text: /* vi: set sw=4 ts=4: */
  /*
   * shows keys pressed. inspired by kbd package
   *
   * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
   *
   * Licensed under GPLv2, see file LICENSE in this source tree.
   */
  
  //usage:#define showkey_trivial_usage
  //usage:       "[-a | -k | -s]"
  //usage:#define showkey_full_usage "\n\n"
  //usage:       "Show keys pressed\n"
  //usage:     "\n	-a	Display decimal/octal/hex values of the keys"
  //usage:     "\n	-k	Display interpreted keycodes (default)"
  //usage:     "\n	-s	Display raw scan-codes"
  
  #include "libbb.h"
  #include <linux/kd.h>
  
  
  struct globals {
  	int kbmode;
  	struct termios tio, tio0;
  };
  #define G (*ptr_to_globals)
  #define kbmode (G.kbmode)
  #define tio    (G.tio)
  #define tio0   (G.tio0)
  #define INIT_G() do { \
  	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
  } while (0)
  
  
  // set raw tty mode
  // also used by microcom
  // libbb candidates?
  static void xget1(struct termios *t, struct termios *oldt)
  {
  	tcgetattr(STDIN_FILENO, oldt);
  	*t = *oldt;
  	cfmakeraw(t);
  }
  
  static void xset1(struct termios *t)
  {
  	int ret = tcsetattr(STDIN_FILENO, TCSAFLUSH, t);
  	if (ret) {
  		bb_perror_msg("can't tcsetattr for stdin");
  	}
  }
  
  int showkey_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  int showkey_main(int argc UNUSED_PARAM, char **argv)
  {
  	enum {
  		OPT_a = (1<<0), // display the decimal/octal/hex values of the keys
  		OPT_k = (1<<1), // display only the interpreted keycodes (default)
  		OPT_s = (1<<2), // display only the raw scan-codes
  	};
  
  	INIT_G();
  
  	// FIXME: aks are all mutually exclusive
  	getopt32(argv, "aks");
  
  	// prepare for raw mode
  	xget1(&tio, &tio0);
  	// put stdin in raw mode
  	xset1(&tio);
  
  #define press_keys "Press any keys, program terminates %s:\r\n\n"
  
  	if (option_mask32 & OPT_a) {
  		// just read stdin char by char
  		unsigned char c;
  
  		printf(press_keys, "on EOF (ctrl-D)");
  
  		// read and show byte values
  		while (1 == read(STDIN_FILENO, &c, 1)) {
  			printf("%3u 0%03o 0x%02x\r\n", c, c, c);
  			if (04 /*CTRL-D*/ == c)
  				break;
  		}
  	} else {
  		// we assume a PC keyboard
  		xioctl(STDIN_FILENO, KDGKBMODE, &kbmode);
  		printf("Keyboard mode was %s.\r\n\n",
  			kbmode == K_RAW ? "RAW" :
  				(kbmode == K_XLATE ? "XLATE" :
  					(kbmode == K_MEDIUMRAW ? "MEDIUMRAW" :
  						(kbmode == K_UNICODE ? "UNICODE" : "UNKNOWN")))
  		);
  
  		// set raw keyboard mode
  		xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)((option_mask32 & OPT_k) ? K_MEDIUMRAW : K_RAW));
  
  		// we should exit on any signal; signals should interrupt read
  		bb_signals_recursive_norestart(BB_FATAL_SIGS, record_signo);
  
  		// inform user that program ends after time of inactivity
  		printf(press_keys, "10s after last keypress");
  
  		// read and show scancodes
  		while (!bb_got_signal) {
  			char buf[18];
  			int i, n;
  
  			// setup 10s watchdog
  			alarm(10);
  
  			// read scancodes
  			n = read(STDIN_FILENO, buf, sizeof(buf));
  			i = 0;
  			while (i < n) {
  				if (option_mask32 & OPT_s) {
  					// show raw scancodes
  					printf("0x%02x ", buf[i++]);
  				} else {
  					// show interpreted scancodes (default)
  					char c = buf[i];
  					int kc;
  					if (i+2 < n
  					 && (c & 0x7f) == 0
  					 && (buf[i+1] & 0x80) != 0
  					 && (buf[i+2] & 0x80) != 0
  					) {
  						kc = ((buf[i+1] & 0x7f) << 7) | (buf[i+2] & 0x7f);
  						i += 3;
  					} else {
  						kc = (c & 0x7f);
  						i++;
  					}
  					printf("keycode %3u %s", kc, (c & 0x80) ? "release" : "press");
  				}
  			}
  			puts("\r");
  		}
  
  		// restore keyboard mode
  		xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)kbmode);
  	}
  
  	// restore console settings
  	xset1(&tio0);
  
  	return EXIT_SUCCESS;
  }
  