rtems/rtems-docs
1
0
Fork 0
mirror of https://git.rtems.org/rtems-docs/ synced 2025-07-25 06:23:14 +08:00
Code Issues Packages Projects Releases Wiki Activity

Fix filesystem formatting.

Browse Source
This commit is contained in:
Chris Johns 2016-10-27 18:01:51 -07:00
parent b0f29772e2
commit 4cacea0963
11 changed files with 1154 additions and 1393 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

774
filesystem/call_development.rst
View File

File diff suppressed because it is too large Load Diff

3
filesystem/command_and_variable.rst
View File

@ -4,6 +4,3 @@ Command and Variable Index
##########################
There are currently no Command and Variable Index entries.
.. COMMENT: @printindex fn

509
filesystem/fileystem_implmentation.rst
View File

@ -1,5 +1,9 @@
.. comment SPDX-License-Identifier: CC-BY-SA-4.0
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.
Filesystem Implementation Requirements
######################################
@ -9,45 +13,45 @@ implementations must adhere to.
General
=======
The RTEMS filesystem framework was intended to be compliant with the
POSIX Files and Directories interface standard. The following filesystem
The RTEMS filesystem framework was intended to be compliant with the POSIX
Files and Directories interface standard. The following filesystem
characteristics resulted in a functional switching layer.
.. code:: c
.. code-block:: shell
Figure of the Filesystem Functional Layering goes here.
This figure includes networking and disk caching layering.
# Application programs are presented with a standard set of POSIX
compliant functions that allow them to interface with the files, devices
and directories in the filesystem. The interfaces to these routines do
not reflect the type of subordinate filesystem implementation in which
the file will be found.
# Application programs are presented with a standard set of POSIX compliant
functions that allow them to interface with the files, devices and
directories in the filesystem. The interfaces to these routines do not
reflect the type of subordinate filesystem implementation in which the file
will be found.
# The filesystem framework developed under RTEMS allows for mounting
filesystem of different types under the base filesystem.
# The filesystem framework developed under RTEMS allows for mounting filesystem
of different types under the base filesystem.
# The mechanics of locating file information may be quite different
between filesystem types.
# The mechanics of locating file information may be quite different between
filesystem types.
# The process of locating a file may require crossing filesystem
boundaries.
# The process of locating a file may require crossing filesystem boundaries.
# The transitions between filesystem and the processing required to
access information in different filesystem is not visible at the level
of the POSIX function call.
# The transitions between filesystem and the processing required to access
information in different filesystem is not visible at the level of the POSIX
function call.
# The POSIX interface standard provides file access by character
pathname to the file in some functions and through an integer file
descriptor in other functions.
# The POSIX interface standard provides file access by character pathname to
the file in some functions and through an integer file descriptor in other
functions.
# The nature of the integer file descriptor and its associated
processing is operating system and filesystem specific.
# The nature of the integer file descriptor and its associated processing is
operating system and filesystem specific.
# Directory and device information must be processed with some of the
same routines that apply to files.
# Directory and device information must be processed with some of the same
routines that apply to files.
# The form and content of directory and device information differs
greatly from that of a regular file.
# The form and content of directory and device information differs greatly from
that of a regular file.
# Files, directories and devices represent elements (nodes) of a tree
hierarchy.
@ -56,15 +60,16 @@ characteristics resulted in a functional switching layer.
filesystem are node specific but are still not reflected in the POSIX
interface routines.
.. code:: c
.. code-block:: shell
Figure of the Filesystem Functional Layering goes here.
This figure focuses on the Base Filesystem and IMFS.
.. code:: c
.. code-block:: shell
Figure of the IMFS Memfile control blocks
.. _file-and-directory-removal-constraints:
File and Directory Removal Constraints
======================================
@ -73,15 +78,15 @@ The following POSIX constraints must be honored by all filesystems.
- If a node is a directory with children it cannot be removed.
- The root node of any filesystem, whether the base filesystem or a
mounted filesystem, cannot be removed.
- The root node of any filesystem, whether the base filesystem or a mounted
filesystem, cannot be removed.
- A node that is a directory that is acting as the mount point of a file
system cannot be removed.
- A node that is a directory that is acting as the mount point of a file system
cannot be removed.
- On filesystems supporting hard links, a link count is maintained.
Prior to node removal, the node's link count is decremented by one. The
link count must be less than one to allow for removal of the node.
- On filesystems supporting hard links, a link count is maintained. Prior to
node removal, the node's link count is decremented by one. The link count
must be less than one to allow for removal of the node.
API Layering
============
@ -89,16 +94,16 @@ API Layering
Mapping of Generic System Calls to Filesystem Specific Functions
----------------------------------------------------------------
The list of generic system calls includes the routines open(), read(),
write(), close(), etc..
The list of generic system calls includes the routines open(), read(), write(),
close(), etc..
The Files and Directories section of the POSIX Application Programs
Interface specifies a set of functions with calling arguments that are
used to gain access to the information in a filesystem. To the
application program, these functions allow access to information in any
mounted filesystem without explicit knowledge of the filesystem type or
the filesystem mount configuration. The following are functions that are
provided to the application:
The Files and Directories section of the POSIX Application Programs Interface
specifies a set of functions with calling arguments that are used to gain
access to the information in a filesystem. To the application program, these
functions allow access to information in any mounted filesystem without
explicit knowledge of the filesystem type or the filesystem mount
configuration. The following are functions that are provided to the
application:
# access()
@ -170,59 +175,56 @@ provided to the application:
# write()
The filesystem's type as well as the node type within the filesystem
determine the nature of the processing that must be performed for each of
the functions above. The RTEMS filesystem provides a framework that
allows new filesystem to be developed and integrated without alteration
to the basic framework.
