source: rtems/c/src/exec/libcsupport/src/unmount.c @ d71fcab

4.104.114.84.95
Last change on this file since d71fcab was d71fcab, checked in by Joel Sherrill <joel.sherrill@…>, on 10/12/99 at 18:44:40

Added call to freenod to let each filesystem free its own internal
node used to manage file access.

  • Property mode set to 100644
File size: 6.3 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    if ( temp_loc.ops->freenod )
88      (*temp_loc.ops->freenod)( &temp_loc );
89    set_errno_and_return_minus_one( EBUSY );
90  }
91
92  /*
93   *  Run the file descriptor table to determine if there are any file
94   *  descriptors that are currently active and reference nodes in the
95   *  file system that we are trying to unmount
96   */
97
98  if ( rtems_libio_is_open_files_in_fs( temp_loc.mt_entry ) == 1 ) {
99    if ( temp_loc.ops->freenod )
100      (*temp_loc.ops->freenod)( &temp_loc );
101    set_errno_and_return_minus_one( EBUSY );
102  }
103 
104  /*
105   * Allow the file system being mounted on to do its cleanup.
106   * XXX - Did I change these correctly ??? It looks like either I did
107   * XXX   this backwards or the IMFS_unmount and IMFS_fsumount are swaped.
108   * XXX   Add to the mt_point_node unmount to set the mt_entry back to null
109   * XXX   I will step off in space when evaluating past the end of the node.
110   */
111
112  if ((temp_mt_entry.mt_point_node.ops->unmount )( temp_loc.mt_entry ) != 0 ) {
113    if ( temp_loc.ops->freenod )
114      (*temp_loc.ops->freenod)( &temp_loc );
115    return -1;
116  }
117
118  /*
119   * Run the unmount function for the subordinate file system.
120   */
121
122  if ((temp_mt_entry.mt_fs_root.ops->fsunmount_me )( temp_loc.mt_entry ) != 0){
123    if ( temp_loc.ops->freenod )
124      (*temp_loc.ops->freenod)( &temp_loc );
125     return -1;
126  }
127
128  /*
129   * Allow the file system to clean up.
130   */
131
132  result = (*temp_loc.ops->fsunmount_me)( temp_loc.mt_entry );
133
134  /*
135   *  Extract the mount table entry from the chain
136   */
137
138  Chain_Extract( ( Chain_Node * ) temp_loc.mt_entry );
139
140  /*
141   *  Free the memory associated with the extracted mount table entry.
142   */
143
144  free( temp_loc.mt_entry );
145  if ( temp_loc.ops->freenod )
146    (*temp_loc.ops->freenod)( &temp_loc );
147
148  return result;
149
150}
151
152
153/*
154 *  file_systems_below_this_mountpoint
155 *
156 *  This routine will run through the entries that currently exist in the
157 *  mount table chain. For each entry in the mount table chain it will
158 *  compare the mount tables mt_fs_root to the new_fs_root_node. If any of the
159 *  mount table file system root nodes matches the new file system root node
160 *  this indicates that we are trying to mount a file system that has already
161 *  been mounted. This is not a permitted operation. temp_loc is set to
162 *  the root node of the file system being unmounted.
163 */
164
165int file_systems_below_this_mountpoint(
166  const char                            *mount_path,
167  rtems_filesystem_location_info_t      *temp_loc,
168  rtems_filesystem_mount_table_entry_t  *temp_mt_entry
169)
170{
171  Chain_Node                           *the_node;
172  rtems_filesystem_mount_table_entry_t *the_mount_entry;
173  rtems_filesystem_mount_table_entry_t *current_fs_mt_entry;
174
175  /*
176   *  Is the mount_path even a valid node name in the existing tree?
177   */
178
179  if ( rtems_filesystem_evaluate_path( mount_path, 0x0, temp_loc, TRUE ) )
180    return -1;
181 
182  /*
183   *  Look for the node defined in temp_loc as a mount point in the
184   *  mount table chain.
185   */
186
187  for ( the_node = rtems_filesystem_mount_table_control.first;
188        !Chain_Is_tail( &rtems_filesystem_mount_table_control, the_node );
189        the_node = the_node->next ) {
190
191     the_mount_entry = ( rtems_filesystem_mount_table_entry_t * )the_node;
192     if  (the_mount_entry->mt_point_node.node_access  ==
193          temp_loc->node_access ) {
194        current_fs_mt_entry = the_mount_entry;
195        *temp_loc = current_fs_mt_entry->mt_fs_root;
196        goto after_real_mount_point_found;
197     }
198  }
199  set_errno_and_return_minus_one( EACCES );
200
201
202after_real_mount_point_found:
203
204  for ( the_node = rtems_filesystem_mount_table_control.first;
205        !Chain_Is_tail( &rtems_filesystem_mount_table_control, the_node );
206        the_node = the_node->next ) {
207
208     the_mount_entry = (  rtems_filesystem_mount_table_entry_t * )the_node;
209
210     /*
211      *  Exclude the current file systems mount table entry from the test
212      */
213
214     if ( current_fs_mt_entry != the_mount_entry ) {
215       if ( the_mount_entry->mt_point_node.mt_entry  == current_fs_mt_entry ) {
216
217          /*
218           *  There is at least one fs below the fs on the mount_path.
219           */
220          set_errno_and_return_minus_one( EBUSY );
221       }
222     }
223  }
224
225  *temp_mt_entry = *current_fs_mt_entry;
226
227  return 0;
228}
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