Mon Mar 19 11:30:27 2012

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 Mark Michelson <mmichelson@digium.com>
00027  *
00028  * \ingroup functions
00029  */
00030 
00031 /*** MODULEINFO
00032    <support_level>core</support_level>
00033  ***/
00034 
00035 #include "asterisk.h"
00036 #include "asterisk/datastore.h"
00037 #include "asterisk/channel.h"
00038 #include "asterisk/logger.h"
00039 #include "asterisk/audiohook.h"
00040 #include "asterisk/pbx.h"
00041 #include "asterisk/module.h"
00042 
00043 /*** DOCUMENTATION
00044    <function name = "AUDIOHOOK_INHERIT" language="en_US">
00045       <synopsis>
00046          Set whether an audiohook may be inherited to another channel
00047       </synopsis>
00048       <syntax>
00049          <parameter name="source" required="true">
00050             <para>The built-in sources in Asterisk are</para>
00051             <enumlist>
00052                <enum name="MixMonitor" />
00053                <enum name="Chanspy" />
00054                <enum name="Volume" />
00055                <enum name="Speex" />
00056                <enum name="JACK_HOOK" />
00057             </enumlist>
00058             <para>Note that the names are not case-sensitive</para>
00059          </parameter>
00060       </syntax>
00061       <description>
00062          <para>By enabling audiohook inheritance on the channel, you are giving
00063          permission for an audiohook to be inherited by a descendent channel.
00064          Inheritance may be be disabled at any point as well.</para>
00065 
00066          <para>Example scenario:</para>
00067          <para>exten => 2000,1,MixMonitor(blah.wav)</para>
00068          <para>exten => 2000,n,Set(AUDIOHOOK_INHERIT(MixMonitor)=yes)</para>
00069          <para>exten => 2000,n,Dial(SIP/2000)</para>
00070          <para>
00071          </para>
00072          <para>exten => 4000,1,Dial(SIP/4000)</para>
00073          <para>
00074          </para>
00075          <para>exten => 5000,1,MixMonitor(blah2.wav)</para>
00076          <para>exten => 5000,n,Dial(SIP/5000)</para>
00077          <para>
00078          </para>
00079          <para>In this basic dialplan scenario, let's consider the following sample calls</para>
00080          <para>Call 1: Caller dials 2000. The person who answers then executes an attended</para>
00081          <para>        transfer to 4000.</para>
00082          <para>Result: Since extension 2000 set MixMonitor to be inheritable, after the</para>
00083          <para>        transfer to 4000 has completed, the call will continue to be recorded
00084          to blah.wav</para>
00085          <para>
00086          </para>
00087          <para>Call 2: Caller dials 5000. The person who answers then executes an attended</para>
00088          <para>        transfer to 4000.</para>
00089          <para>Result: Since extension 5000 did not set MixMonitor to be inheritable, the</para>
00090          <para>        recording will stop once the call has been transferred to 4000.</para>
00091       </description>
00092    </function>
00093  ***/
00094 
00095 struct inheritable_audiohook {
00096    AST_LIST_ENTRY(inheritable_audiohook) list;
00097    char source[1];
00098 };
00099 
00100 struct audiohook_inheritance_datastore {
00101    AST_LIST_HEAD (, inheritable_audiohook) allowed_list;
00102 };
00103 
00104 static void audiohook_inheritance_fixup(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan);
00105 static void audiohook_inheritance_destroy (void *data);
00106 static const struct ast_datastore_info audiohook_inheritance_info = {
00107    .type = "audiohook inheritance",
00108    .destroy = audiohook_inheritance_destroy,
00109    .chan_fixup = audiohook_inheritance_fixup,
00110 };
00111 
00112 /*! \brief Move audiohooks as defined by previous calls to the AUDIOHOOK_INHERIT function
00113  *
00114  * Move allowed audiohooks from the old channel to the new channel.
