/****************************************************************************
 *                                                                          *
 *                         GNAT COMPILER COMPONENTS                         *
 *                                                                          *
 *                                  E N V                                   *
 *                                                                          *
 *                          C Implementation File                           *
 *                                                                          *
 *            Copyright (C) 2005-2009, Free Software Foundation, Inc.       *
 *                                                                          *
 * GNAT is free software;  you can  redistribute it  and/or modify it under *
 * terms of the  GNU General Public License as published  by the Free Soft- *
 * ware  Foundation;  either version 3,  or (at your option) any later ver- *
 * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
 * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
 * or FITNESS FOR A PARTICULAR PURPOSE.                                     *
 *                                                                          *
 * As a special exception under Section 7 of GPL version 3, you are granted *
 * additional permissions described in the GCC Runtime Library Exception,   *
 * version 3.1, as published by the Free Software Foundation.               *
 *                                                                          *
 * You should have received a copy of the GNU General Public License and    *
 * a copy of the GCC Runtime Library Exception along with this program;     *
 * see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    *
 * <http://www.gnu.org/licenses/>.                                          *
 *                                                                          *
 * GNAT was originally developed  by the GNAT team at  New York University. *
 * Extensive contributions were provided by Ada Core Technologies Inc.      *
 *                                                                          *
 ****************************************************************************/

/* Tru64 UNIX V4.0F <stdlib.h> declares unsetenv() only if AES_SOURCE (which
   is plain broken, this should be _AES_SOURCE instead as everywhere else;
   Tru64 UNIX V5.1B declares it only if _BSD.  */
#if defined (__alpha__) && defined (__osf__)
#define AES_SOURCE
#define _BSD
#endif

#ifdef IN_RTS
#include "tconfig.h"
#include "tsystem.h"

#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#ifdef VMS
#include <unixio.h>
#endif

#if defined (__MINGW32__)
#include <stdlib.h>
#endif

#if defined (__vxworks) && ! (defined (__RTP__) || defined (__COREOS__))
#include "envLib.h"
extern char** ppGlobalEnviron;
#endif

/* We don't have libiberty, so use malloc.  */
#define xmalloc(S) malloc (S)
#else /* IN_RTS */
#include "config.h"
#include "system.h"
#endif /* IN_RTS */

#if defined (__APPLE__)
#include <crt_externs.h>
#endif

#include "env.h"

void
__gnat_getenv (char *name, int *len, char **value)
{
  *value = getenv (name);
  if (!*value)
    *len = 0;
  else
    *len = strlen (*value);

  return;
}

/* VMS specific declarations for set_env_value.  */

#ifdef VMS

static char *to_host_path_spec (char *);

struct descriptor_s
{
  unsigned short len, mbz;
  __char_ptr32 adr;
};

typedef struct _ile3
{
  unsigned short len, code;
  __char_ptr32 adr;
  unsigned short *retlen_adr;
} ile_s;

#endif

void
__gnat_setenv (char *name, char *value)
{
#ifdef MSDOS

#elif defined (VMS)
  struct descriptor_s name_desc;
  /* Put in JOB table for now, so that the project stuff at least works.  */
  struct descriptor_s table_desc = {7, 0, "LNM$JOB"};
  char *host_pathspec = value;
  char *copy_pathspec;
  int num_dirs_in_pathspec = 1;
  char *ptr;
  long status;

  name_desc.len = strlen (name);
  name_desc.mbz = 0;
  name_desc.adr = name;

  if (*host_pathspec == 0)
    /* deassign */
    {
      status = LIB$DELETE_LOGICAL (&name_desc, &table_desc);
      /* no need to check status; if the logical name is not
         defined, that's fine. */
      return;
    }

  ptr = host_pathspec;
  while (*ptr++)
    if (*ptr == ',')
      num_dirs_in_pathspec++;

  {
    int i, status;
    ile_s *ile_array = alloca (sizeof (ile_s) * (num_dirs_in_pathspec + 1));
    char *copy_pathspec = alloca (strlen (host_pathspec) + 1);
    char *curr, *next;

    strcpy (copy_pathspec, host_pathspec);
    curr = copy_pathspec;
    for (i = 0; i < num_dirs_in_pathspec; i++)
      {
	next = strchr (curr, ',');
	if (next == 0)
	  next = strchr (curr, 0);

	*next = 0;
	ile_array[i].len = strlen (curr);

	/* Code 2 from lnmdef.h means it's a string.  */
	ile_array[i].code = 2;
	ile_array[i].adr = curr;

	/* retlen_adr is ignored.  */
	ile_array[i].retlen_adr = 0;
	curr = next + 1;
      }

    /* Terminating item must be zero.  */
    ile_array[i].len = 0;
    ile_array[i].code = 0;
    ile_array[i].adr = 0;
    ile_array[i].retlen_adr = 0;

    status = LIB$SET_LOGICAL (&name_desc, 0, &table_desc, 0, ile_array);
    if ((status & 1) != 1)
      LIB$SIGNAL (status);
  }

