries[d->num_entries].private_data = private_data;
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d->entries[d->num_entries].server = notify->server;
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d->entries[d->num_entries].path_len = strlen(e->path);
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d->max_mask |= e->filter;
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d->max_mask_subdir |= e->subdir_filter;
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if (d->num_entries > 1) {
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qsort(d->entries, d->num_entries, sizeof(d->entries[0]), notify_compare);
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/* recalculate the maximum masks */
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d->max_mask_subdir = 0;
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for (i=0;i<d->num_entries;i++) {
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d->max_mask |= d->entries[i].filter;
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d->max_mask_subdir |= d->entries[i].subdir_filter;
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return notify_save(notify);
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add a notify watch. This is called when a notify is first setup on a open
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NTSTATUS notify_add(struct notify_context *notify, struct notify_entry *e0,
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void (*callback)(void *, const struct notify_event *),
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struct notify_entry e = *e0;
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char *tmp_path = NULL;
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struct notify_list *listel;
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/* see if change notify is enabled at all */
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if (notify == NULL) {
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return NT_STATUS_NOT_IMPLEMENTED;
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status = notify_lock(notify);
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NT_STATUS_NOT_OK_RETURN(status);
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status = notify_load(notify);
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if (!NT_STATUS_IS_OK(status)) {
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/* cope with /. on the end of the path */
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len = strlen(e.path);
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if (len > 1 && e.path[len-1] == '.' && e.path[len-2] == '/') {
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tmp_path = talloc_strndup(notify, e.path, len-2);
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if (tmp_path == NULL) {
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status = NT_STATUS_NO_MEMORY;
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depth = count_chars(e.path, '/');
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listel = talloc_zero(notify, struct notify_list);
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if (listel == NULL) {
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status = NT_STATUS_NO_MEMORY;
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listel->private_data = private_data;
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listel->callback = callback;
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listel->depth = depth;
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DLIST_ADD(notify->list, listel);
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/* ignore failures from sys_notify */
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if (notify->sys_notify_ctx != NULL) {
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this call will modify e.filter and e.subdir_filter
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to remove bits handled by the backend
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status = sys_notify_watch(notify->sys_notify_ctx, &e,
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sys_notify_callback, listel,
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&listel->sys_notify_handle);
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if (NT_STATUS_IS_OK(status)) {
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talloc_steal(listel, listel->sys_notify_handle);
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/* if the system notify handler couldn't handle some of the
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filter bits, or couldn't handle a request for recursion
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then we need to install it in the array used for the
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intra-samba notify handling */
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if (e.filter != 0 || e.subdir_filter != 0) {
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status = notify_add_array(notify, &e, private_data, depth);
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notify_unlock(notify);
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talloc_free(tmp_path);
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remove a notify watch. Called when the directory handle is closed
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NTSTATUS notify_remove(struct notify_context *notify, void *private_data)
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struct notify_list *listel;
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struct notify_depth *d;
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/* see if change notify is enabled at all */
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if (notify == NULL) {
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return NT_STATUS_NOT_IMPLEMENTED;
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for (listel=notify->list;listel;listel=listel->next) {
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if (listel->private_data == private_data) {
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DLIST_REMOVE(notify->list, listel);
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if (listel == NULL) {
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return NT_STATUS_OBJECT_NAME_NOT_FOUND;
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depth = listel->depth;
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status = notify_lock(notify);
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NT_STATUS_NOT_OK_RETURN(status);
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status = notify_load(notify);
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if (!NT_STATUS_IS_OK(status)) {
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notify_unlock(notify);
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if (depth >= notify->array->num_depths) {
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notify_unlock(notify);
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return NT_STATUS_OBJECT_NAME_NOT_FOUND;
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/* we only have to search at the depth of this element */
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d = ¬ify->array->depth[depth];
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for (i=0;i<d->num_entries;i++) {
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if (private_data == d->entries[i].private_data &&
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cluster_id_equal(¬ify->server, &d->entries[i].server)) {
