Sat Aug 6 00:39:29 2011

Asterisk developer's documentation


func_audiohookinherit.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright (C) 2008, Digium, Inc.
00005  *
00006  * Mark Michelson <mmichelson@digium.com>
00007  *
00008  * See http://www.asterisk.org for more information about
00009  * the Asterisk project. Please do not directly contact
00010  * any of the maintainers of this project for assistance;
00011  * the project provides a web site, mailing lists and IRC
00012  * channels for your use.
00013  *
00014  * This program is free software, distributed under the terms of
00015  * the GNU General Public License Version 2. See the LICENSE file
00016  * at the top of the source tree.
00017  *
00018  * Please follow coding guidelines
00019  * http://svn.digium.com/view/asterisk/trunk/doc/CODING-GUIDELINES
00020  */
00021 
00022 /*! \file
00023  *
00024  * \brief Audiohook inheritance function
00025  *
00026  * \author \verbatim Mark Michelson <mmichelson@digium.com> \endverbatim
00027  *
00028  * \ingroup functions
00029  */
00030 
00031 #include "asterisk.h"
00032 #include "asterisk/channel.h"
00033 #include "asterisk/audiohook.h"
00034 #include "asterisk/pbx.h"
00035 #include "asterisk/module.h"
00036 #include "asterisk/options.h"
00037 
00038 struct inheritable_audiohook {
00039    AST_LIST_ENTRY(inheritable_audiohook) list;
00040    char source[1];
00041 };
00042 
00043 struct audiohook_inheritance_datastore {
00044    AST_LIST_HEAD (, inheritable_audiohook) allowed_list;
00045 };
00046 
00047 static void audiohook_inheritance_fixup(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan);
00048 static void audiohook_inheritance_destroy (void *data);
00049 static const struct ast_datastore_info audiohook_inheritance_info = {
00050    .type = "audiohook inheritance",
00051    .destroy = audiohook_inheritance_destroy,
00052    .chan_fixup = audiohook_inheritance_fixup,
00053 };
00054 
00055 /*! \brief Move audiohooks as defined by previous calls to the AUDIOHOOK_INHERIT function
00056  *
00057  * Move allowed audiohooks from the old channel to the new channel.
00058  *
00059  * \param data The ast_datastore containing audiohook inheritance information that will be moved
00060  * \param old_chan The "clone" channel from a masquerade. We are moving the audiohook in question off of this channel
00061  * \param new_chan The "original" channel from a masquerade. We are moving the audiohook in question to this channel
00062  * \return Void
00063  */
00064 static void audiohook_inheritance_fixup(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan)
00065 {
00066    struct inheritable_audiohook *audiohook = NULL;
00067    struct audiohook_inheritance_datastore *datastore = data;
00068 
00069    if (option_debug > 1) {
00070       ast_log(LOG_DEBUG, "inheritance fixup occurring for channels %s(%p) and %s(%p)", old_chan->name, old_chan, new_chan->name, new_chan);
00071    }
00072 
00073    AST_LIST_TRAVERSE(&datastore->allowed_list, audiohook, list) {
00074       ast_audiohook_move_by_source(old_chan, new_chan, audiohook->source);
00075       if (option_debug > 2) {
00076          ast_log(LOG_DEBUG, "Moved audiohook %s from %s(%p) to %s(%p)\n",
00077             audiohook->source, old_chan->name, old_chan, new_chan->name, new_chan);
00078       }
00079    }
00080    return;
00081 }
00082 
00083 /*! \brief Destroy dynamically allocated data on an audiohook_inheritance_datastore
00084  *
00085  * \param data Pointer to the audiohook_inheritance_datastore in question.
