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/* microcom.c - Simple serial console.
*
* Copyright 2017 The Android Open Source Project.
USE_MICROCOM(NEWTOY(microcom, "<1>1s:X", TOYFLAG_BIN))
config MICROCOM
bool "microcom"
default n
help
usage: microcom [-s SPEED] [-X]
Simple serial console.
-s Set baud rate to SPEED
-X Ignore ^@ (send break) and ^X (exit).
*/
#define FOR_microcom
#include "toys.h"
GLOBALS(
char *speed;
int fd;
struct termios original_stdin_state, original_fd_state;
)
// Puts `fd` into raw mode, setting the baud rate if `speed` != 0,
// and saving the original terminal state.
static void xraw(int fd, const char *name, speed_t speed,
struct termios *original)
{
struct termios t;
if (tcgetattr(fd, &t)) perror_exit("tcgetattr %s", name);
*original = t;
cfmakeraw(&t);
if (speed && cfsetspeed(&t, speed)) perror_exit("cfsetspeed");
if (tcsetattr(fd, TCSAFLUSH, &t)) perror_exit("tcsetattr %s", name);
}
static void restore_states(int i)
{
tcsetattr(0, TCSAFLUSH, &TT.original_stdin_state);
tcsetattr(TT.fd, TCSAFLUSH, &TT.original_fd_state);
}
void microcom_main(void)
{
speed_t speed = B115200;
struct pollfd fds[2];
int flags;
// TODO: move this into lib and support all known baud rates?
if (TT.speed) {
switch (atolx(TT.speed)) {
case 9600: speed = B9600; break;
case 19200: speed = B19200; break;
case 38400: speed = B38400; break;
case 115200: speed = B115200; break;
default: error_exit("unknown speed: %s", TT.speed);
}
}
// Open with O_NDELAY, but switch back to blocking for reads.
TT.fd = xopen(*toys.optargs, O_RDWR | O_NOCTTY | O_NDELAY);
flags = fcntl(TT.fd, F_GETFL, 0);
if (flags == -1) perror_exit("fcntl F_GETFL");
if (fcntl(TT.fd, F_SETFL, flags & ~O_NDELAY)) perror_exit("fcntl F_SETFL");
// Set both input and output to raw mode.
xraw(TT.fd, "fd", speed, &TT.original_fd_state);
xraw(0, "stdin", 0, &TT.original_stdin_state);
// ...and arrange to restore things, however we may exit.
sigatexit(restore_states);
fds[0].fd = TT.fd;
fds[0].events = POLLIN;
fds[1].fd = 0;
fds[1].events = POLLIN;
while (poll(fds, 2, -1) > 0) {
char buf[BUFSIZ];
// Read from connection, write to stdout.
if (fds[0].revents) {
ssize_t n = read(TT.fd, buf, sizeof(buf));
if (n > 0) xwrite(0, buf, n);
else break;
}
// Read from stdin, write to connection.
if (fds[1].revents) {
if (read(0, buf, 1) == 1) {
if (buf[0] == 0) tcsendbreak(TT.fd, 0);
else if (buf[0] == ('X'-'@')) break;
else xwrite(TT.fd, buf, 1);
} else break;
}
}
}
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