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Remove deadlock when starting dynamic channel on non-direct-sampling …
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…front end
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@ka9q
ka9q committed Apr 11, 2024
1 parent 35d4bc9 commit c796b10
Showing 1 changed file with 70 additions and 68 deletions.
138 changes: 70 additions & 68 deletions radio.c
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Expand Up @@ -93,7 +93,7 @@ struct channel *create_chan(uint32_t ssrc){
// Copy template
// Although there are some pointers in here (filter.out, filter.energies), they're all NULL until the chan actually starts
chan->lifetime = 20 * 1000 / Blocktime; // If freq == 0, goes away 20 sec after last command

// Get the local socket for the output stream
// Going connectionless with Output_fd broke this. The source port is filled in, but the source address is all zeroes because
// it depends on the specific output address, which is only known from a routing table lookup. Oh well.
Expand Down Expand Up @@ -131,7 +131,7 @@ static float estimate_noise(struct channel *chan,int shift){
// Compute average power per sample, should match input level calculated in time domain
chan->tp1 = power2dB(total_energy) - voltage2dB((float)master->bins + Frontend.reference);
}
#endif
#endif

int mbin = shift - slave->bins/2;
float min_bin_energy = INFINITY;
Expand Down Expand Up @@ -268,7 +268,7 @@ int close_chan(struct channel *chan){
chan->inuse = false;
Active_channel_count--;
}
pthread_mutex_unlock(&Channel_list_mutex);
pthread_mutex_unlock(&Channel_list_mutex);
return 0;
}

Expand Down Expand Up @@ -334,7 +334,7 @@ double set_first_LO(struct channel const * const chan,double const first_LO){
return (*Frontend.tune)(&Frontend,first_LO);
}
return first_LO;
}
}

// Compute FFT bin shift and time-domain fine tuning offset for specified LO frequency
// N = input fft length
Expand Down Expand Up @@ -391,58 +391,58 @@ void *sap_send(void *p){
char message[PKTSIZE],*wp;
int space = sizeof(message);
wp = message;

*wp++ = 0x20; // SAP version 1, ipv4 address, announce, not encrypted, not compressed
*wp++ = 0; // No authentication
*wp++ = id >> 8;
*wp++ = id & 0xff;
space -= 4;

// our sending ipv4 address
struct sockaddr_in const *sin = (struct sockaddr_in *)&chan->output.source_socket;
uint32_t *src = (uint32_t *)wp;
*src = sin->sin_addr.s_addr; // network byte order
wp += 4;
space -= 4;

int len = snprintf(wp,space,"application/sdp");
wp += len + 1; // allow space for the trailing null
space -= (len + 1);

// End of SAP header, beginning of SDP

// Version v=0 (always)
len = snprintf(wp,space,"v=0\r\n");
wp += len;
space -= len;

{
// Originator o=
char hostname[sysconf(_SC_HOST_NAME_MAX)];
gethostname(hostname,sizeof(hostname));

struct passwd pwd,*result = NULL;
char buf[1024];

getpwuid_r(getuid(),&pwd,buf,sizeof(buf),&result);
len = snprintf(wp,space,"o=%s %lld %d IN IP4 %s\r\n",
result ? result->pw_name : "-",
(long long)start_time,sess_version,hostname);

wp += len;
space -= len;
}

// s= (session name)
len = snprintf(wp,space,"s=radio %s\r\n",Frontend.description);
wp += len;
space -= len;

// i= (human-readable session information)
len = snprintf(wp,space,"i=PCM output stream from ka9q-radio on %s\r\n",Frontend.description);
wp += len;
space -= len;

{
char *mcast = strdup(formatsock(&chan->output.dest_socket));
// Remove :port field, confuses the vlc listener
Expand All @@ -453,8 +453,8 @@ void *sap_send(void *p){
wp += len;
space -= len;
FREE(mcast);
}
}


#if 0 // not currently used
int64_t current_time = utc_time_sec() + NTP_EPOCH;
Expand All @@ -464,7 +464,7 @@ void *sap_send(void *p){
len = snprintf(wp,space,"t=%lld %lld\r\n",(long long)start_time,0LL); // unbounded
wp += len;
space -= len;

// m = media description
// set from current state. This will require changing the session version and IDs, and
// it's not clear that clients like VLC will do the right thing anyway
Expand Down Expand Up @@ -500,63 +500,66 @@ void *sap_send(void *p){

