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/*
Unix SMB/CIFS implementation.
POSIX NTVFS backend - notify
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/>.
*/
#include "includes.h"
#include "vfs_posix.h"
#include "lib/messaging/irpc.h"
#include "messaging/messaging.h"
#include "../lib/util/dlinklist.h"
#include "lib/events/events.h"
/* pending notifies buffer, hung off struct pvfs_file for open directories
that have used change notify */
struct pvfs_notify_buffer {
struct pvfs_file *f;
uint32_t num_changes;
struct notify_changes *changes;
uint32_t max_buffer_size;
uint32_t current_buffer_size;
bool overflowed;
/* a list of requests waiting for events on this handle */
struct notify_pending {
struct notify_pending *next, *prev;
struct ntvfs_request *req;
union smb_notify *info;
} *pending;
};
/*
send a notify on the next event run.
*/
static void pvfs_notify_send_next(struct tevent_context *ev, struct tevent_timer *te,
struct timeval t, void *ptr)
{
struct ntvfs_request *req = talloc_get_type(ptr, struct ntvfs_request);
req->async_states->send_fn(req);
}
/*
send a reply to a pending notify request
*/
static void pvfs_notify_send(struct pvfs_notify_buffer *notify_buffer,
NTSTATUS status, bool immediate)
{
struct notify_pending *pending = notify_buffer->pending;
struct ntvfs_request *req;
union smb_notify *info;
if (notify_buffer->current_buffer_size > notify_buffer->max_buffer_size &&
notify_buffer->num_changes != 0) {
/* on buffer overflow return no changes and destroys the notify buffer */
notify_buffer->num_changes = 0;
while (notify_buffer->pending) {
pvfs_notify_send(notify_buffer, NT_STATUS_OK, immediate);
}
notify_buffer->overflowed = true;
return;
}
/* see if there is anyone waiting */
if (notify_buffer->pending == NULL) {
return;
}
DLIST_REMOVE(notify_buffer->pending, pending);
req = pending->req;
info = pending->info;
info->nttrans.out.num_changes = notify_buffer->num_changes;
info->nttrans.out.changes = talloc_steal(req, notify_buffer->changes);
notify_buffer->num_changes = 0;
notify_buffer->overflowed = false;
notify_buffer->changes = NULL;
notify_buffer->current_buffer_size = 0;
talloc_free(pending);
if (info->nttrans.out.num_changes != 0) {
status = NT_STATUS_OK;
}
req->async_states->status = status;
if (immediate) {
req->async_states->send_fn(req);
return;
}
/* we can't call pvfs_notify_send() directly here, as that
would free the request, and the ntvfs modules above us
could use it, so call it on the next event */
tevent_add_timer(req->ctx->event_ctx,
req, timeval_zero(), pvfs_notify_send_next, req);
}
/*
destroy a notify buffer. Called when the handle is closed
*/
static int pvfs_notify_destructor(struct pvfs_notify_buffer *n)
{
notify_remove(n->f->pvfs->notify_context, n);
n->f->notify_buffer = NULL;
pvfs_notify_send(n, NT_STATUS_OK, true);
return 0;
}
/*
called when a async notify event comes in
*/
static void pvfs_notify_callback(void *private_data, const struct notify_event *ev)
{
struct pvfs_notify_buffer *n = talloc_get_type(private_data, struct pvfs_notify_buffer);
size_t len;
struct notify_changes *n2;
char *new_path;
if (n->overflowed) {
return;
}
n2 = talloc_realloc(n, n->changes, struct notify_changes, n->num_changes+1);
if (n2 == NULL) {
/* nothing much we can do for this */
return;
}
n->changes = n2;
new_path = talloc_strdup(n->changes, ev->path);
if (new_path == NULL) {
return;
}
string_replace(new_path, '/', '\\');
n->changes[n->num_changes].action = ev->action;
n->changes[n->num_changes].name.s = new_path;
n->num_changes++;
/*
work out how much room this will take in the buffer
*/
len = 12 + strlen_m(ev->path)*2;
if (len & 3) {
len += 4 - (len & 3);
}
n->current_buffer_size += len;
