Basic buddy status notification

This program is a very simple usage example of liblinphone, demonstrating how to initiate SIP subscriptions and receive notifications from a sip uri identity passed from the command line.
Argument must be like sip:jehan.nosp@m.@sip.nosp@m..linp.nosp@m.hone.nosp@m..org .
ex budy_list sip:jehan.nosp@m.@sip.nosp@m..linp.nosp@m.hone.nosp@m..org
Subscription is cleared on SIGINT

/*
buddy_status
Copyright (C) 2010  Belledonne Communications SARL

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

#include "linphone/core.h"

#include <signal.h>

static bool_t running=TRUE;

static void stop(int signum){
        running=FALSE;
}

static void notify_presence_recv_updated (LinphoneCore *lc,  LinphoneFriend *friend) {
        const LinphoneAddress* friend_address = linphone_friend_get_address(friend);
        if (friend_address != NULL) {
                const LinphonePresenceModel* model = linphone_friend_get_presence_model(friend);
                LinphonePresenceActivity *activity = linphone_presence_model_get_activity(model);
                char *activity_str = linphone_presence_activity_to_string(activity);
                char *str = linphone_address_as_string (friend_address);
                printf("New state state [%s] for user id [%s] \n"
                                        ,activity_str
                                        ,str);
                ms_free(str);
        }
}
static void new_subscription_requested (LinphoneCore *lc,  LinphoneFriend *friend, const char* url) {
        const LinphoneAddress* friend_address = linphone_friend_get_address(friend);

        if (friend_address != NULL) {
                char *str = linphone_address_as_string (friend_address);
                printf(" [%s] wants to see your status, accepting\n", str);
                ms_free(str);
        }
        linphone_friend_edit(friend); /* start editing friend */
        linphone_friend_set_inc_subscribe_policy(friend,LinphoneSPAccept); /* Accept incoming subscription request for this friend*/
        linphone_friend_done(friend); /*commit change*/
        linphone_core_add_friend(lc,friend); /* add this new friend to the buddy list*/

}
static void registration_state_changed(struct _LinphoneCore *lc, LinphoneProxyConfig *cfg, LinphoneRegistrationState cstate, const char *message){
                printf("New registration state %s for user id [%s] at proxy [%s]"
                                ,linphone_registration_state_to_string(cstate)
                                ,linphone_proxy_config_get_identity(cfg)
                                ,linphone_proxy_config_get_addr(cfg));
}

LinphoneCore *lc;
int main(int argc, char *argv[]){
        LinphoneCoreVTable vtable={0};

        char* dest_friend=NULL;
        char* identity=NULL;
        char* password=NULL;

        LinphoneFriend* my_friend=NULL;

        /* takes   sip uri  identity from the command line arguments */
        if (argc>1){
                dest_friend=argv[1];
        }
        /* takes   sip uri  identity from the command line arguments */
        if (argc>2){
                identity=argv[2];
        }
        /* takes   password from the command line arguments */
        if (argc>3){
                password=argv[3];
        }
        signal(SIGINT,stop);
//#define DEBUG
#ifdef DEBUG
        linphone_core_enable_logs(NULL); /*enable liblinphone logs.*/
#endif
        /*
         Fill the LinphoneCoreVTable with application callbacks.
         All are optional. Here we only use the both notify_presence_received and new_subscription_requested callbacks
         in order to get notifications about friend status.
         */
        vtable.notify_presence_received=notify_presence_recv_updated;
        vtable.new_subscription_requested=new_subscription_requested;
        vtable.registration_state_changed=registration_state_changed; /*just in case sip proxy is used*/

        /*
         Instantiate a LinphoneCore object given the LinphoneCoreVTable
        */
        lc=linphone_core_new(&vtable,NULL,NULL,NULL);
        /*sip proxy might be requested*/
        if (identity != NULL)  {
                /*create proxy config*/
                LinphoneProxyConfig* proxy_cfg = linphone_proxy_config_new();
                /*parse identity*/
                LinphoneAddress *from = linphone_address_new(identity);
                LinphoneAuthInfo *info;
                if (from==NULL){
                        printf("%s not a valid sip uri, must be like sip:toto@sip.linphone.org \n",identity);
                        goto end;
                }
                if (password!=NULL){
                        info=linphone_auth_info_new(linphone_address_get_username(from),NULL,password,NULL,NULL,NULL); /*create authentication structure from identity*/
                        linphone_core_add_auth_info(lc,info); /*add authentication info to LinphoneCore*/
                }

                // configure proxy entries
                linphone_proxy_config_set_identity(proxy_cfg,identity); /*set identity with user name and domain*/
                linphone_proxy_config_set_server_addr(proxy_cfg,linphone_address_get_domain(from)); /* we assume domain = proxy server address*/
                linphone_proxy_config_enable_register(proxy_cfg,TRUE); /*activate registration for this proxy config*/
                linphone_proxy_config_enable_publish(proxy_cfg,TRUE); /* enable presence satus publication for this proxy*/
                linphone_address_unref(from); /*release resource*/

                linphone_core_add_proxy_config(lc,proxy_cfg); /*add proxy config to linphone core*/
                linphone_core_set_default_proxy(lc,proxy_cfg); /*set to default proxy*/


                /* Loop until registration status is available */
                do {
                        linphone_core_iterate(lc); /* first iterate initiates registration */
                        ms_usleep(100000);
                }
                while(  running && linphone_proxy_config_get_state(proxy_cfg) == LinphoneRegistrationProgress);

        }

        if (dest_friend) {
                my_friend = linphone_core_create_friend_with_address(lc, dest_friend); /*creates friend object from dest*/
                if (my_friend == NULL) {
                        printf("bad destination uri for friend [%s]\n",dest_friend);
                        goto end;
                }

                linphone_friend_enable_subscribes(my_friend,TRUE); /*configure this friend to emit SUBSCRIBE message after being added to LinphoneCore*/
                linphone_friend_set_inc_subscribe_policy(my_friend,LinphoneSPAccept); /* Accept incoming subscription request for this friend*/
                linphone_core_add_friend(lc,my_friend); /* add my friend to the buddy list, initiate SUBSCRIBE message*/

        }

        /*set my status to online*/
        linphone_core_set_presence_model(lc, linphone_presence_model_new_with_activity(LinphonePresenceActivityOnline, NULL));

        /* main loop for receiving notifications and doing background linphone core work: */
        while(running){
                linphone_core_iterate(lc); /* first iterate initiates subscription */
                ms_usleep(50000);
        }

        /* change my presence status to offline*/
        linphone_core_set_presence_model(lc, linphone_presence_model_new_with_activity(LinphonePresenceActivityOffline, NULL));
        linphone_core_iterate(lc); /* just to make sure new status is initiate message is issued */

        linphone_friend_edit(my_friend); /* start editing friend */
        linphone_friend_enable_subscribes(my_friend,FALSE); /*disable subscription for this friend*/
        linphone_friend_done(my_friend); /*commit changes triggering an UNSUBSCRIBE message*/

        linphone_core_iterate(lc); /* just to make sure unsubscribe message is issued */

end:
        printf("Shutting down...\n");
        linphone_core_destroy(lc);
        printf("Exited\n");
        return 0;
}