SystemConfiguration.fproj/SCDynamicStorePrivate.h

   1 /*
   2  * Copyright (c) 2000, 2001, 2004, 2005, 2010, 2011, 2013 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 #ifndef _SCDYNAMICSTOREPRIVATE_H
  25 #define _SCDYNAMICSTOREPRIVATE_H
  26
  27 #include <sys/cdefs.h>
  28 #include <mach/message.h>
  29 #include <CoreFoundation/CoreFoundation.h>
  30 #include <SystemConfiguration/SCDynamicStore.h>
  31
  32 /*!
  33         @header SCDynamicStorePrivate
  34         @discussion The SCDynamicStore APIs provide access to a key-value
  35                 dictionary maintained by a server process.  The dictionary is
  36                 accessible by all processes on the system.  The APIs allow you
  37                 to list the current key-value pairs, add or remove key-value
  38                 pairs, add or change the values associated with a key, and
  39                 request change notifications.
  40
  41                 The SCDynamicStore is not "persistent" (the store content
  42                 starts off empty and is not saved across boot).
  43
  44                 All interaction with the SCDynamicStore [server] is via Mach
  45                 IPC (MiG) messages.
  46
  47                 A client process, using the SCDynamicStoreSetNotificationKeys
  48                 API, specifies a list of specific keys of interest and/or a
  49                 list of regex(3) pattern strings that will be matched on
  50                 current (and future) keys in the store.  Any matched keys that
  51                 are added, updated, or removed will trigger a notification.
  52                 The notification is delivered to the monitoring session via
  53                 a "something has changed" Mach IPC message.  The callback
  54                 notification, as part of its implementation, issues a request
  55                 to the server to identify the specific list of changes and
  56                 this list is passed along as part of the callback.  Any
  57                 subsequent changes to the SCDynamicStore will trigger a new
  58                 "something has changed" Mach IPC message and an additional
  59                 callback.
  60
  61                 Note: the list (array) of changed keys passed to the
  62                       notification callback will be always be non-NULL
  63                       and non-empty with one exception.  That exception
  64                       is when the SCDynamicStore server has been restarted.
  65                       In that case, if no reconnect callback was setup
  66                       with the SCDynamicStoreSetReconnectCallBack API
  67                       then a non-NULL but empty array will be passed.
  68
  69                 Disconnect/reconnect considerations:
  70
  71                 1. We don't expect the SCDynamicStore server to fail but one
  72                    should always be prepared for the unexpected.
  73
  74                 2. Processes that write to the SCDynamicStore should be
  75                    prepared to repost any content when/if the server fails.
  76                    A callout, registered with the SCDynamicStoreSetReconnectCallBack
  77                    API, should be used to post any updates the SCDynamicStore
  78                    after a failure.
  79
  80                 3. Processes that cache SCDynamicStore content (or otherwise
  81                    maintain state based on previous notifications) should be
  82                    aware that all store content is lost when/if the server
  83                    fails.  After handling a SCDynamicStore notification with
  84                    no keys or a disconnect/reconnect callout, your code should
  85                    assume that any cached content is no longer valid.
  86
  87                 Performance considerations:
  88
  89                 1. We recommend that any code trying to capture a snapshot of
  90                    more than one SCDynamicStore key should use the SCDynamicStoreCopyMultiple
  91                    API (and not make multiple calls to SCDynamicStoreCopyValue).
  92
  93                 2. We recommend that any code making multiple (and related)
  94                    changes to the SCDynamicStore should batch them into a
  95                    single call using the SCDynamicStoreSetMultiple API (and
  96                    not make multiple calls to SCDynamicStoreSetValue).
  97  */
  98
  99 /*!
 100         @typedef SCDynamicStoreDisconnectCallBack
 101         @discussion Type of callback function used when notification of
 102                 the dynamic store session being disconnected is delivered.
 103         @param store The dynamic store session.
 104         @param info A C pointer to a user-specified block of data.
 105  */
 106 typedef void (*SCDynamicStoreDisconnectCallBack)        (
 107                                                          SCDynamicStoreRef      store,
 108                                                          void                   *info
 109                                                          );
 110
 111
 112
 113 __BEGIN_DECLS
 114
 115 /*!
 116         @function SCDynamicStoreAddWatchedKey
 117         @discussion Adds the specified key to the list of "dynamic store"
 118                 values that are being monitored for changes.
 119         @param store The "dynamic store" session being watched.
 120         @param key The key to be monitored.
 121         @param isRegex A booolean indicating whether a specific key should
 122                 be monitored or if it consists of a regex(3) pattern string
 123                 of keys.
 124         @result TRUE if the key was successfully added to the "watch"
 125                 list; FALSE if an error was encountered.
