Thu Jul 9 13:40:34 2009

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

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