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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [lib/] [libc/] [unmount.c] - Rev 751
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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: unmount.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 <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; /* * 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 ) { rtems_filesystem_freenode( &temp_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( temp_loc.mt_entry ) == 1 ) { rtems_filesystem_freenode( &temp_loc ); 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 swapped. * 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 ) { rtems_filesystem_freenode( &temp_loc ); 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){ rtems_filesystem_freenode( &temp_loc ); return -1; } /* * 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. */ rtems_filesystem_freenode( &temp_loc.mt_entry->mt_point_node ); free( temp_loc.mt_entry ); rtems_filesystem_freenode( &temp_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 *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; }
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