1 /* $NetBSD: interp_backslash.c,v 1.3 2009/07/20 04:59:03 kiyohara Exp $ */ 2 3 /*- 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * Jordan K. Hubbard 14 * 29 August 1998 15 * 16 * Routine for doing backslash elimination. 17 */ 18 19 #include <sys/cdefs.h> 20 /* __FBSDID("$FreeBSD: src/sys/boot/common/interp_backslash.c,v 1.6 2003/08/25 23:30:41 obrien Exp $"); */ 21 22 #include <lib/libsa/stand.h> 23 #include <lib/libsa/loadfile.h> 24 #include <lib/libkern/libkern.h> 25 26 #include "bootstrap.h" 27 28 #define DIGIT(x) (isdigit(x) ? (x) - '0' : islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A') 29 30 /* 31 * backslash: Return malloc'd copy of str with all standard "backslash 32 * processing" done on it. Original can be free'd if desired. 33 */ 34 char * backslash(char * str)35backslash(char *str) 36 { 37 /* 38 * Remove backslashes from the strings. Turn \040 etc. into a single 39 * character (we allow eight bit values). Currently NUL is not 40 * allowed. 41 * 42 * Turn "\n" and "\t" into '\n' and '\t' characters. Etc. 43 * 44 */ 45 char *new_str; 46 int seenbs = 0; 47 int i = 0; 48 49 if ((new_str = strdup(str)) == NULL) 50 return NULL; 51 52 while (*str) { 53 if (seenbs) { 54 seenbs = 0; 55 switch (*str) { 56 case '\\': 57 new_str[i++] = '\\'; 58 str++; 59 break; 60 61 /* preserve backslashed quotes, dollar signs */ 62 case '\'': 63 case '"': 64 case '$': 65 new_str[i++] = '\\'; 66 new_str[i++] = *str++; 67 break; 68 69 case 'b': 70 new_str[i++] = '\b'; 71 str++; 72 break; 73 74 case 'f': 75 new_str[i++] = '\f'; 76 str++; 77 break; 78 79 case 'r': 80 new_str[i++] = '\r'; 81 str++; 82 break; 83 84 case 'n': 85 new_str[i++] = '\n'; 86 str++; 87 break; 88 89 case 's': 90 new_str[i++] = ' '; 91 str++; 92 break; 93 94 case 't': 95 new_str[i++] = '\t'; 96 str++; 97 break; 98 99 case 'v': 100 new_str[i++] = '\13'; 101 str++; 102 break; 103 104 case 'z': 105 str++; 106 break; 107 108 case '0': case '1': case '2': case '3': case '4': 109 case '5': case '6': case '7': case '8': case '9': { 110 char val; 111 112 /* Three digit octal constant? */ 113 if (*str >= '0' && *str <= '3' && 114 *(str + 1) >= '0' && *(str + 1) <= '7' && 115 *(str + 2) >= '0' && *(str + 2) <= '7') { 116 117 val = (DIGIT(*str) << 6) + (DIGIT(*(str + 1)) << 3) + 118 DIGIT(*(str + 2)); 119 120 /* Allow null value if user really wants to shoot 121 at feet, but beware! */ 122 new_str[i++] = val; 123 str += 3; 124 break; 125 } 126 127 /* One or two digit hex constant? 128 * If two are there they will both be taken. 129 * Use \z to split them up if this is not wanted. 130 */ 131 if (*str == '0' && 132 (*(str + 1) == 'x' || *(str + 1) == 'X') && 133 isxdigit(*(str + 2))) { 134 val = DIGIT(*(str + 2)); 135 if (isxdigit(*(str + 3))) { 136 val = (val << 4) + DIGIT(*(str + 3)); 137 str += 4; 138 } 139 else 140 str += 3; 141 /* Yep, allow null value here too */ 142 new_str[i++] = val; 143 break; 144 } 145 } 146 break; 147 148 default: 149 new_str[i++] = *str++; 150 break; 151 } 152 } 153 else { 154 if (*str == '\\') { 155 seenbs = 1; 156 str++; 157 } 158 else 159 new_str[i++] = *str++; 160 } 161 } 162 163 if (seenbs) { 164 /* 165 * The final character was a '\'. Put it in as a single backslash. 166 */ 167 new_str[i++] = '\\'; 168 } 169 new_str[i] = '\0'; 170 return new_str; 171 } 172