Home | History | Annotate | Line # | Download | only in common
interp_backslash.c revision 1.2.74.1 
      1 /*	$NetBSD: interp_backslash.c,v 1.2.74.1 2009/08/19 18:46:24 yamt 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 $"); */
     21 
     22 #include <lib/libsa/stand.h>
     23 #include <lib/libsa/loadfile.h>
     24 #include <lib/libkern/libkern.h>
     25 
     26 #include "bootstrap.h"
     27 
     28 #define DIGIT(x) (isdigit(x) ? (x) - '0' : islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A')
     29 
     30 /*
     31  * backslash: Return malloc'd copy of str with all standard "backslash
     32  * processing" done on it.  Original can be free'd if desired.
     33  */
     34 char *
     35 backslash(char *str)
     36 {
     37     /*
     38      * Remove backslashes from the strings. Turn \040 etc. into a single
     39      * character (we allow eight bit values). Currently NUL is not
     40      * allowed.
     41      *
     42      * Turn "\n" and "\t" into '\n' and '\t' characters. Etc.
     43      *
     44      */
     45     char *new_str;
     46     int seenbs = 0;
     47     int i = 0;
     48 
     49     if ((new_str = strdup(str)) == NULL)
     50 	return NULL;
     51 
     52     while (*str) {
     53 	if (seenbs) {
     54 	    seenbs = 0;
     55 	    switch (*str) {
     56 	    case '\\':
     57 		new_str[i++] = '\\';
     58 		str++;
     59 		break;
     60 
     61 	    /* preserve backslashed quotes, dollar signs */
     62 	    case '\'':
     63 	    case '"':
     64 	    case '$':
     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