For all you C gurus out there. I'm working on a little program that
when an event occurs, it dials out a Verizon Wireless AirCard, does
it's thing and then when all events are done, the last event close the
card. To close the ppp connection you send it a Ctrl-C, which I'm
doing, however it is never working. The code I'm using is as follows:
void *sound_alarm ( void * rd_struct )
{
RADSPY_STRUCT *ptr_rd_struct;
ptr_rd_struct = ( RADSPY_STRUCT * ) rd_struct;
/* lock the modem_in_use variable to check to dial modem */
pthread_mutex_lock ( &modem_mutex );
if ( modem_in_use++ == 0 )
{
/* we need to dial out the modem */
printf ( "Dialing the modem: %d\n", modem_in_use );
modem_pid = fork();
if ( 0 == modem_pid )
{
int ret;
/* we are the child so dial out the modem */
ret = execl ( "/usr/sbin/pppd", "pppd", "call", "ac555qnc", NULL );
if ( -1 == ret )
printf ( "Problem dialing modem: %s\n", strerror ( errno ) );
printf ( "Got here.\n" );
exit ( 0 );
}
/* hack to wait enough time to let the modem dial */
sleep ( 10 );
}
pthread_mutex_unlock ( &modem_mutex );
/* perform the sending of the data */
printf ( "Sounding the alarm: %d.\n", modem_in_use );
sleep ( 1 ); /* code to send away alarms will go here,
sleep for now */
/* release the modem in use */
pthread_mutex_lock ( &modem_mutex );
if ( --modem_in_use == 0 )
{
/* we need to hangup the modem */
printf ("Hanging up the modem: %d\n", modem_in_use );
kill ( SIGINT, modem_pid );
}
pthread_mutex_unlock ( &modem_mutex );
pthread_exit ( (void *) 0 );
}
This function is a thread that is spawned by the main loop when an
event occurs. This event can occur multiple times, which is why I
have the shared variable of how many events are currently occuring
(modem_in_use). When I run this program, I'm always getting an error
about the modem being locked by pid XXX, so it's never being closed.
Anyone have any experience with this kinda thing?
Chuck
--
Chuck Haines
chaines(a)gmail.com
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