/* Copyright (C) 1992-2024 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
#include "environ.h"

#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;
}