Subversion Repositories openrisc_2011-10-31

/*

 *  XXX

 *

 *  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: imfs_directory.c,v 1.2 2001-09-27 12:01:15 chris Exp $

 */

#include <sys/types.h>

#include <sys/stat.h>

#include <chain.h>

#include <fcntl.h>

#include <errno.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <assert.h>

#include <dirent.h>

#include "imfs.h"

#include "libio_.h"

/* -----------------------------------------------------------------------

 * This rountine will verify that the node being opened as a directory is

 * in fact a directory node. If it is then the offset into the directory

 * will be set to 0 to position to the first directory entry.

 */

int imfs_dir_open(

  rtems_libio_t  *iop,

  const char *pathname,

  unsigned32 flag,

  unsigned32 mode

)

{

  IMFS_jnode_t      *the_jnode;

  /* Is the node a directory ? */

  the_jnode = (IMFS_jnode_t *) iop->file_info;

  if ( the_jnode->type != IMFS_DIRECTORY )

     return -1;         /* It wasn't a directory --> return error */

  iop->offset = 0;

  return 0;

}

/* -----------------------------------------------------------------------

 * This routine will read the next directory entry based on the directory

 * offset. The offset should be equal to -n- time the size of an individual

 * dirent structure. If n is not an integer multiple of the sizeof a

 * dirent structure, an integer division will be performed to determine

 * directory entry that will be returned in the buffer. Count should reflect

 * -m- times the sizeof dirent bytes to be placed in the buffer.

 * If there are not -m- dirent elements from the current directory position

 * to the end of the exisiting file, the remaining entries will be placed in

 * the buffer and the returned value will be equal to -m actual- times the

 * size of a directory entry.

 */

int imfs_dir_read(

  rtems_libio_t  *iop,

  void *buffer,

  unsigned32 count

)

{

  /*

   *  Read up to element  iop->offset in the directory chain of the

   *  imfs_jnode_t struct for this file descriptor.

   */

   Chain_Node        *the_node;

   Chain_Control     *the_chain;

   IMFS_jnode_t      *the_jnode;

   int                bytes_transferred;

   int                current_entry;

   int                first_entry;

   int                last_entry;

   struct dirent      tmp_dirent;

   the_jnode = (IMFS_jnode_t *)iop->file_info;

   the_chain = &the_jnode->info.directory.Entries;

   if ( Chain_Is_empty( the_chain ) )

      return 0;

   /* Move to the first of the desired directory entries */

   the_node = the_chain->first;

   bytes_transferred = 0;

   first_entry = iop->offset;

   /* protect against using sizes that are not exact multiples of the */

   /* -dirent- size. These could result in unexpected results          */

   last_entry = first_entry + (count/sizeof(struct dirent)) * sizeof(struct dirent);

   /* The directory was not empty so try to move to the desired entry in chain*/

   for(

      current_entry = 0;

      current_entry < last_entry;

      current_entry = current_entry + sizeof(struct dirent) ){

      if ( Chain_Is_tail( the_chain, the_node ) ){

         /* We hit the tail of the chain while trying to move to the first */

         /* entry in the read */

         return bytes_transferred;  /* Indicate that there are no more */

                                    /* entries to return */

      }

      if( current_entry >= first_entry ) {

         /* Move the entry to the return buffer */

         tmp_dirent.d_ino = 1;

         tmp_dirent.d_off = current_entry;

         tmp_dirent.d_reclen = sizeof( struct dirent );

         the_jnode = (IMFS_jnode_t *) the_node;

         tmp_dirent.d_namlen = strlen( the_jnode->name );

         strcpy( tmp_dirent.d_name, the_jnode->name );

         memcpy(

            buffer + bytes_transferred,

            (void *)&tmp_dirent,

            sizeof( struct dirent )

         );

         iop->offset = iop->offset + sizeof(struct dirent);

         bytes_transferred = bytes_transferred + sizeof( struct dirent );

      }

      the_node = the_node->next;

   }

   /* Success */

   return bytes_transferred;

}

/* -----------------------------------------------------------------------

 * This routine will be called by the generic close routine to cleanup any

 * resources that have been allocated for the management of the file

 */

int imfs_dir_close(

  rtems_libio_t  *iop

)

{

  /* The generic close routine handles the deallocation of the file control */

  /* and associated memory. At present the imfs_dir_close simply      */

  /* returns a successful completion status                                 */

  return 0;

}

/* -----------------------------------------------------------------------

 * This routine will behave in one of three ways based on the state of

 * argument whence. Based on the state of its value the offset argument will

 * be interpreted using one of the following methods:

 *

 *      SEEK_SET - offset is the absolute byte offset from the start of the

 *                 logical start of the dirent sequence that represents the

 *                 directory

 *      SEEK_CUR - offset is used as the relative byte offset from the current

 *                 directory position index held in the iop structure

 *      SEEK_END - N/A --> This will cause an assert.