/* send what we have, unless its the first part of a rename */
if (ev->action != NOTIFY_ACTION_OLD_NAME) {
pvfs_notify_send(n, NT_STATUS_OK, true);
}
}
/*
setup a notify buffer on a directory handle
*/
static NTSTATUS pvfs_notify_setup(struct pvfs_state *pvfs, struct pvfs_file *f,
uint32_t buffer_size, uint32_t filter, bool recursive)
{
NTSTATUS status;
struct notify_entry e;
/* We may not fill in all the elements in this entry -
* structure may in future be shared with Samba3 */
ZERO_STRUCT(e);
/* We may not fill in all the elements in this entry -
* structure may in future be shared with Samba3 */
ZERO_STRUCT(e);
f->notify_buffer = talloc_zero(f, struct pvfs_notify_buffer);
NT_STATUS_HAVE_NO_MEMORY(f->notify_buffer);
f->notify_buffer->max_buffer_size = buffer_size;
f->notify_buffer->f = f;
e.filter = filter;
e.path = f->handle->name->full_name;
if (recursive) {
e.subdir_filter = filter;
} else {
e.subdir_filter = 0;
}
status = notify_add(pvfs->notify_context, &e,
pvfs_notify_callback, f->notify_buffer);
NT_STATUS_NOT_OK_RETURN(status);
talloc_set_destructor(f->notify_buffer, pvfs_notify_destructor);
return NT_STATUS_OK;
}
/*
called from the pvfs_wait code when either an event has come in, or
the notify request has been cancelled
*/
static void pvfs_notify_end(void *private_data, enum pvfs_wait_notice reason)
{
struct pvfs_notify_buffer *notify_buffer = talloc_get_type(private_data,
struct pvfs_notify_buffer);
if (reason == PVFS_WAIT_CANCEL) {
pvfs_notify_send(notify_buffer, NT_STATUS_CANCELLED, false);
} else {
pvfs_notify_send(notify_buffer, NT_STATUS_OK, true);
}
}
/* change notify request - always async. This request blocks until the
event buffer is non-empty */
NTSTATUS pvfs_notify(struct ntvfs_module_context *ntvfs,
struct ntvfs_request *req,
union smb_notify *info)
{
struct pvfs_state *pvfs = talloc_get_type(ntvfs->private_data,
struct pvfs_state);
struct pvfs_file *f;
NTSTATUS status;
struct notify_pending *pending;
if (info->nttrans.level != RAW_NOTIFY_NTTRANS) {
return ntvfs_map_notify(ntvfs, req, info);
}
f = pvfs_find_fd(pvfs, req, info->nttrans.in.file.ntvfs);
if (!f) {
return NT_STATUS_INVALID_HANDLE;
}
/* this request doesn't make sense unless its async */
if (!(req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) {
return NT_STATUS_INVALID_PARAMETER;
}
/* its only valid for directories */
if (f->handle->fd != -1) {
return NT_STATUS_INVALID_PARAMETER;
}
/* if the handle doesn't currently have a notify buffer then
create one */
if (f->notify_buffer == NULL) {
status = pvfs_notify_setup(pvfs, f,
info->nttrans.in.buffer_size,
info->nttrans.in.completion_filter,
info->nttrans.in.recursive);
NT_STATUS_NOT_OK_RETURN(status);
}
/* we update the max_buffer_size on each call, but we do not
update the recursive flag or filter */
f->notify_buffer->max_buffer_size = info->nttrans.in.buffer_size;
pending = talloc(f->notify_buffer, struct notify_pending);
NT_STATUS_HAVE_NO_MEMORY(pending);
pending->req = talloc_reference(pending, req);
NT_STATUS_HAVE_NO_MEMORY(pending->req);
pending->info = info;
DLIST_ADD_END(f->notify_buffer->pending, pending, struct notify_pending *);
/* if the buffer is empty then start waiting */
if (f->notify_buffer->num_changes == 0 &&
!f->notify_buffer->overflowed) {
struct pvfs_wait *wait_handle;
wait_handle = pvfs_wait_message(pvfs, req, -1,
timeval_zero(),
pvfs_notify_end,
f->notify_buffer);
NT_STATUS_HAVE_NO_MEMORY(wait_handle);
talloc_steal(req, wait_handle);
return NT_STATUS_OK;
}
req->async_states->state |= NTVFS_ASYNC_STATE_ASYNC;
pvfs_notify_send(f->notify_buffer, NT_STATUS_OK, false);
return NT_STATUS_OK;
}
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