00115  *
00116  * \param data The ast_datastore containing audiohook inheritance information that will be moved
00117  * \param old_chan The "clone" channel from a masquerade. We are moving the audiohook in question off of this channel
00118  * \param new_chan The "original" channel from a masquerade. We are moving the audiohook in question to this channel
00119  * \return Void
00120  */
00121 static void audiohook_inheritance_fixup(void *data, struct ast_channel *old_chan, struct ast_channel *new_chan)
00122 {
00123    struct inheritable_audiohook *audiohook = NULL;
00124    struct audiohook_inheritance_datastore *datastore = data;
00125 
00126    ast_debug(2, "inheritance fixup occurring for channels %s(%p) and %s(%p)", old_chan->name, old_chan, new_chan->name, new_chan);
00127 
00128    AST_LIST_TRAVERSE(&datastore->allowed_list, audiohook, list) {
00129       ast_audiohook_move_by_source(old_chan, new_chan, audiohook->source);
00130       ast_debug(3, "Moved audiohook %s from %s(%p) to %s(%p)\n",
00131          audiohook->source, old_chan->name, old_chan, new_chan->name, new_chan);
00132    }
00133    return;
00134 }
00135 
00136 /*! \brief Destroy dynamically allocated data on an audiohook_inheritance_datastore
00137  *
00138  * \param data Pointer to the audiohook_inheritance_datastore in question.
00139  * \return Void
00140  */
00141 static void audiohook_inheritance_destroy(void *data)
00142 {
00143    struct audiohook_inheritance_datastore *audiohook_inheritance_datastore = data;
00144    struct inheritable_audiohook *inheritable_audiohook = NULL;
00145 
00146    while ((inheritable_audiohook = AST_LIST_REMOVE_HEAD(&audiohook_inheritance_datastore->allowed_list, list))) {
00147       ast_free(inheritable_audiohook);
00148    }
00149 
00150    ast_free(audiohook_inheritance_datastore);
00151 }
00152 
00153 /*! \brief create an audiohook_inheritance_datastore and attach it to a channel
00154  *
00155  * \param chan The channel to which we wish to attach the new datastore
00156  * \return Returns the newly created audiohook_inheritance_datastore or NULL on error
00157  */
00158 static struct audiohook_inheritance_datastore *setup_inheritance_datastore(struct ast_channel *chan)
00159 {
00160    struct ast_datastore *datastore = NULL;
00161    struct audiohook_inheritance_datastore *audiohook_inheritance_datastore = NULL;
00162 
00163    if (!(datastore = ast_datastore_alloc(&audiohook_inheritance_info, NULL))) {
00164       return NULL;
00165    }
00166 
00167    if (!(audiohook_inheritance_datastore = ast_calloc(1, sizeof(*audiohook_inheritance_datastore)))) {
00168       ast_datastore_free(datastore);
00169       return NULL;
00170    }
00171 
00172    datastore->data = audiohook_inheritance_datastore;
00173    ast_channel_lock(chan);
00174    ast_channel_datastore_add(chan, datastore);
00175    ast_channel_unlock(chan);
00176    return audiohook_inheritance_datastore;
00177 }
00178 
00179 /*! \brief Create a new inheritable_audiohook structure and add it to an audiohook_inheritance_datastore
00180  *
00181  * \param audiohook_inheritance_datastore The audiohook_inheritance_datastore we want to add the new inheritable_audiohook to
00182  * \param source The audiohook source for the newly created inheritable_audiohook
00183  * \retval 0 Success
00184  * \retval non-zero Failure
00185  */
00186 static int setup_inheritable_audiohook(struct audiohook_inheritance_datastore *audiohook_inheritance_datastore, const char *source)
00187 {
00188    struct inheritable_audiohook *inheritable_audiohook = NULL;
00189 
00190    inheritable_audiohook = ast_calloc(1, sizeof(*inheritable_audiohook) + strlen(source));
00191 
00192    if (!inheritable_audiohook) {
00193       return -1;
00194    }
00195 
00196    strcpy(inheritable_audiohook->source, source);
00197    AST_LIST_INSERT_TAIL(&audiohook_inheritance_datastore->allowed_list, inheritable_audiohook, list);
00198    ast_debug(3, "Set audiohook %s to be inheritable\n", source);
00199    return 0;
00200 }
00201 
00202 /*! \brief Set the permissibility of inheritance for a particular audiohook source on a channel
00203  *
