diff options
Diffstat (limited to 'c/src/lib/libc/unmount.c')
| -rw-r--r-- | c/src/lib/libc/unmount.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/c/src/lib/libc/unmount.c b/c/src/lib/libc/unmount.c new file mode 100644 index 0000000000..f50e63ff42 --- /dev/null +++ b/c/src/lib/libc/unmount.c @@ -0,0 +1,214 @@ +/* + * 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) 1989-1998. + * On-Line Applications Research Corporation (OAR). + * Copyright assigned to U.S. Government, 1994. + * + * 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. + * + * $Id$ + */ + +#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 "imfs.h" +#include "libio_.h" + +/* + * Data structures and routines private to mount/unmount pair. + */ + +extern Chain_Control rtems_filesystem_mount_table_control; +extern rtems_filesystem_location_info_t rtems_filesystem_current; + +int search_mt_for_mount_point( + rtems_filesystem_location_info_t *location_of_mount_point +); + + +int file_systems_below_this_mountpoint( + const char *mount_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 mount_path. If the operation is successful, 0 will + * be returned to the calling routine. Otherwise, 1 will be returned. + */ + +int unmount( + const char *mount_path +) +{ + int status; + rtems_filesystem_location_info_t temp_loc; + rtems_filesystem_mount_table_entry_t temp_mt_entry; + int result; + + /* + * Are there any file systems below the mount_path specified + */ + + status = file_systems_below_this_mountpoint( + mount_path, + &temp_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 == temp_loc.mt_entry ) + 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( temp_loc.mt_entry ) == 1 ) + set_errno_and_return_minus_one( EBUSY ); + + /* + * Allow the file system being mounted on to do its cleanup. + * XXX - Did I change these correctly ??? It looks like either I did + * XXX this backwards or the IMFS_unmount and IMFS_fsumount are swaped. + * XXX Add to the mt_point_node unmount to set the mt_entry back to null + * XXX I will step off in space when evaluating past the end of the node. + */ + + if ( ( temp_mt_entry.mt_point_node.ops->unmount )( temp_loc.mt_entry ) != 0 ) + return -1; + + /* + * Run the unmount function for the subordinate file system. + */ + + if ( ( temp_mt_entry.mt_fs_root.ops->fsunmount_me )( temp_loc.mt_entry ) != 0 ) + return -1; + + /* + * Allow the file system to clean up. + */ + + result = (*temp_loc.ops->fsunmount_me)( temp_loc.mt_entry ); + + /* + * Extract the mount table entry from the chain + */ + + Chain_Extract( ( Chain_Node * ) temp_loc.mt_entry ); + + /* + * Free the memory associated with the extracted mount table entry. + */ + + free( temp_loc.mt_entry ); + + return result; + +} + + +/* + * 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 *mount_path, + rtems_filesystem_location_info_t *temp_loc, + rtems_filesystem_mount_table_entry_t *temp_mt_entry +) +{ + Chain_Node *the_node; + rtems_filesystem_mount_table_entry_t *the_mount_entry; + rtems_filesystem_mount_table_entry_t *current_fs_mt_entry; + + /* + * Is the mount_path even a valid node name in the existing tree? + */ + + if ( rtems_filesystem_evaluate_path( mount_path, 0x0, temp_loc, TRUE ) ) + return -1; + + /* + * Look for the node defined in temp_loc as a mount point in the + * mount table chain. + */ + + 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.node_access == + temp_loc->node_access ) { + current_fs_mt_entry = the_mount_entry; + *temp_loc = current_fs_mt_entry->mt_fs_root; + goto after_real_mount_point_found; + } + } + set_errno_and_return_minus_one( EACCES ); + + +after_real_mount_point_found: + + 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; + + /* + * Exclude the current file systems mount table entry from the test + */ + + if ( current_fs_mt_entry != the_mount_entry ) { + if ( the_mount_entry->mt_point_node.mt_entry == current_fs_mt_entry ) { + + /* + * There is at least one fs below the fs on the mount_path. + */ + set_errno_and_return_minus_one( EBUSY ); + } + } + } + + *temp_mt_entry = *current_fs_mt_entry; + + return 0; +} |