diff options
| -rw-r--r-- | toys/pending/microcom.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/toys/pending/microcom.c b/toys/pending/microcom.c new file mode 100644 index 00000000..d41a9a21 --- /dev/null +++ b/toys/pending/microcom.c @@ -0,0 +1,104 @@ +/* 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; + } + } +} |