LXR toybox/toys/net/microcom.c

   1/* microcom.c - Simple serial console.
   2 *
   3 * Copyright 2017 The Android Open Source Project.
   4
   5USE_MICROCOM(NEWTOY(microcom, "<1>1s:X", TOYFLAG_USR|TOYFLAG_BIN))
   6
   7config MICROCOM
   8  bool "microcom"
   9  default y
  10  help
  11    usage: microcom [-s SPEED] [-X] DEVICE
  12
  13    Simple serial console.
  14
  15    -s  Set baud rate to SPEED
  16    -X  Ignore ^@ (send break) and ^] (exit)
  17*/
  18
  19#define FOR_microcom
  20#include "toys.h"
  21
  22GLOBALS(
  23  char *s;
  24
  25  int fd;
  26  struct termios original_stdin_state, original_fd_state;
  27)
  28
  29// TODO: tty_sigreset outputs ansi escape sequences, how to disable?
  30static void restore_states(int i)
  31{
  32  tcsetattr(0, TCSAFLUSH, &TT.original_stdin_state);
  33  tcsetattr(TT.fd, TCSAFLUSH, &TT.original_fd_state);
  34}
  35
  36void microcom_main(void)
  37{
  38  struct pollfd fds[2];
  39  int i, speed;
  40
  41  if (!TT.s) speed = 115200;
  42  else speed = atoi(TT.s);
  43
  44  // Open with O_NDELAY, but switch back to blocking for reads.
  45  TT.fd = xopen(*toys.optargs, O_RDWR | O_NOCTTY | O_NDELAY);
  46  if (-1==(i = fcntl(TT.fd, F_GETFL, 0)) || fcntl(TT.fd, F_SETFL, i&~O_NDELAY))
  47    perror_exit_raw(*toys.optargs);
  48
  49  // Set both input and output to raw mode.
  50  xset_terminal(TT.fd, 1, speed, &TT.original_fd_state);
  51  set_terminal(0, 1, 0, &TT.original_stdin_state);
  52  // ...and arrange to restore things, however we may exit.
  53  sigatexit(restore_states);
  54
  55  fds[0].fd = TT.fd;
  56  fds[0].events = POLLIN;
  57  fds[1].fd = 0;
  58  fds[1].events = POLLIN;
  59
  60  while (poll(fds, 2, -1) > 0) {
  61    char buf[BUFSIZ];
  62
  63    // Read from connection, write to stdout.
  64    if (fds[0].revents) {
  65      ssize_t n = read(TT.fd, buf, sizeof(buf));
  66      if (n > 0) xwrite(0, buf, n);
  67      else break;
  68    }
  69
  70    // Read from stdin, write to connection.
  71    if (fds[1].revents) {
  72      if (read(0, buf, 1) != 1) break;
  73      if (!(toys.optflags & FLAG_X)) {
  74        if (!*buf) {
  75          tcsendbreak(TT.fd, 0);
  76          continue;
  77        } else if (*buf == (']'-'@')) break;
  78      }
  79      xwrite(TT.fd, buf, 1);
  80    }
  81  }
  82}
  83