source: rtems/cpukit/libcsupport/src/unmount.c @ c7016198

4.104.114.84.95
Last change on this file since c7016198 was 04df848, checked in by Jennifer Averett <Jennifer.Averett@…>, on 10/25/99 at 14:23:03

Added code to correctly free any allocated space during the evaluation
process.

  • Property mode set to 100644
File size: 6.2 KB
Line 
1/*
2 *  unmount() - Unmount a File System
3 *
4 *  This routine is not defined in the POSIX 1003.1b standard but
5 *  in some form is supported on most UNIX and POSIX systems.  This
6 *  routine is necessary to mount instantiations of a file system
7 *  into the file system name space.
8 *
9 *  COPYRIGHT (c) 1989-1998.
10 *  On-Line Applications Research Corporation (OAR).
11 *  Copyright assigned to U.S. Government, 1994.
12 *
13 *  The license and distribution terms for this file may be
14 *  found in the file LICENSE in this distribution or at
15 *  http://www.OARcorp.com/rtems/license.html.
16 *
17 *  $Id$
18 */
19
20#include <sys/types.h>
21#include <sys/stat.h>
22#include <chain.h>
23#include <fcntl.h>
24#include <unistd.h>
25#include <errno.h>
26#include <stdlib.h>
27#include <string.h>
28#include <assert.h>
29
30#include "imfs.h"
31#include "libio_.h"
32
33/*
34 *  Data structures and routines private to mount/unmount pair.
35 */
36
37extern Chain_Control                    rtems_filesystem_mount_table_control;
38extern rtems_filesystem_location_info_t rtems_filesystem_current;
39
40int search_mt_for_mount_point(
41  rtems_filesystem_location_info_t *location_of_mount_point
42);
43
44
45int file_systems_below_this_mountpoint(
46  const char                            *mount_path,
47  rtems_filesystem_location_info_t      *temp_loc,
48  rtems_filesystem_mount_table_entry_t  *temp_mt_entry
49);
50
51/*
52 *  unmount
53 *
54 *  This routine will attempt to unmount the file system that has been
55 *  is mounted a mount_path.  If the operation is successful, 0 will
56 *  be returned to the calling routine.  Otherwise, 1 will be returned.
57 */
58
59int unmount(
60  const char *mount_path
61)
62{
63  int                                   status;
64  rtems_filesystem_location_info_t      temp_loc;
65  rtems_filesystem_mount_table_entry_t  temp_mt_entry;
66  int                                   result;
67
68  /*
69   *  Are there any file systems below the mount_path specified
70   */
71
72  status = file_systems_below_this_mountpoint(
73    mount_path,
74    &temp_loc,
75    &temp_mt_entry
76  );
77
78  if ( status != 0 )
79    return -1;
80
81  /*
82   *  Is the current node reference pointing to a node in the file system
83   *  we are attempting to unmount ?
84   */
85
86  if ( rtems_filesystem_current.mt_entry == temp_loc.mt_entry ) {
87    rtems_filesystem_freenode( &temp_loc );
88    set_errno_and_return_minus_one( EBUSY );
89  }
90
91  /*
92   *  Run the file descriptor table to determine if there are any file
93   *  descriptors that are currently active and reference nodes in the
94   *  file system that we are trying to unmount
95   */
96
97  if ( rtems_libio_is_open_files_in_fs( temp_loc.mt_entry ) == 1 ) {
98    rtems_filesystem_freenode( &temp_loc );
99    set_errno_and_return_minus_one( EBUSY );
100  }
101 
102  /*
103   * Allow the file system being mounted on to do its cleanup.
104   * XXX - Did I change these correctly ??? It looks like either I did
105   * XXX   this backwards or the IMFS_unmount and IMFS_fsumount are swaped.
106   * XXX   Add to the mt_point_node unmount to set the mt_entry back to null
107   * XXX   I will step off in space when evaluating past the end of the node.
108   */
109
110  if ((temp_mt_entry.mt_point_node.ops->unmount )( temp_loc.mt_entry ) != 0 ) {
