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Unix SMB/CIFS implementation.
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POSIX NTVFS backend - notify
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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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#include "vfs_posix.h"
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#include "lib/messaging/irpc.h"
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#include "messaging/messaging.h"
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#include "../lib/util/dlinklist.h"
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#include "lib/events/events.h"
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/* pending notifies buffer, hung off struct pvfs_file for open directories
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that have used change notify */
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struct pvfs_notify_buffer {
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struct notify_changes *changes;
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uint32_t max_buffer_size;
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uint32_t current_buffer_size;
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/* a list of requests waiting for events on this handle */
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struct notify_pending {
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struct notify_pending *next, *prev;
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struct ntvfs_request *req;
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union smb_notify *info;
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send a notify on the next event run.
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static void pvfs_notify_send_next(struct tevent_context *ev, struct tevent_timer *te,
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struct timeval t, void *ptr)
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struct ntvfs_request *req = talloc_get_type(ptr, struct ntvfs_request);
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req->async_states->send_fn(req);
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send a reply to a pending notify request
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static void pvfs_notify_send(struct pvfs_notify_buffer *notify_buffer,
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NTSTATUS status, bool immediate)
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struct notify_pending *pending = notify_buffer->pending;
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struct ntvfs_request *req;
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union smb_notify *info;
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if (notify_buffer->current_buffer_size > notify_buffer->max_buffer_size &&
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notify_buffer->num_changes != 0) {
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/* on buffer overflow return no changes and destroys the notify buffer */
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notify_buffer->num_changes = 0;
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while (notify_buffer->pending) {
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pvfs_notify_send(notify_buffer, NT_STATUS_OK, immediate);
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talloc_free(notify_buffer);
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/* see if there is anyone waiting */
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if (notify_buffer->pending == NULL) {
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DLIST_REMOVE(notify_buffer->pending, pending);
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info->nttrans.out.num_changes = notify_buffer->num_changes;
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info->nttrans.out.changes = talloc_steal(req, notify_buffer->changes);
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notify_buffer->num_changes = 0;
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notify_buffer->changes = NULL;
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notify_buffer->current_buffer_size = 0;
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if (info->nttrans.out.num_changes != 0) {
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status = NT_STATUS_OK;
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req->async_states->status = status;
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req->async_states->send_fn(req);
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/* we can't call pvfs_notify_send() directly here, as that
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would free the request, and the ntvfs modules above us
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could use it, so call it on the next event */
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event_add_timed(req->ctx->event_ctx,
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req, timeval_zero(), pvfs_notify_send_next, req);
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destroy a notify buffer. Called when the handle is closed
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static int pvfs_notify_destructor(struct pvfs_notify_buffer *n)
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notify_remove(n->f->pvfs->notify_context, n);
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n->f->notify_buffer = NULL;
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pvfs_notify_send(n, NT_STATUS_OK, true);
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called when a async notify event comes in
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static void pvfs_notify_callback(void *private_data, const struct notify_event *ev)
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struct pvfs_notify_buffer *n = talloc_get_type(private_data, struct pvfs_notify_buffer);
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struct notify_changes *n2;
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n2 = talloc_realloc(n, n->changes, struct notify_changes, n->num_changes+1);
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/* nothing much we can do for this */
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new_path = talloc_strdup(n->changes, ev->path);
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if (new_path == NULL) {
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string_replace(new_path, '/', '\\');
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n->changes[n->num_changes].action = ev->action;
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n->changes[n->num_changes].name.s = new_path;
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work out how much room this will take in the buffer
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len = 12 + strlen_m(ev->path)*2;
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len += 4 - (len & 3);
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n->current_buffer_size += len;
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/* send what we have, unless its the first part of a rename */
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if (ev->action != NOTIFY_ACTION_OLD_NAME) {
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pvfs_notify_send(n, NT_STATUS_OK, true);
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setup a notify buffer on a directory handle
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static NTSTATUS pvfs_notify_setup(struct pvfs_state *pvfs, struct pvfs_file *f,
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uint32_t buffer_size, uint32_t filter, bool recursive)
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struct notify_entry e;
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f->notify_buffer = talloc_zero(f, struct pvfs_notify_buffer);
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NT_STATUS_HAVE_NO_MEMORY(f->notify_buffer);
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f->notify_buffer->max_buffer_size = buffer_size;
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f->notify_buffer->f = f;
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e.path = f->handle->name->full_name;
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e.subdir_filter = filter;
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status = notify_add(pvfs->notify_context, &e,
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pvfs_notify_callback, f->notify_buffer);
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NT_STATUS_NOT_OK_RETURN(status);
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talloc_set_destructor(f->notify_buffer, pvfs_notify_destructor);
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called from the pvfs_wait code when either an event has come in, or
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the notify request has been cancelled
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static void pvfs_notify_end(void *private_data, enum pvfs_wait_notice reason)
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struct pvfs_notify_buffer *notify_buffer = talloc_get_type(private_data,
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struct pvfs_notify_buffer);
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if (reason == PVFS_WAIT_CANCEL) {
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pvfs_notify_send(notify_buffer, NT_STATUS_CANCELLED, false);
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pvfs_notify_send(notify_buffer, NT_STATUS_OK, true);
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/* change notify request - always async. This request blocks until the
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event buffer is non-empty */
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NTSTATUS pvfs_notify(struct ntvfs_module_context *ntvfs,
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struct ntvfs_request *req,
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union smb_notify *info)
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struct pvfs_state *pvfs = talloc_get_type(ntvfs->private_data,
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struct notify_pending *pending;
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if (info->nttrans.level != RAW_NOTIFY_NTTRANS) {
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return ntvfs_map_notify(ntvfs, req, info);
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f = pvfs_find_fd(pvfs, req, info->nttrans.in.file.ntvfs);
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return NT_STATUS_INVALID_HANDLE;
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/* this request doesn't make sense unless its async */
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if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
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return NT_STATUS_INVALID_PARAMETER;
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/* its only valid for directories */
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if (f->handle->fd != -1) {
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return NT_STATUS_INVALID_PARAMETER;
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/* if the handle doesn't currently have a notify buffer then
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if (f->notify_buffer == NULL) {
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status = pvfs_notify_setup(pvfs, f,
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info->nttrans.in.buffer_size,
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info->nttrans.in.completion_filter,
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info->nttrans.in.recursive);
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NT_STATUS_NOT_OK_RETURN(status);
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/* we update the max_buffer_size on each call, but we do not
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update the recursive flag or filter */
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f->notify_buffer->max_buffer_size = info->nttrans.in.buffer_size;
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pending = talloc(f->notify_buffer, struct notify_pending);
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NT_STATUS_HAVE_NO_MEMORY(pending);
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pending->req = talloc_reference(pending, req);
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NT_STATUS_HAVE_NO_MEMORY(pending->req);
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pending->info = info;
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DLIST_ADD_END(f->notify_buffer->pending, pending, struct notify_pending *);
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/* if the buffer is empty then start waiting */
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if (f->notify_buffer->num_changes == 0) {
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struct pvfs_wait *wait_handle;
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wait_handle = pvfs_wait_message(pvfs, req, -1,
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NT_STATUS_HAVE_NO_MEMORY(wait_handle);
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talloc_steal(req, wait_handle);
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req->async_states->state |= NTVFS_ASYNC_STATE_ASYNC;
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pvfs_notify_send(f->notify_buffer, NT_STATUS_OK, false);