 126  */
 127 Boolean
 128 SCDynamicStoreAddWatchedKey             (SCDynamicStoreRef              store,
 129                                          CFStringRef                    key,
 130                                          Boolean                        isRegex);
 131
 132 /*!
 133         @function SCDynamicStoreRemoveWatchedKey
 134         @discussion Removes the specified key from the list of "dynamic store"
 135                 values that are being monitored for changes.
 136         @param store The "dynamic store" session being watched.
 137         @param key The key that should no longer be monitored.
 138         @param isRegex A booolean indicating whether a specific key should
 139                 be monitored or if it consists of a regex(3) pattern string
 140                 of keys.
 141         @result TRUE if the key was successfully removed from the "watch"
 142                 list; FALSE if an error was encountered.
 143  */
 144 Boolean
 145 SCDynamicStoreRemoveWatchedKey          (SCDynamicStoreRef              store,
 146                                          CFStringRef                    key,
 147                                          Boolean                        isRegex);
 148
 149 /*!
 150         @function SCDynamicStoreNotifyFileDescriptor
 151         @discussion Allocates a file descriptor that can be used to detect changes
 152                 to one of the system configuration data entries associated with the
 153                 current session's notifier keys. When a change is detected, the
 154                 specified identifier (4 bytes) will be delivered to the calling
 155                 application via the allocated file descriptor.
 156
 157         @param store An SCDynamicStoreRef that should be used for communication with the server.
 158         @param identifier A (4 byte) integer that can be used to identify this
 159                 notification.
 160         @param fd A pointer to a file descriptor.  Upon return, fd will
 161                 contain the file descriptor that will be used for any notifications.
 162         @result A boolean indicating the success (or failure) of the call.
 163  */
 164 Boolean
 165 SCDynamicStoreNotifyFileDescriptor      (SCDynamicStoreRef              store,
 166                                          int32_t                        identifier,
 167                                          int                            *fd);
 168
 169 /*!
 170         @function SCDynamicStoreNotifySignal
 171         @discussion Requests that the specified BSD signal be sent to the process
 172                 with the indicated process id whenever a change has been detected
 173                 to one of the system configuration data entries associated with the
 174                 current session's notifier keys.
 175
 176                 Note: this function is not valid for "configd" plug-ins.
 177
 178         @param store An SCDynamicStoreRef that should be used for communication with the server.
 179         @param pid A UNIX process ID that should be signalled for any notifications.
 180         @param sig A signal number to be used.
 181         @result A boolean indicating the success (or failure) of the call.
 182  */
 183 Boolean
 184 SCDynamicStoreNotifySignal              (SCDynamicStoreRef              store,
 185                                          pid_t                          pid,
 186                                          int                            sig);
 187
 188 /*!
 189         @function SCDynamicStoreNotifyWait
 190         @discussion Waits for a change to be made to a value in the
 191                 "dynamic store" that is being monitored.
 192         @param store The "dynamic store" session.
 193         @result TRUE if a change has been detected; FALSE if an error was encountered.
 194  */
 195 Boolean
 196 SCDynamicStoreNotifyWait                (SCDynamicStoreRef              store);
 197
 198 /*!
 199         @function SCDynamicStoreNotifyCancel
 200         @discussion Cancels any outstanding notification requests for
 201                 this "dynamic store" session.
 202
 203         @param store The "dynamic store" session.
 204         @result TRUE if all notifications have been cancelled; FALSE if an
 205                 error was encountered.
 206  */
 207 Boolean
 208 SCDynamicStoreNotifyCancel              (SCDynamicStoreRef              store);
 209
 210 /*!
 211         @function SCDynamicStoreSetDisconnectCallBack
 212         @discussion Assigns a callback to a SCDynamicStore session.  The function
 213                 is called when the session has been disconnected.  The callback
 214                 should be established before a client writes any content to the
 215                 SCDynamicStore to ensure that the information can be re-posted
 216                 when/if a disconnect is detected.
 217         @param store A reference to the dynamic store session.
 218         @param callout The function to be called when the session was disconnected.
 219                 If NULL, the current callback is removed.
 220         @result Returns TRUE on success, FALSE on failure.
 221  */
 222 Boolean
 223 SCDynamicStoreSetDisconnectCallBack     (
 224                                          SCDynamicStoreRef                      store,
 225                                          SCDynamicStoreDisconnectCallBack       callout
 226                                         )                               __OSX_AVAILABLE_STARTING(__MAC_10_7,__IPHONE_5_0/*SPI*/);
 227
 228 Boolean
 229 SCDynamicStoreSnapshot                  (SCDynamicStoreRef              store);
 230
 231 __END_DECLS
 232
 233 #endif /* _SCDYNAMICSTOREPRIVATE_H */