source: rtems/cpukit/libcsupport/src/unmount.c @ 9b05600

4.104.114.84.95
Last change on this file since 9b05600 was df49c60, checked in by Joel Sherrill <joel.sherrill@…>, on 06/12/00 at 15:00:15

Merged from 4.5.0-beta3a

  • Property mode set to 100644
File size: 6.0 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) 1989-1999.
10 *  On-Line Applications Research Corporation (OAR).
11 *
12 *  The license and distribution terms for this file may be
13 *  found in the file LICENSE in this distribution or at
14 *  http://www.OARcorp.com/rtems/license.html.
15 *
16 *  $Id$
17 */
18
19#include <sys/types.h>
20#include <sys/stat.h>
21#include <chain.h>
22#include <fcntl.h>
23#include <unistd.h>
24#include <errno.h>
25#include <stdlib.h>
26#include <string.h>
27#include <assert.h>
28
29#include "imfs.h"
30#include "libio_.h"
31
32/*
33 *  Data structures and routines private to mount/unmount pair.
34 */
35
36extern Chain_Control                    rtems_filesystem_mount_table_control;
37extern rtems_filesystem_location_info_t rtems_filesystem_current;
38
39int search_mt_for_mount_point(
40  rtems_filesystem_location_info_t *location_of_mount_point
41);
42
43
44int file_systems_below_this_mountpoint(
45  const char                            *mount_path,
46  rtems_filesystem_location_info_t      *temp_loc,
47  rtems_filesystem_mount_table_entry_t  *temp_mt_entry
48);
49
50/*
51 *  unmount
52 *
53 *  This routine will attempt to unmount the file system that has been
54 *  is mounted a mount_path.  If the operation is successful, 0 will
55 *  be returned to the calling routine.  Otherwise, 1 will be returned.
56 */
57
58int unmount(
59  const char *mount_path
60)
61{
62  int                                   status;
63  rtems_filesystem_location_info_t      temp_loc;
64  rtems_filesystem_mount_table_entry_t  temp_mt_entry;
65
66  /*
67   *  Are there any file systems below the mount_path specified
68   */
69
70  status = file_systems_below_this_mountpoint(
71    mount_path,
72    &temp_loc,
73    &temp_mt_entry
74  );
75
76  if ( status != 0 )
77    return -1;
78
79  /*
80   *  Is the current node reference pointing to a node in the file system
81   *  we are attempting to unmount ?
82   */
83
84  if ( rtems_filesystem_current.mt_entry == temp_loc.mt_entry ) {
85    rtems_filesystem_freenode( &temp_loc );
86    set_errno_and_return_minus_one( EBUSY );
87  }
88
89  /*
90   *  Run the file descriptor table to determine if there are any file
91   *  descriptors that are currently active and reference nodes in the
92   *  file system that we are trying to unmount
93   */
94
95  if ( rtems_libio_is_open_files_in_fs( temp_loc.mt_entry ) == 1 ) {
96    rtems_filesystem_freenode( &temp_loc );
97    set_errno_and_return_minus_one( EBUSY );
98  }
99 
100  /*
101   * Allow the file system being mounted on to do its cleanup.
102   * XXX - Did I change these correctly ??? It looks like either I did
103   * XXX   this backwards or the IMFS_unmount and IMFS_fsumount are swapped.
104   * XXX   Add to the mt_point_node unmount to set the mt_entry back to null
105   * XXX   I will step off in space when evaluating past the end of the node.
106   */
107
108  if ((temp_mt_entry.mt_point_node.ops->unmount )( temp_loc.mt_entry ) != 0 ) {
109    rtems_filesystem_freenode( &temp_loc );
110    return -1;
111  }
112
113  /*
114   * Run the unmount function for the subordinate file system.
115   */
116
117  if ((temp_mt_entry.mt_fs_root.ops->fsunmount_me )( temp_loc.mt_entry ) != 0){
118    rtems_filesystem_freenode( &temp_loc );
119    return -1;
120  }
121
122  /*
123   *  Extract the mount table entry from the chain
124   */
125
126  Chain_Extract( ( Chain_Node * ) temp_loc.mt_entry );
127
128  /*
129   *  Free the memory associated with the extracted mount table entry.
130   */
131
132  rtems_filesystem_freenode( &temp_loc.mt_entry->mt_point_node );
133  free( temp_loc.mt_entry );
134  rtems_filesystem_freenode( &temp_loc );
135
136  return 0;
137}
138
139
140/*
141 *  file_systems_below_this_mountpoint
142 *
143 *  This routine will run through the entries that currently exist in the
144 *  mount table chain. For each entry in the mount table chain it will
145 *  compare the mount tables mt_fs_root to the new_fs_root_node. If any of the
146 *  mount table file system root nodes matches the new file system root node
147 *  this indicates that we are trying to mount a file system that has already
148 *  been mounted. This is not a permitted operation. temp_loc is set to
149 *  the root node of the file system being unmounted.
150 */
151
152int file_systems_below_this_mountpoint(
153  const char                            *mount_path,
154  rtems_filesystem_location_info_t      *temp_loc,
155  rtems_filesystem_mount_table_entry_t  *temp_mt_entry
156)
157{
158  Chain_Node                           *the_node;
159  rtems_filesystem_mount_table_entry_t *the_mount_entry;
160  rtems_filesystem_mount_table_entry_t *current_fs_mt_entry;
161
162  /*
163   *  Is the mount_path even a valid node name in the existing tree?
164   */
165
166  if ( rtems_filesystem_evaluate_path( mount_path, 0x0, temp_loc, TRUE ) )
167    return -1;
168 
169  /*
170   *  Look for the node defined in temp_loc as a mount point in the
171   *  mount table chain.
172   */
173
174  for ( the_node = rtems_filesystem_mount_table_control.first;
175        !Chain_Is_tail( &rtems_filesystem_mount_table_control, the_node );
176        the_node = the_node->next ) {
177
178     the_mount_entry = ( rtems_filesystem_mount_table_entry_t * )the_node;
179     if  (the_mount_entry->mt_point_node.node_access  ==
180          temp_loc->node_access ) {
181        current_fs_mt_entry = the_mount_entry;
182        *temp_loc = current_fs_mt_entry->mt_fs_root;
183        goto after_real_mount_point_found;
184     }
185  }
186  set_errno_and_return_minus_one( EACCES );
187
188
189after_real_mount_point_found:
190
191  for ( the_node = rtems_filesystem_mount_table_control.first;
192        !Chain_Is_tail( &rtems_filesystem_mount_table_control, the_node );
193        the_node = the_node->next ) {
194
195     the_mount_entry = (  rtems_filesystem_mount_table_entry_t * )the_node;
196
197     /*
198      *  Exclude the current file systems mount table entry from the test
199      */
200
201     if ( current_fs_mt_entry != the_mount_entry ) {
202       if ( the_mount_entry->mt_point_node.mt_entry  == current_fs_mt_entry ) {
203
204          /*
205           *  There is at least one fs below the fs on the mount_path.
206           */
207          set_errno_and_return_minus_one( EBUSY );
208       }
209     }
210  }
211
212  *temp_mt_entry = *current_fs_mt_entry;
213
214  return 0;
215}
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