serial_port.c

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#include "serial_port.h"

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

// IUCLC flag translates upper case to lower case (actually needed here?)
// but is not in POSIX and OSX
#ifndef IUCLC
#define IUCLC 0
#endif

//#define TRACE(type,fmt,args...)    fprintf(stderr, fmt, args)
#define TRACE(type,fmt,args...)
#define TRACE_ERROR 1

struct SerialPort *serial_port_new(void)
{
  struct SerialPort *me = malloc(sizeof(struct SerialPort));
  return me;
}

void serial_port_free(struct SerialPort *me)
{
  free(me);
}


void serial_port_flush(struct SerialPort *me)
{
  /*
   * flush any input that might be on the port so we start fresh.
   */
  if (tcflush(me->fd, TCIFLUSH)) {
    TRACE(TRACE_ERROR, "%s, set term attr failed: %s (%d)\n", "", strerror(errno), errno);
    fprintf(stderr, "flush (%d) failed: %s (%d)\n", me->fd, strerror(errno), errno);
  }
}

void serial_port_flush_output(struct SerialPort *me)
{
  /*
   * flush any input that might be on the port so we start fresh.
   */
  if (tcflush(me->fd, TCOFLUSH)) {
    TRACE(TRACE_ERROR, "%s, set term attr failed: %s (%d)\n", "", strerror(errno), errno);
    fprintf(stderr, "flush (%d) failed: %s (%d)\n", me->fd, strerror(errno), errno);
  }
}

int  serial_port_open_raw(struct SerialPort *me, const char *device, speed_t speed)
{
  if ((me->fd = open(device, O_RDWR | O_NONBLOCK | O_NOCTTY)) < 0) {
    TRACE(TRACE_ERROR, "%s, open failed: %s (%d)\n", device, strerror(errno), errno);
    return -1;
  }
  if (tcgetattr(me->fd, &me->orig_termios) < 0) {
    TRACE(TRACE_ERROR, "%s, get term settings failed: %s (%d)\n", device, strerror(errno), errno);
    close(me->fd);
    return -1;
  }
  me->cur_termios = me->orig_termios;
  /* input modes  */
  me->cur_termios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | INPCK | ISTRIP | INLCR | IGNCR
                               | ICRNL | IUCLC | IXON | IXANY | IXOFF | IMAXBEL);
  me->cur_termios.c_iflag |= IGNPAR;
  /* control modes*/
  me->cur_termios.c_cflag &= ~(CSIZE | PARENB | CRTSCTS | PARODD | HUPCL | CSTOPB);
  me->cur_termios.c_cflag |= CREAD | CS8 | CLOCAL;
  /* local modes  */
  me->cur_termios.c_lflag &= ~(ISIG | ICANON | IEXTEN | ECHO | FLUSHO | PENDIN);
  me->cur_termios.c_lflag |= NOFLSH;
  /* output modes */
  me->cur_termios.c_oflag &=~(OPOST|ONLCR|OCRNL|ONOCR|ONLRET);

  if (cfsetispeed(&me->cur_termios, speed)) {
    TRACE(TRACE_ERROR, "%s, set term speed failed: %s (%d)\n", device, strerror(errno), errno);
    close(me->fd);
    return -1;
  }
  if (tcsetattr(me->fd, TCSADRAIN, &me->cur_termios)) {
    TRACE(TRACE_ERROR, "%s, set term attr failed: %s (%d)\n", device, strerror(errno), errno);
    close(me->fd);
    return -1;
  }
  serial_port_flush(me);
  return 0;
}

int  serial_port_open(struct SerialPort *me, const char *device,
                      void(*term_conf_callback)(struct termios *, speed_t *))
{

  speed_t speed;
  if ((me->fd = open(device, O_RDWR | O_NONBLOCK)) < 0) {
    TRACE(TRACE_ERROR, "%s, open failed: %s (%d)\n", device, strerror(errno), errno);
    return -1;
  }
  if (tcgetattr(me->fd, &me->orig_termios) < 0) {
    TRACE(TRACE_ERROR, "%s, get term settings failed: %s (%d)\n", device, strerror(errno), errno);
    close(me->fd);
    return -1;
  }
  me->cur_termios = me->orig_termios;
  term_conf_callback(&me->cur_termios, &speed);
  if (cfsetispeed(&me->cur_termios, speed)) {
    TRACE(TRACE_ERROR, "%s, set term speed failed: %s (%d)\n", device, strerror(errno), errno);
    close(me->fd);
    return -1;
  }
  if (tcsetattr(me->fd, TCSADRAIN, &me->cur_termios)) {
    TRACE(TRACE_ERROR, "%s, set term attr failed: %s (%d)\n", device, strerror(errno), errno);
    close(me->fd);
    return -1;
  }
  serial_port_flush(me);
  return 0;

}

void serial_port_close(struct SerialPort *me)
{

  /* if null pointer or file descriptor indicates error just bail */
  if (!me || me->fd < 0) {
    return;
  }
  if (tcflush(me->fd, TCIOFLUSH)) {
    TRACE(TRACE_ERROR, "flushing (%s) (%d)\n", strerror(errno), errno);
    close(me->fd);
    return;
  }
  if (tcsetattr(me->fd, TCSADRAIN, &me->orig_termios)) {        // Restore modes.
    TRACE(TRACE_ERROR, "restoring term attributes (%s) (%d)\n", strerror(errno), errno);
    close(me->fd);
    return;
  }
  if (close(me->fd)) {
    TRACE(TRACE_ERROR, "closing %s (%d)\n", strerror(errno), errno);
    return;
  }
  return;


}