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/* 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 <reent.h>

#include <stddef.h>

#include <stdlib.h>

#include <string.h>

#include <time.h>

#include <errno.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_r is defined in getenv_r.c.  */

extern char *_findenv_r _PARAMS ((struct _reent *, const char *, int *));

/*

 * _setenv_r --

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

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

 *      If "name" contains equal sign, -1 is returned, and errno is

 *      set to EINVAL;

 */

int

_DEFUN (_setenv_r, (reent_ptr, name, value, rewrite),

        struct _reent *reent_ptr _AND

        _CONST char *name _AND

        _CONST char *value _AND

        int rewrite)

{

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

  register char *C;

  int l_value, offset;

  if (strchr(name, '='))

    {

      errno = EINVAL;

      return -1;

    }

  ENV_LOCK;

  l_value = strlen (value);

  if ((C = _findenv_r (reent_ptr, name, &offset)))

    {                           /* find if already exists */

      if (!rewrite)

        {

          ENV_UNLOCK;

          return 0;

        }

      if (strlen (C) >= l_value)

        {                       /* old larger; copy over */

          while ((*C++ = *value++) != 0);

          ENV_UNLOCK;

          /* if we are changing the TZ environment variable, update timezone info */

          if (strcmp (name, "TZ") == 0)

            tzset ();

          return 0;

        }

    }

  else

    {                           /* create new slot */

      register int cnt;

      register char **P;

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

      if (alloced)

        {                       /* just increase size */

          *p_environ = (char **) _realloc_r (reent_ptr, (char *) environ,

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

          if (!*p_environ)

            {

              ENV_UNLOCK;

              return -1;

            }

        }

      else

        {                       /* get new space */

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

          P = (char **) _malloc_r (reent_ptr, (size_t) (sizeof (char *) * (cnt + 2)));

          if (!P)

            {

              ENV_UNLOCK;

              return (-1);

            }

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

          *p_environ = P;

        }

      (*p_environ)[cnt + 1] = NULL;

      offset = cnt;

    }

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

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

        _malloc_r (reent_ptr, (size_t) ((int) (C - name) + l_value + 2))))

    {

      ENV_UNLOCK;

      return -1;

    }

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

  for (*C++ = '='; (*C++ = *value++) != 0;);

  ENV_UNLOCK;

  /* if we are setting the TZ environment variable, update timezone info */

  if (strncmp ((*p_environ)[offset], "TZ=", 3) == 0)

    tzset ();

  return 0;

}

/*

 * _unsetenv_r(name) --

 *      Delete environmental variable "name".

 */

int

_DEFUN (_unsetenv_r, (reent_ptr, name),

        struct _reent *reent_ptr _AND

        _CONST char *name)

{

  register char **P;

  int offset;

  /* Name cannot be NULL, empty, or contain an equal sign.  */

  if (name == NULL || name[0] == '\0' || strchr(name, '='))

    {

      errno = EINVAL;

      return -1;

    }

  ENV_LOCK;

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

    {

      for (P = &(*p_environ)[offset];; ++P)

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

          break;

    }

  ENV_UNLOCK;

  return 0;

}