#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <stdlib.h>
#include <string.h>


 /* rs232io.c   with no CR LF after output
  * configuration: edit to suit your needs
  * could be done at runtime by reading from a file
  */

#ifdef OLD_PTY
/* may be set with preprocessor flags */
#ifndef DEVICE
//#define DEVICE		"/dev/ttyS0"
#define DEVICE	"/dev/ttyS1"
#endif
#endif

//#define BAUDRATE	B115200
#define BAUDRATE	B9600

//#define ARGPOSTFIX	"\r\n"
#define ARGPOSTFIX	""

void send(int fd,const char *buf,int len) {
  int c = write(fd,buf,len);
  if(c != len) {
    fprintf(stderr,"*** write: %s\n",strerror(errno));
    exit(1);
  }
}

int main(int argc,char* argv[]) {
  int fd;
  struct termios oldtio,newtio;
  char *device;

#ifdef OLD_PTY
  device = DEVICE;
#else
  device = getenv("DEVICE");
  if(device != 0) {
  } else {
    char dev[64];
    int len1;
    FILE *fp = fopen("/tmp/rs232dev","r");
    if(fp == 0) {
      fprintf(stderr,"*** fopen /tmp/rs232dev: %s\n",strerror(errno));
      exit(-1);
    }
    if(fgets(dev,sizeof(dev),fp) == 0) {
      fprintf(stderr,"*** fgets: %s\n",strerror(errno));
      exit(-1);
    }
    fclose(fp);
    len1 = strlen(dev)-1;
    if(dev[strlen(dev)-1] == '\n')
      dev[len1] = 0;
    device = dev;
  }
#endif
  fd = open(device,O_RDWR);
  if(fd < 0) {
    fprintf(stderr,"*** open %s: %s\n",device,strerror(errno));
    exit(-1);
  }

  /* set correct baudrate, etc ...
   * (WARNING: doesn't work because the kernel has no support for that yet)
   */
  tcgetattr(fd,&oldtio);	/* save current port settings */

  bzero(&newtio,sizeof(newtio));
  newtio.c_cflag = (CS8 | CREAD | CLOCAL | CRTSCTS);
  newtio.c_lflag = 0;
  newtio.c_iflag = IGNPAR;
  newtio.c_oflag = 0;
  cfsetospeed(&newtio,BAUDRATE);
  newtio.c_cc[VTIME] = 0;	/* inter-character timer unused */
  newtio.c_cc[VMIN] = 1;	/* blocking read until 1 char received */
      
  tcflush(fd,TCIFLUSH);
  tcsetattr(fd,TCSANOW,&newtio);

  if(argc > 1) {
    int postlen = strlen(ARGPOSTFIX);
    int i;

    for(i = 1; i < argc; i++) {
      send(fd,argv[i],strlen(argv[i]));
      if(postlen)
	send(fd,ARGPOSTFIX,postlen);
    }
  } else {
    char buf[512];

    while(1) {
      int count = fread(buf,1,sizeof(buf),stdin);
      if(count == 0) {
	if(feof(stdin))
	  break;
	fprintf(stderr,"*** read: %s\n",strerror(errno));
	return 1;
      }
#if 0
      {
	int i;

	fprintf(stderr,"got %d bytes:",count);
	for(i = 0; i < count; i++)
	  fprintf(stderr," %d(0x%02x)",buf[i],buf[i]);
	fprintf(stderr,"\n");
      }
#endif
      send(fd,buf,count);
    }
  }
  return 0;
}