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//// sidd.c: A VLF signal monitor.//// author: Paul Nicholson, paul@abelian.demon.co.uk//#include <stdlib.h>#include <unistd.h>#include <math.h>#include <stdio.h>#include <sys/stat.h>#include <sys/ioctl.h>#include <sys/time.h>#include <sys/param.h>#include <fcntl.h>#include <errno.h>#include <stdarg.h>#include <ctype.h>#include <string.h>#include <signal.h>#include <time.h>#include <sched.h>#include <linux/soundcard.h>#include <fftw3.h>///////////////////////////////////////////////////////////////////////////////// Tuneable Settings /////////////////////////////////////////////////////////////////////////////////#define VERSION "0.94"//// Number of soundcard bytes to read at a time.#define NREAD 2048//// Max number of bands which can be read from the config file.#define MAXBANDS 20//// Name of the configuration file.#define CONFIG_FILE "sidd.conf"///////////////////////////////////////////////////////////////////////////////// Globals and fixed definitions ///////////////////////////////////////////////////////////////////////////////////// Default values here are over-ridden by the config file.int mode = 1; // 1 = mono, 2 = stereoint bits = 16; // Sample width, 8 or 16 bitsint BINS = 2048; // Number of frequency bins#define FFTWID (2 * BINS) // Number of samples in FFT periodint background = 1; // Set zero if running in foregroundint fdi; // Input file handleint fdm; // Mixer file handleint VFLAG = 0; // Set non-zero by -v optionint MFLAG = 0; // Set non-zero by -m optionint spec_max = 100; // Issue a spectrum for every spec_max output recordsint spec_cnt = 0;int sample_rate = 100000; // Samples per secondint chans = 1;int alert_on = 0;int priority = 0; // Set to 1 if high scheduling prioritystruct sigaction sa;char mailaddr[100];double los_thresh = 0; // Threshold for loss of signal, 0..1int los_timeout = 0; // Number of seconds before loss of signal declareddouble DF; // Frequency resolution of the FFTint bailout_flag = 0; // To prevent bailout() loopingint grab_cnt = 0; // Count of samples into the FFT buffer// Mixer gain settings requested by config file.int req_lgain = -1; // Line gainint req_mgain = -1; // Microphone gainint req_igain = -1; // Input gainint req_rgain = -1; // Record level// Actual mixer values, read by open_mixer()int mixer_recmask; // Recording device maskint mixer_stereo; // Stereo device maskint mixer_line; // Line input gain settingint mixer_microphone; // Microphone input gainint mixer_igain; // Overall input gain settingint mixer_reclev; // Recording level settingint mixer_recsrc; // Mask indicating which inputs are set to record//// Various filenames, contents set by config file.//char logfile[100] = "";char device[100] = "/dev/dsp";char mixer[100] = "/dev/mixer";char spectrum_file[100] = "/tmp/sidspec";char datadir[100] = ".";//// Table of frequency bands to monitor//struct BAND{char ident[50];int start;int end;}bands[MAXBANDS]; // Table of bands to be monitoredint nbands = 0;//// Independent state variables and buffers for left and right channels//struct CHAN{char *name;double *signal_avg;double *powspec;double *fft_inbuf;fftw_complex *fft_data;fftw_plan ffp;double peak;double sum_sq;int los_state;time_t los_time;FILE *fo;char fname[100];}left = { "left" }, right = { "right" };///////////////////////////////////////////////////////////////////////////////// Various Utility Functions ///////////////////////////////////////////////////////////////////////////////////// Issue a message to the log file, if the verbosity level is high enough...