Contents of /tags/mkinitrd-6_1_7/busybox/libbb/read_key.c
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Fri Oct 16 13:40:14 2009 UTC (14 years, 11 months ago) by niro
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Fri Oct 16 13:40:14 2009 UTC (14 years, 11 months ago) by niro
File MIME type: text/plain
File size: 4717 byte(s)
tagged 'mkinitrd-6_1_7'
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Utility routines. |
4 | * |
5 | * Copyright (C) 2008 Rob Landley <rob@landley.net> |
6 | * Copyright (C) 2008 Denys Vlasenko <vda.linux@googlemail.com> |
7 | * |
8 | * Licensed under GPL version 2, see file LICENSE in this tarball for details. |
9 | */ |
10 | #include "libbb.h" |
11 | |
12 | int FAST_FUNC read_key(int fd, smalluint *nbuffered, char *buffer) |
13 | { |
14 | struct pollfd pfd; |
15 | const char *seq; |
16 | int n; |
17 | int c; |
18 | |
19 | /* Known escape sequences for cursor and function keys */ |
20 | static const char esccmds[] ALIGN1 = { |
21 | 'O','A' |0x80,KEYCODE_UP , |
22 | 'O','B' |0x80,KEYCODE_DOWN , |
23 | 'O','C' |0x80,KEYCODE_RIGHT , |
24 | 'O','D' |0x80,KEYCODE_LEFT , |
25 | 'O','H' |0x80,KEYCODE_HOME , |
26 | 'O','F' |0x80,KEYCODE_END , |
27 | #if 0 |
28 | 'O','P' |0x80,KEYCODE_FUN1 , |
29 | /* [ESC] ESC O [2] P - [Alt-][Shift-]F1 */ |
30 | /* Ctrl- seems to not affect sequences */ |
31 | 'O','Q' |0x80,KEYCODE_FUN2 , |
32 | 'O','R' |0x80,KEYCODE_FUN3 , |
33 | 'O','S' |0x80,KEYCODE_FUN4 , |
34 | #endif |
35 | '[','A' |0x80,KEYCODE_UP , |
36 | '[','B' |0x80,KEYCODE_DOWN , |
37 | '[','C' |0x80,KEYCODE_RIGHT , |
38 | '[','D' |0x80,KEYCODE_LEFT , |
39 | '[','H' |0x80,KEYCODE_HOME , /* xterm */ |
40 | /* [ESC] ESC [ [2] H - [Alt-][Shift-]Home */ |
41 | '[','F' |0x80,KEYCODE_END , /* xterm */ |
42 | '[','1','~' |0x80,KEYCODE_HOME , /* vt100? linux vt? or what? */ |
43 | '[','2','~' |0x80,KEYCODE_INSERT , |
44 | '[','3','~' |0x80,KEYCODE_DELETE , |
45 | /* [ESC] ESC [ 3 [;2] ~ - [Alt-][Shift-]Delete */ |
46 | '[','4','~' |0x80,KEYCODE_END , /* vt100? linux vt? or what? */ |
47 | '[','5','~' |0x80,KEYCODE_PAGEUP , |
48 | '[','6','~' |0x80,KEYCODE_PAGEDOWN, |
49 | '[','7','~' |0x80,KEYCODE_HOME , /* vt100? linux vt? or what? */ |
50 | '[','8','~' |0x80,KEYCODE_END , /* vt100? linux vt? or what? */ |
51 | #if 0 |
52 | '[','1','1','~'|0x80,KEYCODE_FUN1 , |
53 | '[','1','2','~'|0x80,KEYCODE_FUN2 , |
54 | '[','1','3','~'|0x80,KEYCODE_FUN3 , |
55 | '[','1','4','~'|0x80,KEYCODE_FUN4 , |
56 | '[','1','5','~'|0x80,KEYCODE_FUN5 , |
57 | /* [ESC] ESC [ 1 5 [;2] ~ - [Alt-][Shift-]F5 */ |
58 | '[','1','7','~'|0x80,KEYCODE_FUN6 , |
59 | '[','1','8','~'|0x80,KEYCODE_FUN7 , |
60 | '[','1','9','~'|0x80,KEYCODE_FUN8 , |
61 | '[','2','0','~'|0x80,KEYCODE_FUN9 , |
62 | '[','2','1','~'|0x80,KEYCODE_FUN10 , |
63 | '[','2','3','~'|0x80,KEYCODE_FUN11 , |
