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/*
* unmount() - Unmount a File System
*
* This routine is not defined in the POSIX 1003.1b standard but
* in some form is supported on most UNIX and POSIX systems. This
* routine is necessary to mount instantiations of a file system
* into the file system name space.
*
* 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 <sys/types.h>
#include <sys/stat.h>
#include <chain.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <rtems/libio_.h>
/*
* Data structures and routines private to mount/unmount pair.
*/
extern Chain_Control rtems_filesystem_mount_table_control;
int search_mt_for_mount_point(
rtems_filesystem_location_info_t *location_of_mount_point
);
int file_systems_below_this_mountpoint(
const char *path,
rtems_filesystem_location_info_t *temp_loc,
rtems_filesystem_mount_table_entry_t *temp_mt_entry
);
/*
* unmount
*
* This routine will attempt to unmount the file system that has been
* is mounted a path. If the operation is successful, 0 will
* be returned to the calling routine. Otherwise, 1 will be returned.
*/
int unmount(
const char *path
)
{
int status;
rtems_filesystem_location_info_t fs_root_loc;
rtems_filesystem_mount_table_entry_t temp_mt_entry;
/*
* Are there any file systems below the path specified
*/
status = file_systems_below_this_mountpoint(
path,
&fs_root_loc,
&temp_mt_entry
);
if ( status != 0 )
return -1;
/*
* Is the current node reference pointing to a node in the file system
* we are attempting to unmount ?
*/
if ( rtems_filesystem_current.mt_entry == fs_root_loc.mt_entry ) {
rtems_filesystem_freenode( &fs_root_loc );
set_errno_and_return_minus_one( EBUSY );
}
/*
* Run the file descriptor table to determine if there are any file
* descriptors that are currently active and reference nodes in the
* file system that we are trying to unmount
*/
if ( rtems_libio_is_open_files_in_fs( fs_root_loc.mt_entry ) == 1 ) {
rtems_filesystem_freenode( &fs_root_loc );
set_errno_and_return_minus_one( EBUSY );
}
/*
* Allow the file system being unmounted on to do its cleanup.
*/
if ((temp_mt_entry.mt_point_node.ops->unmount_h )( fs_root_loc.mt_entry ) != 0 ) {
rtems_filesystem_freenode( &fs_root_loc );
return -1;
}
/*
* Run the unmount function for the subordinate file system.
*/
if ((temp_mt_entry.mt_fs_root.ops->fsunmount_me_h )( fs_root_loc.mt_entry ) != 0){
rtems_filesystem_freenode( &fs_root_loc );
return -1;
}
/*
* Extract the mount table entry from the chain
*/
Chain_Extract( ( Chain_Node * ) fs_root_loc.mt_entry );
/*
* Free the memory associated with the extracted mount table entry.
*/
rtems_filesystem_freenode( &fs_root_loc.mt_entry->mt_point_node );
free( fs_root_loc.mt_entry );
rtems_filesystem_freenode( &fs_root_loc );
return 0;
}
/*
* file_systems_below_this_mountpoint
*
* This routine will run through the entries that currently exist in the
* mount table chain. For each entry in the mount table chain it will
* compare the mount tables mt_fs_root to the new_fs_root_node. If any of the
* mount table file system root nodes matches the new file system root node
* this indicates that we are trying to mount a file system that has already
* been mounted. This is not a permitted operation. temp_loc is set to
* the root node of the file system being unmounted.
*/
int file_systems_below_this_mountpoint(
const char *path,
rtems_filesystem_location_info_t *fs_root_loc,
rtems_filesystem_mount_table_entry_t *fs_to_unmount
)
{
Chain_Node *the_node;
rtems_filesystem_mount_table_entry_t *the_mount_entry;
/*
* Is the path even a valid node name in the existing tree?
*/
if ( rtems_filesystem_evaluate_path( path, 0x0, fs_root_loc, TRUE ) )
return -1;
/*
* Verify this is the root node for the file system to be unmounted.
*/
*fs_to_unmount = *fs_root_loc->mt_entry;
if ( fs_to_unmount->mt_fs_root.node_access != fs_root_loc->node_access ){
rtems_filesystem_freenode(fs_root_loc);
set_errno_and_return_minus_one( EACCES );
}
/*
* Search the mount table for any mount entries referencing this
* mount entry.
*/
for ( the_node = rtems_filesystem_mount_table_control.first;
!Chain_Is_tail( &rtems_filesystem_mount_table_control, the_node );
the_node = the_node->next ) {
the_mount_entry = ( rtems_filesystem_mount_table_entry_t * )the_node;
if (the_mount_entry->mt_point_node.mt_entry == fs_root_loc->mt_entry ) {
rtems_filesystem_freenode(fs_root_loc);
set_errno_and_return_minus_one( EBUSY );
}
}
return 0;
}
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