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/* Copyright (C) 1992, 1995, 1996, 1997, 2002, 2011 Free Software Foundation,

   Inc.

   This file based on setenv.c in the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Library General Public License as

   published by the Free Software Foundation; either version 2 of the

   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public

   License along with the GNU C Library; see the file COPYING.LIB.  If not,

   write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,

   Boston, MA 02110-1301, USA.  */

/*

@deftypefn Supplemental int setenv (const char *@var{name}, @

  const char *@var{value}, int @var{overwrite})

@deftypefnx Supplemental void unsetenv (const char *@var{name})

@code{setenv} adds @var{name} to the environment with value

@var{value}.  If the name was already present in the environment,

the new value will be stored only if @var{overwrite} is nonzero.

The companion @code{unsetenv} function removes @var{name} from the

environment.  This implementation is not safe for multithreaded code.

@end deftypefn

*/

#if HAVE_CONFIG_H

# include <config.h>

#endif

#define setenv libiberty_setenv

#define unsetenv libiberty_unsetenv

#include "ansidecl.h"

#include <sys/types.h> /* For `size_t' */

#include <stdio.h>     /* For `NULL' */

#include <errno.h>

#if !defined(errno) && !defined(HAVE_ERRNO_DECL)

extern int errno;

#endif

#define __set_errno(ev) ((errno) = (ev))

#if HAVE_STDLIB_H

# include <stdlib.h>

#endif

#if HAVE_STRING_H

# include <string.h>

#endif

#if HAVE_UNISTD_H

# include <unistd.h>

#endif

#define __environ       environ

#ifndef HAVE_ENVIRON_DECL

extern char **environ;

#endif

#undef setenv

#undef unsetenv

/* LOCK and UNLOCK are defined as no-ops.  This makes the libiberty

 * implementation MT-Unsafe. */

#define LOCK

#define UNLOCK

/* Below this point, it's verbatim code from the glibc-2.0 implementation */

/* If this variable is not a null pointer we allocated the current

   environment.  */

static char **last_environ;

int

setenv (const char *name, const char *value, int replace)

{

  register char **ep = 0;

  register size_t size;

  const size_t namelen = strlen (name);

  const size_t vallen = strlen (value) + 1;

  LOCK;

  size = 0;

  if (__environ != NULL)

    {

      for (ep = __environ; *ep != NULL; ++ep)

        if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')

          break;

        else

          ++size;

    }

  if (__environ == NULL || *ep == NULL)

    {

      char **new_environ;

      if (__environ == last_environ && __environ != NULL)

        /* We allocated this space; we can extend it.  */

        new_environ = (char **) realloc (last_environ,

                                         (size + 2) * sizeof (char *));

      else

        new_environ = (char **) malloc ((size + 2) * sizeof (char *));

      if (new_environ == NULL)

        {

          UNLOCK;

          return -1;

        }

      new_environ[size] = (char *) malloc (namelen + 1 + vallen);

      if (new_environ[size] == NULL)

        {

          free ((char *) new_environ);

          __set_errno (ENOMEM);

          UNLOCK;

          return -1;

        }

      if (__environ != last_environ)

        memcpy ((char *) new_environ, (char *) __environ,

                size * sizeof (char *));

      memcpy (new_environ[size], name, namelen);

      new_environ[size][namelen] = '=';

      memcpy (&new_environ[size][namelen + 1], value, vallen);

      new_environ[size + 1] = NULL;

      last_environ = __environ = new_environ;

    }

  else if (replace)

    {

      size_t len = strlen (*ep);

      if (len + 1 < namelen + 1 + vallen)

        {

          /* The existing string is too short; malloc a new one.  */

          char *new_string = (char *) malloc (namelen + 1 + vallen);

          if (new_string == NULL)

            {

              UNLOCK;

              return -1;

            }

          *ep = new_string;

        }

      memcpy (*ep, name, namelen);

      (*ep)[namelen] = '=';

      memcpy (&(*ep)[namelen + 1], value, vallen);

    }

  UNLOCK;

  return 0;

}

void

unsetenv (const char *name)

{

  const size_t len = strlen (name);

  char **ep;

  LOCK;

  for (ep = __environ; *ep; ++ep)

    if (!strncmp (*ep, name, len) && (*ep)[len] == '=')

      {

        /* Found it.  Remove this pointer by moving later ones back.  */

        char **dp = ep;

        do

          dp[0] = dp[1];

        while (*dp++);

        /* Continue the loop in case NAME appears again.  */

      }

  UNLOCK;

}