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/*

FUNCTION

<<_getenv_r>>---look up environment variable

INDEX

        _getenv_r

INDEX

        environ

ANSI_SYNOPSIS

        #include <stdlib.h>

        char *_getenv_r(struct _reent *<[reent_ptr]>, const char *<[name]>);

TRAD_SYNOPSIS

        #include <stdlib.h>

        char *_getenv_r(<[reent_ptr]>, <[name]>)

        struct _reent *<[reent_ptr]>;

        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.

<<_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

 * and in all advertising materials mentioning features or use of this

 * software. 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.

 */

#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).

 *      Explicitly removes '=' in argument name.

 *

 *      This routine *should* be a static; don't use it.

 */

char *

_DEFUN (_findenv_r, (reent_ptr, name, offset),

        struct _reent *reent_ptr   _AND

        register _CONST char *name _AND

        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)

    return NULL;

  c = name;

  len = 0;

  while (*c && *c != '=')

    {

      c++;

      len++;

    }

  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;

}

/*

 * _getenv_r --

 *      Returns ptr to value associated with name, if any, else NULL.

 */

char *

_DEFUN (_getenv_r, (reent_ptr, name),

        struct _reent *reent_ptr _AND

        _CONST char *name)

{

  int offset;

  char *_findenv_r ();

  return _findenv_r (reent_ptr, name, &offset);

}