FreeBSD/Linux Kernel Cross Reference
sys/kern/cnmagic.c
1 /* $NetBSD: cnmagic.c,v 1.5 2003/08/22 02:01:32 junyoung 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 * 3. All advertising materials mentioning features or use of this software
16 * must display the following acknowledgement:
17 * This product includes software developed by Eduardo Horvath.
18 * 4. The name of the author may not be used to endorse or promote products
19 * derived from this software without specific prior written permission
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 #include <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: cnmagic.c,v 1.5 2003/08/22 02:01:32 junyoung Exp $");
35
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/kernel.h>
39
40 #define ENCODE_STATE(c, n) (short)(((c)&0x1ff)|(((n)&0x7f)<<9))
41
42 static unsigned short cn_magic[CNS_LEN];
43
44 /*
45 * Initialize a cnm_state_t.
46 */
47 void
48 cn_init_magic(cnm_state_t *cnm)
49 {
50 cnm->cnm_state = 0;
51 cnm->cnm_magic = cn_magic;
52 }
53
54 /*
55 * Destroy a cnm_state_t.
56 */
57 void
58 cn_destroy_magic(cnm_state_t *cnm)
59 {
60 cnm->cnm_state = 0;
61 cnm->cnm_magic = NULL;
62 }
63
64 /*
65 * Translate a magic string to a state
66 * machine table.
67 */
68 int
69 cn_set_magic(char *magic)
70 {
71 unsigned int i, c, n;
72 unsigned short m[CNS_LEN];
73
74 for (i = 0; i < CNS_LEN; i++) {
75 c = (*magic++) & 0xff;
76 n = *magic ? i+1 : CNS_TERM;
77 switch (c) {
78 case 0:
79 /* End of string */
80 if (i == 0) {
81 /* empty string? */
82 cn_magic[0] = 0;
83 #ifdef DEBUG
84 printf("cn_set_magic(): empty!\n");
85 #endif
86 return (0);
87 }
88 do {
89 cn_magic[i] = m[i];
90 } while (i--);
91 return(0);
92 case 0x27:
93 /* Escape sequence */
94 c = (*magic++) & 0xff;
95 n = *magic ? i+1 : CNS_TERM;
96 switch (c) {
97 case 0x27:
98 break;
99 case 0x01:
100 /* BREAK */
101 c = CNC_BREAK;
102 break;
103 case 0x02:
104 /* NUL */
105 c = 0;
106 break;
107 }
108 /* FALLTHROUGH */
109 default:
110 /* Transition to the next state. */
111 #ifdef DEBUG
112 if (!cold)
113 printf("mag %d %x:%x\n", i, c, n);
114 #endif
115 m[i] = ENCODE_STATE(c, n);
116 break;
117 }
118 }
119 return (EINVAL);
120 }
121
122 /*
123 * Translatea state machine table back to
124 * a magic string.
125 */
126 int
127 cn_get_magic(char *magic, int maglen)
128 {
129 unsigned int i, c;
130
131 for (i = 0; i < CNS_LEN;) {
132 c = cn_magic[i];
133 /* Translate a character */
134 switch (CNS_MAGIC_VAL(c)) {
135 case CNC_BREAK:
136 *magic++ = 0x27;
137 *magic++ = 0x01;
138 break;
139 case 0:
140 *magic++ = 0x27;
141 *magic++ = 0x02;
142 break;
143 case 0x27:
144 *magic++ = 0x27;
145 *magic++ = 0x27;
146 break;
147 default:
148 *magic++ = (c & 0x0ff);
149 break;
150 }
151 /* Now go to the next state */
152 i = CNS_MAGIC_NEXT(c);
153 if (i == CNS_TERM || i == 0) {
154 /* Either termination state or empty machine */
155 *magic++ = 0;
156 return (0);
157 }
158 }
159 return (EINVAL);
160 }
161
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