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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.rtems.com/license/LICENSE.
*
* $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <rtems/chain.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <rtems/libio_.h>
#include <rtems/seterr.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
);
rtems_boolean rtems_filesystem_nodes_equal(
const rtems_filesystem_location_info_t *loc1,
const rtems_filesystem_location_info_t *loc2
){
return ( loc1->node_access == loc2->node_access );
}
/*
* 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.
*/
rtems_boolean 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;
/*
* 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 ) {
return TRUE;
}
}
return FALSE;
}
/*
* 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
)
{
rtems_filesystem_location_info_t loc;
rtems_filesystem_location_info_t *fs_root_loc;
rtems_filesystem_location_info_t *fs_mount_loc;
rtems_filesystem_mount_table_entry_t *mt_entry;
/*
* Get
* The root node of the mounted filesytem.
* The node for the directory that the fileystem is mounted on.
* The mount entry that is being refered to.
*/
if ( rtems_filesystem_evaluate_path( path, 0x0, &loc, TRUE ) )
return -1;
mt_entry = loc.mt_entry;
fs_mount_loc = &mt_entry->mt_point_node;
fs_root_loc = &mt_entry->mt_fs_root;
/*
* Verify this is the root node for the file system to be unmounted.
*/
if ( !rtems_filesystem_nodes_equal( fs_root_loc, &loc) ){
rtems_filesystem_freenode( &loc );
rtems_set_errno_and_return_minus_one( EACCES );
}
/*
* Free the loc node and just use the nodes from the mt_entry .
*/
rtems_filesystem_freenode( &loc );
/*
* Verify Unmount is supported by both filesystems.
*/
if ( !fs_mount_loc->ops->unmount_h )
rtems_set_errno_and_return_minus_one( ENOTSUP );
if ( !fs_root_loc->ops->fsunmount_me_h )
rtems_set_errno_and_return_minus_one( ENOTSUP );
/*
* Verify the current node is not in this filesystem.
* XXX - Joel I have a question here wasn't code added
* that made the current node thread based instead
* of system based? I thought it was but it doesn't
* look like it in this version.
*/
if ( rtems_filesystem_current.mt_entry == mt_entry )
rtems_set_errno_and_return_minus_one( EBUSY );
/*
* Verify there are no file systems below the path specified
*/
if ( file_systems_below_this_mountpoint( path, fs_root_loc, mt_entry ) != 0 )
rtems_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( mt_entry ) == 1 )
rtems_set_errno_and_return_minus_one( EBUSY );
/*
* Allow the file system being unmounted on to do its cleanup.
* If it fails it will set the errno to the approprate value
* and the fileystem will not be modified.
*/
if (( fs_mount_loc->ops->unmount_h )( mt_entry ) != 0 )
return -1;
/*
* Allow the mounted filesystem to unmark the use of the root node.
*
* Run the unmount function for the subordinate file system.
*
* If we fail to unmount the filesystem remount it on the base filesystems
* directory node.
*
* NOTE: Fatal error is called in a case which should never happen
* This was response was questionable but the best we could
* come up with.
*/
if ((fs_root_loc->ops->fsunmount_me_h )( mt_entry ) != 0){
if (( fs_mount_loc->ops->mount_h )( mt_entry ) != 0 )
rtems_fatal_error_occurred( 0 );
return -1;
}
/*
* Extract the mount table entry from the chain
*/
Chain_Extract( ( Chain_Node * ) mt_entry );
/*
* Free the memory node that was allocated in mount
* Free the memory associated with the extracted mount table entry.
*/
rtems_filesystem_freenode( fs_mount_loc );
free( mt_entry );
return 0;
}
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