//void report( int level, char *format, ...){va_list ap;void bailout( char *format, ...);char temp[ 200];if( VFLAG < level) return;va_start( ap, format);vsprintf( temp, format, ap);va_end( ap);if( !logfile[0] || !background)if( background != 2) fprintf( stderr, "%s\n", temp);if( logfile[0]){time_t now = time( NULL);struct tm *tm = gmtime( &now);FILE *flog = NULL;if( (flog = fopen( logfile, "a+")) == NULL)bailout( "cannot open logfile [%s]: %s", logfile, strerror( errno));fprintf( flog, "%04d/%02d/%02d %02d:%02d:%02d %s\n",tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,tm->tm_hour, tm->tm_min, tm->tm_sec, temp);fclose( flog);}}void alert( char *format, ...){FILE *f;va_list( ap);char cmd[100], temp[100];va_start( ap, format);vsprintf( temp, format, ap);va_end( ap);report( -1, "%s", temp);if( !alert_on || !mailaddr[0]) return;sprintf( cmd, "mail -s 'sidd alert' '%s'", mailaddr);if( (f=popen( cmd, "w")) == NULL){report( 0, "cannot exec [%s]: %s", cmd, strerror( errno));return;}fprintf( f, "sidd: %s\n", temp);fclose( f);}//// We try to exit the program through here, if possible.//void bailout( char *format, ...){va_list ap;char temp[ 200];if( bailout_flag) exit( 1);bailout_flag = 1;va_start( ap, format);vsprintf( temp, format, ap);va_end( ap);alert( "terminating: %s", temp);exit( 1);}//// Exit with a message if we get any signals.//void handle_sigs( int signum){bailout( "got signal %d", signum);}///////////////////////////////////////////////////////////////////////////////// Soundcard Setup ///////////////////////////////////////////////////////////////////////////////////// Prepare the input stream, setting up the soundcard if the input// is a character device.//void setup_input_stream( void){struct stat st;report( 1, "taking data from [%s]", device);if( (fdi = open( device, O_RDONLY)) < 0)bailout( "cannot open [%s]: %s", strerror( errno));if( fstat( fdi, &st) < 0)bailout( "cannot stat input stream: %s", strerror( errno));if( S_ISCHR( st.st_mode)){int blksize;int fragreq = 0x7fff000a;unsigned int format;unsigned int req_format = AFMT_S16_LE;if( bits == 8) req_format = AFMT_U8;if (ioctl( fdi, SNDCTL_DSP_SETFRAGMENT, &fragreq))report( 01, "cannot set fragment size");if( ioctl( fdi, SNDCTL_DSP_RESET, NULL) < 0)bailout( "cannot reset input device");chans = mode;if( ioctl( fdi, SNDCTL_DSP_CHANNELS, &chans) < 0)bailout( "cannot set channels on input device");if( ioctl( fdi, SNDCTL_DSP_GETFMTS, &format) < 0)bailout( "cannot get formats from input device");report( 2, "formats available: %08X", format);if( (format & req_format) == 0){report( 0, "available dsp modes are %08X", format);bailout( "unable to set %d bit dsp mode", bits);}format = req_format;if( ioctl( fdi, SNDCTL_DSP_SETFMT, &format) < 0)bailout( "cannot set dsp format on input device");if( ioctl( fdi, SNDCTL_DSP_GETBLKSIZE, &blksize) < 0)bailout( "cannot get block size from input device");report( 2, "dsp block size: %d", blksize);if( ioctl( fdi, SNDCTL_DSP_CHANNELS, &chans) < 0)bailout( "cannot get channels from input device");report( 1, "requesting rate %d", sample_rate);if( ioctl( fdi, SNDCTL_DSP_SPEED, &sample_rate) < 0)bailout( "cannot set sample rate of input device");report( 1, "actual rate set: %d samples/sec", sample_rate);report( 1, "soundcard channels: %d bits: %d", chans, bits);}}///////////////////////////////////////////////////////////////////////////////// Output Functions /////////////////////////////////////////////////////////////////////////////////void maybe_output_spectrum( void){FILE *f;int i;if( ++spec_cnt < spec_max) return; // Wait for spec_max recordsspec_cnt = 0;if( !spectrum_file[0]) return; // Spectrum file not