/* Copyright (C) 1991-2018 Free Software Foundation, Inc.

   This file is part of 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 Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 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

   Lesser General Public License for more details.

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

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#if defined _AIX && !defined __GNUC__

 #pragma alloca

#endif

#if HAVE_CONFIG_H

# include <config.h>

#endif

#if _LIBC || HAVE_STDLIB_H

# include <stdlib.h>

#endif

#if _LIBC || HAVE_STRING_H

# include <string.h>

#endif

#if !__GNU_LIBRARY__ && !HAVE_STRCHR

# define strchr index

#endif

#ifndef _LIBC

# ifdef HAVE_ALLOCA_H

#  include <alloca.h>

# else

#  ifdef __GNUC__

#   define alloca __builtin_alloca

#  else

extern char *alloca ();

#  endif /* __GNUC__ */

# endif /* HAVE_ALLOCA_H */

#endif /* _LIBC */

/* Put STRING, which is of the form "NAME=VALUE", in the environment.  */

int

putenv (char *string)

{

  const char *const name_end = strchr (string, '=');

  if (name_end != NULL)

    {

      char *name;

#ifdef _LIBC

      int use_malloc = !__libc_use_alloca (name_end - string + 1);

      if (__builtin_expect (use_malloc, 0))

	{

	  name = __strndup (string, name_end - string);

	  if (name == NULL)

	    return -1;

	}

      else

	name = strndupa (string, name_end - string);

#else

# define use_malloc 1

      name = malloc (name_end - string + 1);

      if (name == NULL)

	return -1;

      memcpy (name, string, name_end - string);

      name[name_end - string] = '\0';

#endif

      int result = __add_to_environ (name, NULL, string, 1);

      if (__glibc_unlikely (use_malloc))

	free (name);

      return result;

    }

  __unsetenv (string);

  return 0;

}