00204  * For details regarding what happens in the function, see the inline comments
00205  *
00206  * \param chan The channel we are operating on
00207  * \param function The name of the dialplan function (AUDIOHOOK_INHERIT)
00208  * \param data The audiohook source for which we are setting inheritance permissions
00209  * \param value The value indicating the permission for audiohook inheritance
00210  */
00211 static int func_inheritance_write(struct ast_channel *chan, const char *function, char *data, const char *value)
00212 {
00213    int allow;
00214    struct ast_datastore *datastore = NULL;
00215    struct audiohook_inheritance_datastore *inheritance_datastore = NULL;
00216    struct inheritable_audiohook *inheritable_audiohook;
00217 
00218    /* Step 1: Get data from function call */
00219    if (ast_strlen_zero(data)) {
00220       ast_log(LOG_WARNING, "No argument provided to INHERITANCE function.\n");
00221       return -1;
00222    }
00223 
00224    if (ast_strlen_zero(value)) {
00225       ast_log(LOG_WARNING, "No value provided to INHERITANCE function.\n");
00226       return -1;
00227    }
00228 
00229    allow = ast_true(value);
00230 
00231    /* Step 2: retrieve or set up datastore */
00232    ast_channel_lock(chan);
00233    if (!(datastore = ast_channel_datastore_find(chan, &audiohook_inheritance_info, NULL))) {
00234       ast_channel_unlock(chan);
00235       /* In the case where we cannot find the datastore, we can take a few shortcuts */
00236       if (!allow) {
00237          ast_debug(1, "Audiohook %s is already set to not be inheritable on channel %s\n", data, chan->name);
00238          return 0;
00239       } else if (!(inheritance_datastore = setup_inheritance_datastore(chan))) {
00240          ast_log(LOG_WARNING, "Unable to set up audiohook inheritance datastore on channel %s\n", chan->name);
00241          return -1;
00242       } else {
00243          return setup_inheritable_audiohook(inheritance_datastore, data);
00244       }
00245    } else {
00246       inheritance_datastore = datastore->data;
00247    }
00248    ast_channel_unlock(chan);
00249 
00250    /* Step 3: Traverse the list to see if we're trying something redundant */
00251 
00252    AST_LIST_TRAVERSE_SAFE_BEGIN(&inheritance_datastore->allowed_list, inheritable_audiohook, list) {
00253       if (!strcasecmp(inheritable_audiohook->source, data)) {
00254          if (allow) {
00255             ast_debug(2, "Audiohook source %s is already set up to be inherited from channel %s\n", data, chan->name);
00256             return 0;
00257          } else {
00258             ast_debug(2, "Removing inheritability of audiohook %s from channel %s\n", data, chan->name);
00259             AST_LIST_REMOVE_CURRENT(list);
00260             ast_free(inheritable_audiohook);
00261             return 0;
00262          }
00263       }
00264    }
00265    AST_LIST_TRAVERSE_SAFE_END;
00266 
00267    /* Step 4: There is no step 4 */
00268 
00269    /* Step 5: This means we are addressing an audiohook source which we have not encountered yet for the channel. Create a new inheritable
00270     * audiohook structure if we're allowing inheritance, or just return if not
00271     */
00272 
00273    if (allow) {
00274       return setup_inheritable_audiohook(inheritance_datastore, data);
00275    } else {
00276       ast_debug(1, "Audiohook %s is already set to not be inheritable on channel %s\n", data, chan->name);
00277       return 0;
00278    }
00279 }
00280 
00281 static struct ast_custom_function inheritance_function = {
00282    .name = "AUDIOHOOK_INHERIT",
00283    .write = func_inheritance_write,
00284 };
00285 
00286 static int unload_module(void)
00287 {
00288    return ast_custom_function_unregister(&inheritance_function);
00289 }
00290 
00291 static int load_module(void)
00292 {
00293    if (ast_custom_function_register(&inheritance_function)) {
00294       return AST_MODULE_LOAD_DECLINE;
00295    } else {
00296       return AST_MODULE_LOAD_SUCCESS;
00297    }
00298 }
00299 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Audiohook inheritance function");

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