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if (i == d->num_entries) {
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notify_unlock(notify);
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return NT_STATUS_OBJECT_NAME_NOT_FOUND;
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if (i < d->num_entries-1) {
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memmove(&d->entries[i], &d->entries[i+1],
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sizeof(d->entries[i])*(d->num_entries-(i+1)));
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status = notify_save(notify);
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notify_unlock(notify);
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remove all notify watches for this messaging server
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static NTSTATUS notify_remove_all(struct notify_context *notify)
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int i, depth, del_count=0;
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if (notify->list == NULL) {
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status = notify_lock(notify);
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NT_STATUS_NOT_OK_RETURN(status);
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status = notify_load(notify);
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if (!NT_STATUS_IS_OK(status)) {
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notify_unlock(notify);
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/* we have to search for all entries across all depths, looking for matches
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for (depth=0;depth<notify->array->num_depths;depth++) {
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struct notify_depth *d = ¬ify->array->depth[depth];
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for (i=0;i<d->num_entries;i++) {
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if (cluster_id_equal(¬ify->server, &d->entries[i].server)) {
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if (i < d->num_entries-1) {
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memmove(&d->entries[i], &d->entries[i+1],
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sizeof(d->entries[i])*(d->num_entries-(i+1)));
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status = notify_save(notify);
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notify_unlock(notify);
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send a notify message to another messaging server
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static void notify_send(struct notify_context *notify, struct notify_entry *e,
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const char *path, uint32_t action)
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struct notify_event ev;
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enum ndr_err_code ndr_err;
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ev.private_data = e->private_data;
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tmp_ctx = talloc_new(notify);
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ndr_err = ndr_push_struct_blob(&data, tmp_ctx, notify->iconv_convenience, &ev, (ndr_push_flags_fn_t)ndr_push_notify_event);
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if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
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talloc_free(tmp_ctx);
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status = messaging_send(notify->messaging_ctx, e->server,
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MSG_PVFS_NOTIFY, &data);
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talloc_free(tmp_ctx);
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trigger a notify message for anyone waiting on a matching event
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This function is called a lot, and needs to be very fast. The unusual data structure
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and traversal is designed to be fast in the average case, even for large numbers of
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void notify_trigger(struct notify_context *notify,
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uint32_t action, uint32_t filter, const char *path)
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const char *p, *next_p;
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/* see if change notify is enabled at all */
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if (notify == NULL) {
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status = notify_load(notify);
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if (!NT_STATUS_IS_OK(status)) {
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/* loop along the given path, working with each directory depth separately */
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p && depth < notify->array->num_depths;
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int p_len = p - path;
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struct notify_depth *d = ¬ify->array->depth[depth];
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next_p = strchr(p+1, '/');
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/* see if there are any entries at this depth */
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if (d->num_entries == 0) continue;
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/* try to skip based on the maximum mask. If next_p is
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NULL then we know it will be a 'this directory'
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match, otherwise it must be a subdir match */
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if (next_p != NULL) {
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if (0 == (filter & d->max_mask_subdir)) {
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if (0 == (filter & d->max_mask)) {
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/* we know there is an entry here worth looking
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for. Use a bisection search to find the first entry
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with a matching path */
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max_i = d->num_entries-1;
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while (min_i < max_i) {
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struct notify_entry *e;
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cmp = strncmp(path, e->path, p_len);
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if (p_len == e->path_len) {
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} else if (cmp < 0) {
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if (min_i != max_i) {
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/* we now know that the entries start at min_i */
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for (i=min_i;i<d->num_entries;i++) {
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struct notify_entry *e = &d->entries[i];
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if (p_len != e->path_len ||
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strncmp(path, e->path, p_len) != 0) break;
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if (next_p != NULL) {
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if (0 == (filter & e->subdir_filter)) {
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if (0 == (filter & e->filter)) {
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notify_send(notify, e, path + e->path_len + 1, action);