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Diffstat (limited to 'cpukit/libcsupport/src/unmount.c')
| -rw-r--r-- | cpukit/libcsupport/src/unmount.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/cpukit/libcsupport/src/unmount.c b/cpukit/libcsupport/src/unmount.c new file mode 100644 index 0000000000..f37d3f2e56 --- /dev/null +++ b/cpukit/libcsupport/src/unmount.c @@ -0,0 +1,219 @@ +/* + * 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; +} |