| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Fiddling with environment variables |
| 4 | * |
| 5 | * (c) 1999 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of the mLib utilities library. |
| 11 | * |
| 12 | * mLib is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU Library General Public License as |
| 14 | * published by the Free Software Foundation; either version 2 of the |
| 15 | * License, or (at your option) any later version. |
| 16 | * |
| 17 | * mLib is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU Library General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU Library General Public |
| 23 | * License along with mLib; if not, write to the Free |
| 24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 25 | * MA 02111-1307, USA. |
| 26 | */ |
| 27 | |
| 28 | /*----- Header files ------------------------------------------------------*/ |
| 29 | |
| 30 | #include <stdio.h> |
| 31 | #include <stdlib.h> |
| 32 | #include <string.h> |
| 33 | |
| 34 | #include "alloc.h" |
| 35 | #include "sym.h" |
| 36 | |
| 37 | /*----- Data structures ---------------------------------------------------*/ |
| 38 | |
| 39 | typedef struct var { |
| 40 | sym_base _base; |
| 41 | char *v; |
| 42 | } var; |
| 43 | |
| 44 | /*----- Main code ---------------------------------------------------------*/ |
| 45 | |
| 46 | /* --- @env_get@ --- * |
| 47 | * |
| 48 | * Arguments: @sym_table *t@ = pointer to a symbol table |
| 49 | * @const char *name@ = pointer to variable name to look up |
| 50 | * |
| 51 | * Returns: Pointer to corresponding value string, or null. |
| 52 | * |
| 53 | * Use: Looks up an environment variable in the table and returns its |
| 54 | * value. If the variable can't be found, a null pointer is |
| 55 | * returned. |
| 56 | */ |
| 57 | |
| 58 | char *env_get(sym_table *t, const char *name) |
| 59 | { |
| 60 | var *e = sym_find(t, name, -1, 0, 0); |
| 61 | return (e ? e->v : 0); |
| 62 | } |
| 63 | |
| 64 | /* --- @env_put@ --- * |
| 65 | * |
| 66 | * Arguments: @sym_table *t@ = pointer to a symbol table |
| 67 | * @const char *name@ = pointer to variable name to set |
| 68 | * @const char *value@ = pointer to value string to assign |
| 69 | * |
| 70 | * Returns: --- |
| 71 | * |
| 72 | * Use: Assigns a value to a variable. If the @name@ contains an |
| 73 | * equals character, then it's assumed to be of the form |
| 74 | * `VAR=VALUE' and @value@ argument is ignored. Otherwise, if |
| 75 | * @value@ is null, the variable is deleted. Finally, the |
| 76 | * normal case: @name@ is a plain name, and @value@ is a normal |
| 77 | * string causes the variable to be assigned the value in the |
| 78 | * way you'd expect. |
| 79 | */ |
| 80 | |
| 81 | void env_put(sym_table *t, const char *name, const char *value) |
| 82 | { |
| 83 | char *q = 0; |
| 84 | |
| 85 | /* --- Sort out the mess with `NAME=VALUE' forms --- */ |
| 86 | |
| 87 | { |
| 88 | size_t eq = strcspn(name, "="); |
| 89 | if (name[eq] == '=') { |
| 90 | q = x_alloc(t->t.a, eq + 1); |
| 91 | memcpy(q, name, eq); |
| 92 | q[eq] = 0; |
| 93 | value = name + eq + 1; |
| 94 | name = q; |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | /* --- Read the current value --- */ |
| 99 | |
| 100 | if (!value) { |
| 101 | var *v; |
| 102 | if ((v = sym_find(t, name, -1, 0, 0)) != 0) { |
| 103 | x_free(t->t.a, v->v); |
| 104 | sym_remove(t, v); |
| 105 | } |
| 106 | } else { |
| 107 | unsigned found; |
| 108 | var *v = sym_find(t, name, -1, sizeof(*v), &found); |
| 109 | if (found) |
| 110 | x_free(t->t.a, v->v); |
| 111 | v->v = x_strdup(t->t.a, value); |
| 112 | } |
| 113 | |
| 114 | /* --- Tidying --- */ |
| 115 | |
| 116 | if (q) |
| 117 | xfree(q); |
| 118 | } |
| 119 | |
| 120 | /* --- @env_import@ --- * |
| 121 | * |
| 122 | * Arguments: @sym_table *t@ = pointer to a symbol table |
| 123 | * @char **env@ = pointer to an environment list |
| 124 | * |
| 125 | * Returns: --- |
| 126 | * |
| 127 | * Use: Inserts all of the environment variables listed into a symbol |
| 128 | * table for rapid access. Equivalent to a lot of calls to |
| 129 | * @env_put@. |
| 130 | */ |
| 131 | |
| 132 | void env_import(sym_table *t, char **env) |
| 133 | { |
| 134 | while (*env) { |
| 135 | env_put(t, *env, 0); |
| 136 | env++; |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | /* --- @env_export@ --- * |
| 141 | * |
| 142 | * Arguments: @sym_table *t@ = pointer to a symbol table |
| 143 | * |
| 144 | * Returns: A big environment list. |
| 145 | * |
| 146 | * Use: Extracts an environment table from a symbol table |
| 147 | * representation of an environment. The table and all of the |
| 148 | * strings are in one big block allocated from the heap. |
| 149 | */ |
| 150 | |
| 151 | char **env_export(sym_table *t) |
| 152 | { |
| 153 | size_t n = 1; |
| 154 | size_t sz = 0; |
| 155 | sym_iter i; |
| 156 | var *v; |
| 157 | char **env; |
| 158 | char *p, **pp; |
| 159 | |
| 160 | /* --- Work out sizes for everything --- */ |
| 161 | |
| 162 | for (sym_mkiter(&i, t); (v = sym_next(&i)) != 0; ) { |
| 163 | n++; |
| 164 | sz += SYM_LEN(v) + strlen(v->v) + 2; |
| 165 | } |
| 166 | |
| 167 | /* --- Allocate the big chunk of memory --- */ |
| 168 | |
| 169 | env = pp = xmalloc(n * sizeof(char *) + sz); |
| 170 | p = (char *)(env + n); |
| 171 | |
| 172 | /* --- Dump the output in the big chunk of memory --- */ |
| 173 | |
| 174 | for (sym_mkiter(&i, t); (v = sym_next(&i)) != 0; ) { |
| 175 | const char *name = SYM_NAME(v); |
| 176 | size_t nlen = strlen(name), vlen = strlen(v->v); |
| 177 | *pp++ = p; |
| 178 | memcpy(p, name, nlen); p += nlen; |
| 179 | *p++ = '='; |
| 180 | memcpy(p, v->v, vlen); p += vlen; |
| 181 | *p++ = 0; |
| 182 | } |
| 183 | *pp++ = 0; |
| 184 | return (env); |
| 185 | } |
| 186 | |
| 187 | /* --- @env_destroy@ --- * |
| 188 | * |
| 189 | * Arguments: @sym_table *t@ = pointer to symbol table |
| 190 | * |
| 191 | * Returns: --- |
| 192 | * |
| 193 | * Use: Destroys all the variables in the symbol table. |
| 194 | */ |
| 195 | |
| 196 | void env_destroy(sym_table *t) |
| 197 | { |
| 198 | sym_iter i; |
| 199 | var *v; |
| 200 | |
| 201 | for (sym_mkiter(&i, t); (v = sym_next(&i)) != 0; ) |
| 202 | x_free(t->t.a, v->v); |
| 203 | sym_destroy(t); |
| 204 | } |
| 205 | |
| 206 | /*----- That's all, folks -------------------------------------------------*/ |