The filesystem's type as well as the node type within the filesystem determine
the nature of the processing that must be performed for each of the functions
above. The RTEMS filesystem provides a framework that allows new filesystem to
be developed and integrated without alteration to the basic framework.
To provide the functional switching that is required, each of the POSIX
file and directory functions have been implemented as a shell function.
The shell function adheres to the POSIX interface standard. Within this
functional shell, filesystem and node type information is accessed which
is then used to invoke the appropriate filesystem and node type specific
routine to process the POSIX function call.
To provide the functional switching that is required, each of the POSIX file
and directory functions have been implemented as a shell function. The shell
function adheres to the POSIX interface standard. Within this functional shell,
filesystem and node type information is accessed which is then used to invoke
the appropriate filesystem and node type specific routine to process the POSIX
function call.
File/Device/Directory function access via file control block - rtems_libio_t structure
--------------------------------------------------------------------------------------
The POSIX open() function returns an integer file descriptor that is used
as a reference to file control block information for a specific file. The
file control block contains information that is used to locate node, file
system, mount table and functional handler information. The diagram in
Figure 8 depicts the relationship between and among the following
components.
The POSIX open() function returns an integer file descriptor that is used as a
reference to file control block information for a specific file. The file
control block contains information that is used to locate node, file system,
mount table and functional handler information. The diagram in Figure 8 depicts
the relationship between and among the following components.
# File Descriptor Table
This is an internal RTEMS structure that tracks all currently defined file
descriptors in the system. The index that is returned by the file open()
operation references a slot in this table. The slot contains a pointer to
the file descriptor table entry for this file. The rtems_libio_t structure
operation references a slot in this table. The slot contains a pointer to the
file descriptor table entry for this file. The rtems_libio_t structure
represents the file control block.
# Allocation of entry in the File Descriptor Table
Access to the file descriptor table is controlled through a semaphore that
is implemented using the rtems_libio_allocate() function. This routine
will grab a semaphore and then scan the file control blocks to determine
which slot is free for use. The first free slot is marked as used and the
index to this slot is returned as the file descriptor for the open()
request. After the alterations have been made to the file control block
table, the semaphore is released to allow further operations on the table.
Access to the file descriptor table is controlled through a semaphore that is
implemented using the rtems_libio_allocate() function. This routine will grab
a semaphore and then scan the file control blocks to determine which slot is
free for use. The first free slot is marked as used and the index to this
slot is returned as the file descriptor for the open() request. After the
alterations have been made to the file control block table, the semaphore is
released to allow further operations on the table.
# Maximum number of entries in the file descriptor table is
configurable through the src/exec/sapi/headers/confdefs.h file. If the
CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS constant is defined its value
will represent the maximum number of file descriptors that are allowed.
If CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS is not specified a default
value of 20 will be used as the maximum number of file descriptors
allowed.
# Maximum number of entries in the file descriptor table is configurable
through the src/exec/sapi/headers/confdefs.h file. If the
CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS constant is defined its value will
represent the maximum number of file descriptors that are allowed. If
CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS is not specified a default value of
20 will be used as the maximum number of file descriptors allowed.
# File control block - rtems_libio_t structure
.. code:: c
.. code-block:: c
struct rtems_libio_tt {
rtems_driver_name_t \*driver;
rtems_driver_name_t *driver;
off_t size;
off_t offset;
unsigned32 flags;
@ -237,22 +239,21 @@ components.
A file control block can exist for regular files, devices and directories.
The following fields are important for regular file and directory access:
- Size - For a file this represents the number of bytes currently
stored in a file. For a directory this field is not filled in.
- Size - For a file this represents the number of bytes currently stored in a
file. For a directory this field is not filled in.
- Offset - For a file this is the byte file position index relative to
the start of the file. For a directory this is the byte offset into a
sequence of dirent structures.
- Offset - For a file this is the byte file position index relative to the
start of the file. For a directory this is the byte offset into a sequence
of dirent structures.
- Pathinfo - This is a structure that provides a pointer to node
information, OPS table functions, Handler functions and the mount table
entry associated with this node.
- Pathinfo - This is a structure that provides a pointer to node information,
OPS table functions, Handler functions and the mount table entry associated
with this node.
- file_info - A pointer to node information that is used by Handler
functions
- file_info - A pointer to node information that is used by Handler functions
- handlers - A pointer to a table of handler functions that operate on
a file, device or directory through a file descriptor index
- handlers - A pointer to a table of handler functions that operate on a
file, device or directory through a file descriptor index
File/Directory function access via rtems_filesystem_location_info_t structure
-----------------------------------------------------------------------------
@ -260,41 +261,40 @@ File/Directory function access via rtems_filesystem_location_info_t structure
The rtems_filesystem_location_info_tt structure below provides sufficient
information to process nodes under a mounted filesystem.
.. code:: c
.. code-block:: c
struct rtems_filesystem_location_info_tt {
void \*node_access;
rtems_filesystem_file_handlers_r \*handlers;
rtems_filesystem_operations_table \*ops;
rtems_filesystem_mount_table_entry_t \*mt_entry;
void *node_access;
rtems_filesystem_file_handlers_r *handlers;
rtems_filesystem_operations_table *ops;
rtems_filesystem_mount_table_entry_t *mt_entry;
};
It contains a void pointer to filesystem specific nodal structure,
pointers to the OPS table for the filesystem that contains the node, the
node type specific handlers for the node and a reference pointer to the
mount table entry associated with the filesystem containing the node
It contains a void pointer to filesystem specific nodal structure, pointers to
the OPS table for the filesystem that contains the node, the node type specific
handlers for the node and a reference pointer to the mount table entry
associated with the filesystem containing the node
Operation Tables
================
Filesystem specific operations are invoked indirectly. The set of
routines that implement the filesystem are configured into two tables.
