| estabroo |
09-11-2010 10:53 PM |
Code:
/*
* siso
* like a breakout box for serial connections
* put the computer running siso in the data
* flow of a serial connection
* PC -> serial -> PC(siso) -> serial -> device
*
* selectable items are
* -b baud_rate
* -f logfile
* -i input_serial_device
* -o output_serial_device
*
* default connection is
* 9600 8N1 ttyS0 to ttyS1
*
*/
/* this is for snprintf (under debian) */
#define _ISOC99_SOURCE 1
#define _POSIX_SOURCE 1
#include <stdio.h>
#include <termios.h>
#include <sys/types.h>
#include <errno.h>
#include <sys/poll.h>
#include <fcntl.h>
#include <unistd.h>
#include <getopt.h>
#include <syslog.h>
#define DEFAULT_SERIAL_IN_PORT "/dev/ttyS0"
#define DEFAULT_SERIAL_OUT_PORT "/dev/ttyS1"
int
set_baud(char* baud_s) {
int b;
int baud;
b = atoi(baud_s);
switch (b) {
case 300 : baud = B300; break;
case 1200 : baud = B1200; break;
case 2400 : baud = B2400; break;
case 9600 : baud = B9600; break;
case 19200 : baud = B19200; break;
case 38400 : baud = B38400; break;
case 57600 : baud = B57600; break;
case 115200 : baud = B115200; break;
default : baud = 0;
};
return baud;
}
int main (int argc, char* argv[]) {
int err;
int fdi;
int fdo;
int fdl;
int opt;
int n;
int baud;
char buf[8];
char log[1024];
char s_in[128];
char s_out[128];
char buffer[2048];
struct pollfd poll_fd[2];
struct termios info;
openlog("SiSo", LOG_PID, LOG_USER);
/* setup defaults */
baud = B9600;
snprintf(s_in, sizeof(s_in), "%s", DEFAULT_SERIAL_IN_PORT);
snprintf(s_out, sizeof(s_out), "%s", DEFAULT_SERIAL_OUT_PORT);
for(opt=getopt(argc, argv, "f:i:o:b:"); opt != -1;
opt=getopt(argc, argv, "f:i:o:b:")) {
switch (opt) {
case 'b' : { /* set baud rate */
n = snprintf(buf, sizeof(buf), "%s", optarg);
if (n < 0 || n > sizeof(buf)) {
syslog(LOG_ERR, "couldn't convert -b option into a baud rate");
return n;
}
baud = set_baud(buf);
if (baud == 0) {
syslog(LOG_ERR, "baud rate [%s] not supported", buf);
return 0;
}
}; break;
case 'f' : { /* output file */
n = snprintf(log, sizeof(log), "%s", optarg);
if (n < 0 || n > sizeof(log)) {
syslog(LOG_ERR, "output filename truncated, longer than %d bytes", sizeof(log));
closelog();
return n;
}
}; break;
case 'i' : { /* serial input device */
n = snprintf(s_in, sizeof(s_in), "%s", optarg);
if (n < 0 || n > sizeof(s_in)) {
syslog(LOG_ERR, "output filename truncated, longer than %d bytes",
sizeof(s_in));
closelog();
return n;
}
}; break;
case 'o' : { /* serial output device */
n = snprintf(s_in, sizeof(s_out), "%s", optarg);
if (n < 0 || n > sizeof(s_out)) {
syslog(LOG_ERR, "output filename truncated, longer than %d bytes",
sizeof(s_out));
closelog();
return n;
}
}; break;
}; /* end switch */
} /* end for */
fdi = open (s_in, O_RDWR);
if (fdi < 0) {
syslog(LOG_ERR, "couldn't open %s : %m", s_in);
exit(0);
}
fdo = open (s_out, O_RDWR);
if (fdo < 0) {
syslog(LOG_ERR, "couldn't open %s : %m", s_out);
exit(0);
}
fdl = open(log, O_RDWR|O_CREAT);
if (fdl < 0) {
syslog(LOG_ERR, "couldn't open %s : %m", log);
exit(0);
}
/* set up modem connection */
err = tcgetattr(fdi, &info);
info.c_cflag = (CS8 | CREAD) & ~PARENB; /* 8N1 */
info.c_iflag |= IXON | IXOFF;
info.c_lflag &= ~ICANON & ~ISIG;
err = cfsetospeed(&info, baud);
err = cfsetispeed(&info, baud);
err = tcsetattr(fdi, TCSANOW, &info);
/* set up serial connection */
err = tcgetattr(fdo, &info);
info.c_cflag = (CS8 | CREAD) & ~PARENB; /* 8N1 */
info.c_iflag |= IXON | IXOFF;
info.c_lflag &= ~ICANON & ~ISIG;
err = cfsetospeed(&info, baud);
err = cfsetispeed(&info, baud);
err = tcsetattr(fdo, TCSANOW, &info);
/* set up poll structure */
poll_fd[0].fd = fdi;
poll_fd[1].fd = fdo;
poll_fd[0].events = POLLIN;
poll_fd[1].events = POLLIN;
poll_fd[0].revents = 0;
poll_fd[1].revents = 0;
/* main loop */
while (1) {
n = poll(poll_fd, 2, -1); /* wait here */
if (n < 0) {
break;
}
if (poll_fd[0].revents & POLLIN) {
n = read(poll_fd[0].fd, buffer, sizeof(buffer));
if (n > 0) {
write(poll_fd[1].fd, buffer, n);
write(fdl, buffer, n);
}
poll_fd[0].revents = 0;
}
if (poll_fd[1].revents & POLLIN) {
n = read(poll_fd[1].fd, buffer, sizeof(buffer));
if (n > 0) {
write(poll_fd[0].fd, buffer, n);
write(fdl, buffer, n);
}
poll_fd[1].revents = 0;
}
}
close(fdl);
close(fdi);
close(fdo);
exit(0);
}
|
