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/* 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 <stddef.h>

#include <stdlib.h>

#include <string.h>

/* _findenv is defined in getenv.c.  */

extern char *_findenv _PARAMS ((const char *, int *));

/*

 * setenv --

 *      Set the value of the environmental variable "name" to be

 *      "value".  If rewrite is set, replace any current value.

 */

int

_DEFUN (setenv, (name, value, rewrite),

        _CONST char *name _AND

        _CONST char *value _AND

        int rewrite)

{

  extern char **environ;

  static int alloced;           /* if allocated space before */

  register char *C;

  int l_value, offset;

  if (*value == '=')            /* no `=' in value */

    ++value;

  l_value = strlen (value);

  if ((C = _findenv (name, &offset)))

    {                           /* find if already exists */

      if (!rewrite)

        return 0;

      if (strlen (C) >= l_value)

        {                       /* old larger; copy over */

          while (*C++ = *value++);

          return 0;

        }

    }

  else

    {                           /* create new slot */

      register int cnt;

      register char **P;

      for (P = environ, cnt = 0; *P; ++P, ++cnt);

      if (alloced)

        {                       /* just increase size */

          environ = (char **) realloc ((char *) environ,

                                       (size_t) (sizeof (char *) * (cnt + 2)));

          if (!environ)

            return -1;

        }

      else

        {                       /* get new space */

          alloced = 1;          /* copy old entries into it */

          P = (char **) malloc ((size_t) (sizeof (char *) * (cnt + 2)));

          if (!P)

            return (-1);

          bcopy ((char *) environ, (char *) P, cnt * sizeof (char *));

          environ = P;

        }

      environ[cnt + 1] = NULL;

      offset = cnt;

    }

  for (C = (char *) name; *C && *C != '='; ++C);        /* no `=' in name */

  if (!(environ[offset] =       /* name + `=' + value */

        malloc ((size_t) ((int) (C - name) + l_value + 2))))

    return -1;

  for (C = environ[offset]; (*C = *name++) && *C != '='; ++C);

  for (*C++ = '='; *C++ = *value++;);

  return 0;

}

/*

 * unsetenv(name) --

 *      Delete environmental variable "name".

 */

void

_DEFUN (unsetenv, (name),

        _CONST char *name)

{

  extern char **environ;

  register char **P;

  int offset;

  while (_findenv (name, &offset))      /* if set multiple times */

    for (P = &environ[offset];; ++P)

      if (!(*P = *(P + 1)))

        break;

}