The Filesystem Handler Table has routines that are specific to a
filesystem but remain constant regardless of the actual file type.
The File Handler Table has routines that are both filesystem and file type
specific.
Filesystem specific operations are invoked indirectly. The set of routines
that implement the filesystem are configured into two tables. The Filesystem
Handler Table has routines that are specific to a filesystem but remain
constant regardless of the actual file type. The File Handler Table has
routines that are both filesystem and file type specific.
Filesystem Handler Table Functions
----------------------------------
OPS table functions are defined in a ``rtems_filesystem_operations_table``
structure. It defines functions that are specific to a given filesystem.
One table exists for each filesystem that is supported in the RTEMS
structure. It defines functions that are specific to a given filesystem. One
table exists for each filesystem that is supported in the RTEMS
configuration. The structure definition appears below and is followed by
general developmental information on each of the functions contained in this
function management structure.
.. code:: c
.. code-block:: c
typedef struct {
rtems_filesystem_evalpath_t evalpath;
@ -315,8 +315,6 @@ function management structure.
rtems_filesystem_symlink_t symlink;
} rtems_filesystem_operations_table;
.. COMMENT: @page
evalpath Handler
~~~~~~~~~~~~~~~~
@ -326,27 +324,25 @@ evalpath
**Arguments:**
.. code:: c
.. code-block:: c
const char \*pathname, /* IN \*/
int flags, /* IN \*/
rtems_filesystem_location_info_t \*pathloc /* IN/OUT \*/
const char *pathname, /* IN */
int flags, /* IN */
rtems_filesystem_location_info_t *pathloc /* IN/OUT */
**Description:**
This routine is responsible for evaluating the pathname passed in
based upon the flags and the valid ``rthems_filesystem_location_info_t``.
Additionally, it must make any changes to pathloc necessary to identify
the pathname node. This should include calling the evalpath for a mounted
filesystem, if the given filesystem supports the mount command.
This routine is responsible for evaluating the pathname passed in based upon
the flags and the valid ``rthems_filesystem_location_info_t``. Additionally,
it must make any changes to pathloc necessary to identify the pathname node.
This should include calling the evalpath for a mounted filesystem, if the given
filesystem supports the mount command.
This routine returns a 0 if the evaluation was successful.
Otherwise, it returns a -1 and sets errno to the correct error.
This routine returns a 0 if the evaluation was successful. Otherwise, it
returns a -1 and sets errno to the correct error.
This routine is required and should NOT be set to NULL.
.. COMMENT: @page
evalformake Handler
~~~~~~~~~~~~~~~~~~~
@ -356,29 +352,27 @@ evalformake
**Arguments:**
.. code:: c
.. code-block:: c
const char \*path, /* IN \*/
rtems_filesystem_location_info_t \*pathloc, /* IN/OUT \*/
const char \**name /* OUT \*/
const char *path, /* IN */
rtems_filesystem_location_info_t *pathloc, /* IN/OUT */
const char **name /* OUT */
**Description:**
This method is given a path to evaluate and a valid start location. It
is responsible for finding the parent node for a requested make command,
setting pathloc information to identify the parent node, and setting
the name pointer to the first character of the name of the new node.
Additionally, if the filesystem supports the mount command, this method
should call the evalformake routine for the mounted filesystem.
This method is given a path to evaluate and a valid start location. It is
responsible for finding the parent node for a requested make command, setting
pathloc information to identify the parent node, and setting the name pointer
to the first character of the name of the new node. Additionally, if the
filesystem supports the mount command, this method should call the evalformake
routine for the mounted filesystem.
This routine returns a 0 if the evaluation was successful. Otherwise, it
returns a -1 and sets errno to the correct error.
This routine is required and should NOT be set to NULL. However, if
the filesystem does not support user creation of a new node, it may
set errno to ENOSYS and return -1.
.. COMMENT: @page
This routine is required and should NOT be set to NULL. However, if the
filesystem does not support user creation of a new node, it may set errno to
ENOSYS and return -1.
link Handler
~~~~~~~~~~~~
@ -389,26 +383,24 @@ link
**Arguments:**
.. code:: c
.. code-block:: c
rtems_filesystem_location_info_t \*to_loc, /* IN \*/
rtems_filesystem_location_info_t \*parent_loc, /* IN \*/
const char \*token /* IN \*/
rtems_filesystem_location_info_t *to_loc, /* IN */
rtems_filesystem_location_info_t *parent_loc, /* IN */
const char *token /* IN */
**Description:**
This routine is used to create a hard-link.
It will first examine the st_nlink count of the node that we are trying to.
If the link count exceeds LINK_MAX an error will be returned.
It will first examine the st_nlink count of the node that we are trying to. If
the link count exceeds LINK_MAX an error will be returned.
The name of the link will be normalized to remove extraneous separators from
the end of the name.
This routine is not required and may be set to NULL.
