Listing 2: keyfree.c

/* keyfree.c
*
* A program to unlock the keyboard on another
*      terminal.
*
* Make:        cc -o keyfree -O keyfree.c
* Usage:       keyfree <tty_pathname>
* Example:     keyfree /dev/tty1d
*/

#include <stdio.h>

#define CTRLQ1 0x11
#define CTRLQ2 0x91

#define ESCAPE 0x1B

#define CTRLB  0x02

#define CTRLF  0x07

main(argc, argv)
int     argc;
char    **argv;
{
FILE    *outfile;
int     status;

/*
* Check the command line and open the tty line
* as a stream I/O file.
*/

if (argc < 2)
{
fprintf(stderr,
"Usage:\t%s <tty_pathname>\n",
argv[0]);
exit(1);
}
if (!(outfile = fopen(argv[1], "a")))
{
perror(argv[1]);
fprintf(stderr,
"Usage:\t%s <tty_pathname>\n",
argv[0]);
exit(1);
}
/*
* First, send a control-Q and a control-Q
*      with the high bit set.
*
* This will restart data from the terminal
*      to the host if the problem
*      is caused by a flow control lock in
*      the terminal, multiplexer, or modem.
*/

fprintf(outfile, "%c\"", CTRLQ1);
fprintf(outfile, "%c\"", CTRLQ2);

/*
* Next, send the command that unlocks
* the keyboard on any of several types
* of keyboards.
*/

/* ASCII type terminals, including Wyse 50, 60, 350,
TeleVideo 9xx, Qume QVT, Freedom 1, 100, 200, etc. */
/* Escape, double-quote */

fprintf(outfile, "%c\"", ESCAPE);

/* ANSI type terminals, including
*      DEC vt100, vt220, vt320, vt420, Visual 603,
*      Altos 3 and 5, Wyse 75, 285, 370, Consoles,
*      and PC terminal emulators */
/* Escape, left-bracket, two, lower-case-ell */
fprintf(outfile, "%c[2l", ESCAPE);
/* Escape, left-bracket, question-mark, two,
lower-case-ell */
fprintf(outfile, "%c[?2l", ESCAPE);

/* HP terminals like the 2390 and the 2626 */
/* Escape, lower-case-bee */
fprintf(outfile, "%cb", ESCAPE);

/* Some NCR and ADDS terminals */
/* Escape, six */
fprintf(outfile, "%c6", ESCAPE);

/* Some other NCR and ADDS terminals */
/* Control-B */
fprintf(outfile, "%c", CTRLB);

/* IBM terminals in the 31xx series */
/* Escape, semi-colon */
fprintf(outfile, "%c;", ESCAPE);

/* Hazeltine 1500 */
/* tilde, control-F */
fprintf(outfile, "~%c", CTRLF);

/*
* Flush the line and close.
*/
fflush(outfile);
fclose(outfile);
}

/* End of File */