wanted.if( (f=fopen( spectrum_file, "w+")) == NULL)bailout( "cannot open spectrum file %s, %s", strerror( errno));if( mode == 1){fprintf( f, "Frequency PowerL \n");for( i=0; i<BINS; i++) fprintf( f, "%.5e %.5e\n",(i+0.5) * DF, left.signal_avg[i]/spec_max);}else{fprintf( f, "Frequncy PowerL PowerR \n");for( i=0; i<BINS; i++) fprintf( f, "%.5e %.5e %.5e\n",(i+0.5) * DF, left.signal_avg[i]/spec_max,right.signal_avg[i]/spec_max);}fclose( f);for( i=0; i<BINS; i++) left.signal_avg[i] = 0;if( mode == 2) for( i=0; i<BINS; i++) right.signal_avg[i] = 0;}void output_record( struct CHAN *c, char *prefix, double fsecs){int i, j;char test[100];if( mode == 1)sprintf( test, "%s.dat", prefix);elsesprintf( test, "%s.%s.dat", prefix, c->name);if( !c->fo || strcmp( test, c->fname)){if( c->fo) fclose( c->fo);strcpy( c->fname, test);report( 0, "using output file [%s]", c->fname);if( (c->fo=fopen( c->fname, "a+")) == NULL)bailout( "cannot open [%s], %s", c->fname, strerror( errno));}fprintf( c->fo, "%.3f %.3f %.3f", fsecs, c->peak, sqrt( c->sum_sq/FFTWID));for( i=0; i<nbands; i++){double e = 0;int n1 = bands[i].start/DF;int n2 = bands[i].end/DF;for( j=n1; j<= n2; j++) e += c->powspec[j];e /= n2 - n1 + 1;fprintf( c->fo, " %.2e", e);}fprintf( c->fo, "\n");fflush( c->fo);c->peak = c->sum_sq = 0;}void output_records( void){struct timeval tv;struct tm *tm;double fsecs;time_t ud;char prefix[100];gettimeofday( &tv, NULL);fsecs = tv.tv_sec + 1e-6 * tv.tv_usec;ud = tv.tv_sec - tv.tv_sec % 86400;tm = gmtime( &ud);sprintf( prefix, "%s/%02d%02d%02d", datadir,tm->tm_year - 100, tm->tm_mon+1, tm->tm_mday);output_record( &left, prefix, fsecs);if( mode == 2) output_record( &right, prefix, fsecs);}void check_los( struct CHAN *c){if( !c->los_state){if( !c->los_time && c->peak < los_thresh) time( &c->los_time);if( c->los_time && c->peak > los_thresh) c->los_time = 0;if( c->los_time && c->los_time + los_timeout < time( NULL)){c->los_state = 1;c->los_time = 0;if( mode == 1) alert( "loss of signal");else alert( "loss of signal on %s", c->name);}}else{if( !c->los_time && c->peak > los_thresh) time( &c->los_time);if( c->los_time && c->peak < los_thresh) c->los_time = 0;if( c->los_time && c->los_time + los_timeout < time( NULL)){c->los_state = 0;c->los_time = 0;if( mode == 1) alert( "signal restored");else alert( "signal restored on %s", c->name);}}}///////////////////////////////////////////////////////////////////////////////// Signal Processing /////////////////////////////////////////////////////////////////////////////////void process_fft( struct CHAN *c){int i;//// Do the FFT. First time through, initialise the fft plan.//if( !c->ffp)c->ffp = fftw_plan_dft_r2c_1d( FFTWID, c->fft_inbuf, c->fft_data,FFTW_ESTIMATE | FFTW_DESTROY_INPUT);fftw_execute( c->ffp);//// Obtain squared amplitude of each bin.//c->powspec[ 0] = 0.0; // Zero the DC componentfor( i=1; i<BINS; i++){double t1 = c->fft_data[ i][0];double t2 = c->fft_data[ i][1];c->powspec[ i] = t1*t1 + t2*t2;}//// Accumulate average signal levels in each bin. signal_avg is used// only for the spectrum file output.//for( i=0; i<BINS; i++) c->signal_avg[ i] += c->powspec[i];check_los( c);}void insert_sample( struct CHAN *c, double f){c->sum_sq += f * f;if( f > c->peak) c->peak = f;if( f < -c->peak) c->peak = -f;c->fft_inbuf[ grab_cnt] = f * sin( grab_cnt/(double) FFTWID * M_PI);}void maybe_do_fft( void){if( ++grab_cnt < FFTWID) return;grab_cnt = 0;process_fft( &left);if( mode == 2) process_fft( &right);output_records();maybe_output_spectrum();}//// Main signal processing loop. Never returns.