.. COMMENT: @page
unlink Handler
~~~~~~~~~~~~~~
@ -424,8 +416,6 @@ XXX
XXX
.. COMMENT: @page
node_type Handler
~~~~~~~~~~~~~~~~~
@ -435,16 +425,14 @@ node_type()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_filesystem_location_info_t \*pathloc /* IN \*/
rtems_filesystem_location_info_t *pathloc /* IN */
**Description:**
XXX
.. COMMENT: @page
mknod Handler
~~~~~~~~~~~~~
@ -454,19 +442,17 @@ mknod()
**Arguments:**
.. code:: c
.. code-block:: c
const char \*token, /* IN \*/
mode_t mode, /* IN \*/
dev_t dev, /* IN \*/
rtems_filesystem_location_info_t \*pathloc /* IN/OUT \*/
const char *token, /* IN */
mode_t mode, /* IN */
dev_t dev, /* IN */
rtems_filesystem_location_info_t *pathloc /* IN/OUT */
**Description:**
XXX
.. COMMENT: @page
rmnod Handler
~~~~~~~~~~~~~
@ -482,8 +468,6 @@ XXX
XXX
.. COMMENT: @page
chown Handler
~~~~~~~~~~~~~
@ -493,11 +477,11 @@ chown()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_filesystem_location_info_t \*pathloc /* IN \*/
uid_t owner /* IN \*/
gid_t group /* IN \*/
rtems_filesystem_location_info_t *pathloc /* IN */
uid_t owner /* IN */
gid_t group /* IN */
**Description:**
@ -514,21 +498,19 @@ freenod()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_filesystem_location_info_t \*pathloc /* IN \*/
rtems_filesystem_location_info_t *pathloc /* IN */
**Description:**
This routine is used by the generic code to allow memory to be allocated
during the evaluate routines, and set free when the generic code is finished
accessing a node. If the evaluate routines allocate memory to identify
a node this routine should be utilized to free that memory.
This routine is used by the generic code to allow memory to be allocated during
the evaluate routines, and set free when the generic code is finished accessing
a node. If the evaluate routines allocate memory to identify a node this
routine should be utilized to free that memory.
This routine is not required and may be set to NULL.
.. COMMENT: @page
mount Handler
~~~~~~~~~~~~~
@ -538,16 +520,14 @@ mount()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_filesystem_mount_table_entry_t \*mt_entry
rtems_filesystem_mount_table_entry_t *mt_entry
**Description:**
XXX
.. COMMENT: @page
fsmount_me Handler
~~~~~~~~~~~~~~~~~~
@ -557,15 +537,15 @@ XXX
**Arguments:**
.. code:: c
.. code-block:: c
rtems_filesystem_mount_table_entry_t \*mt_entry
rtems_filesystem_mount_table_entry_t *mt_entry
**Description:**
This function is provided with a filesystem to take care of the internal
filesystem management details associated with mounting that filesystem
under the RTEMS environment.
filesystem management details associated with mounting that filesystem under
the RTEMS environment.
It is not responsible for the mounting details associated the filesystem
containing the mount point.
@ -573,37 +553,46 @@ containing the mount point.
The rtems_filesystem_mount_table_entry_t structure contains the key elements
below:
rtems_filesystem_location_info_t \*mt_point_node,
.. code-block:: c
rtems_filesystem_location_info_t *mt_point_node,
This structure contains information about the mount point. This
allows us to find the ops-table and the handling functions
associated with the filesystem containing the mount point.
rtems_filesystem_location_info_t \*fs_root_node,
.. code-block:: c
rtems_filesystem_location_info_t *fs_root_node,
This structure contains information about the root node in the file
system to be mounted. It allows us to find the ops-table and the
handling functions associated with the filesystem to be mounted.
.. code-block:: c
rtems_filesystem_options_t options,
Read only or read/write access
void \*fs_info,
.. code-block:: c
This points to an allocated block of memory the will be used to
hold any filesystem specific information of a global nature. This
allocated region if important because it allows us to mount the
same filesystem type more than once under the RTEMS system.
Each instance of the mounted filesystem has its own set of global
management information that is separate from the global
management information associated with the other instances of the
mounted filesystem type.
void *fs_info,
This points to an allocated block of memory the will be used to hold any
filesystem specific information of a global nature. This allocated region if
important because it allows us to mount the same filesystem type more than once
under the RTEMS system. Each instance of the mounted filesystem has its own
set of global management information that is separate from the global
management information associated with the other instances of the mounted
filesystem type.
.. code-block:: c
rtems_filesystem_limits_and_options_t pathconf_info,
The table contains the following set of values associated with the
mounted filesystem:
The table contains the following set of values associated with the mounted
filesystem:
- link_max
@ -629,29 +618,29 @@ mounted filesystem:
- posix_vdisable
These values are accessed with the pathconf() and the fpathconf ()
functions.
These values are accessed with the pathconf() and the fpathconf () functions.
const char \*dev
.. code-block:: c
const char *dev
The is intended to contain a string that identifies the device that contains
the filesystem information. The filesystems that are currently implemented
are memory based and don't require a device specification.
the filesystem information. The filesystems that are currently implemented are
memory based and don't require a device specification.
If the mt_point_node.node_access is NULL then we are mounting the base file
system.
The routine will create a directory node for the root of the IMFS file
system.
The routine will create a directory node for the root of the IMFS file system.
The node will have read, write and execute permissions for owner, group and
others.
The node's name will be a null string.
A filesystem information structure(fs_info) will be allocated and
initialized for the IMFS filesystem. The fs_info pointer in the mount table
entry will be set to point the filesystem information structure.
A filesystem information structure(fs_info) will be allocated and initialized
for the IMFS filesystem. The fs_info pointer in the mount table entry will be
set to point the filesystem information structure.
The pathconf_info element of the mount table will be set to the appropriate
table of path configuration constants (LIMITS_AND_OPTIONS).
@ -664,10 +653,8 @@ The fs_root_node structure will be filled in with the following:
- OPS table functions for the IMFS
A 0 will be returned to the calling routine if the process succeeded,
otherwise a 1 will be returned.
