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-rw-r--r--read_key.c293
1 files changed, 293 insertions, 0 deletions
diff --git a/read_key.c b/read_key.c
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+/* vi: set sw=4 ts=4: */
+/*
+ * Utility routines.
+ *
+ * Copyright (C) 2008 Rob Landley <rob@landley.net>
+ * Copyright (C) 2008 Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+#include "libbb.h"
+
+int64_t FAST_FUNC read_key(int fd, char *buffer, int timeout)
+{
+ struct pollfd pfd;
+ const char *seq;
+ int n;
+
+ /* Known escape sequences for cursor and function keys.
+ * See "Xterm Control Sequences"
+ * http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
+ * Array should be sorted from shortest to longest.
+ */
+ static const char esccmds[] ALIGN1 = {
+ '\x7f' |0x80,KEYCODE_ALT_BACKSPACE,
+ '\b' |0x80,KEYCODE_ALT_BACKSPACE,
+ 'd' |0x80,KEYCODE_ALT_D ,
+ /* lineedit mimics bash: Alt-f and Alt-b are forward/backward
+ * word jumps. We cheat here and make them return ALT_LEFT/RIGHT
+ * keycodes. This way, lineedit need no special code to handle them.
+ * If we'll need to distinguish them, introduce new ALT_F/B keycodes,
+ * and update lineedit to react to them.
+ */
+ 'f' |0x80,KEYCODE_ALT_RIGHT,
+ 'b' |0x80,KEYCODE_ALT_LEFT,
+ 'O','A' |0x80,KEYCODE_UP ,
+ 'O','B' |0x80,KEYCODE_DOWN ,
+ 'O','C' |0x80,KEYCODE_RIGHT ,
+ 'O','D' |0x80,KEYCODE_LEFT ,
+ 'O','H' |0x80,KEYCODE_HOME ,
+ 'O','F' |0x80,KEYCODE_END ,
+#if 0
+ 'O','P' |0x80,KEYCODE_FUN1 ,
+ /* [ESC] ESC O [2] P - [Alt-][Shift-]F1 */
+ /* ESC [ O 1 ; 2 P - Shift-F1 */
+ /* ESC [ O 1 ; 3 P - Alt-F1 */
+ /* ESC [ O 1 ; 4 P - Alt-Shift-F1 */
+ /* ESC [ O 1 ; 5 P - Ctrl-F1 */
+ /* ESC [ O 1 ; 6 P - Ctrl-Shift-F1 */
+ 'O','Q' |0x80,KEYCODE_FUN2 ,
+ 'O','R' |0x80,KEYCODE_FUN3 ,
+ 'O','S' |0x80,KEYCODE_FUN4 ,
+#endif
+ '[','A' |0x80,KEYCODE_UP ,
+ '[','B' |0x80,KEYCODE_DOWN ,
+ '[','C' |0x80,KEYCODE_RIGHT ,
+ '[','D' |0x80,KEYCODE_LEFT ,
+ /* ESC [ 1 ; 2 x, where x = A/B/C/D: Shift-<arrow> */
+ /* ESC [ 1 ; 3 x, where x = A/B/C/D: Alt-<arrow> - implemented below */
+ /* ESC [ 1 ; 4 x, where x = A/B/C/D: Alt-Shift-<arrow> */
+ /* ESC [ 1 ; 5 x, where x = A/B/C/D: Ctrl-<arrow> - implemented below */
+ /* ESC [ 1 ; 6 x, where x = A/B/C/D: Ctrl-Shift-<arrow> */
+ /* ESC [ 1 ; 7 x, where x = A/B/C/D: Ctrl-Alt-<arrow> */
+ /* ESC [ 1 ; 8 x, where x = A/B/C/D: Ctrl-Alt-Shift-<arrow> */
+ '[','H' |0x80,KEYCODE_HOME , /* xterm */
+ '[','F' |0x80,KEYCODE_END , /* xterm */
+ /* [ESC] ESC [ [2] H - [Alt-][Shift-]Home (End similarly?) */
+ /* '[','Z' |0x80,KEYCODE_SHIFT_TAB, */
+ '[','1','~' |0x80,KEYCODE_HOME , /* vt100? linux vt? or what? */
+ '[','2','~' |0x80,KEYCODE_INSERT ,
+ /* ESC [ 2 ; 3 ~ - Alt-Insert */
+ '[','3','~' |0x80,KEYCODE_DELETE ,
+ /* [ESC] ESC [ 3 [;2] ~ - [Alt-][Shift-]Delete */
+ /* ESC [ 3 ; 3 ~ - Alt-Delete */
+ /* ESC [ 3 ; 5 ~ - Ctrl-Delete */
+ '[','4','~' |0x80,KEYCODE_END , /* vt100? linux vt? or what? */
