79 lines
2.4 KiB
C
79 lines
2.4 KiB
C
/*
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* Copyright (c) 2013
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* The President and Fellows of Harvard College.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE UNIVERSITY OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <stdlib.h>
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#include <string.h>
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/*
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* getenv(): ANSI C
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*
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* Get an environment variable.
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*/
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/*
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* This is initialized by crt0, though it actually lives in errno.c
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*/
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extern char **__environ;
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/*
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* This is what we use by default if the kernel didn't supply an
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* environment.
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*/
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static const char *__default_environ[] = {
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"PATH=/bin:/sbin:/testbin",
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"SHELL=/bin/sh",
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"TERM=vt220",
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NULL
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};
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char *
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getenv(const char *var)
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{
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size_t varlen, thislen;
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char *s;
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unsigned i;
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if (__environ == NULL) {
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__environ = (char **)__default_environ;
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}
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varlen = strlen(var);
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for (i=0; __environ[i] != NULL; i++) {
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s = strchr(__environ[i], '=');
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if (s == NULL) {
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/* ? */
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continue;
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}
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thislen = s - __environ[i];
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if (thislen == varlen && !memcmp(__environ[i], var, thislen)) {
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return s + 1;
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}
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}
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return NULL;
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}
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