111    rtems_filesystem_freenode( &temp_loc );
112    return -1;
113  }
114
115  /*
116   * Run the unmount function for the subordinate file system.
117   */
118
119  if ((temp_mt_entry.mt_fs_root.ops->fsunmount_me )( temp_loc.mt_entry ) != 0){
120    rtems_filesystem_freenode( &temp_loc );
121    return -1;
122  }
123
124  /*
125   * Allow the file system to clean up.
126   */
127
128  result = (*temp_loc.ops->fsunmount_me)( temp_loc.mt_entry );
129
130  /*
131   *  Extract the mount table entry from the chain
132   */
133
134  Chain_Extract( ( Chain_Node * ) temp_loc.mt_entry );
135
136  /*
137   *  Free the memory associated with the extracted mount table entry.
138   */
139
140  rtems_filesystem_freenode( &temp_loc.mt_entry->mt_point_node );
141  free( temp_loc.mt_entry );
142  rtems_filesystem_freenode( &temp_loc );
143
144  return result;
145
146}
147
148
149/*
150 *  file_systems_below_this_mountpoint
151 *
152 *  This routine will run through the entries that currently exist in the
153 *  mount table chain. For each entry in the mount table chain it will
154 *  compare the mount tables mt_fs_root to the new_fs_root_node. If any of the
155 *  mount table file system root nodes matches the new file system root node
156 *  this indicates that we are trying to mount a file system that has already
157 *  been mounted. This is not a permitted operation. temp_loc is set to
158 *  the root node of the file system being unmounted.
159 */
160
161int file_systems_below_this_mountpoint(
162  const char                            *mount_path,
163  rtems_filesystem_location_info_t      *temp_loc,
164  rtems_filesystem_mount_table_entry_t  *temp_mt_entry
165)
166{
167  Chain_Node                           *the_node;
168  rtems_filesystem_mount_table_entry_t *the_mount_entry;
169  rtems_filesystem_mount_table_entry_t *current_fs_mt_entry;
170
171  /*
172   *  Is the mount_path even a valid node name in the existing tree?
173   */
174
175  if ( rtems_filesystem_evaluate_path( mount_path, 0x0, temp_loc, TRUE ) )
176    return -1;
177 
178  /*
179   *  Look for the node defined in temp_loc as a mount point in the
180   *  mount table chain.
181   */
182
183  for ( the_node = rtems_filesystem_mount_table_control.first;
184        !Chain_Is_tail( &rtems_filesystem_mount_table_control, the_node );
185        the_node = the_node->next ) {
186
187     the_mount_entry = ( rtems_filesystem_mount_table_entry_t * )the_node;
188     if  (the_mount_entry->mt_point_node.node_access  ==
189          temp_loc->node_access ) {
190        current_fs_mt_entry = the_mount_entry;
191        *temp_loc = current_fs_mt_entry->mt_fs_root;
192        goto after_real_mount_point_found;
193     }
194  }
195  set_errno_and_return_minus_one( EACCES );
196
197
198after_real_mount_point_found:
199
200  for ( the_node = rtems_filesystem_mount_table_control.first;
201        !Chain_Is_tail( &rtems_filesystem_mount_table_control, the_node );
202        the_node = the_node->next ) {
203
204     the_mount_entry = (  rtems_filesystem_mount_table_entry_t * )the_node;
205
206     /*
207      *  Exclude the current file systems mount table entry from the test
208      */
209
210     if ( current_fs_mt_entry != the_mount_entry ) {
211       if ( the_mount_entry->mt_point_node.mt_entry  == current_fs_mt_entry ) {
212
213          /*
214           *  There is at least one fs below the fs on the mount_path.
215           */
216          set_errno_and_return_minus_one( EBUSY );
217       }
218     }
219  }
220
221  *temp_mt_entry = *current_fs_mt_entry;
222
223  return 0;
224}
Note: See TracBrowser for help on using the repository browser.