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_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// Puts `fd` into raw mode, setting the baud rate if `speed` != 0,
  30// and saving the original terminal state.
  31static void xraw(int fd, const char *name, speed_t speed,
  32                 struct termios *original)
  33{
  34  struct termios t;
  35
  36  if (tcgetattr(fd, &t)) perror_exit("tcgetattr %s", name);
  37  *original = t;
  38
  39  cfmakeraw(&t);
  40  if (speed) cfsetspeed(&t, speed);
  41
  42  if (tcsetattr(fd, TCSAFLUSH, &t)) perror_exit("tcsetattr %s", name);
  43}
  44
  45static void restore_states(int i)
  46{
  47  tcsetattr(0, TCSAFLUSH, &TT.original_stdin_state);
  48  tcsetattr(TT.fd, TCSAFLUSH, &TT.original_fd_state);
  49}
  50
  51void microcom_main(void)
  52{
  53  int speeds[] = {50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400,
  54                  4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800,
  55                  500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000,
  56                  2500000, 3000000, 3500000, 4000000};
  57  struct pollfd fds[2];
  58  int i, speed;
  59
  60  if (!TT.s) speed = 115200;
  61  else speed = atoi(TT.s);
  62
  63  // Find speed in table, adjust to constant
  64  for (i = 0; i < ARRAY_LEN(speeds); i++) if (speeds[i] == speed) break;
  65  if (i == ARRAY_LEN(speeds)) error_exit("unknown speed: %s", TT.s);
  66  speed = i+1+4081*(i>15);
  67
  68  // Open with O_NDELAY, but switch back to blocking for reads.
  69  TT.fd = xopen(*toys.optargs, O_RDWR | O_NOCTTY | O_NDELAY);
  70  if (-1==(i = fcntl(TT.fd, F_GETFL, 0)) || fcntl(TT.fd, F_SETFL, i&~O_NDELAY))
  71    perror_exit_raw(*toys.optargs);
  72
  73  // Set both input and output to raw mode.
  74  xraw(TT.fd, "fd", speed, &TT.original_fd_state);
  75  xraw(0, "stdin", 0, &TT.original_stdin_state);
  76  // ...and arrange to restore things, however we may exit.
  77  sigatexit(restore_states);
  78
  79  fds[0].fd = TT.fd;
  80  fds[0].events = POLLIN;
  81  fds[1].fd = 0;
  82  fds[1].events = POLLIN;
  83
  84  while (poll(fds, 2, -1) > 0) {
  85    char buf[BUFSIZ];
  86
  87    // Read from connection, write to stdout.
  88    if (fds[0].revents) {
  89      ssize_t n = read(TT.fd, buf, sizeof(buf));
  90      if (n > 0) xwrite(0, buf, n);
  91      else break;
  92    }
  93
  94    // Read from stdin, write to connection.
  95    if (fds[1].revents) {
  96      if (read(0, buf, 1) != 1) break;
  97      if (!(toys.optflags & FLAG_X)) {
  98        if (!*buf) {
  99          tcsendbreak(TT.fd, 0);
 100          continue;
 101        } else if (*buf == (']'-'@')) break;
 102      }
 103      xwrite(TT.fd, buf, 1);
 104    }
 105  }
 106}
 107