scoutos / prex-0.9.0 / usr / bin / sh / var.c @ 03e9c04a
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1 | 03e9c04a | Brad Neuman | /*
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2 | * Copyright (c) 2009, Kohsuke Ohtani
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3 | * All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of the author nor the names of any co-contributors
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14 | * may be used to endorse or promote products derived from this software
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15 | * without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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27 | * SUCH DAMAGE.
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28 | */
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29 | |||
30 | #include <unistd.h> |
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31 | #include <stdlib.h> |
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32 | #include <string.h> |
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33 | #include <stdio.h> |
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34 | #include <errno.h> |
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35 | |||
36 | extern char **environ; |
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37 | |||
38 | /*
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39 | * Shell variables.
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40 | */
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41 | |||
42 | #define VTABSIZE 20 |
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43 | #define MAXVARNAME 32 |
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44 | |||
45 | struct var {
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46 | char *name;
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47 | char *val;
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48 | }; |
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49 | |||
50 | static struct var vartab[VTABSIZE]; |
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51 | |||
52 | static int |
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53 | is_name(char c)
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54 | { |
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55 | |||
56 | if ((c >= 'a' && c <= 'z') || |
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57 | (c >= 'A' && c <= 'Z') || c == '_') |
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58 | return 1; |
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59 | return 0; |
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60 | } |
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61 | |||
62 | static int |
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63 | is_validname(char *name)
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64 | { |
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65 | char *p;
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66 | |||
67 | for (p = name; *p != '\0'; p++) { |
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68 | if (!is_name(*p))
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69 | return 0; |
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70 | } |
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71 | return 1; |
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72 | } |
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73 | |||
74 | static struct var * |
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75 | lookupvar(char *name)
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76 | { |
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77 | struct var *var;
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78 | int i;
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79 | |||
80 | var = &vartab[0];
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81 | for (i = 0; i < VTABSIZE; i++) { |
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82 | if (var->name != NULL && !strcmp(var->name, name)) |
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83 | return var;
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84 | var++; |
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85 | } |
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86 | return NULL; |
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87 | } |
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88 | |||
89 | void
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90 | setvar(char *name, char *val) |
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91 | { |
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92 | struct var *var, *free;
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93 | int i;
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94 | |||
95 | /*
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96 | * Lookup existing name in variable table.
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97 | */
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98 | var = lookupvar(name); |
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99 | |||
100 | if (var == NULL) { |
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101 | /*
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102 | * Not found. Find empty slot.
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103 | */
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104 | free = NULL;
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105 | var = &vartab[0];
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106 | for (i = 0; i < VTABSIZE; i++) { |
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107 | if (var->name == NULL) { |
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108 | free = var; |
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109 | break;
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110 | } |
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111 | var++; |
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112 | } |
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113 | if (free == NULL) { |
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114 | fprintf(stderr, "too many variables\n");
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115 | return;
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116 | } |
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117 | var = free; |
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118 | } |
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119 | |||
120 | if (!is_validname(name)) {
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121 | fprintf(stderr, "%s: bad vairable name\n", name);
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122 | return;
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123 | } |
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124 | if ((var->name = strdup(name)) == NULL) { |
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125 | fprintf(stderr, "out of memory\n");
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126 | return;
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127 | } |
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128 | var->val = strdup(val); |
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129 | } |
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130 | |||
131 | void
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132 | unsetvar(char *name)
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133 | { |
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134 | struct var *var;
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135 | |||
136 | /* Find target slot in variable table */
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137 | var = lookupvar(name); |
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138 | if (var == NULL) |
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139 | return;
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140 | |||
141 | free(var->name); |
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142 | free(var->val); |
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143 | var->name = NULL;
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144 | var->val = NULL;
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145 | } |
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146 | |||
147 | void
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148 | setvareq(char *str)
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149 | { |
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150 | char name[MAXVARNAME];
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151 | char *p, *s;
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152 | int i;
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153 | |||
154 | s = str; |
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155 | p = name; |
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156 | for (i = 0; i < MAXVARNAME - 1; i++) { |
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157 | *p++ = *s++; |
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158 | if (*s == '=') |
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159 | break;
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160 | } |
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161 | *p = '\0';
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162 | p = strchr(str, '=');
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163 | setvar(name, p + 1);
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164 | } |
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165 | |||
166 | int
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167 | cmd_showvars(int argc, char *argv[]) |
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168 | { |
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169 | struct var *var;
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170 | int i;
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171 | |||
172 | var = &vartab[0];
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173 | for (i = 0; i < VTABSIZE; i++) { |
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174 | if (var->name != NULL) |
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175 | printf("%s=%s\n", var->name, var->val);
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176 | var++; |
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177 | } |
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178 | return 0; |
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179 | } |
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180 | |||
181 | int
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182 | cmd_unsetvar(int argc, char *argv[]) |
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183 | { |
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184 | |||
185 | if (argc != 2) { |
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186 | fprintf(stderr, "usage: unset name\n");
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187 | return 0; |
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188 | } |
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189 | |||
190 | unsetvar(argv[1]);
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191 | return 0; |
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192 | } |
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193 | |||
194 | int
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195 | cmd_export(int argc, char *argv[]) |
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196 | { |
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197 | struct var *var;
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198 | int i;
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199 | |||
200 | if (argc == 1) { |
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201 | fprintf(stderr, "usage: export name\n");
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202 | return 0; |
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203 | } |
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204 | for (i = 1; i < argc; i++) { |
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205 | var = lookupvar(argv[i]); |
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206 | if (var != NULL) |
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207 | setenv(var->name, var->val, 1);
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208 | } |
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209 | return 0; |
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210 | } |
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211 | |||
212 | void
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213 | initvar(void)
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214 | { |
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215 | char **envp;
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216 | int i;
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217 | |||
218 | for (i = 0; i < VTABSIZE; i++) |
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219 | vartab[i].name = NULL;
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220 | |||
221 | for (envp = environ; *envp; envp++) {
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222 | if (strchr(*envp, '=')) |
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223 | setvareq(*envp); |
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224 | } |
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225 | } |