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/* vi: set sw=4 ts=4: */
/*
* bare bones 'talk to modem' program - similar to 'cu -l $device'
* inspired by mgetty's microcom
*
* Copyright (C) 2007 by Vladimir Dronnikov <dronnikov@gmail.ru>
*
* Licensed under GPLv2, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
/* All known arches use small ints for signals */
static volatile smallint signalled;
static void signal_handler(int signo)
{
signalled = signo;
}
// set canonical tty mode
static void xget1(int fd, struct termios *t, struct termios *oldt)
{
tcgetattr(fd, oldt);
*t = *oldt;
cfmakeraw(t);
// t->c_lflag &= ~(ISIG|ICANON|ECHO|IEXTEN);
// t->c_iflag &= ~(BRKINT|IXON|ICRNL);
// t->c_oflag &= ~(ONLCR);
// t->c_cc[VMIN] = 1;
// t->c_cc[VTIME] = 0;
}
static int xset1(int fd, struct termios *tio, const char *device)
{
int ret = tcsetattr(fd, TCSANOW, tio);
if (ret) {
bb_perror_msg("can't tcsetattr for %s", device);
}
return ret;
}
int microcom_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int microcom_main(int argc, char **argv)
{
struct pollfd pfd[2];
int nfd;
int sfd;
/* #define sfd (pfd[0].fd) - gcc 4.2.1 is still not smart enough */
char *device_lock_file;
const char *opt_s = "9600";
speed_t speed;
const char *opt_t = "100"; // 0.1 sec timeout
unsigned timeout;
struct termios tio0, tiosfd, tio;
bool istty;
// fetch options
opt_complementary = "-1"; /* at least one arg should be there */
getopt32(argv, "s:t:", &opt_s, &opt_t);
argc -= optind;
argv += optind;
// check sanity
speed = xatou(opt_s);
timeout = xatou(opt_t);
device_lock_file = (char *)bb_basename(argv[0]);
// try to create lock file in /var/lock
device_lock_file = xasprintf("/var/lock/LCK..%s", device_lock_file);
sfd = open(device_lock_file, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL, 0644);
if (sfd < 0) {
if (errno == EEXIST)
bb_perror_msg_and_die("can't lock device");
// We don't abort on other errors: /var/lock can be
// non-writable or non-existent
if (ENABLE_FEATURE_CLEAN_UP)
free(device_lock_file);
device_lock_file = NULL;
} else {
// %4d to make mgetty happy. It treats 4-bytes lock files as binary,
// not text, PID. Making 5+ char file. Brrr...
char *s = xasprintf("%4d\n", getpid());
write(sfd, s, strlen(s));
if (ENABLE_FEATURE_CLEAN_UP)
free(s);
close(sfd);
}
// setup signals
sig_catch(SIGHUP, signal_handler);
sig_catch(SIGINT, signal_handler);
sig_catch(SIGTERM, signal_handler);
sig_catch(SIGPIPE, signal_handler);
// error exit code if we fail to open the device
signalled = 1;
// open device
sfd = open_or_warn(argv[0], O_RDWR | O_NOCTTY | O_NONBLOCK);
if (sfd < 0)
goto unlock_and_exit;
fcntl(sfd, F_SETFL, O_RDWR | O_NOCTTY);
/* put stdin to "raw mode" (if stdin is a TTY),
handle one character at a time */
istty = isatty(STDIN_FILENO);
if (istty) {
xget1(STDIN_FILENO, &tio, &tio0);
if (xset1(STDIN_FILENO, &tio, "stdin"))
goto close_unlock_and_exit;
// tcflush(STDIN_FILENO, TCIFLUSH);
timeout = -1; // tty input? -> set infinite timeout for poll()
}
// same thing for modem
xget1(sfd, &tio, &tiosfd);
// order device to hang up at exit
tio.c_cflag |= (CREAD|HUPCL);
// set device speed
cfsetspeed(&tio, tty_value_to_baud(speed));
if (xset1(sfd, &tio, argv[0]))
goto restore0_close_unlock_and_exit;
// main loop: check with poll(), then read/write bytes across
pfd[0].fd = sfd;
pfd[0].events = POLLIN;
pfd[1].fd = STDIN_FILENO;
pfd[1].events = POLLIN;
// TODO: on piped input should we treat NL as CRNL?!
signalled = 0;
// initially we have to poll() both stdin and device
nfd = 2;
while (!signalled && nfd && safe_poll(pfd, nfd, timeout) > 0) {
int i;
for (i = 0; i < nfd; ++i) {
if (pfd[i].revents & (POLLIN | POLLHUP)) {
// int fd;
char c;
// read a byte
if (safe_read(pfd[i].fd, &c, 1) < 1) {
// this can occur at the end of piped input
// from now we only poll() for device
nfd--;
continue;
}
// fd = STDOUT_FILENO;
// stdin requires additional processing
// (TODO: must be controlled by command line switch)
if (i) {
// ^@ sends Break
if (0 == c) {
tcsendbreak(sfd, 0);
continue;
}
// ^X exits
if (24 == c)
goto done;
// fd = sfd;
}
// write the byte
write(i ? sfd : STDOUT_FILENO, &c, 1);
// write(fd, &c, 1);
// give device a chance to get data
// wait 0.01 msec
// (TODO: seems to be arbitrary to me)
if (i)
usleep(10);
}
}
}
done:
tcsetattr(sfd, TCSANOW, &tiosfd);
restore0_close_unlock_and_exit:
if (istty) {
// tcflush(STDIN_FILENO, TCIFLUSH);
tcsetattr(STDIN_FILENO, TCSANOW, &tio0);
}
close_unlock_and_exit:
if (ENABLE_FEATURE_CLEAN_UP)
close(sfd);
unlock_and_exit:
// delete lock file
if (device_lock_file) {
unlink(device_lock_file);
if (ENABLE_FEATURE_CLEAN_UP)
free(device_lock_file);
}
return signalled;
}
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