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/*
FUNCTION
<<_getenv_r>>---look up environment variable
INDEX
_getenv_r
INDEX
environ
SYNOPSIS
#include <stdlib.h>
char *_getenv_r(struct _reent *<[reent_ptr]>, const char *<[name]>);
DESCRIPTION
<<_getenv_r>> searches the list of environment variable names and values
(using the global pointer ``<<char **environ>>'') for a variable whose
name matches the string at <[name]>. If a variable name matches,
<<_getenv_r>> returns a pointer to the associated value.
RETURNS
A pointer to the (string) value of the environment variable, or
<<NULL>> if there is no such environment variable.
PORTABILITY
<<_getenv_r>> is not ANSI; the rules for properly forming names of environment
variables vary from one system to another. This implementation does not
permit '=' to be in identifiers.
<<_getenv_r>> requires a global pointer <<environ>>.
*/
/* This file may have been modified by DJ Delorie (Jan 1991). If so,
** these modifications are Copyright (C) 1991 DJ Delorie.
*/
/*
* Copyright (c) 1987 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that: (1) source distributions retain this entire copyright
* notice and comment, and (2) distributions including binaries display
* the following acknowledgement: ``This product includes software
* developed by the University of California, Berkeley and its contributors''
* in the documentation or other materials provided with the distribution.
* Neither the name of the University nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#define _GNU_SOURCE
#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include "envlock.h"
extern char **environ;
/* Only deal with a pointer to environ, to work around subtle bugs with shared
libraries and/or small data systems where the user declares his own
'environ'. */
static char ***p_environ = &environ;
/*
* _findenv --
* Returns pointer to value associated with name, if any, else NULL.
* Sets offset to be the offset of the name/value combination in the
* environmental array, for use by setenv(3) and unsetenv(3).
*
* This routine *should* be a static; don't use it.
*/
char *
_findenv(register const char *name, int *offset)
{
register int len;
register char **p;
const char *c;
ENV_LOCK;
/* In some embedded systems, this does not get set. This protects
newlib from dereferencing a bad pointer. */
if (!*p_environ) {
ENV_UNLOCK;
return NULL;
}
c = name;
while (*c && *c != '=')
c++;
/* Identifiers may not contain an '=', so cannot match if does */
if (*c != '=') {
len = c - name;
for (p = *p_environ; *p; ++p)
if (!strncmp(*p, name, len))
if (*(c = *p + len) == '=') {
*offset = p - *p_environ;
ENV_UNLOCK;
return (char *)(++c);
}
}
ENV_UNLOCK;
return NULL;
}
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