+ '[','5','~' |0x80,KEYCODE_PAGEUP ,
+ /* ESC [ 5 ; 3 ~ - Alt-PgUp */
+ /* ESC [ 5 ; 5 ~ - Ctrl-PgUp */
+ /* ESC [ 5 ; 7 ~ - Ctrl-Alt-PgUp */
+ '[','6','~' |0x80,KEYCODE_PAGEDOWN,
+ '[','7','~' |0x80,KEYCODE_HOME , /* vt100? linux vt? or what? */
+ '[','8','~' |0x80,KEYCODE_END , /* vt100? linux vt? or what? */
+#if 0
+ '[','1','1','~'|0x80,KEYCODE_FUN1 , /* old xterm, deprecated by ESC O P */
+ '[','1','2','~'|0x80,KEYCODE_FUN2 , /* old xterm... */
+ '[','1','3','~'|0x80,KEYCODE_FUN3 , /* old xterm... */
+ '[','1','4','~'|0x80,KEYCODE_FUN4 , /* old xterm... */
+ '[','1','5','~'|0x80,KEYCODE_FUN5 ,
+ /* [ESC] ESC [ 1 5 [;2] ~ - [Alt-][Shift-]F5 */
+ '[','1','7','~'|0x80,KEYCODE_FUN6 ,
+ '[','1','8','~'|0x80,KEYCODE_FUN7 ,
+ '[','1','9','~'|0x80,KEYCODE_FUN8 ,
+ '[','2','0','~'|0x80,KEYCODE_FUN9 ,
+ '[','2','1','~'|0x80,KEYCODE_FUN10 ,
+ '[','2','3','~'|0x80,KEYCODE_FUN11 ,
+ '[','2','4','~'|0x80,KEYCODE_FUN12 ,
+ /* ESC [ 2 4 ; 2 ~ - Shift-F12 */
+ /* ESC [ 2 4 ; 3 ~ - Alt-F12 */
+ /* ESC [ 2 4 ; 4 ~ - Alt-Shift-F12 */
+ /* ESC [ 2 4 ; 5 ~ - Ctrl-F12 */
+ /* ESC [ 2 4 ; 6 ~ - Ctrl-Shift-F12 */
+#endif
+ /* '[','1',';','5','A' |0x80,KEYCODE_CTRL_UP , - unused */
+ /* '[','1',';','5','B' |0x80,KEYCODE_CTRL_DOWN , - unused */
+ '[','1',';','5','C' |0x80,KEYCODE_CTRL_RIGHT,
+ '[','1',';','5','D' |0x80,KEYCODE_CTRL_LEFT ,
+ /* '[','1',';','3','A' |0x80,KEYCODE_ALT_UP , - unused */
+ /* '[','1',';','3','B' |0x80,KEYCODE_ALT_DOWN , - unused */
+ '[','1',';','3','C' |0x80,KEYCODE_ALT_RIGHT,
+ '[','1',';','3','D' |0x80,KEYCODE_ALT_LEFT ,
+ /* '[','3',';','3','~' |0x80,KEYCODE_ALT_DELETE, - unused */
+ 0
+ };
+
+ pfd.fd = fd;
+ pfd.events = POLLIN;
+
+ buffer++; /* saved chars counter is in buffer[-1] now */
+
+ start_over:
+ errno = 0;
+ n = (unsigned char)buffer[-1];
+ if (n == 0) {
+ /* If no data, wait for input.
+ * If requested, wait TIMEOUT ms. TIMEOUT = -1 is useful
+ * if fd can be in non-blocking mode.
+ */
+ if (timeout >= -1) {
+ if (safe_poll(&pfd, 1, timeout) == 0) {
+ /* Timed out */
+ errno = EAGAIN;
+ return -1;
+ }
+ }
+ /* It is tempting to read more than one byte here,
+ * but it breaks pasting. Example: at shell prompt,
+ * user presses "c","a","t" and then pastes "\nline\n".
+ * When we were reading 3 bytes here, we were eating
+ * "li" too, and cat was getting wrong input.
+ */
+ n = safe_read(fd, buffer, 1);
+ if (n <= 0)
+ return -1;
+ }
+
+ {
+ unsigned char c = buffer[0];
+ n--;
+ if (n)
+ memmove(buffer, buffer + 1, n);
+ /* Only ESC starts ESC sequences */
+ if (c != 27) {
+ buffer[-1] = n;
+ return c;
+ }
+ }
+
+ /* Loop through known ESC sequences */
+ seq = esccmds;
+ while (*seq != '\0') {
+ /* n - position in sequence we did not read yet */
+ int i = 0; /* position in sequence to compare */
+
+ /* Loop through chars in this sequence */
+ while (1) {
+ /* So far escape sequence matched up to [i-1] */
+ if (n <= i) {
+ /* Need more chars, read another one if it wouldn't block.
