don't continue when malloc bails out

[rigol] / rigol.c

/*
Sprite_tms hack to communicate with a Rigol DS1000-series scope using Linux. 
This code is licensed under the GPL V3.

Warning: This code can in theory fubar the communications with the scope to a
point where the Linux USB-stack seems to get confused. Do a 
rmmod uhci_hcd; modprobe uhci_hcd
(or alternately: use ohci_hcd) if that happens and you should be fine.
 */

#include <usb.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>
#include <time.h>

#include <readline/readline.h>
#include <readline/history.h>

#include "png.h"


//This routine locates a scope by VID/PID and returns an opened handle to it.
usb_dev_handle *find_scope() {
	struct usb_bus *bus;
	struct usb_device *dev=NULL;
	usb_find_busses();
	usb_find_devices();
	for (bus=usb_busses; bus; bus=bus->next) {
		for (dev=bus->devices; dev; dev=dev->next) {
			//fprintf(stderr,"Prod/dev: %04X:%04X\n",dev->descriptor.idVendor,dev->descriptor.idProduct);
			if (dev->descriptor.idVendor==0x400 && dev->descriptor.idProduct==0x5dc) {
				return usb_open(dev);
			}
		}
	}
	return NULL;
}

//Helper-routine: Convert a little-endian 4-byte word to an int
void int2chars(unsigned char *buff,unsigned int a) {
	buff[3]=(a>>24)&0xff;
	buff[2]=(a>>16)&0xff;
	buff[1]=(a>>8)&0xff;
	buff[0]=(a)&0xff;
}

//Helper-routine: Convert an int to  little-endian 4-byte word
unsigned int chars2int(unsigned char *buff) {
	unsigned int a;
	a=buff[3]<<24;
	a+=buff[2]<<16;
	a+=buff[1]<<8;
	a+=buff[0];
	return a;
}

#define MIN(a,b) (((a)<(b))?(a):(b))

inline char printable (char ch)
{
	if (ch < ' ') return '.';
	if (ch > '~') return '.';
	return ch;
}

//Debugging: Print a buffers contents in hex
void printb (unsigned char *pkt, int len)
{
	int i, j;

	for (i=0;i<len;i+= 16) {
		printf ("%04x:  ", i);
		for (j=0;j < MIN(len-i, 16);j++) {
			printf (" %02x", pkt[i+j]);
			if (j == 7) printf ("  ");
		}
		if (j < 7) printf ("  ");
		for (;j<17;j++)
			printf ("   ");

		for (j=0;j < MIN(len-i, 16);j++) {
			printf ("%c", printable (pkt[i+j]));
		}
		printf ("\n");
	}
}

//Send a scpi-command to the scope. The response goes into the buffer
//called resp, with a size of resplen. If resp==NULL, no response
//is requested.
int sendscpi(usb_dev_handle *dev, char* cmd, 
		unsigned char *resp, int resplen) {
	unsigned char *buff;
	int len,r,i;
	int cmdlen = strlen(cmd);
	static unsigned char seq=0;


	buff=malloc(0x40);
	seq++;
	buff[0]=1; //func
	buff[1]=seq; buff[2]=~seq; //nseq
	buff[3]=0;
	int2chars(buff+4, cmdlen);
	buff[8]=1;
	buff[9]=0x37;
	buff[10]=0x39;
	buff[11]=0x39;
	//fprintf(stderr,"Writing header len=%d\n", cmdlen);
	//printb(buff,12);
	r=usb_bulk_write(dev, 1, (char*)buff, 12, 1000);
	//fprintf(stderr,"%i bytes written. Writing cmd\n",r);
	//printb(cmd, cmdlen);
	r=usb_bulk_write(dev, 1, cmd, cmdlen, 1000);
	//fprintf(stderr,"%i bytes written.\n",r);
	if (resp != NULL && resplen != 0) {
		//send read command
		buff[0]=2; //func
		seq++;
		buff[1]=seq; buff[2]=~seq; //nseq
		int2chars(buff+4,0x40);
		buff[8]=1;
		buff[9]=0xA;
		buff[10]=0;
		buff[11]=0;
		//fprintf(stderr,"Writing resp req header\n");
		//printb(buff,12);
		r=usb_bulk_write(dev, 1, (char*)buff, 12, 1000);
		//fprintf(stderr,"%i bytes written. Reading response hdr\n",r);
		r=usb_bulk_read(dev, 2, (char*)buff, 0x40, 1000);
		//printb(buff,r);
		len=chars2int(buff+4);
		//fprintf(stderr,"%i bytes read. Resplen=%i\n",r,len);
		for (i=0; i<(r-12); i++) {
			if (i<resplen) resp[i] = buff[i+12];
		}
		//printb(resp,r-12);
		if (len > 0x40-12) {
			//fprintf(stderr," Reading response:\n");
			if (resplen<len) len=resplen;
			r=usb_bulk_read(dev, 2, (char*)resp+(0x40-12), len-(0x40-12),1000);
			//fprintf(stderr,"%i bytes read, wanted %i.\n", r, len-(0x40-12));
			return r+(0x40-12);
		}
		return len;
	}
	return 0;
}

