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/*

FUNCTION

<<getenv>>---look up environment variable

INDEX

        getenv

INDEX

        environ

ANSI_SYNOPSIS

        #include <stdlib.h>

        char *getenv(const char *<[name]>);

TRAD_SYNOPSIS

        #include <stdlib.h>

        char *getenv(<[name]>)

        char *<[name]>;

DESCRIPTION

<<getenv>> 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>> 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>> is ANSI, but the rules for properly forming names of environment

variables vary from one system to another.

<<getenv>> requires a global pointer <<environ>>.

*/

/* This file may have been modified by DJ Delorie (Jan 1991).  If so,

** these modifications are Coyright (C) 1991 DJ Delorie, 24 Kirsten Ave,

** Rochester NH, 03867-2954, USA.

*/

/*

 * 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>

extern char **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, (name, offset),

        register _CONST char *name _AND

        int *offset)

{

  register int len;

  register char **p;

  _CONST char *c;

  /* In some embedded systems, this does not get set.  This protects

     newlib from dereferencing a bad pointer.  */

  if (!environ)

    return NULL;

  c = name;

  len = 0;

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

    {

      c++;

      len++;

    }

  for (p = environ; *p; ++p)

    if (!strncmp (*p, name, len))

      if (*(c = *p + len) == '=')

        {

          *offset = p - environ;

          return (char *) (++c);

        }

  return NULL;

}

/*

 * getenv --

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

 */

char *

_DEFUN (getenv, (name),

        _CONST char *name)

{

  int offset;

  char *_findenv ();

  return _findenv (name, &offset);

}