#elif (defined (__vxworks) && defined (__RTP__)) || defined (__APPLE__)
  setenv (name, value, 1);

#else
  size_t size = strlen (name) + strlen (value) + 2;
  char *expression;

  expression = (char *) xmalloc (size * sizeof (char));

  sprintf (expression, "%s=%s", name, value);
  putenv (expression);
#if (defined (__FreeBSD__) && (__FreeBSD__ < 7)) \
   || defined (__MINGW32__) \
   ||(defined (__vxworks) && ! defined (__RTP__))
  /* On some systems like FreeBSD 6.x and earlier, MacOS X and Windows,
     putenv is making a copy of the expression string so we can free
     it after the call to putenv */
  free (expression);
#endif
#endif
}

char **
__gnat_environ (void)
{
#if defined (VMS) || defined (RTX) || defined (VTHREADS)
  /* Not implemented */
  return NULL;
#elif defined (__APPLE__)
  char ***result = _NSGetEnviron ();
  return *result;
#elif defined (__MINGW32__)
  return _environ;
#elif defined (sun)
  extern char **_environ;
  return _environ;
#else
#if ! (defined (__vxworks) && ! (defined (__RTP__) || defined (__COREOS__)))
  /* in VxWorks kernel mode environ is macro and not a variable */
  /* same thing on 653 in the CoreOS */
  extern char **environ;
#endif
  return environ;
#endif
}

void __gnat_unsetenv (char *name) {
#if defined (VMS)
  /* Not implemented */
  return;
#elif defined (__hpux__) || defined (sun) \
     || (defined (__mips) && defined (__sgi)) \
     || (defined (__vxworks) && ! defined (__RTP__)) \
     || defined (_AIX) || defined (__Lynx__)

  /* On Solaris, HP-UX and IRIX there is no function to clear an environment
     variable. So we look for the variable in the environ table and delete it
     by setting the entry to NULL. This can clearly cause some memory leaks
     but free cannot be used on this context as not all strings in the environ
     have been allocated using malloc. To avoid this memory leak another
     method can be used. It consists in forcing the reallocation of all the
     strings in the environ table using malloc on the first call on the
     functions related to environment variable management. The disadvantage
     is that if a program makes a direct call to getenv the return string
     may be deallocated at some point. */
  /* Note that on AIX, unsetenv is not supported on 5.1 but it is on 5.3.
     As we are still supporting AIX 5.1 we cannot use unsetenv */
  char **env = __gnat_environ ();
  int index = 0;
  size_t size = strlen (name);

  while (env[index] != NULL) {
     if (strlen (env[index]) > size) {
       if (strstr (env[index], name) == env[index] &&
	   env[index][size] == '=') {
#if defined (__vxworks) && ! defined (__RTP__)
         /* on Vxworks we are sure that the string has been allocated using
            malloc */
         free (env[index]);
#endif
         while (env[index] != NULL) {
          env[index]=env[index + 1];
          index++;
         }
       } else
           index++;
     } else
         index++;
  }
#elif defined (__MINGW32__)
  /* On Windows platform putenv ("key=") is equivalent to unsetenv (a
     subsequent call to getenv ("key") will return NULL and not the "\0"
     string */
  size_t size = strlen (name) + 2;
  char *expression;
  expression = (char *) xmalloc (size * sizeof (char));

  sprintf (expression, "%s=", name);
  putenv (expression);
  free (expression);
#else
  unsetenv (name);
#endif
}

void __gnat_clearenv (void) {
#if defined (VMS)
  /* not implemented */
  return;
#elif defined (sun) || (defined (__mips) && defined (__sgi)) \
   || (defined (__vxworks) && ! defined (__RTP__)) || defined (__Lynx__)
  /* On Solaris, IRIX, VxWorks (not RTPs), and Lynx there is no system
     call to unset a variable or to clear the environment so set all
     the entries in the environ table to NULL (see comment in
     __gnat_unsetenv for more explanation). */
  char **env = __gnat_environ ();
  int index = 0;

  while (env[index] != NULL) {
    env[index]=NULL;
    index++;
  }
#elif defined (__MINGW32__) || defined (__FreeBSD__) || defined (__APPLE__) \
   || (defined (__vxworks) && defined (__RTP__)) || defined (__CYGWIN__) \
   || defined (__NetBSD__) || defined (__OpenBSD__) || defined (__rtems__)
  /* On Windows, FreeBSD and MacOS there is no function to clean all the
     environment but there is a "clean" way to unset a variable. So go
     through the environ table and call __gnat_unsetenv on all entries */
  char **env = __gnat_environ ();
  size_t size;

  while (env[0] != NULL) {
    size = 0;
    while (env[0][size] != '=')
      size++;
    /* create a string that contains "name" */
    size++;
    {
      char expression[size];
      strncpy (expression, env[0], size);
      expression[size - 1] = 0;
      __gnat_unsetenv (expression);
    }
  }
#else
  clearenv ();
#endif
}