| 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 | |