/**
 * Created by Peter Stuge <peter@stuge.se> and placed in the Public Domain.
 *
 * To compile:
 *   gcc -O2 -o io io.c
 * To use (as root):
 *   read from port 0x80: ./io r80
 *   write 0x69 to port 0x80: ./io w80=69
 *
 * Multiple commands can be given at once, any whitespace will be ignored.
 */
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/time.h>
#include <sys/types.h>
#include <errno.h>
#include <string.h>

#if defined(__FreeBSD__)
#include <machine/cpufunc.h>
void do_outb(unsigned char d,u_int p) {
  outb(p,d);
}
unsigned char do_inb(u_int p) {
  return inb(p);
}
#else
#include <sys/io.h>
void do_outb(unsigned char d,unsigned short p) {
  outb(d,p);
}
unsigned char do_inb(unsigned short p) {
  return inb(p);
}
#endif

void ib(unsigned short p) {
  static unsigned short op=0;
  static unsigned char oc=0;
  unsigned char c;
  c=do_inb(p);
  printf("r0x%04x=%02x\n",p,c);
  oc=c;
  op=p;
}

void ob(unsigned short p,unsigned char c) {
  static unsigned short op=0;
  static unsigned char oc=0;
  do_outb(c,p);
  printf("w0x%04x=%02x\n",p,c);
  oc=c;
  op=p;
}

int main(int argc,char *argv[]) {
  char *s;
  int ret,arg=1;
#if defined(__FreeBSD__)
  int iofd;
#endif
  unsigned int i,j;
  unsigned char c;
  if(argc<2)
    return 0;
#if defined(__FreeBSD__)
  if((iofd=open("/dev/io",O_RDWR))<0) {
#else
  if(iopl(3)) {
#endif
    perror("iopl");
    return 1;
  }
  for(s=argv[arg];*s;) {
    switch(*(s++)) {
    case 'r':
      if(1!=(ret=sscanf(s,"%x%n",&i,&j))) {
        fprintf(stderr,"sscanf=%d: %s\n",ret,strerror(errno));
        return 1;
      }
      ib(i);
      s+=j;
      usleep(10000);
      break;
    case 'w':
      if(2!=(ret=sscanf(s,"%x=%hhx%n",&i,&c,&j))) {
        fprintf(stderr,"sscanf=%d: %s\n",ret,strerror(errno));
        return 1;
      }
      ob(i,c);
      s+=j;
      usleep(1000);
      break;
    default:
      printf("unknown command '%c'\n",*(s-1));
      break;
    }
    if(!*s&&arg<argc-1)
      s=argv[++arg];
  }
#if defined(__FreeBSD__)
  close(iofd);
#else
  iopl(0);
#endif
  return 0;
}