/*
 *  IMFS file change mode routine.
 *
 *  COPYRIGHT (c) 1989-1999.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.OARcorp.com/rtems/license.html.
 *
 *  $Id$
 */

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

#include <errno.h>

#include <rtems/libio_.h>
#include <rtems/seterr.h>
#include "imfs.h"

int IMFS_fchmod(
  rtems_filesystem_location_info_t *loc,
  mode_t                            mode
)
{
  IMFS_jnode_t  *jnode;
#if defined(RTEMS_POSIX_API)
  uid_t          st_uid;
#endif
   int IMFS_memfile_write(
      IMFS_jnode_t          *the_jnode,
      off_t                  start,
      const unsigned char   *source,
      unsigned int           length
   );

    
  jnode = loc->node_access;

  /*
   *  Verify I am the owner of the node or the super user.
   */
#if defined(RTEMS_POSIX_API)
  st_uid = geteuid();

  if ( ( st_uid != jnode->st_uid ) && ( st_uid != 0 ) )
    rtems_set_errno_and_return_minus_one( EPERM );
#endif

  /*
   * Change only the RWX permissions on the jnode to mode.
   */
  if ( mode & (~ (S_IRWXU | S_IRWXG | S_IRWXO ) ) )
    rtems_set_errno_and_return_minus_one( EPERM );

  /*
   * If we make a linear-file writeable, construct a block file
   * from it first.
   */
  if ( (jnode->type == IMFS_LINEAR_FILE) &&
       (mode & (S_IWUSR | S_IWGRP | S_IWOTH)) )
  {
    unsigned32 count = jnode->info.linearfile.size;
    const unsigned char *buffer = jnode->info.linearfile.direct;

    jnode->type = IMFS_MEMORY_FILE;
    jnode->info.file.size            = 0;
    jnode->info.file.indirect        = 0;
    jnode->info.file.doubly_indirect = 0;
    jnode->info.file.triply_indirect = 0;
    if (IMFS_memfile_write(jnode, 0, buffer, count) == -1)
       return(-1);
  }

  jnode->st_mode &= ~(S_IRWXU | S_IRWXG | S_IRWXO);
  jnode->st_mode |= mode;

  IMFS_update_ctime( jnode );

  return 0;
}