//void process_signal( void){unsigned char buff[ NREAD];while( 1){int i, q;if( (q=read( fdi, buff, NREAD)) <= 0){if( !q || errno == ENOENT || errno == 0){sched_yield();usleep( 50000);continue;}report( 0, "input file: read error, count=%d errno=%d", q, errno);exit( 1);}// Unpack the input buffer into signed 16 bit words.// then scale to -1..+1 for further processing.// We use 'chans' to decide if the soundcard is giving stereo or// mono samples, rather than 'mode', because some cards will refuse// to do mono.if( bits == 16){if( chans == 1){for( i=0; i<q; i += 2){int fh = *(short *)(buff + i);insert_sample( &left, fh/32768.0);maybe_do_fft();}}else // chans must be 2{if( mode == 1)for( i=0; i<q; i += 4){int fh = *(short *)(buff + i);insert_sample( &left, fh/32768.0);maybe_do_fft();}else // mode == 2for( i=0; i<q; i += 4){int fh = *(short *)(buff + i);insert_sample( &left, fh/32768.0);fh = *(short *)(buff + i + 2);insert_sample( &right, fh/32768.0);maybe_do_fft();}}}else // bits must be 8{if( chans == 1){for( i=0; i<q; i++){int fh = ((short)buff[i] - 128)*256;insert_sample( &left, fh/32768.0);maybe_do_fft();}}else // chans must be 2{if( mode == 1)for( i=0; i<q; i += 2){int fh = ((short)buff[i] - 128)*256;insert_sample( &left, fh/32768.0);maybe_do_fft();}else // mode == 2for( i=0; i<q; i += 2){int fh = ((short)buff[i] - 128)*256;insert_sample( &left, fh/32768.0);fh = ((short)buff[i+1] - 128)*256;insert_sample( &right, fh/32768.0);maybe_do_fft();}}}}}///////////////////////////////////////////////////////////////////////////////// Configuration File Stuff /////////////////////////////////////////////////////////////////////////////////void config_band( char *ident, char *start, char *end){struct BAND *b = bands + nbands++;if( nbands == MAXBANDS) bailout( "too many bands specified in config file");strcpy( b->ident, ident);b->start = atoi( start);b->end = atoi( end);report( 1, "band %s %d %d", b->ident, b->start, b->end);}void load_config( void){int lino = 0, nf;FILE *f;char buff[100], *p, *fields[20];if( (f=fopen( CONFIG_FILE, "r")) == NULL)bailout( "no config file found");while( fgets( buff, 99, f)){lino++;if( (p=strchr( buff, '\r')) != NULL) *p = 0;if( (p=strchr( buff, '\n')) != NULL) *p = 0;if( (p=strchr( buff, ';')) != NULL) *p = 0;p = buff; nf = 0;while( 1){while( *p && isspace( *p)) p++;if( !*p) break;fields[nf++] = p;while( *p && !isspace( *p)) p++;if( *p) *p++ = 0;}if( !nf) continue;if( nf == 4 && !strcasecmp( fields[0], "band"))config_band( fields[1], fields[2], fields[3]);elseif( nf == 2 && !strcasecmp( fields[0], "logfile")){strcpy( logfile, fields[1]);report( 1, "logfile %s", logfile);}elseif( nf == 3 && !strcasecmp( fields[0], "los")){los_thresh = atof( fields[1]);los_timeout = atoi( fields[2]);report( 1, "los threshold %.3f, timeout %d seconds",los_thresh, los_timeout);}elseif( nf == 2 && !strcasecmp( fields[0], "device"))strcpy( device, fields[1]);elseif( nf == 2 && !strcasecmp( fields[0], "mixer"))strcpy( mixer, fields[1]);elseif( nf == 2 && !strcasecmp( fields[0], "mode")){if( !strcasecmp( fields[1], "mono")) mode = 1;elseif( !strcasecmp( fields[1], "stereo")) mode = 2;elsebailout( "error in config file, line %d", lino);}elseif( nf == 2 && !strcasecmp( fields[0], "bits")){bits = atoi( fields[1]);if( bits != 8 && bits != 16)bailout( "can only do 8 or 16 bits, config file line %d", lino);}elseif( nf == 3 && !strcasecmp( fields[0], "spectrum")){strcpy( spectrum_file, fields[1]);spec_max = atoi( fields[2]);}elseif( nf == 2 && !strcasecmp( fields[0], "sched")&& !strcasecmp( fields[1], "high")){priority = 1;}elseif( nf == 4 && !strcasecmp( fields[0], "gain")){int left = atoi( fields[2]);int right = atoi( fields[3]);int