summaryrefslogtreecommitdiff
path: root/source4/ntvfs/posix/pvfs_notify.c
blob: 3e289a09485f764bfdf20236fb53322e68eb3b1c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
/* 
   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;

	/* 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 event_context *ev, struct timed_event *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);
		}
		talloc_free(notify_buffer);
		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->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 */
	event_add_timed(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, const struct notify_event *ev)
{
	struct pvfs_notify_buffer *n = talloc_get_type(private, struct pvfs_notify_buffer);
	size_t len;
	struct notify_changes *n2;
	char *new_path;

	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;

	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, enum pvfs_wait_notice reason)
{
	struct pvfs_notify_buffer *notify_buffer = talloc_get_type(private, 
								   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) {
		void *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;
}