dist/ipf/lib/var.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * Copyright (C) 2002-2004 by Darren Reed.
   5  *
   6  * See the IPFILTER.LICENCE file for details on licencing.
   7  *
   8  * Id: var.c,v 1.4.2.3 2006/06/16 17:21:18 darrenr Exp
   9  */
  10
  11 #include <ctype.h>
  12
  13 #include "ipf.h"
  14
  15 typedef struct  variable        {
  16         struct  variable        *v_next;
  17         char    *v_name;
  18         char    *v_value;
  19 } variable_t;
  20
  21 static  variable_t      *vtop = NULL;
  22
  23 static variable_t *find_var __P((char *));
  24 static char *expand_string __P((char *, int));
  25
  26
  27 static variable_t *find_var(name)
  28 char *name;
  29 {
  30         variable_t *v;
  31
  32         for (v = vtop; v != NULL; v = v->v_next)
  33                 if (!strcmp(name, v->v_name))
  34                         return v;
  35         return NULL;
  36 }
  37
  38
  39 char *get_variable(string, after, line)
  40 char *string, **after;
  41 int line;
  42 {
  43         char c, *s, *t, *value;
  44         variable_t *v;
  45
  46         s = string;
  47
  48         if (*s == '{') {
  49                 s++;
  50                 for (t = s; *t != '\0'; t++)
  51                         if (*t == '}')
  52                                 break;
  53                 if (*t == '\0') {
  54                         fprintf(stderr, "%d: { without }\n", line);
  55                         return NULL;
  56                 }
  57         } else if (ISALPHA(*s)) {
  58                 for (t = s + 1; *t != '\0'; t++)
  59                         if (!ISALPHA(*t) && !ISDIGIT(*t) && (*t != '_'))
  60                                 break;
  61         } else {
  62                 fprintf(stderr, "%d: variables cannot start with '%c'\n",
  63                         line, *s);
  64                 return NULL;
  65         }
  66
  67         if (after != NULL)
  68                 *after = t;
  69         c = *t;
  70         *t = '\0';
  71         v = find_var(s);
  72         *t = c;
  73         if (v == NULL) {
  74                 fprintf(stderr, "%d: unknown variable '%s'\n", line, s);
  75                 return NULL;
  76         }
  77
  78         s = strdup(v->v_value);
  79         value = expand_string(s, line);
  80         if (value != s)
  81                 free(s);
  82         return value;
  83 }
  84
  85
  86 static char *expand_string(oldstring, line)
  87 char *oldstring;
  88 int line;
  89 {
  90         char c, *s, *p1, *p2, *p3, *newstring, *value;
  91         int len;
  92
  93         p3 = NULL;
  94         newstring = oldstring;
  95
  96         for (s = oldstring; *s != '\0'; s++)
  97                 if (*s == '$') {
  98                         *s = '\0';
  99                         s++;
 100
 101                         switch (*s)
 102                         {
 103                         case '$' :
 104                                 bcopy(s, s - 1, strlen(s));
 105                                 break;
 106                         default :
 107                                 c = *s;
 108                                 if (c == '\0')
 109                                         return newstring;
 110
 111                                 value = get_variable(s, &p3, line);
 112                                 if (value == NULL)
 113                                         return NULL;
 114
 115                                 p2 = expand_string(value, line);
 116                                 if (p2 == NULL)
 117                                         return NULL;
 118
 119                                 len = strlen(newstring) + strlen(p2);
 120                                 if (p3 != NULL) {
 121                                         if (c == '{' && *p3 == '}')
 122                                                 p3++;
 123                                         len += strlen(p3);
 124                                 }
 125                                 p1 = malloc(len + 1);
 126                                 if (p1 == NULL)
 127                                         return NULL;
 128
 129                                 *(s - 1) = '\0';
 130                                 strcpy(p1, newstring);
 131                                 strcat(p1, p2);
 132                                 if (p3 != NULL)
 133                                         strcat(p1, p3);
 134
 135                                 s = p1 + len - strlen(p3) - 1;
 136                                 if (newstring != oldstring)
 137                                         free(newstring);
 138                                 newstring = p1;
 139                                 break;
 140                         }
 141                 }
 142         return newstring;
 143 }
 144
 145
 146 void set_variable(name, value)
 147 char *name;
 148 char *value;
 149 {
 150         variable_t *v;
 151         int len;
 152
 153         if (name == NULL || value == NULL || *name == '\0')
 154                 return;
 155
 156         v = find_var(name);
 157         if (v != NULL) {
 158                 free(v->v_value);
 159                 v->v_value = strdup(value);
 160                 return;
 161         }
 162
 163         len = strlen(value);
 164
 165         if ((*value == '"' && value[len - 1] == '"') ||
 166             (*value == '\'' && value[len - 1] == '\'')) {
 167                 value[len - 1] = '\0';
 168                 value++;
 169                 len -=2;
 170         }
 171
 172         v = (variable_t *)malloc(sizeof(*v));
 173         if (v == NULL)
 174                 return;
 175         v->v_name = strdup(name);
 176         v->v_value = strdup(value);
 177         v->v_next = vtop;
 178         vtop = v;
 179 }