00086  * \return Void
00087  */
00088 static void audiohook_inheritance_destroy(void *data)
00089 {
00090    struct audiohook_inheritance_datastore *audiohook_inheritance_datastore = data;
00091    struct inheritable_audiohook *inheritable_audiohook = NULL;
00092 
00093    while ((inheritable_audiohook = AST_LIST_REMOVE_HEAD(&audiohook_inheritance_datastore->allowed_list, list))) {
00094       ast_free(inheritable_audiohook);
00095    }
00096 
00097    ast_free(audiohook_inheritance_datastore);
00098 }
00099 
00100 /*! \brief create an audiohook_inheritance_datastore and attach it to a channel
00101  *
00102  * \param chan The channel to which we wish to attach the new datastore
00103  * \return Returns the newly created audiohook_inheritance_datastore or NULL on error
00104  */
00105 static struct audiohook_inheritance_datastore *setup_inheritance_datastore(struct ast_channel *chan)
00106 {
00107    struct ast_datastore *datastore = NULL;
00108    struct audiohook_inheritance_datastore *audiohook_inheritance_datastore = NULL;
00109 
00110    if (!(datastore = ast_channel_datastore_alloc(&audiohook_inheritance_info, NULL))) {
00111       return NULL;
00112    }
00113 
00114    if (!(audiohook_inheritance_datastore = ast_calloc(1, sizeof(*audiohook_inheritance_datastore)))) {
00115       ast_channel_datastore_free(datastore);
00116       return NULL;
00117    }
00118 
00119    datastore->data = audiohook_inheritance_datastore;
00120    ast_channel_lock(chan);
00121    ast_channel_datastore_add(chan, datastore);
00122    ast_channel_unlock(chan);
00123    return audiohook_inheritance_datastore;
00124 }
00125 
00126 /*! \brief Create a new inheritable_audiohook structure and add it to an audiohook_inheritance_datastore
00127  *
00128  * \param audiohook_inheritance_datastore The audiohook_inheritance_datastore we want to add the new inheritable_audiohook to
00129  * \param source The audiohook source for the newly created inheritable_audiohook
00130  * \retval 0 Success
00131  * \retval non-zero Failure
00132  */
00133 static int setup_inheritable_audiohook(struct audiohook_inheritance_datastore *audiohook_inheritance_datastore, const char *source)
00134 {
00135    struct inheritable_audiohook *inheritable_audiohook = NULL;
00136 
00137    inheritable_audiohook = ast_calloc(1, sizeof(*inheritable_audiohook) + strlen(source));
00138 
00139    if (!inheritable_audiohook) {
00140       return -1;
00141    }
00142 
00143    strcpy(inheritable_audiohook->source, source);
00144    AST_LIST_INSERT_TAIL(&audiohook_inheritance_datastore->allowed_list, inheritable_audiohook, list);
00145    if (option_debug > 2) {
00146       ast_log(LOG_DEBUG, "Set audiohook %s to be inheritable\n", source);
00147    }
00148    return 0;
00149 }
00150 
00151 /*! \brief Set the permissibility of inheritance for a particular audiohook source on a channel
00152  *
00153  * For details regarding what happens in the function, see the inline comments
00154  *
00155  * \param chan The channel we are operating on
00156  * \param function The name of the dialplan function (AUDIOHOOK_INHERIT)
00157  * \param data The audiohook source for which we are setting inheritance permissions
00158  * \param value The value indicating the permission for audiohook inheritance
00159  */
00160 static int func_inheritance_write(struct ast_channel *chan, char *function, char *data, const char *value)
00161 {
00162    int allow;
00163    struct ast_datastore *datastore = NULL;
00164    struct audiohook_inheritance_datastore *inheritance_datastore = NULL;
00165    struct inheritable_audiohook *inheritable_audiohook;
00166 
00167    /* Step 1: Get data from function call */
00168    if (ast_strlen_zero(data)) {
00169       ast_log(LOG_WARNING, "No argument provided to INHERITANCE function.\n");
00170       return -1;
00171    }
00172 
00173    if (ast_strlen_zero(value)) {
00174       ast_log(LOG_WARNING, "No value provided to INHERITANCE function.\n");
00175       return -1;
00176    }
00177 
00178    allow = ast_true(value);
00179 
00180    /* Step 2: retrieve or set up datastore */
00181    ast_channel_lock(chan);
00182    if (!(datastore = ast_channel_datastore_find(chan, &audiohook_inheritance_info, NULL))) {
00183       ast_channel_unlock(chan);
00184       /* In the case where we cannot find the datastore, we can take a few shortcuts */
00185       if (!allow) {
00186          if (option_debug) {
