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