+ * Note that escape sequences come in as a unit,
+ * so if we block for long it's not really an escape sequence.
+ * Timeout is needed to reconnect escape sequences
+ * split up by transmission over a serial console. */
+ if (safe_poll(&pfd, 1, 50) == 0) {
+ /* No more data!
+ * Array is sorted from shortest to longest,
+ * we can't match anything later in array -
+ * anything later is longer than this seq.
+ * Break out of both loops. */
+ goto got_all;
+ }
+ errno = 0;
+ if (safe_read(fd, buffer + n, 1) <= 0) {
+ /* If EAGAIN, then fd is O_NONBLOCK and poll lied:
+ * in fact, there is no data. */
+ if (errno != EAGAIN) {
+ /* otherwise: it's EOF/error */
+ buffer[-1] = 0;
+ return -1;
+ }
+ goto got_all;
+ }
+ n++;
+ }
+ if (buffer[i] != (seq[i] & 0x7f)) {
+ /* This seq doesn't match, go to next */
+ seq += i;
+ /* Forward to last char */
+ while (!(*seq & 0x80))
+ seq++;
+ /* Skip it and the keycode which follows */
+ seq += 2;
+ break;
+ }
+ if (seq[i] & 0x80) {
+ /* Entire seq matched */
+ n = 0;
+ /* n -= i; memmove(...);
+ * would be more correct,
+ * but we never read ahead that much,
+ * and n == i here. */
+ buffer[-1] = 0;
+ return (signed char)seq[i+1];
+ }
+ i++;
+ }
+ }
+ /* We did not find matching sequence.
+ * We possibly read and stored more input in buffer[] by now.
+ * n = bytes read. Try to read more until we time out.
+ */
+ while (n < KEYCODE_BUFFER_SIZE-1) { /* 1 for count byte at buffer[-1] */
+ if (safe_poll(&pfd, 1, 50) == 0) {
+ /* No more data! */
+ break;
+ }
+ errno = 0;
+ if (safe_read(fd, buffer + n, 1) <= 0) {
+ /* If EAGAIN, then fd is O_NONBLOCK and poll lied:
+ * in fact, there is no data. */
+ if (errno != EAGAIN) {
+ /* otherwise: it's EOF/error */
+ buffer[-1] = 0;
+ return -1;
+ }
+ break;
+ }
+ n++;
+ /* Try to decipher "ESC [ NNN ; NNN R" sequence */
+ if ((ENABLE_FEATURE_EDITING_ASK_TERMINAL
+ || ENABLE_FEATURE_VI_ASK_TERMINAL
+ || ENABLE_FEATURE_LESS_ASK_TERMINAL
+ )
+ && n >= 5
+ && buffer[0] == '['
+ && buffer[n-1] == 'R'
+ && isdigit(buffer[1])
+ ) {
+ char *end;
+ unsigned long row, col;
+
+ row = strtoul(buffer + 1, &end, 10);
+ if (*end != ';' || !isdigit(end[1]))
+ continue;
+ col = strtoul(end + 1, &end, 10);
+ if (*end != 'R')
+ continue;
+ if (row < 1 || col < 1 || (row | col) > 0x7fff)
+ continue;
+
+ buffer[-1] = 0;
+ /* Pack into "1 <row15bits> <col16bits>" 32-bit sequence */
+ col |= (((-1 << 15) | row) << 16);
+ /* Return it in high-order word */
+ return ((int64_t) col << 32) | (uint32_t)KEYCODE_CURSOR_POS;
+ }
+ }
+ got_all:
+
+ if (n <= 1) {
+ /* Alt-x is usually returned as ESC x.
+ * Report ESC, x is remembered for the next call.
+ */
+ buffer[-1] = n;
+ return 27;
+ }
+
+ /* We were doing "buffer[-1] = n; return c;" here, but this results
+ * in unknown key sequences being interpreted as ESC + garbage.
+ * This was not useful. Pretend there was no key pressed,
+ * go and wait for a new keypress:
+ */
+ buffer[-1] = 0;
+ goto start_over;
+}
+
+void FAST_FUNC read_key_ungets(char *buffer, const char *str, unsigned len)
+{
+ unsigned cur_len = (unsigned char)buffer[0];
+ if (len > KEYCODE_BUFFER_SIZE-1 - cur_len)
+ len = KEYCODE_BUFFER_SIZE-1 - cur_len;
+ memcpy(buffer + 1 + cur_len, str, len);
+ buffer[0] += len;
+}
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