1/*
2 * Copyright (c) 2000, 2001, 2004, 2006, 2009-2011 Apple Inc. All rights reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. Please obtain a copy of the License at
10 * http://www.opensource.apple.com/apsl/ and read it before using this
11 * file.
12 *
13 * The Original Code and all software distributed under the License are
14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
18 * Please see the License for the specific language governing rights and
19 * limitations under the License.
20 *
21 * @APPLE_LICENSE_HEADER_END@
22 */
23
24/*
25 * Modification History
26 *
27 * June 1, 2001			Allan Nathanson <ajn@apple.com>
28 * - public API conversion
29 *
30 * March 31, 2000		Allan Nathanson <ajn@apple.com>
31 * - initial revision
32 */
33
34#include <mach/mach.h>
35#include <mach/mach_error.h>
36
37#include <SystemConfiguration/SystemConfiguration.h>
38#include <SystemConfiguration/SCPrivate.h>
39#include "SCDynamicStoreInternal.h"
40#include "config.h"		/* MiG generated file */
41
42static mach_msg_id_t
43waitForMachMessage(mach_port_t port)
44{
45	union {
46		u_int8_t		buf[sizeof(mach_msg_empty_t) + MAX_TRAILER_SIZE];
47		mach_msg_empty_rcv_t	msg;
48	} notify_msg;
49	kern_return_t 	status;
50
51	status = mach_msg(&notify_msg.msg.header,	/* msg */
52			  MACH_RCV_MSG,			/* options */
53			  0,				/* send_size */
54			  sizeof(notify_msg),		/* rcv_size */
55			  port,				/* rcv_name */
56			  MACH_MSG_TIMEOUT_NONE,	/* timeout */
57			  MACH_PORT_NULL);		/* notify */
58	if (status != KERN_SUCCESS) {
59		SCLog(TRUE, LOG_DEBUG, CFSTR("waitForMachMessage mach_msg(): %s"), mach_error_string(status));
60		return -1;
61	}
62
63	return notify_msg.msg.header.msgh_id;
64}
65
66
67Boolean
68SCDynamicStoreNotifyWait(SCDynamicStoreRef store)
69{
70	SCDynamicStorePrivateRef	storePrivate = (SCDynamicStorePrivateRef)store;
71	kern_return_t			status;
72	mach_port_t			port;
73	mach_port_t			oldNotify;
74	int				sc_status;
75	mach_msg_id_t			msgid;
76
77	if (store == NULL) {
78		/* sorry, you must provide a session */
79		_SCErrorSet(kSCStatusNoStoreSession);
80		return FALSE;
81	}
82
83	if (storePrivate->server == MACH_PORT_NULL) {
84		/* sorry, you must have an open session to play */
85		_SCErrorSet(kSCStatusNoStoreServer);
86		return FALSE;
87	}
88
89	if (storePrivate->notifyStatus != NotifierNotRegistered) {
90		/* sorry, you can only have one notification registered at once */
91		_SCErrorSet(kSCStatusNotifierActive);
92		return FALSE;
93	}
94
95	/* Allocating port (for server response) */
96	status = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &port);
97	if (status != KERN_SUCCESS) {
98		SCLog(TRUE, LOG_ERR, CFSTR("SCDynamicStoreNotifyWait mach_port_allocate(): %s"), mach_error_string(status));
99		_SCErrorSet(status);
100		return FALSE;
101	}
102
103	status = mach_port_insert_right(mach_task_self(),
104					port,
105					port,
106					MACH_MSG_TYPE_MAKE_SEND);
107	if (status != KERN_SUCCESS) {
108		/*
109		 * We can't insert a send right into our own port!  This should
110		 * only happen if someone stomped on OUR port (so let's leave
111		 * the port alone).
112		 */
113		SCLog(TRUE, LOG_ERR, CFSTR("SCDynamicStoreNotifyWait mach_port_insert_right(): %s"), mach_error_string(status));
114		_SCErrorSet(status);
115		return FALSE;
116	}
117
118	/* Request a notification when/if the server dies */
119	status = mach_port_request_notification(mach_task_self(),
120						port,
121						MACH_NOTIFY_NO_SENDERS,
122						1,
123						port,
124						MACH_MSG_TYPE_MAKE_SEND_ONCE,
125						&oldNotify);
126	if (status != KERN_SUCCESS) {
127		/*
128		 * We can't request a notification for our own port!  This should
129		 * only happen if someone stomped on OUR port (so let's leave
130		 * the port alone).
131		 */
132		SCLog(TRUE, LOG_ERR, CFSTR("SCDynamicStoreNotifyWait mach_port_request_notification(): %s"), mach_error_string(status));
133		_SCErrorSet(status);
134		return FALSE;
135	}
136
137	if (oldNotify != MACH_PORT_NULL) {
138		SCLog(TRUE, LOG_ERR, CFSTR("SCDynamicStoreNotifyWait(): oldNotify != MACH_PORT_NULL"));
139	}
140
141    retry :
142
143	status = notifyviaport(storePrivate->server,
144			       port,
145			       0,
146			       (int *)&sc_status);
147
148	if (__SCDynamicStoreCheckRetryAndHandleError(store,
149						     status,
150						     &sc_status,
151						     "SCDynamicStoreNotifyWait notifyviaport()")) {
152		goto retry;
153	}
154
155	if (status != KERN_SUCCESS) {
156		if ((status == MACH_SEND_INVALID_DEST) || (status == MIG_SERVER_DIED)) {
157			/* remove the send right that we tried (but failed) to pass to the server */
158			(void) mach_port_deallocate(mach_task_self(), port);
159		}
160
161		/* remove our receive right  */
162		(void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE, -1);
163	}
164
165	if (sc_status != kSCStatusOK) {
166		_SCErrorSet(sc_status);
167		return FALSE;
168	}
169
170	/* set notifier active */
171	storePrivate->notifyStatus = Using_NotifierWait;
172
173	msgid = waitForMachMessage(port);
174
175	/* set notifier inactive */
176	storePrivate->notifyStatus = NotifierNotRegistered;
177
178	if (msgid == MACH_NOTIFY_NO_SENDERS) {
179		/* the server closed the notifier port */
180#ifdef	DEBUG
181		SCLog(_sc_verbose, LOG_DEBUG, CFSTR("SCDynamicStoreNotifyWait notifier port closed, destroying port %d"), port);
182#endif	/* DEBUG */
183		_SCErrorSet(kSCStatusNoStoreServer);
184		return FALSE;
185	}
186
187	if (msgid == -1) {
188		/* one of the mach routines returned an error */
189#ifdef	DEBUG
190		SCLog(_sc_verbose, LOG_DEBUG, CFSTR("SCDynamicStoreNotifyWait communication with server failed, destroying port %d"), port);
191#endif	/* DEBUG */
192		(void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE , -1);
193		_SCErrorSet(kSCStatusNoStoreServer);
194		return FALSE;
195	}
196
197	// something changed, cancelling notification request
198	status = notifycancel(storePrivate->server,
199			      (int *)&sc_status);
200
201	if (__SCDynamicStoreCheckRetryAndHandleError(store,
202						     status,
203						     &sc_status,
204						     "SCDynamicStoreNotifyWait notifycancel()")) {
205		sc_status = kSCStatusOK;
206	}
207
208	/* remove our receive right  */
209	(void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE , -1);
210
211	if (sc_status != kSCStatusOK) {
212		_SCErrorSet(sc_status);
213		return FALSE;
214	}
215
216	return TRUE;
217}
218