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1/*
2 * Copyright (c) 2000, 2001, 2004, 2006, 2009-2011, 2015-2017, 2019 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 "SCDynamicStoreInternal.h"
35#include "config.h" /* MiG generated file */
36#include <mach/mach_error.h>
37
38
39static mach_msg_id_t
40waitForMachMessage(mach_port_t port)
41{
42 union {
43 u_int8_t buf[sizeof(mach_msg_empty_t) + MAX_TRAILER_SIZE];
44 mach_msg_empty_rcv_t msg;
45 } notify_msg;
46 kern_return_t status;
47
48 status = mach_msg(¬ify_msg.msg.header, /* msg */
49 MACH_RCV_MSG, /* options */
50 0, /* send_size */
51 sizeof(notify_msg), /* rcv_size */
52 port, /* rcv_name */
53 MACH_MSG_TIMEOUT_NONE, /* timeout */
54 MACH_PORT_NULL); /* notify */
55 if (status != KERN_SUCCESS) {
56 SC_log(LOG_NOTICE, "mach_msg() failed: %s", mach_error_string(status));
57 return -1;
58 }
59
60 return notify_msg.msg.header.msgh_id;
61}
62
63
64Boolean
65SCDynamicStoreNotifyWait(SCDynamicStoreRef store)
66{
67 SCDynamicStorePrivateRef storePrivate = (SCDynamicStorePrivateRef)store;
68 kern_return_t status;
69 mach_port_t port;
70 mach_port_t oldNotify;
71 int sc_status;
72 mach_msg_id_t msgid;
73
74 if (store == NULL) {
75 /* sorry, you must provide a session */
76 _SCErrorSet(kSCStatusNoStoreSession);
77 return FALSE;
78 }
79
80 if (storePrivate->server == MACH_PORT_NULL) {
81 /* sorry, you must have an open session to play */
82 _SCErrorSet(kSCStatusNoStoreServer);
83 return FALSE;
84 }
85
86 if (storePrivate->notifyStatus != NotifierNotRegistered) {
87 /* sorry, you can only have one notification registered at once */
88 _SCErrorSet(kSCStatusNotifierActive);
89 return FALSE;
90 }
91
92 /* Allocating port (for server response) */
93 status = mach_port_allocate(mach_task_self(), MACH_PORT_RIGHT_RECEIVE, &port);
94 if (status != KERN_SUCCESS) {
95 SC_log(LOG_ERR, "mach_port_allocate() failed: %s", mach_error_string(status));
96 _SCErrorSet(status);
97 return FALSE;
98 }
99
100 status = mach_port_insert_right(mach_task_self(),
101 port,
102 port,
103 MACH_MSG_TYPE_MAKE_SEND);
104 if (status != KERN_SUCCESS) {
105 /*
106 * We can't insert a send right into our own port! This should
107 * only happen if someone stomped on OUR port (so let's leave
108 * the port alone).
109 */
110 SC_log(LOG_NOTICE, "mach_port_insert_right() failed: %s", mach_error_string(status));
111 _SCErrorSet(status);
112 return FALSE;
113 }
114
115 /* Request a notification when/if the server dies */
116 status = mach_port_request_notification(mach_task_self(),
117 port,
118 MACH_NOTIFY_NO_SENDERS,
119 1,
120 port,
121 MACH_MSG_TYPE_MAKE_SEND_ONCE,
122 &oldNotify);
123 if (status != KERN_SUCCESS) {
124 /*
125 * We can't request a notification for our own port! This should
126 * only happen if someone stomped on OUR port (so let's leave
127 * the port alone).
128 */
129 SC_log(LOG_NOTICE, "mach_port_request_notification() failed: %s", mach_error_string(status));
130 _SCErrorSet(status);
131 return FALSE;
132 }
133
134 if (oldNotify != MACH_PORT_NULL) {
135 SC_log(LOG_NOTICE, "oldNotify != MACH_PORT_NULL");
136 }
137
138 retry :
139
140 status = notifyviaport(storePrivate->server,
141 port,
142 0,
143 (int *)&sc_status);
144
145 if (__SCDynamicStoreCheckRetryAndHandleError(store,
146 status,
147 &sc_status,
148 "SCDynamicStoreNotifyWait notifyviaport()")) {
149 goto retry;
150 }
151
152 if (status != KERN_SUCCESS) {
153 if ((status == MACH_SEND_INVALID_DEST) || (status == MIG_SERVER_DIED)) {
154 /* remove the send right that we tried (but failed) to pass to the server */
155 (void) mach_port_deallocate(mach_task_self(), port);
156 }
157
158 /* remove our receive right */
159 (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE, -1);
160 }
161
162 if (sc_status != kSCStatusOK) {
163 _SCErrorSet(sc_status);
164 return FALSE;
165 }
166
167 /* set notifier active */
168 storePrivate->notifyStatus = Using_NotifierWait;
169
170 msgid = waitForMachMessage(port);
171
172 /* set notifier inactive */
173 storePrivate->notifyStatus = NotifierNotRegistered;
174
175 if (msgid == MACH_NOTIFY_NO_SENDERS) {
176 /* the server closed the notifier port */
177#ifdef DEBUG
178 SC_log(LOG_DEBUG, "notifier port closed, port %d", port);
179#endif /* DEBUG */
180 _SCErrorSet(kSCStatusNoStoreServer);
181 return FALSE;
182 }
183
184 if (msgid == -1) {
185 /* one of the mach routines returned an error */
186#ifdef DEBUG
187 SC_log(LOG_DEBUG, "communication with server failed, remove port right %d", port);
188#endif /* DEBUG */
189 (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE , -1);
190 _SCErrorSet(kSCStatusNoStoreServer);
191 return FALSE;
192 }
193
194 // something changed, cancelling notification request
195 status = notifycancel(storePrivate->server,
196 (int *)&sc_status);
197
198 if (__SCDynamicStoreCheckRetryAndHandleError(store,
199 status,
200 &sc_status,
201 "SCDynamicStoreNotifyWait notifycancel()")) {
202 sc_status = kSCStatusOK;
203 }
204
205 /* remove our receive right */
206 (void) mach_port_mod_refs(mach_task_self(), port, MACH_PORT_RIGHT_RECEIVE , -1);
207
208 if (sc_status != kSCStatusOK) {
209 _SCErrorSet(sc_status);
210 return FALSE;
211 }
212
213 return TRUE;
214}