1 | /* $NetBSD: cnmagic.c,v 1.13 2011/11/19 17:34:41 christos Exp $ */ |
2 | |
3 | /* |
4 | * Copyright (c) 2000 Eduardo Horvath |
5 | * All rights reserved. |
6 | * |
7 | * Redistribution and use in source and binary forms, with or without |
8 | * modification, are permitted provided that the following conditions |
9 | * are met: |
10 | * 1. Redistributions of source code must retain the above copyright |
11 | * notice, this list of conditions and the following disclaimer. |
12 | * 2. Redistributions in binary form must reproduce the above copyright |
13 | * notice, this list of conditions and the following disclaimer in the |
14 | * documentation and/or other materials provided with the distribution. |
15 | * |
16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | */ |
27 | |
28 | #include <sys/cdefs.h> |
29 | __KERNEL_RCSID(0, "$NetBSD: cnmagic.c,v 1.13 2011/11/19 17:34:41 christos Exp $" ); |
30 | |
31 | #include <sys/param.h> |
32 | #include <sys/systm.h> |
33 | #include <sys/kernel.h> |
34 | |
35 | #define ENCODE_STATE(c, n) (short)(((c)&0x1ff)|(((n)&0x7f)<<9)) |
36 | |
37 | static unsigned short cn_magic[CNS_LEN]; |
38 | |
39 | /* |
40 | * Initialize a cnm_state_t. |
41 | */ |
42 | void |
43 | cn_init_magic(cnm_state_t *cnm) |
44 | { |
45 | cnm->cnm_state = 0; |
46 | cnm->cnm_magic = cn_magic; |
47 | } |
48 | |
49 | /* |
50 | * Destroy a cnm_state_t. |
51 | */ |
52 | void |
53 | cn_destroy_magic(cnm_state_t *cnm) |
54 | { |
55 | cnm->cnm_state = 0; |
56 | cnm->cnm_magic = NULL; |
57 | } |
58 | |
59 | /* |
60 | * Translate a magic string to a state |
61 | * machine table. |
62 | */ |
63 | int |
64 | cn_set_magic(const char *smagic) |
65 | { |
66 | const unsigned char *magic = (const unsigned char *)smagic; |
67 | unsigned short i, c, n; |
68 | unsigned short m[CNS_LEN]; |
69 | |
70 | for (i = 0; i < CNS_LEN; i++) { |
71 | c = *magic++; |
72 | switch (c) { |
73 | case 0: |
74 | /* End of string */ |
75 | if (i == 0) { |
76 | /* empty string? */ |
77 | #ifdef DEBUG |
78 | printf("cn_set_magic(): empty!\n" ); |
79 | #endif |
80 | } |
81 | cn_magic[i] = 0; |
82 | while (i--) |
83 | cn_magic[i] = m[i]; |
84 | return 0; |
85 | case 0x27: |
86 | /* Escape sequence */ |
87 | c = *magic++; |
88 | switch (c) { |
89 | case 0x27: |
90 | break; |
91 | case 0x01: |
92 | /* BREAK */ |
93 | c = CNC_BREAK; |
94 | break; |
95 | case 0x02: |
96 | /* NUL */ |
97 | c = 0; |
98 | break; |
99 | } |
100 | /* FALLTHROUGH */ |
101 | default: |
102 | /* Transition to the next state. */ |
103 | n = *magic ? i + 1 : CNS_TERM; |
104 | #ifdef DEBUG |
105 | if (!cold) |
106 | aprint_normal("mag %d %x:%x\n" , i, c, n); |
107 | #endif |
108 | m[i] = ENCODE_STATE(c, n); |
109 | break; |
110 | } |
111 | } |
112 | return EINVAL; |
113 | } |
114 | |
115 | /* |
116 | * Translatea state machine table back to |
117 | * a magic string. |
118 | */ |
119 | int |
120 | cn_get_magic(char *magic, size_t maglen) |
121 | { |
122 | size_t i, n = 0; |
123 | |
124 | #define ADD_CHAR(x) \ |
125 | do \ |
126 | if (n < maglen) \ |
127 | magic[n++] = (x); \ |
128 | else \ |
129 | goto error; \ |
130 | while (/*CONSTCOND*/0) |
131 | |
132 | for (i = 0; i < CNS_LEN; /* empty */) { |
133 | unsigned short c = cn_magic[i]; |
134 | i = CNS_MAGIC_NEXT(c); |
135 | if (i == 0) |
136 | goto finish; |
137 | |
138 | /* Translate a character */ |
139 | switch (CNS_MAGIC_VAL(c)) { |
140 | case CNC_BREAK: |
141 | ADD_CHAR(0x27); |
142 | ADD_CHAR(0x01); |
143 | break; |
144 | case 0: |
145 | ADD_CHAR(0x27); |
146 | ADD_CHAR(0x02); |
147 | break; |
148 | case 0x27: |
149 | ADD_CHAR(0x27); |
150 | ADD_CHAR(0x27); |
151 | break; |
152 | default: |
153 | ADD_CHAR(c); |
154 | break; |
155 | } |
156 | /* Now go to the next state */ |
157 | if (i == CNS_TERM) |
158 | goto finish; |
159 | } |
160 | |
161 | error: |
162 | return EINVAL; |
163 | |
164 | finish: |
165 | /* Either termination state or empty machine */ |
166 | ADD_CHAR('\0'); |
167 | return 0; |
168 | } |
169 | |
170 | |