79 lines
1.2 KiB
C
79 lines
1.2 KiB
C
/*
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* getkey.c - Single-key TTY input
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*
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* Written 2010 by Werner Almesberger
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* Copyright 2010 Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <termios.h>
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#include <sys/types.h>
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#include "getkey.h"
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#define TTY_NAME "/dev/tty"
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static int tty = -1;
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static struct termios old;
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static void reset_tty(void)
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{
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if (tty >= 0)
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if (tcsetattr(tty, TCSADRAIN, &old) < 0)
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perror("tcsetattr");
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}
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static void tty_open(void)
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{
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struct termios new;
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tty = open(TTY_NAME, O_RDONLY | O_NOCTTY);
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if (tty < 0) {
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perror(TTY_NAME);
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exit(1);
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}
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if (tcgetattr(tty, &old) < 0) {
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perror("tcgetattr");
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exit(1);
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}
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atexit(reset_tty);
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new = old;
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cfmakeraw(&new);
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if (tcsetattr(tty, TCSANOW, &new) < 0) {
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perror("tcsetattr");
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exit(1);
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}
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}
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char getkey(void)
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{
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char buf;
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ssize_t got;
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if (tty == -1)
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tty_open();
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got = read(tty, &buf, 1);
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if (got < 0) {
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perror("read");
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reset_tty();
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exit(1);
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}
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return got ? buf : 0;
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}
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