/* vi: set sw=4 ts=4: */ /* * bare bones 'talk to modem' program - similar to 'cu -l $device' * inspired by mgetty's microcom * * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com> * * Licensed under GPLv2, see file LICENSE in this tarball for details. */ #include "libbb.h" // set raw 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, TCSAFLUSH, 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 UNUSED_PARAM, char **argv) { int sfd; int nfd; struct pollfd pfd[2]; struct termios tio0, tiosfd, tio; char *device_lock_file; enum { OPT_X = 1 << 0, // do not respect Ctrl-X, Ctrl-@ OPT_s = 1 << 1, // baudrate OPT_d = 1 << 2, // wait for device response, ms OPT_t = 1 << 3, // timeout, ms }; speed_t speed = 9600; int delay = -1; int timeout = -1; unsigned opts; // fetch options opt_complementary = "=1:s+:d+:t+"; // exactly one arg, numeric options opts = getopt32(argv, "Xs:d:t:", &speed, &delay, &timeout); // argc -= optind; argv += optind; // try to create lock file in /var/lock device_lock_file = (char *)bb_basename(argv[0]); 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) { // device already locked -> bail out if (errno == EEXIST) bb_perror_msg_and_die("can't create %s", device_lock_file); // can't create lock -> don't care if (ENABLE_FEATURE_CLEAN_UP) free(device_lock_file); device_lock_file = NULL; } else { // %4d to make concurrent mgetty (if any) happy. // Mgetty treats 4-bytes lock files as binary, // not text, PID. Making 5+ char file. Brrr... fdprintf(sfd, "%4d\n", getpid()); close(sfd); } // setup signals bb_signals(0 + (1 << SIGHUP) + (1 << SIGINT) + (1 << SIGTERM) + (1 << SIGPIPE) , record_signo); // error exit code if we fail to open the device bb_got_signal = 1; // open device sfd = open_or_warn(argv[0], O_RDWR | O_NOCTTY | O_NONBLOCK); if (sfd < 0) goto done; fcntl(sfd, F_SETFL, O_RDWR); // put device to "raw mode" xget1(sfd, &tio, &tiosfd); // set device speed cfsetspeed(&tio, tty_value_to_baud(speed)); if (xset1(sfd, &tio, argv[0])) goto done; // put stdin to "raw mode" (if stdin is a TTY), // handle one character at a time if (isatty(STDIN_FILENO)) { xget1(STDIN_FILENO, &tio, &tio0); if (xset1(STDIN_FILENO, &tio, "stdin")) goto done; } // 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; bb_got_signal = 0; nfd = 2; while (!bb_got_signal && safe_poll(pfd, nfd, timeout) > 0) { if (nfd > 1 && pfd[1].revents) { char c; // read from stdin -> write to device if (safe_read(STDIN_FILENO, &c, 1) < 1) { // don't poll stdin anymore if we got EOF/error nfd--; goto skip_write; } // do we need special processing? if (!(opts & OPT_X)) { // ^@ sends Break if (VINTR == c) { tcsendbreak(sfd, 0); goto skip_write; } // ^X exits if (24 == c) break; } write(sfd, &c, 1); if (delay >= 0) safe_poll(pfd, 1, delay); skip_write: ; } if (pfd[0].revents) { #define iobuf bb_common_bufsiz1 ssize_t len; // read from device -> write to stdout len = safe_read(sfd, iobuf, sizeof(iobuf)); if (len > 0) full_write(STDOUT_FILENO, iobuf, len); else { // EOF/error -> bail out bb_got_signal = SIGHUP; break; } } } // restore device mode tcsetattr(sfd, TCSAFLUSH, &tiosfd); if (isatty(STDIN_FILENO)) tcsetattr(STDIN_FILENO, TCSAFLUSH, &tio0); done: if (device_lock_file) unlink(device_lock_file); return bb_got_signal; }