gain = (right << 8) | left;if( !strcasecmp( fields[1], "line")){req_lgain = gain;mixer_recsrc = SOUND_MASK_LINE;}elseif( !strcasecmp( fields[1], "mic")){req_mgain = gain;mixer_recsrc = SOUND_MASK_MIC;}elseif( !strcasecmp( fields[1], "overall")) req_igain = gain;elseif( !strcasecmp( fields[1], "record")) req_rgain = gain;elsebailout( "unknown gain control [%s]", fields[1]);}elseif( nf == 2 && !strcasecmp( fields[0], "rate"))sample_rate = atoi( fields[1]);elseif( nf == 2 && !strcasecmp( fields[0], "bins"))BINS = atoi( fields[1]);elseif( nf == 2 && !strcasecmp( fields[0], "datadir")){struct stat st;strcpy( datadir, fields[1]);if( stat( datadir, &st) < 0 || !S_ISDIR( st.st_mode))bailout( "no data directory, %s", datadir);}elsebailout( "error in config file, line %d", lino);}fclose( f);}///////////////////////////////////////////////////////////////////////////////// Mixer Stuff /////////////////////////////////////////////////////////////////////////////////void open_mixer( void){if( (fdm = open( mixer, O_RDWR)) < 0)bailout( "cannot open [%s]: %s", mixer, strerror( errno));// Determine the available mixer recording gain controls.// We must at least have a line input.if( ioctl( fdm, SOUND_MIXER_READ_RECMASK, &mixer_recmask) < 0)bailout( "cannot read mixer devmask");if( (mixer_recmask & SOUND_MASK_LINE) == 0)bailout( "mixer has no line device");if( ioctl( fdm, SOUND_MIXER_READ_STEREODEVS, &mixer_stereo) < 0)bailout( "cannot read mixer stereodevs");if( ioctl( fdm, SOUND_MIXER_READ_RECSRC, &mixer_recsrc) < 0)bailout( "cannot read mixer recsrc");// Read the line input gain.if( ioctl( fdm, SOUND_MIXER_READ_LINE, &mixer_line) < 0)bailout( "cannot read mixer line");// Read overall input gain? Optional.if( (mixer_recmask & SOUND_MASK_IGAIN) &&ioctl( fdm, SOUND_MIXER_READ_IGAIN, &mixer_igain) < 0)bailout( "cannot read mixer igain");// Read overall recording level? Optional.if( (mixer_recmask & SOUND_MASK_RECLEV) &&ioctl( fdm, SOUND_MIXER_READ_RECLEV, &mixer_reclev) < 0)bailout( "cannot read mixer reclev");}void report_mixer_settings( void){report( 1, "mixer: line input is %s",mixer_stereo & SOUND_MASK_LINE ? "stereo" : "mono");report( 1, "mixer: line input is %s",mixer_recsrc & SOUND_MASK_LINE ? "on" : "off");report( 1, "mixer: line input gain: left=%d right=%d",mixer_line & 0xff, (mixer_line >> 8) & 0xff);// Overall input gain? Optional.if( mixer_recmask & SOUND_MASK_IGAIN){report( 1, "mixer: igain: left=%d right=%d",mixer_igain & 0xff, (mixer_igain >> 8) & 0xff);}else report( 1, "mixer: igain: n/a");// Overall recording level? Optional.if( mixer_recmask & SOUND_MASK_RECLEV){report( 1, "mixer: reclev: left=%d right=%d",mixer_reclev & 0xff, (mixer_reclev >> 8) & 0xff);}else report( 1, "mixer: reclev: n/a");}void setup_mixer( void){if( req_lgain >= 0){report( 1, "requesting line input gains left=%d right=%d",req_lgain & 0xff, (req_lgain >> 8) & 0xff);if( ioctl( fdm, SOUND_MIXER_WRITE_LINE, &req_lgain) < 0 ||ioctl( fdm, SOUND_MIXER_READ_LINE, &mixer_line) < 0)bailout( "error setting mixer line gain");report( 1, "line input gains set to: left=%d right=%d",mixer_line & 0xff, (mixer_line >> 8) & 0xff);}if( req_mgain >= 0){report( 1, "requesting microphone input gains left=%d right=%d",req_mgain & 0xff, (req_mgain >> 8) & 0xff);if( ioctl( fdm, SOUND_MIXER_WRITE_MIC, &req_mgain) < 0 ||ioctl( fdm, SOUND_MIXER_READ_MIC, &mixer_microphone) < 0)bailout( "error setting mixer microphone gain");report( 1, "Microphone input gains set to: left=%d right=%d",mixer_microphone & 0xff, (mixer_microphone >> 8) & 0xff);}if( req_igain >= 0 &&(mixer_recmask & SOUND_MASK_IGAIN)){report( 1, "requesting