/* Support for *xattr interfaces on GNU/Hurd.

   Copyright (C) 2006-2018 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/>.  */

#include <hurd.h>

#include <hurd/xattr.h>

#include <string.h>

#include <sys/mman.h>

/* Right now we support only a fixed set of xattr names for Hurd features.

   There are no RPC interfaces for free-form xattr names and values.

   Name			Value encoding

   ----			----- --------

   gnu.author		empty if st_author==st_uid

			uid_t giving st_author value

   gnu.translator	empty if no passive translator

			translator and arguments: "/hurd/foo\0arg1\0arg2\0"

*/

error_t

_hurd_xattr_get (io_t port, const char *name, void *value, size_t *size)

{

  if (strncmp (name, "gnu.", 4))

    return EOPNOTSUPP;

  name += 4;

  if (!strcmp (name, "author"))

    {

      struct stat64 st;

      error_t err = __io_stat (port, &st);

      if (err)

	return err;

      if (st.st_author == st.st_uid)

	*size = 0;

      else if (value)

	{

	  if (*size < sizeof st.st_author)

	    return ERANGE;

	  memcpy (value, &st.st_author, sizeof st.st_author);

	}

      *size = sizeof st.st_author;

      return 0;

    }

  if (!strcmp (name, "translator"))

    {

      char *buf = value;

      size_t bufsz = value ? *size : 0;

      error_t err = __file_get_translator (port, &buf, &bufsz);

      if (err)

	return err;

      if (value != NULL && *size < bufsz)

	{

	  if (buf != value)

	    __munmap (buf, bufsz);

	  return -ERANGE;

	}

      if (buf != value && bufsz > 0)

	{

	  if (value != NULL)

	    memcpy (value, buf, bufsz);

	  __munmap (buf, bufsz);

	}

      *size = bufsz;

      return 0;

    }

  return EOPNOTSUPP;

}

error_t

_hurd_xattr_set (io_t port, const char *name, const void *value, size_t size,

		 int flags)

{

  if (strncmp (name, "gnu.", 4))

    return EOPNOTSUPP;

  name += 4;

  if (!strcmp (name, "author"))

    switch (size)

      {

      default:

	return EINVAL;

      case 0:			/* "Clear" author by setting to st_uid. */

	{

	  struct stat64 st;

	  error_t err = __io_stat (port, &st);

	  if (err)

	    return err;

	  if (st.st_author == st.st_uid)

	    {

	      /* Nothing to do.  */

	      if (flags & XATTR_REPLACE)

		return ENODATA;

	      return 0;

	    }

	  if (flags & XATTR_CREATE)

	    return EEXIST;

	  return __file_chauthor (port, st.st_uid);

	}

      case sizeof (uid_t):	/* Set the author.  */

	{

	  uid_t id;

	  memcpy (&id, value, sizeof id);

	  if (flags & (XATTR_CREATE|XATTR_REPLACE))

	    {

	      struct stat64 st;

	      error_t err = __io_stat (port, &st);

	      if (err)

		return err;

	      if (st.st_author == st.st_uid)

		{

		  if (flags & XATTR_REPLACE)

		    return ENODATA;

		}

	      else if (flags & XATTR_CREATE)

		return EEXIST;

	      if (st.st_author == id)

		/* Nothing to do.  */

		return 0;

	    }

	  return __file_chauthor (port, id);

	}

      }

  if (!strcmp (name, "translator"))

    {

      if (flags & XATTR_REPLACE)

	{

	  /* Must make sure it's already there.  */

	  char *buf = NULL;

	  size_t bufsz = 0;

	  error_t err = __file_get_translator (port, &buf, &bufsz);

	  if (err)

	    return err;

	  if (bufsz > 0)

	    {

	      __munmap (buf, bufsz);

	      return ENODATA;

	    }

	}

      return __file_set_translator (port,

				    FS_TRANS_SET | ((flags & XATTR_CREATE)

						    ? FS_TRANS_EXCL : 0), 0, 0,

				    value, size,

				    MACH_PORT_NULL, MACH_MSG_TYPE_COPY_SEND);

    }

  return EOPNOTSUPP;

}

error_t

_hurd_xattr_remove (io_t port, const char *name)

{

  return _hurd_xattr_set (port, name, NULL, 0, XATTR_REPLACE);

}

error_t

_hurd_xattr_list (io_t port, void *buffer, size_t *size)

{

  size_t total = 0;

  char *bufp = buffer;

  inline void add (const char *name, size_t len)

    {

      total += len;

      if (bufp != NULL && total <= *size)

	bufp = __mempcpy (bufp, name, len);

    }

#define add(s) add (s, sizeof s)

  struct stat64 st;

  error_t err = __io_stat (port, &st);

  if (err)

    return err;

  if (st.st_author != st.st_uid)

    add ("gnu.author");

  if (st.st_mode & S_IPTRANS)

    add ("gnu.translator");

  if (buffer != NULL && total > *size)

    return ERANGE;

  *size = total;

  return 0;

}