 */

int imfs_dir_lseek(

  rtems_libio_t  *iop,

  off_t           offset,

  int             whence

)

{

  off_t normal_offset;

  normal_offset = (offset/sizeof(struct dirent)) * sizeof(struct dirent);

  switch( whence )

  {

     case SEEK_SET:     /* absolute move from the start of the file */

        iop->offset = normal_offset;

        break;

     case SEEK_CUR:     /* relative move */

        iop->offset = iop->offset + normal_offset;

        break;

     case SEEK_END:     /* Movement past the end of the directory via lseek */

                        /* is not a permitted operation                     */

      default:

        set_errno_and_return_minus_one( EINVAL );

        break;

  }

  return 0;

}

/* -----------------------------------------------------------------------

 * This routine will obtain the following information concerning the current

 * directory:

 *      st_dev          0ll

 *      st_ino          1

 *      st_mode         mode extracted from the jnode

 *      st_nlink        number of links to this node

 *      st_uid          uid extracted from the jnode

 *      st_gid          gid extracted from the jnode

 *      st_rdev         0ll

 *      st_size         the number of bytes in the directory

 *                      This is calculated by taking the number of entries

 *                      in the directory and multiplying by the size of a

 *                      dirent structure

 *      st_blksize      0

 *      st_blocks       0

 *      stat_atime      time of last access

 *      stat_mtime      time of last modification

 *      stat_ctime      time of the last change

 *

 * This information will be returned to the calling function in a -stat- struct

 *

 */

int imfs_dir_fstat(

  rtems_filesystem_location_info_t *loc,

  struct stat                      *buf

)

{

   Chain_Node        *the_node;

   Chain_Control     *the_chain;

   IMFS_jnode_t      *the_jnode;

   the_jnode = (IMFS_jnode_t *) loc->node_access;

   buf->st_dev = 0ll;

   buf->st_ino   = the_jnode->st_ino;

   buf->st_mode  = the_jnode->st_mode;

   buf->st_nlink = the_jnode->st_nlink;

   buf->st_uid   = the_jnode->st_uid;

   buf->st_gid   = the_jnode->st_gid;

   buf->st_rdev = 0ll;

   buf->st_blksize = 0;

   buf->st_blocks = 0;

   buf->st_atime = the_jnode->stat_atime;

   buf->st_mtime = the_jnode->stat_mtime;

   buf->st_ctime = the_jnode->stat_ctime;

   buf->st_size = 0;

   the_chain = &the_jnode->info.directory.Entries;

   /* Run through the chain and count the number of directory entries */

   /* that are subordinate to this directory node                     */

   for ( the_node = the_chain->first ;

         !_Chain_Is_tail( the_chain, the_node ) ;

         the_node = the_node->next ) {

      buf->st_size = buf->st_size + sizeof( struct dirent );

   }

   return 0;

}

/*

 *  IMFS_dir_rmnod

 *

 *  This routine is available from the optable to remove a node

 *  from the IMFS file system.

 */

int imfs_dir_rmnod(

  rtems_filesystem_location_info_t      *pathloc       /* IN */

)

{

  IMFS_jnode_t *the_jnode;

  the_jnode = (IMFS_jnode_t *) pathloc->node_access;

  /*

   * You cannot remove a node that still has children

   */

  if ( ! Chain_Is_empty( &the_jnode->info.directory.Entries ) )

     set_errno_and_return_minus_one( ENOTEMPTY );

  /*

   * You cannot remove the file system root node.

   */

  if ( pathloc->mt_entry->mt_fs_root.node_access == pathloc->node_access )

     set_errno_and_return_minus_one( EBUSY );

  /*

   * You cannot remove a mountpoint.

   */

   if ( the_jnode->info.directory.mt_fs != NULL )

     set_errno_and_return_minus_one( EBUSY );

  /*

   * Take the node out of the parent's chain that contains this node

   */

  if ( the_jnode->Parent != NULL ) {

    Chain_Extract( (Chain_Node *) the_jnode );

    the_jnode->Parent = NULL;

  }

  /*

   * Decrement the link counter and see if we can free the space.

   */

  the_jnode->st_nlink--;

  IMFS_update_ctime( the_jnode );

  /*

   * The file cannot be open and the link must be less than 1 to free.

   */

  if ( !rtems_libio_is_file_open( the_jnode ) && (the_jnode->st_nlink < 1) ) {

    /*

     * Is the rtems_filesystem_current is this node?

     */

    if ( rtems_filesystem_current.node_access == pathloc->node_access )

       rtems_filesystem_current.node_access = NULL;

    /*

     * Free memory associated with a memory file.

     */

    free( the_jnode );

  }

  return 0;

}