.. COMMENT: @page
A 0 will be returned to the calling routine if the process succeeded, otherwise
a 1 will be returned.
unmount Handler
~~~~~~~~~~~~~~~
@ -684,8 +671,6 @@ XXX
XXX
.. COMMENT: @page
fsunmount_me Handler
~~~~~~~~~~~~~~~~~~~~
@ -695,16 +680,14 @@ imfs_fsunmount_me()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_filesystem_mount_table_entry_t \*mt_entry
rtems_filesystem_mount_table_entry_t *mt_entry
**Description:**
XXX
.. COMMENT: @page
utime Handler
~~~~~~~~~~~~~
@ -720,8 +703,6 @@ XXX
XXX
.. COMMENT: @page
eval_link Handler
~~~~~~~~~~~~~~~~~
@ -737,8 +718,6 @@ XXX
XXX
.. COMMENT: @page
symlink Handler
~~~~~~~~~~~~~~~
@ -754,8 +733,6 @@ XXX
XXX
.. COMMENT: @page
File Handler Table Functions
----------------------------
@ -763,9 +740,10 @@ Handler table functions are defined in a ``rtems_filesystem_file_handlers_r``
structure. It defines functions that are specific to a node type in a given
filesystem. One table exists for each of the filesystem's node types. The
structure definition appears below. It is followed by general developmental
information on each of the functions associated with regular files contained
in this function management structure.
.. code:: c
information on each of the functions associated with regular files contained in
this function management structure.
.. code-block:: c
typedef struct {
rtems_filesystem_open_t open;
@ -783,8 +761,6 @@ in this function management structure.
rtems_filesystem_fcntl_t fcntl;
} rtems_filesystem_file_handlers_r;
.. COMMENT: @page
open Handler
~~~~~~~~~~~~
@ -794,10 +770,10 @@ open()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_libio_t \*iop,
const char \*pathname,
rtems_libio_t *iop,
const char *pathname,
unsigned32 flag,
unsigned32 mode
@ -805,8 +781,6 @@ open()
XXX
.. COMMENT: @page
close Handler
~~~~~~~~~~~~~
@ -816,9 +790,9 @@ close()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_libio_t \*iop
rtems_libio_t *iop
**Description:**
@ -828,8 +802,6 @@ XXX
XXX
.. COMMENT: @page
read Handler
~~~~~~~~~~~~
@ -839,10 +811,10 @@ read()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_libio_t \*iop,
void \*buffer,
rtems_libio_t *iop,
void *buffer,
unsigned32 count
**Description:**
@ -853,8 +825,6 @@ XXX
XXX
.. COMMENT: @page
write Handler
~~~~~~~~~~~~~
@ -874,8 +844,6 @@ XXX
XXX
.. COMMENT: @page
ioctl Handler
~~~~~~~~~~~~~
@ -885,11 +853,11 @@ XXX
**Arguments:**
.. code:: c
.. code-block:: c
rtems_libio_t \*iop,
rtems_libio_t *iop,
unsigned32 command,
void \*buffer
void *buffer
**Description:**
@ -899,8 +867,6 @@ XXX
XXX
.. COMMENT: @page
lseek Handler
~~~~~~~~~~~~~
@ -910,9 +876,9 @@ lseek()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_libio_t \*iop,
rtems_libio_t *iop,
off_t offset,
int whence
@ -924,8 +890,6 @@ XXX
XXX
.. COMMENT: @page
fstat Handler
~~~~~~~~~~~~~
@ -935,15 +899,15 @@ fstat()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_filesystem_location_info_t \*loc,
struct stat \*buf
rtems_filesystem_location_info_t *loc,
struct stat *buf
**Description:**
The following information is extracted from the filesystem
specific node and placed in the ``stat`` structure:
The following information is extracted from the filesystem specific node and
placed in the ``stat`` structure:
- st_mode
@ -963,16 +927,12 @@ specific node and placed in the ``stat`` structure:
**NOTES:**
Both the ``stat()`` and ``lstat()`` services are
implemented directly using the ``fstat()`` handler. The
difference in behavior is determined by how the path is evaluated
prior to this handler being called on a particular
file entity.
Both the ``stat()`` and ``lstat()`` services are implemented directly using the
``fstat()`` handler. The difference in behavior is determined by how the path
is evaluated prior to this handler being called on a particular file entity.
The ``fstat()`` system call is implemented directly
on top of this filesystem handler.
.. COMMENT: @page
The ``fstat()`` system call is implemented directly on top of this filesystem
handler.
fchmod Handler
~~~~~~~~~~~~~~
@ -983,9 +943,9 @@ fchmod()
**Arguments:**
.. code:: c
.. code-block:: c
rtems_libio_t \*iop
rtems_libio_t *iop
mode_t mode
**Description:**
@ -996,8 +956,6 @@ XXX
XXX
.. COMMENT: @page
ftruncate Handler
~~~~~~~~~~~~~~~~~
@ -1036,8 +994,6 @@ XXX
XXX
.. COMMENT: @page
fsync Handler
~~~~~~~~~~~~~
@ -1057,8 +1013,6 @@ XXX
XXX
.. COMMENT: @page
fdatasync Handler
~~~~~~~~~~~~~~~~~
@ -1078,8 +1032,6 @@ XXX
XXX
.. COMMENT: @page
fcntl Handler
~~~~~~~~~~~~~
@ -1098,10 +1050,3 @@ XXX
**NOTES:**
XXX
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.

623
filesystem/in-memory.rst
View File

File diff suppressed because it is too large Load Diff

51
filesystem/index.rst
View File

@ -4,41 +4,38 @@
RTEMS Filesystem Design Guide
=============================
COPYRIGHT (c) 1988 - 2015.
| COPYRIGHT (c) 1988 - 2015.
| On-Line Applications Research Corporation (OAR).
On-Line Applications Research Corporation (OAR).
