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158 lines
4.6 KiB
C
158 lines
4.6 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Utility routines.
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*
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* Copyright (C) 2008 Rob Landley <rob@landley.net>
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* Copyright (C) 2008 Denys Vlasenko <vda.linux@googlemail.com>
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*
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* Licensed under GPL version 2, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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int FAST_FUNC read_key(int fd, smalluint *nbuffered, char *buffer)
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{
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struct pollfd pfd;
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const char *seq;
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int n;
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int c;
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/* Known escape sequences for cursor and function keys */
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static const char esccmds[] ALIGN1 = {
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'O','A' |0x80,KEYCODE_UP ,
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'O','B' |0x80,KEYCODE_DOWN ,
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'O','C' |0x80,KEYCODE_RIGHT ,
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'O','D' |0x80,KEYCODE_LEFT ,
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'O','H' |0x80,KEYCODE_HOME ,
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'O','F' |0x80,KEYCODE_END ,
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#if 0
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'O','P' |0x80,KEYCODE_FUN1 ,
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/* [ESC] ESC O [2] P - [Alt-][Shift-]F1 */
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/* Ctrl- seems to not affect sequences */
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'O','Q' |0x80,KEYCODE_FUN2 ,
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'O','R' |0x80,KEYCODE_FUN3 ,
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'O','S' |0x80,KEYCODE_FUN4 ,
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#endif
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'[','A' |0x80,KEYCODE_UP ,
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'[','B' |0x80,KEYCODE_DOWN ,
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'[','C' |0x80,KEYCODE_RIGHT ,
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'[','D' |0x80,KEYCODE_LEFT ,
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'[','H' |0x80,KEYCODE_HOME , /* xterm */
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/* [ESC] ESC [ [2] H - [Alt-][Shift-]Home */
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'[','F' |0x80,KEYCODE_END , /* xterm */
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'[','1','~' |0x80,KEYCODE_HOME , /* vt100? linux vt? or what? */
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'[','2','~' |0x80,KEYCODE_INSERT ,
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'[','3','~' |0x80,KEYCODE_DELETE ,
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/* [ESC] ESC [ 3 [;2] ~ - [Alt-][Shift-]Delete */
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'[','4','~' |0x80,KEYCODE_END , /* vt100? linux vt? or what? */
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'[','5','~' |0x80,KEYCODE_PAGEUP ,
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'[','6','~' |0x80,KEYCODE_PAGEDOWN,
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'[','7','~' |0x80,KEYCODE_HOME , /* vt100? linux vt? or what? */
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'[','8','~' |0x80,KEYCODE_END , /* vt100? linux vt? or what? */
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#if 0
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'[','1','1','~'|0x80,KEYCODE_FUN1 ,
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'[','1','2','~'|0x80,KEYCODE_FUN2 ,
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'[','1','3','~'|0x80,KEYCODE_FUN3 ,
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'[','1','4','~'|0x80,KEYCODE_FUN4 ,
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'[','1','5','~'|0x80,KEYCODE_FUN5 ,
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/* [ESC] ESC [ 1 5 [;2] ~ - [Alt-][Shift-]F5 */
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'[','1','7','~'|0x80,KEYCODE_FUN6 ,
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'[','1','8','~'|0x80,KEYCODE_FUN7 ,
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'[','1','9','~'|0x80,KEYCODE_FUN8 ,
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'[','2','0','~'|0x80,KEYCODE_FUN9 ,
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'[','2','1','~'|0x80,KEYCODE_FUN10 ,
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'[','2','3','~'|0x80,KEYCODE_FUN11 ,
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'[','2','4','~'|0x80,KEYCODE_FUN12 ,
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#endif
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0
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};
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n = 0;
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if (nbuffered)
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n = *nbuffered;
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if (n == 0) {
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/* If no data, block waiting for input. If we read more
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* than the minimal ESC sequence size, the "n=0" below
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* would instead have to figure out how much to keep,
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* resulting in larger code. */
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n = safe_read(fd, buffer, 3);
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if (n <= 0)
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return -1;
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}
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/* Grab character to return from buffer */
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c = (unsigned char)buffer[0];
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n--;
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if (n)
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memmove(buffer, buffer + 1, n);
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/* Only ESC starts ESC sequences */
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if (c != 27)
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goto ret;
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/* Loop through known ESC sequences */
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pfd.fd = fd;
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pfd.events = POLLIN;
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seq = esccmds;
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while (*seq != '\0') {
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/* n - position in sequence we did not read yet */
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int i = 0; /* position in sequence to compare */
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/* Loop through chars in this sequence */
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while (1) {
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/* So far escape sequence matched up to [i-1] */
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if (n <= i) {
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/* Need more chars, read another one if it wouldn't block.
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* Note that escape sequences come in as a unit,
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* so if we block for long it's not really an escape sequence.
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* Timeout is needed to reconnect escape sequences
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* split up by transmission over a serial console. */
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if (safe_poll(&pfd, 1, 50) == 0) {
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/* No more data!
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* Array is sorted from shortest to longest,
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* we can't match anything later in array,
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* break out of both loops. */
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goto ret;
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}
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errno = 0;
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if (safe_read(fd, buffer + n, 1) <= 0) {
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/* If EAGAIN, then fd is O_NONBLOCK and poll lied:
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* in fact, there is no data. */
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if (errno != EAGAIN)
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c = -1; /* otherwise it's EOF/error */
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goto ret;
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}
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n++;
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}
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if (buffer[i] != (seq[i] & 0x7f)) {
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/* This seq doesn't match, go to next */
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seq += i;
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/* Forward to last char */
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while (!(*seq & 0x80))
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seq++;
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/* Skip it and the keycode which follows */
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seq += 2;
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break;
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}
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if (seq[i] & 0x80) {
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/* Entire seq matched */
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c = (signed char)seq[i+1];
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n = 0;
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/* n -= i; memmove(...);
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* would be more correct,
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* but we never read ahead that much,
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* and n == i here. */
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goto ret;
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}
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i++;
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}
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}
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/* We did not find matching sequence, it was a bare ESC.
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* We possibly read and stored more input in buffer[]
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* by now. */
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ret:
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if (nbuffered)
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*nbuffered = n;
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return c;
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}
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