overall input gains left=%d right=%d",req_igain & 0xff, (req_igain >> 8) & 0xff);if( ioctl( fdm, SOUND_MIXER_WRITE_IGAIN, &req_igain) < 0 ||ioctl( fdm, SOUND_MIXER_READ_IGAIN, &mixer_igain) < 0)bailout( "error setting mixer overall input gain");report( 1, "overall input gains set to: left=%d right=%d",mixer_igain & 0xff, (mixer_igain >> 8) & 0xff);}if( req_rgain >= 0 &&(mixer_recmask & SOUND_MASK_RECLEV)){report( 1, "requesting overall record levels left=%d right=%d",req_rgain & 0xff, (req_rgain >> 8) & 0xff);if( ioctl( fdm, SOUND_MIXER_WRITE_RECLEV, &req_rgain) < 0 ||ioctl( fdm, SOUND_MIXER_READ_RECLEV, &mixer_reclev) < 0)bailout( "error setting mixer record level");report( 1, "mixer record levels set to: left=%d right=%d",mixer_reclev & 0xff, (mixer_reclev >> 8) & 0xff);}//mixer_recsrc= SOUND_MASK_LINE;mixer_recsrc= SOUND_MASK_MIC;switch (mixer_recsrc){case SOUND_MASK_MIC:if( ioctl( fdm, SOUND_MIXER_WRITE_RECSRC, &mixer_recsrc) < 0)bailout( "cannot set mixer recsrc to microphone");else report(1, "Input device set to microphone");break;case SOUND_MASK_LINE:if( ioctl( fdm, SOUND_MIXER_WRITE_RECSRC, &mixer_recsrc) < 0)bailout( "cannot set mixer recsrc to line");else report(1, "Input device set to line");break;}}///////////////////////////////////////////////////////////////////////////////// Main /////////////////////////////////////////////////////////////////////////////////void make_daemon( void){int childpid, fd;if( (childpid = fork()) < 0)bailout( "cannot fork: %s", strerror( errno));else if( childpid > 0) exit( 0);if( setpgrp() == -1) bailout( "cannot setpgrp");if( (childpid = fork()) < 0)bailout( "cannot fork: %s", strerror( errno));else if( childpid > 0) exit( 0);for( fd = 0; fd <NOFILE; fd++) if( fd != fdi) close( fd);errno = 0;background = 2;}void initialise_channel( struct CHAN *c){int i;c->fft_inbuf = (double *) malloc( BINS * 2 * sizeof( double));c->fft_data = fftw_malloc( sizeof( fftw_complex) * FFTWID);c->powspec = (double *) malloc( BINS * sizeof( double));c->signal_avg = (double *) malloc( BINS * sizeof( double));for( i=0; i<BINS; i++) c->signal_avg[i] = 0;}void setup_signal_handling( void){sa.sa_handler = handle_sigs;sigemptyset( &sa.sa_mask);sa.sa_flags = 0;sigaction( SIGINT, &sa, NULL);sigaction( SIGTERM, &sa, NULL);sigaction( SIGHUP, &sa, NULL);sigaction( SIGQUIT, &sa, NULL);sigaction( SIGFPE, &sa, NULL);sigaction( SIGBUS, &sa, NULL);sigaction( SIGSEGV, &sa, NULL);}// Set scheduling priority to the minimum SCHED_FIFO value.void set_scheduling( void){struct sched_param pa;int min = sched_get_priority_min( SCHED_FIFO);pa.sched_priority = min;if( sched_setscheduler( 0, SCHED_FIFO, &pa) < 0)report( -1, "cannot set scheduling priority: %s", strerror( errno));elsereport( 0, "using SCHED_FIFO priority %d", min);}int main( int argc, char *argv[]){while( 1){int c = getopt( argc, argv, "vfm");if( c == 'v') VFLAG++;elseif( c == 'm') MFLAG++;elseif( c == 'f') background = 0;else if( c == -1) break;else bailout( "unknown option [%c]", c);}setup_signal_handling();load_config();open_mixer();if( MFLAG){VFLAG = 1;background = 0;report_mixer_settings();exit( 0);}setup_mixer();if( background && !logfile[0])report( -1, "warning: no logfile specified for daemon");setup_input_stream();DF = (double) sample_rate/(double) FFTWID;report( 1, "resolution: bins=%d fftwid=%d df=%f", BINS, FFTWID, DF);report( 1, "spectrum file: %s", spectrum_file);initialise_channel( &left);if( mode == 2) initialise_channel( &right);if( background) make_daemon();if( priority) set_scheduling();report( 0, "sidd version %s: starting work", VERSION);alert_on = 1;process_signal();return 0;}