64 | '[','2','4','~'|0x80,KEYCODE_FUN12 , |
65 | #endif |
66 | 0 |
67 | }; |
68 | |
69 | n = 0; |
70 | if (nbuffered) |
71 | n = *nbuffered; |
72 | if (n == 0) { |
73 | /* If no data, block waiting for input. If we read more |
74 | * than the minimal ESC sequence size, the "n=0" below |
75 | * would instead have to figure out how much to keep, |
76 | * resulting in larger code. */ |
77 | n = safe_read(fd, buffer, 3); |
78 | if (n <= 0) |
79 | return -1; |
80 | } |
81 | |
82 | /* Grab character to return from buffer */ |
83 | c = (unsigned char)buffer[0]; |
84 | n--; |
85 | if (n) |
86 | memmove(buffer, buffer + 1, n); |
87 | |
88 | /* Only ESC starts ESC sequences */ |
89 | if (c != 27) |
90 | goto ret; |
91 | |
92 | /* Loop through known ESC sequences */ |
93 | pfd.fd = fd; |
94 | pfd.events = POLLIN; |
95 | seq = esccmds; |
96 | while (*seq != '\0') { |
97 | /* n - position in sequence we did not read yet */ |
98 | int i = 0; /* position in sequence to compare */ |
99 | |
100 | /* Loop through chars in this sequence */ |
101 | while (1) { |
102 | /* So far escape sequence matched up to [i-1] */ |
103 | if (n <= i) { |
104 | /* Need more chars, read another one if it wouldn't block. |
105 | * Note that escape sequences come in as a unit, |
106 | * so if we block for long it's not really an escape sequence. |
107 | * Timeout is needed to reconnect escape sequences |
108 | * split up by transmission over a serial console. */ |
109 | if (safe_poll(&pfd, 1, 50) == 0) { |
110 | /* No more data! |
111 | * Array is sorted from shortest to longest, |
112 | * we can't match anything later in array, |
113 | * break out of both loops. */ |
114 | goto ret; |
115 | } |
116 | errno = 0; |
117 | if (safe_read(fd, buffer + n, 1) <= 0) { |
118 | /* If EAGAIN, then fd is O_NONBLOCK and poll lied: |
119 | * in fact, there is no data. */ |
120 | if (errno != EAGAIN) |
121 | c = -1; /* otherwise it's EOF/error */ |
122 | goto ret; |
123 | } |
124 | n++; |
125 | } |
126 | if (buffer[i] != (seq[i] & 0x7f)) { |
127 | /* This seq doesn't match, go to next */ |
128 | seq += i; |
129 | /* Forward to last char */ |
130 | while (!(*seq & 0x80)) |
131 | seq++; |
132 | /* Skip it and the keycode which follows */ |
133 | seq += 2; |
134 | break; |
135 | } |
136 | if (seq[i] & 0x80) { |
137 | /* Entire seq matched */ |
138 | c = (signed char)seq[i+1]; |
139 | n = 0; |
140 | /* n -= i; memmove(...); |
141 | * would be more correct, |
142 | * but we never read ahead that much, |
143 | * and n == i here. */ |
144 | goto ret; |
145 | } |
146 | i++; |
147 | } |
148 | } |
149 | /* We did not find matching sequence, it was a bare ESC. |
150 | * We possibly read and stored more input in buffer[] |
151 | * by now. */ |
152 | |
153 | ret: |
154 | if (nbuffered) |
155 | *nbuffered = n; |
156 | return c; |
157 | } |