1 /* $NetBSD: cnmagic.c,v 1.4 2001/11/27 20:00:36 bouyer 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 1.4 2001/11/27 20:00:36 bouyer 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 cnm->cnm_state = 0; 50 cnm->cnm_magic = cn_magic; 51 } 52 53 /* 54 * Destroy a cnm_state_t. 55 */ 56 void 57 cn_destroy_magic(cnm_state_t *cnm) { 58 cnm->cnm_state = 0; 59 cnm->cnm_magic = NULL; 60 } 61 62 /* 63 * Translate a magic string to a state 64 * machine table. 65 */ 66 int 67 cn_set_magic(char *magic) 68 { 69 unsigned int i, c, n; 70 unsigned short m[CNS_LEN]; 71 72 for (i=0; i<CNS_LEN; i++) { 73 c = (*magic++)&0xff; 74 n = *magic ? i+1 : CNS_TERM; 75 switch (c) { 76 case 0: 77 /* End of string */ 78 if (i == 0) { 79 /* empty string? */ 80 cn_magic[0] = 0; 81 #ifdef DEBUG 82 printf("cn_set_magic(): empty!\n"); 83 #endif 84 return (0); 85 } 86 do { 87 cn_magic[i] = m[i]; 88 } while (i--); 89 return(0); 90 case 0x27: 91 /* Escape sequence */ 92 c = (*magic++)&0xff; 93 n = *magic ? i+1 : CNS_TERM; 94 switch (c) { 95 case 0x27: 96 break; 97 case 0x01: 98 /* BREAK */ 99 c = CNC_BREAK; 100 break; 101 case 0x02: 102 /* NUL */ 103 c = 0; 104 break; 105 } 106 /* FALLTHROUGH */ 107 default: 108 /* Transition to the next state. */ 109 #ifdef DEBUG 110 if (!cold) 111 printf("mag %d %x:%x\n", i, c, n); 112 #endif 113 m[i] = ENCODE_STATE(c, n); 114 break; 115 } 116 } 117 return (EINVAL); 118 } 119 120 /* 121 * Translatea state machine table back to 122 * a magic string. 123 */ 124 int 125 cn_get_magic(char *magic, int maglen) { 126 unsigned int i, c; 127 128 for (i=0; i<CNS_LEN;) { 129 c = cn_magic[i]; 130 /* Translate a character */ 131 switch (CNS_MAGIC_VAL(c)) { 132 case CNC_BREAK: 133 *magic++ = 0x27; 134 *magic++ = 0x01; 135 break; 136 case 0: 137 *magic++ = 0x27; 138 *magic++ = 0x02; 139 break; 140 case 0x27: 141 *magic++ = 0x27; 142 *magic++ = 0x27; 143 break; 144 default: 145 *magic++ = (c&0x0ff); 146 break; 147 } 148 /* Now go to the next state */ 149 i = CNS_MAGIC_NEXT(c); 150 if (i == CNS_TERM || i == 0) { 151 /* Either termination state or empty machine */ 152 *magic++ = 0; 153 return (0); 154 } 155 } 156 return (EINVAL); 157 } 158 159