The authors have used their best efforts in preparing this material. These
efforts include the development, research, and testing of the theories and
programs to determine their effectiveness. No warranty of any kind, expressed
or implied, with regard to the software or the material contained in this
document is provided. No liability arising out of the application or use of
any product described in this document is assumed. The authors reserve the
right to revise this material and to make changes from time to time in the
content hereof without obligation to notify anyone of such revision or changes.
The authors have used their best efforts in preparing
this material. These efforts include the development, research,
and testing of the theories and programs to determine their
effectiveness. No warranty of any kind, expressed or implied,
with regard to the software or the material contained in this
document is provided. No liability arising out of the
application or use of any product described in this document is
assumed. The authors reserve the right to revise this material
and to make changes from time to time in the content hereof
without obligation to notify anyone of such revision or changes.
The RTEMS Project is hosted at http://www.rtems.org/. Any inquiries concerning
RTEMS, its related support components, or its documentation should be directed
to the Community Project hosted at http://www.rtems.org/.
The RTEMS Project is hosted at http://www.rtems.org. Any
inquiries concerning RTEMS, its related support components, or its
documentation should be directed to the Community Project hosted athttp://www.rtems.org.
Any inquiries for commercial services including training, support, custom
development, application development assistance should be directed to http://www.rtems.com.
Table of Contents
-----------------
.. toctree::
preface
.. topic:: RTEMS Online Resources
================ =============================
Home https://www.rtems.org/
Developers https://devel.rtems.org/
Documentation https://docs.rtems.org/
Bug Reporting https://devel.rtems.org/query
Mailing Lists https://lists.rtems.org/
Git Repositories https://git.rtems.org/
================ =============================
.. toctree::
:maxdepth: 3
:numbered:
preface
pathname_eval
system_init
mounting_and_unmounting
@ -51,5 +48,3 @@ Table of Contents
* :ref:`genindex`
* :ref:`search`

21
filesystem/minature_in-memory.rst
View File

@ -1,18 +1,15 @@
.. comment SPDX-License-Identifier: CC-BY-SA-4.0
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.
Miniature In-Memory Filesystem
##############################
This chapter describes the Miniature In-Memory FileSystem (miniIMFS).
The miniIMFS is a reduced feature version of the IMFS designed to
provide minimal functionality and have a low memory footprint.
This chapter should be written after the IMFS chapter is completed
and describe the implementation of the mini-IMFS.
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.
This chapter describes the Miniature In-Memory FileSystem (miniIMFS). The
miniIMFS is a reduced feature version of the IMFS designed to provide minimal
functionality and have a low memory footprint.
This chapter should be written after the IMFS chapter is completed and describe
the implementation of the mini-IMFS.

71
filesystem/mounting_and_unmounting.rst
View File

@ -1,5 +1,9 @@
.. comment SPDX-License-Identifier: CC-BY-SA-4.0
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.
Mounting and Unmounting Filesystems
###################################
@ -8,29 +12,30 @@ Mount Points
The following is the list of the characteristics of a mount point:
- The mount point must be a directory. It may have files and other
directories under it. These files and directories will be hidden when the
filesystem is mounted.
- The mount point must be a directory. It may have files and other directories
under it. These files and directories will be hidden when the filesystem is
mounted.
- The task must have read/write/execute permissions to the mount point
or the mount attempt will be rejected.
- The task must have read/write/execute permissions to the mount point or the
mount attempt will be rejected.
- Only one filesystem can be mounted to a single mount point.
- The Root of the mountable filesystem will be referenced by the name
of the mount point after the mount is complete.
- The Root of the mountable filesystem will be referenced by the name of the
mount point after the mount is complete.
Mount Table Chain
=================
The mount table chain is a dynamic list of structures that describe
mounted filesystems a specific points in the filesystem hierarchy. It is
initialized to an empty state during the base filesystem initialization.
The mount operation will add entries to the mount table chain. The
un-mount operation will remove entries from the mount table chain.
The mount table chain is a dynamic list of structures that describe mounted
filesystems a specific points in the filesystem hierarchy. It is initialized to
an empty state during the base filesystem initialization. The mount operation
will add entries to the mount table chain. The un-mount operation will remove
entries from the mount table chain.
Each entry in the mount table chain is of the following type:
.. code:: c
.. code-block:: c
struct rtems_filesystem_mount_table_entry_tt
{
@ -38,7 +43,7 @@ Each entry in the mount table chain is of the following type:
rtems_filesystem_location_info_t mt_point_node;
rtems_filesystem_location_info_t mt_fs_root;
int options;
void \*fs_info;
void *fs_info;
rtems_filesystem_limits_and_options_t pathconf_limits_and_options;
/*
* When someone adds a mounted filesystem on a real device,
@ -46,7 +51,7 @@ Each entry in the mount table chain is of the following type:
*
* The best option long term for this is probably an
* open file descriptor.
\*/
*/
char \*dev;
};
@ -57,15 +62,15 @@ Each entry in the mount table chain is of the following type:
The mt_point_node contains all information necessary to access the
directory where a filesystem is mounted onto. This element may contain
memory that is allocated during a path evaluation of the filesystem
containing the mountpoint directory. The generic code allows this
memory to be returned by unmount when the filesystem identified by
mt_fs_root is unmounted.
containing the mountpoint directory. The generic code allows this memory
to be returned by unmount when the filesystem identified by mt_fs_root is
unmounted.
*mt_fs_root*
The mt_fs_root contains all information necessary to identify the root
of the mounted filesystem. The user is never allowed access to this
node by the generic code, but it is used to identify to the mounted
filesystem where to start evaluation of pathnames at.