//Initialize the scope.
void initscope(usb_dev_handle *dev) {
	int r;
	unsigned char buff[10];
	usb_claim_interface(dev,0);
	//The following code isn't really necessary, the program works
	//OK without it too.
	r=usb_control_msg(dev, 0xC8, 9, 0, 0, (char*)buff, 4, 1000);
	if (r < 0) {
		fprintf (stderr, "Error %d sending init message: %s\n", 
				r, strerror (-r));
		fprintf (stderr, "Do you have permission on the USB device?\n");
		exit (1);
	}
	if (chars2int(buff)!=0x40004dc) {
		fprintf(stderr,"Init: buff[%i]=%x\n",r,chars2int(buff));
	}
	return;
}

#define HAVE_READLINE
#ifndef HAVE_READLINE

char *readline (prompt)
{
	char *buf;

	printf (prompt); 
	fflush (stdout); 
	buf = malloc (1024); 

	if (fgets (buf, 1023, stdin) == NULL) {
		free (buf); 
		return NULL; 
	}
	l = strlen (buf); 
	if (buf[l-1] == '\n') {
		buf[l] = 0;
	}
	return buf; 
}

void add_history (char *buf)
{
}
#endif


void do_plot (struct usb_dev_handle *sc)
{
	unsigned char ch1[1024], ch2[1024];
	int i, l;

	static FILE *gnuplot=NULL;
	FILE *fp;

	l = sendscpi(sc, ":WAV:DATA? CHANEL1", ch1, 1024);

	if (l != 1024) {
		printf ("hmm. didnt' get 1024 bytes. \n"); 
	}

	l = sendscpi(sc, ":WAV:DATA? CHANNEL2", ch2, 1024);

	if (l != 1024) {
		printf ("hmm. didnt' get 1024 bytes. \n"); 
	}

	if (!gnuplot) {
		gnuplot = popen ("gnuplot", "w"); 
	}

	fp = fopen ("temp.dat", "w");
	for (i=0xd4;i<0x32c;i++)
		//for (i=0;i<0x400;i++)
		fprintf (fp, "%d %d\n", 255 - ch1[i], 255 - ch2[i]);
	fclose (fp); 

	fprintf (gnuplot, "plot 'temp.dat' using 1 with lines, 'temp.dat' using 2 with lines\n");
	fflush (gnuplot);
}


#define ERROR -1e100

double get_float_from_scope (struct usb_dev_handle *sc, char *var)
{
	unsigned char buf[1024];
	double temp;
	int l;

	l = sendscpi(sc, var, buf, 1024);
	if (l > 0) {
		sscanf ((char*)buf, "%lf", &temp); 
		return temp;
	}
	return ERROR;
}


void do_get_buf (struct usb_dev_handle *sc)
{
	FILE *fp;
	int i, j, l, bp;
	char buf[1024];
	unsigned char ch1[1024];
	unsigned char data[512*1024];
	double sampfreq;

	sendscpi (sc, ":STOP", NULL, 0); 

	sampfreq = get_float_from_scope (sc, ":ACQ:SAMP?");

	printf ("Got sampling freq: %g\n", sampfreq);  

	sprintf (buf, ":TIM:SCAL %.15f", 50 / sampfreq);
	printf ("sending scale cmd: %s\n", buf); 
	sendscpi (sc, buf, NULL, 0);

	sleep (1);

	bp=0;
	for (i=-254*1024;i< 254*1024;i += 600) {
		sprintf (buf, ":TIM:OFFSET %.15f", i / sampfreq);
		printf ("Sending offset cmd:  %s\n", buf); 
		sendscpi (sc, buf, NULL, 0);

