| /* 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; |
| // Not safe_poll: we want to exit on signal |
| while (!bb_got_signal && 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; |
| } |