The mt_fs_root contains all information necessary to identify the root of
the mounted filesystem. The user is never allowed access to this node by
the generic code, but it is used to identify to the mounted filesystem
where to start evaluation of pathnames at.
*options*
XXX
@ -74,7 +79,8 @@ Each entry in the mount table chain is of the following type:
The fs_info element is a location available for use by the mounted file
system to identify unique things applicable to this instance of the file
system. For example the IMFS uses this space to provide node
identification that is unique for each instance (mounting) of the filesystem.
identification that is unique for each instance (mounting) of the
filesystem.
*pathconf_limits_and_options*
XXX
@ -85,20 +91,13 @@ Each entry in the mount table chain is of the following type:
Adding entries to the chain during mount
========================================
When a filesystem is mounted, its presence and location in the file
system hierarchy is recorded in a dynamic list structure known as a chain.
A unique rtems_filesystem_mount_table_entry_tt structure is logged for
each filesystem that is mounted. This includes the base filesystem.
When a filesystem is mounted, its presence and location in the file system
hierarchy is recorded in a dynamic list structure known as a chain. A unique
rtems_filesystem_mount_table_entry_tt structure is logged for each filesystem
that is mounted. This includes the base filesystem.
Removing entries from the chain during unmount
==============================================
When a filesystem is dismounted its entry in the mount table chain is
extracted and the memory for this entry is freed.
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.
When a filesystem is dismounted its entry in the mount table chain is extracted
and the memory for this entry is freed.

112
filesystem/pathname_eval.rst
View File

@ -1,40 +1,44 @@
.. comment SPDX-License-Identifier: CC-BY-SA-4.0
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.
Pathname Evaluation
###################
This chapter describes the pathname evaluation process for the
RTEMS Filesystem Infrastructure.
.. code:: c
This chapter describes the pathname evaluation process for the RTEMS Filesystem
Infrastructure.
.. code-block:: shell
XXX Include graphic of the path evaluation process
Pathname Evaluation Handlers
============================
There are two pathname evaluation routines. The handler patheval()
is called to find, verify privlages on and return information on a node
that exists. The handler evalformake() is called to find, verify
permissions, and return information on a node that is to become a parent.
Additionally, evalformake() returns a pointer to the start of the name of
the new node to be created.
There are two pathname evaluation routines. The handler patheval() is called
to find, verify privlages on and return information on a node that exists. The
handler ``evalformake()`` is called to find, verify permissions, and return
information on a node that is to become a parent. Additionally, evalformake()
returns a pointer to the start of the name of the new node to be created.
Pathname evaluation is specific to a filesystem.
Each filesystem is required to provide both a patheval() and an evalformake()
routine. Both of these routines gets a name to evaluate and a node indicating
where to start the evaluation.
Pathname evaluation is specific to a filesystem. Each filesystem is required
to provide both a ``patheval()`` and an ``evalformake()`` routine. Both of
these routines gets a name to evaluate and a node indicating where to start the
evaluation.
Crossing a Mount Point During Path Evaluation
=============================================
If the filesystem supports the mount command, the evaluate routines
must handle crossing the mountpoint. The evaluate routine should evaluate
the name upto the first directory node where the new filesystem is mounted.
The filesystem may process terminator characters prior to calling the
evaluate routine for the new filesystem. A pointer to the portion of the
name which has not been evaluated along with the root node of the new
file system ( gotten from the mount table entry ) is passed to the correct
mounted filesystem evaluate routine.
If the filesystem supports the mount command, the evaluate routines must handle
crossing the mountpoint. The evaluate routine should evaluate the name upto
the first directory node where the new filesystem is mounted. The filesystem
may process terminator characters prior to calling the evaluate routine for the
new filesystem. A pointer to the portion of the name which has not been
evaluated along with the root node of the new file system (gotten from the
mount table entry) is passed to the correct mounted filesystem evaluate
routine.
The rtems_filesystem_location_info_t Structure
==============================================
@ -43,55 +47,49 @@ The ``rtems_filesystem_location_info_t`` structure contains all information
necessary for identification of a node.
The generic rtems filesystem code defines two global
rtems_filesystem_location_info_t structures, the``rtems_filesystem_root`` and the ``rtems_filesystem_current``.
Both are initially defined to be the root node of the base filesystem.
Once the chdir command is correctly used the ``rtems_filesystem_current``
is set to the location specified by the command.
rtems_filesystem_location_info_t structures, the``rtems_filesystem_root`` and
the ``rtems_filesystem_current``. Both are initially defined to be the root
node of the base filesystem. Once the chdir command is correctly used the
``rtems_filesystem_current`` is set to the location specified by the command.
The filesystem generic code peeks at the first character in the name to be
evaluated. If this character is a valid seperator, the``rtems_filesystem_root`` is used as the node to start the evaluation
with. Otherwise, the ``rtems_filesystem_current`` node is used as the
node to start evaluating with. Therefore, a valid
rtems_filesystem_location_info_t is given to the evaluate routine to start
evaluation with. The evaluate routines are then responsible for making
any changes necessary to this structure to correspond to the name being
parsed.
.. code:: c
evaluated. If this character is a valid seperator,
the``rtems_filesystem_root`` is used as the node to start the evaluation with.
Otherwise, the ``rtems_filesystem_current`` node is used as the node to start
evaluating with. Therefore, a valid rtems_filesystem_location_info_t is given
to the evaluate routine to start evaluation with. The evaluate routines are
then responsible for making any changes necessary to this structure to
correspond to the name being parsed.