		l = sendscpi(sc, ":WAV:DATA? CHANEL1", ch1, 1024);

		if (l != 1024) {
			printf ("hmm. didnt' get 1024 bytes. \n"); 
		}

		for (j=0;j<600;j++)
			data[bp++] = ch1[j+0xd4];
	}
	printf ("Got %d bytes of data. \n", bp);

	fp = fopen ("ch1.dump", "w");
	fwrite (data, bp, 1, fp);
	fclose (fp); 

	sendscpi (sc, ":TIM:OFFSET 0", NULL, 0);
}

void do_get_screen(struct usb_dev_handle *sc)
{
	unsigned char screen[320*234];
	time_t lt;
	char filename[256];
	unsigned char *png;
	int imglen;
	int ret;
	int l;
	int fd;
	pid_t display;

	/* Hide "RMT" from screen */
	l = sendscpi(sc, ":KEY:LOCK DISABLE", NULL, 0); 
	usleep(20000);

	l = sendscpi(sc, ":LCD:DATA?", screen, sizeof(screen));

	if (l != sizeof(screen)) {
		printf ("hmm. didnt' get %d bytes, but %d\n\n", sizeof(screen), l); 
	}

	png = lcd2png(screen, &imglen);

	lt = time(NULL);
	strftime(filename, sizeof(filename), "screen_%Y%m%d-%H%M%S.png", localtime(&lt));
	fd=open(filename, O_CREAT|O_WRONLY, 0644);
	if (fd == -1) {
		perror("open");
		exit(EXIT_FAILURE);
	}

	while(imglen > 0) {
		ret = write(fd, png, imglen);
		if (ret == -1) {
			perror("write");
			exit(EXIT_FAILURE);
		}
		imglen -= ret;
	}
	close(fd);
	free(png);

	printf("Waveform saved as %s\n", filename);

	display = fork();
	switch(display) {
		case 0:
			execlp("display", "display", filename, NULL);
			exit(0);
			break;
		case -1:
			perror("fork");
			break;
		default:
			break;
	}
}

void child_reaper(int sig)
{
	pid_t child;

	do {
		child = waitpid(-1, NULL, WNOHANG);
	} while(child > 0);
	
}

int main(int argc, char **argv) 
{
	struct usb_dev_handle *sc;
	char *scpi;
	unsigned char *buff;
	int l;
	struct sigaction act;

	//Init libusb
	usb_init();
	//Locate and open the scope
	sc=find_scope();
	if (!sc) {
		printf("No scope found.\n");
		exit(1);
	} else {
		printf("Scope found.\n");
	}
	//Initialize scope
	initscope(sc);
	buff = malloc (1024*1024); 
	if (buff == NULL) {
		perror("malloc");
		exit(EXIT_FAILURE);
	}

	bzero(&act, sizeof(act));
	act.sa_handler = child_reaper;
	act.sa_flags = SA_NOCLDSTOP|SA_RESTART;
	if (sigaction(SIGCHLD, &act, NULL) == -1) {
		perror("sigaction");
		exit(EXIT_FAILURE);
	}

	while (1) {
		scpi = readline ("> ");

		if (!scpi) break;
		if (strlen (scpi) == 0) {
			free (scpi); 
			continue;
		}

		add_history (scpi); 

		if (strncmp (scpi, "quit", 4) == 0) break;
		if (strncmp (scpi, "plot", 4) == 0) {
			do_plot (sc);
			continue;
		}
		if (strncmp (scpi, "databuf", 7) == 0) {
			do_get_buf (sc);
			continue;
		}
		if (strncmp (scpi, "screen", 6) == 0) {
			do_get_screen (sc);
			continue;
		}

		l = strlen (scpi); 
		//printf ("got buf(%d): ", l); 
		//printb (scpi, l+2); 
		if (strchr (scpi, '?')) {
			//printf ("Expecting reply\n");
			l = sendscpi(sc, scpi, buff, 1024*1024);
			//printf ("Got replylen = %d.\n", l); 
			buff[l] = 0; //zero-terminate
			printb (buff, l);
		} else {
			//printf ("No reply expected\n");
			l=sendscpi(sc,scpi,NULL,0);
		}
		free (scpi);
	}
	//Disable keylock, so the user doesn't have to press the 'force'-button
	l=sendscpi(sc, ":KEY:LOCK DISABLE",NULL,0); 

	//Free up and exit
	usb_release_interface(sc,0);
	usb_close(sc);
	return 0;
}