fsal_unlink.c

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/*
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 * Copyright CEA/DAM/DIF  (2008)
 * contributeur : Philippe DENIEL   philippe.deniel@cea.fr
 *                Thomas LEIBOVICI  thomas.leibovici@cea.fr
 *
 *
 * This program 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 3 of the License, or (at your option) any later version.
 *
 * This program 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 this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * ------------- 
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "fsal.h"
#include "fsal_internal.h"
#include "FSAL/access_check.h"
#include "fsal_convert.h"
#include <unistd.h>

fsal_status_t VFSFSAL_unlink(fsal_handle_t * p_parent_directory_handle,    /* IN */
                          fsal_name_t * p_object_name,  /* IN */
                          fsal_op_context_t * p_context,        /* IN */
                          fsal_attrib_list_t * p_parent_directory_attributes    /* [IN/OUT ] */
    )
{

  fsal_status_t status;
  int rc, errsv;
  struct stat buffstat, buffstat_parent;
  int fd;
  uid_t user = ((vfsfsal_op_context_t *)p_context)->credential.user;

  /* sanity checks. */
  if(!p_parent_directory_handle || !p_context || !p_object_name)
    Return(ERR_FSAL_FAULT, 0, INDEX_FSAL_unlink);

  /* build the FID path */
  TakeTokenFSCall();
  status =
      fsal_internal_handle2fd(p_context, p_parent_directory_handle, &fd,
                              O_RDONLY | O_DIRECTORY);
  ReleaseTokenFSCall();
  if(FSAL_IS_ERROR(status))
    ReturnStatus(status, INDEX_FSAL_unlink);

  /* get directory metadata */
  TakeTokenFSCall();
  rc = fstat(fd, &buffstat_parent);
  errsv = errno;
  ReleaseTokenFSCall();
  if(rc)
    {
      close(fd);

      if(errsv == ENOENT)
        Return(ERR_FSAL_STALE, errsv, INDEX_FSAL_unlink);
      else
        Return(posix2fsal_error(errsv), errsv, INDEX_FSAL_unlink);
    }

  /* build the child path */

  /* get file metadata */
  TakeTokenFSCall();
  rc = fstatat(fd, p_object_name->name, &buffstat, AT_SYMLINK_NOFOLLOW);
  errsv = errno;
  ReleaseTokenFSCall();
  if(rc)
    {
      close(fd);
      Return(posix2fsal_error(errno), errno, INDEX_FSAL_unlink);
    }

  /* check access rights */

  /* Sticky bit on the directory => the user who wants to delete the file must own it or its parent dir */
  if((buffstat_parent.st_mode & S_ISVTX)
     && buffstat_parent.st_uid != user
     && buffstat.st_uid != user && user != 0)
    {
      close(fd);
      Return(ERR_FSAL_ACCESS, 0, INDEX_FSAL_unlink);
    }

  /* client must be able to lookup the parent directory and modify it */
  status =
      fsal_check_access(p_context, FSAL_W_OK | FSAL_X_OK, &buffstat_parent, NULL);
  if(FSAL_IS_ERROR(status))
    ReturnStatus(status, INDEX_FSAL_unlink);

  /******************************
   * DELETE FROM THE FILESYSTEM *
   ******************************/
  TakeTokenFSCall();
  /* If the object to delete is a directory, use 'rmdir' to delete the object, else use 'unlink' */
  rc = (S_ISDIR(buffstat.st_mode)) ? unlinkat(fd, p_object_name->name,
                                              AT_REMOVEDIR) : unlinkat(fd,
                                                                       p_object_name->
                                                                       name, 0);
  errsv = errno;
  ReleaseTokenFSCall();

  close(fd);

  if(rc)
    Return(posix2fsal_error(errsv), errsv, INDEX_FSAL_unlink);

  /***********************
   * FILL THE ATTRIBUTES *
   ***********************/

  if(p_parent_directory_attributes)
    {
      status =
          VFSFSAL_getattrs(p_parent_directory_handle, p_context,
                        p_parent_directory_attributes);
      if(FSAL_IS_ERROR(status))
        {
          FSAL_CLEAR_MASK(p_parent_directory_attributes->asked_attributes);
          FSAL_SET_MASK(p_parent_directory_attributes->asked_attributes,
                        FSAL_ATTR_RDATTR_ERR);
        }
    }
  /* OK */
  Return(ERR_FSAL_NO_ERROR, 0, INDEX_FSAL_unlink);

}