// Baseband samples placed in chan->filter.out->output.c
int downconvert(struct channel *chan){
// Should we die?
// Won't work correctly if 0 Hz is outside front end coverage
// Should make this cleaner
if(chan->tune.freq == 0 && chan->lifetime > 0){
chan->lifetime--;
if(chan->lifetime <= 0){
chan->demod_type = -1; // No demodulator
return -1; // terminate needed
}
}
bool restart_needed = false;
pthread_mutex_lock(&chan->status.lock);
// Look on the single-entry command queue and grab it atomically
if(chan->status.command != NULL){
restart_needed = decode_radio_commands(chan,chan->status.command,chan->status.length);
send_radio_status((struct sockaddr *)&Metadata_socket,&Frontend,chan); // Send status in response
chan->status.global_timer = 0; // Just sent one
// Also send to output stream
send_radio_status((struct sockaddr *)&chan->status.dest_socket,&Frontend,chan);
chan->status.output_timer = chan->status.output_interval; // Reload
FREE(chan->status.command);
reset_radio_status(chan); // After both are sent
} else if(chan->status.global_timer != 0 && --chan->status.global_timer <= 0){
// Delayed status request, used mainly by all-channel polls to avoid big bursts
send_radio_status((struct sockaddr *)&Metadata_socket,&Frontend,chan); // Send status in response
chan->status.global_timer = 0; // to make sure
reset_radio_status(chan); // After both are sent
} else if(!chan->output.silent && chan->status.output_interval != 0 && chan->status.output_timer-- <= 0){
// Send status on output channel
send_radio_status((struct sockaddr *)&chan->status.dest_socket,&Frontend,chan);
chan->status.output_timer = chan->status.output_interval; // Reload
reset_radio_status(chan); // After both are sent
}
pthread_mutex_unlock(&chan->status.lock);
if(restart_needed)
return +1; // Restart needed

// To save CPU time when the front end is completely tuned away from us, block (with timeout) until the front
// end status changes rather than process zeroes. We must still poll the terminate flag.
pthread_mutex_lock(&Frontend.status_mutex);
int shift;
double remainder;

int shift = 0;
double remainder = 0;

while(true){
// Should we die?
// Won't work correctly if 0 Hz is outside front end coverage
// Should make this cleaner
if(chan->tune.freq == 0 && chan->lifetime > 0){
chan->lifetime--;
if(chan->lifetime <= 0){
chan->demod_type = -1; // No demodulator
return -1; // terminate needed
}
}

// Process any commands and return status
bool restart_needed = false;
pthread_mutex_lock(&chan->status.lock);
// Look on the single-entry command queue and grab it atomically
if(chan->status.command != NULL){
restart_needed = decode_radio_commands(chan,chan->status.command,chan->status.length);
send_radio_status((struct sockaddr *)&Metadata_socket,&Frontend,chan); // Send status in response
chan->status.global_timer = 0; // Just sent one
// Also send to output stream
send_radio_status((struct sockaddr *)&chan->status.dest_socket,&Frontend,chan);
chan->status.output_timer = chan->status.output_interval; // Reload
FREE(chan->status.command);
reset_radio_status(chan); // After both are sent
} else if(chan->status.global_timer != 0 && --chan->status.global_timer <= 0){
// Delayed status request, used mainly by all-channel polls to avoid big bursts
send_radio_status((struct sockaddr *)&Metadata_socket,&Frontend,chan); // Send status in response
chan->status.global_timer = 0; // to make sure
reset_radio_status(chan); // After both are sent
} else if(!chan->output.silent && chan->status.output_interval != 0 && chan->status.output_timer-- <= 0){
// Send status on output channel
send_radio_status((struct sockaddr *)&chan->status.dest_socket,&Frontend,chan);
chan->status.output_timer = chan->status.output_interval; // Reload
reset_radio_status(chan); // After both are sent
}
pthread_mutex_unlock(&chan->status.lock);
if(restart_needed)
return +1; // Restart needed

// To save CPU time when the front end is completely tuned away from us, block (with timeout) until the front
// end status changes rather than process zeroes. We must still poll the terminate flag.
pthread_mutex_lock(&Frontend.status_mutex);

if(chan->terminate){
pthread_mutex_unlock(&Frontend.status_mutex);
return -1;
}

chan->tune.second_LO = Frontend.frequency - chan->tune.freq;
double const freq = chan->tune.doppler + chan->tune.second_LO; // Total logical oscillator frequency
if(compute_tuning(Frontend.in.ilen + Frontend.in.impulse_length - 1,
Frontend.in.impulse_length,
Frontend.samprate,
&shift,&remainder,freq) == 0)
break; // The carrier is in range

&shift,&remainder,freq) == 0){
pthread_mutex_unlock(&Frontend.status_mutex);
break;
}
// No front end coverage of our carrier; wait for it to retune
chan->sig.bb_power = 0;
chan->sig.bb_energy = 0;
Expand All @@ -565,9 +568,8 @@ int downconvert(struct channel *chan){
clock_gettime(CLOCK_REALTIME,&timeout);
timeout.tv_sec += 1; // 1 sec in the future
pthread_cond_timedwait(&Frontend.status_cond,&Frontend.status_mutex,&timeout);
pthread_mutex_unlock(&Frontend.status_mutex);
}
pthread_mutex_unlock(&Frontend.status_mutex);

// Reasonable parameters?
assert(isfinite(chan->tune.doppler_rate));
assert(isfinite(chan->tune.shift));
Expand Down

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