00187             ast_log(LOG_DEBUG, "Audiohook %s is already set to not be inheritable on channel %s\n", data, chan->name);
00188          }
00189          return 0;
00190       } else if (!(inheritance_datastore = setup_inheritance_datastore(chan))) {
00191          ast_log(LOG_WARNING, "Unable to set up audiohook inheritance datastore on channel %s\n", chan->name);
00192          return -1;
00193       } else {
00194          return setup_inheritable_audiohook(inheritance_datastore, data);
00195       }
00196    } else {
00197       inheritance_datastore = datastore->data;
00198    }
00199    ast_channel_unlock(chan);
00200 
00201    /* Step 3: Traverse the list to see if we're trying something redundant */
00202 
00203    AST_LIST_TRAVERSE_SAFE_BEGIN(&inheritance_datastore->allowed_list, inheritable_audiohook, list) {
00204       if (!strcasecmp(inheritable_audiohook->source, data)) {
00205          if (allow) {
00206             if (option_debug > 1) {
00207                ast_log(LOG_DEBUG, "Audiohook source %s is already set up to be inherited from channel %s\n", data, chan->name);
00208             }
00209             return 0;
00210          } else {
00211             if (option_debug > 1) {
00212                ast_log(LOG_DEBUG, "Removing inheritability of audiohook %s from channel %s\n", data, chan->name);
00213             }
00214             AST_LIST_REMOVE_CURRENT(&inheritance_datastore->allowed_list, list);
00215             ast_free(inheritable_audiohook);
00216             return 0;
00217          }
00218       }
00219    }
00220    AST_LIST_TRAVERSE_SAFE_END;
00221 
00222    /* Step 4: There is no step 4 */
00223 
00224    /* Step 5: This means we are addressing an audiohook source which we have not encountered yet for the channel. Create a new inheritable
00225     * audiohook structure if we're allowing inheritance, or just return if not
00226     */
00227 
00228    if (allow) {
00229       return setup_inheritable_audiohook(inheritance_datastore, data);
00230    } else {
00231       if (option_debug) {
00232          ast_log(LOG_DEBUG, "Audiohook %s is already set to not be inheritable on channel %s\n", data, chan->name);
00233       }
00234       return 0;
00235    }
00236 }
00237 
00238 static struct ast_custom_function inheritance_function = {
00239    .name = "AUDIOHOOK_INHERIT",
00240    .synopsis = "Set whether an audiohook may be inherited to another channel",
00241    .syntax = "AUDIOHOOK_INHERIT(source)",
00242    .desc =
00243       "By enabling audiohook inheritance on the channel, you are giving\n"
00244       "permission for an audiohook to be inherited by a descendent channel.\n"
00245       "Inheritance may be be disabled at any point as well.\n"
00246       "\n"
00247       "  Example scenario:\n"
00248       "  exten => 2000,1,MixMonitor(blah.wav)\n"
00249       "  exten => 2000,n,Set(AUDIOHOOK_INHERIT(MixMonitor)=yes)\n"
00250       "  exten => 2000,n,Dial(SIP/2000)\n"
00251       "\n"
00252       "  exten => 4000,1,Dial(SIP/4000)\n"
00253       "\n"
00254       "  exten => 5000,1,MixMonitor(blah2.wav)\n"
00255       "  exten => 5000,n,Dial(SIP/5000)\n"
00256       "\n"
00257       "  In this basic dialplan scenario, let's consider the following sample calls\n"
00258       "  Call 1: Caller dials 2000. The person who answers then executes an attended\n"
00259       "          transfer to 4000.\n"
00260       "  Result: Since extension 2000 set MixMonitor to be inheritable, after the\n"
00261       "          transfer to 400 has completed, the call will continue to be recorded\n"
00262       "           to blah.wav\n"
00263       "\n"
00264       "  Call 2: Caller dials 5000. The person who answers then executes an attended\n"
00265       "          transfer to 4000.\n"
00266       "  Result: Since extension 5000 did not set MixMonitor to be inheritable, the\n"
00267       "          recording will stop once the call has been transferred to 4000.\n",
00268    .write = func_inheritance_write,
00269 };
00270 
00271 static int unload_module(void)
00272 {
00273    return ast_custom_function_unregister(&inheritance_function);
00274 }
00275 
00276 static int load_module(void)
00277 {
00278    if (ast_custom_function_register(&inheritance_function)) {
00279       return AST_MODULE_LOAD_DECLINE;
00280    } else {
00281       return AST_MODULE_LOAD_SUCCESS;
00282    }
00283 }
00284 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Audiohook inheritance function");

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