.. code-block:: c
struct rtems_filesystem_location_info_tt {
void \*node_access;
rtems_filesystem_file_handlers_r \*handlers;
rtems_filesystem_operations_table \*ops;
rtems_filesystem_mount_table_entry_t \*mt_entry;
void *node_access;
rtems_filesystem_file_handlers_r *handlers;
rtems_filesystem_operations_table *ops;
rtems_filesystem_mount_table_entry_t *mt_entry;
};
*node_access*
This element is filesystem specific. A filesystem can define and store
any information necessary to identify a node at this location. This element
is normally filled in by the filesystem's evaluate routine. For the
filesystem's root node, the filesystem's initilization routine should
fill this in, and it should remain valid until the instance of the
filesystem is unmounted.
This element is filesystem specific. A filesystem can define and store any
information necessary to identify a node at this location. This element is
normally filled in by the filesystem's evaluate routine. For the
filesystem's root node, the filesystem's initilization routine should fill
this in, and it should remain valid until the instance of the filesystem is
unmounted.
*handlers*
This element is defined as a set of routines that may change within a
given filesystem based upon node type. For example a directory and a
memory file may have to completely different read routines. This element
is set to an initialization state defined by the mount table, and may
be set to the desired state by the evaluation routines.
This element is defined as a set of routines that may change within a given
filesystem based upon node type. For example a directory and a memory file
may have to completely different read routines. This element is set to an
initialization state defined by the mount table, and may be set to the
desired state by the evaluation routines.
*ops*
This element is defined as a set of routines that remain static for the
filesystem. This element identifies entry points into the filesystem
to the generic code.
filesystem. This element identifies entry points into the filesystem to
the generic code.
*mt_entry*
This element identifies the mount table entry for this instance of the
filesystem.
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.

72
filesystem/preface.rst
View File

@ -1,12 +1,15 @@
.. comment SPDX-License-Identifier: CC-BY-SA-4.0
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.
=======
Preface
=======
This document describes the implementation of the RTEMS filesystem
infrastructure. This infrastructure supports the following
capabilities:
infrastructure. This infrastructure supports the following capabilities:
- Mountable file systems
@ -15,6 +18,7 @@ capabilities:
- POSIX compliant set of routines for the manipulation of files and directories
- Individual file and directory support for the following:
# Permissions for read, write and execute
# User ID
# Group ID
@ -26,44 +30,34 @@ capabilities:
- Symbolic links to files and directories
This has been implemented to provide the framework for a UNIX-like
file system support. POSIX file and directory functions have been
implemented that allow a standard method of accessing file, device and
directory information within file systems. The file system concept that
has been implemented allows for expansion and adaptation of the file
system to a variety of existing and future data storage devices. To this
end, file system mount and unmount capabilities have been included in this
RTEMS framework.
This has been implemented to provide the framework for a UNIX-like file system
support. POSIX file and directory functions have been implemented that allow a
standard method of accessing file, device and directory information within file
systems. The file system concept that has been implemented allows for expansion
and adaptation of the file system to a variety of existing and future data
storage devices. To this end, file system mount and unmount capabilities have
been included in this RTEMS framework.
This framework slightly alters the manner in which devices are handled
under RTEMS from that of public release 4.0.0 and earlier. Devices that
are defined under a given RTEMS configuration will now be registered as
files in a mounted file system. Access to these device drivers and their
associated devices may now be performed through the traditional file system
open(), read(), write(), lseek(), fstat() and ioctl() functions in addition
to the interface provided by the IO Manager in the RTEMS Classic API.
This framework slightly alters the manner in which devices are handled under
RTEMS from that of public release 4.0.0 and earlier. Devices that are defined
under a given RTEMS configuration will now be registered as files in a mounted
file system. Access to these device drivers and their associated devices may
now be performed through the traditional file system open(), read(), write(),
lseek(), fstat() and ioctl() functions in addition to the interface provided by
the IO Manager in the RTEMS Classic API.
An In-Memory File System (IMFS) is included which provides full POSIX
filesystem functionality yet is RAM based. The IMFS maintains a
node structure for each file, device, and directory in each mounted
instantiation of its file system. The node structure is used to
manage ownership, access rights, access time, modification time,
and creation time. A union of structures within the IMFS nodal
structure provide for manipulation of file data, device selection,
or directory content as required by the nodal type. Manipulation of
these properties is accomplished through the POSIX set of file and
directory functions. In addition to being useful in its own right,
the IMFS serves as a full featured example filesystem.
The intended audience for this document is those persons implementing
their own filesystem. Users of the filesystem may find information
on the implementation useful. But the user interface to the filesystem
is through the ISO/ANSI C Library and POSIX 1003.1b file and directory
APIs.
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.
filesystem functionality yet is RAM based. The IMFS maintains a node structure
for each file, device, and directory in each mounted instantiation of its file
system. The node structure is used to manage ownership, access rights, access
time, modification time, and creation time. A union of structures within the
IMFS nodal structure provide for manipulation of file data, device selection,
or directory content as required by the nodal type. Manipulation of these
properties is accomplished through the POSIX set of file and directory
functions. In addition to being useful in its own right, the IMFS serves as a
full featured example filesystem.
The intended audience for this document is those persons implementing their own
filesystem. Users of the filesystem may find information on the implementation
useful. But the user interface to the filesystem is through the ISO/ANSI C
Library and POSIX 1003.1b file and directory APIs.

76
filesystem/system_init.rst
View File

@ -1,30 +1,33 @@
.. comment SPDX-License-Identifier: CC-BY-SA-4.0
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.
System Initialization
#####################
After the RTEMS initialization is performed, the application's
initialization will be performed. Part of initialization is a call to
rtems_filesystem_initialize(). This routine will mount the 'In Memory File
System' as the base filesystem. Mounting the base filesystem consists
of the following:
After the RTEMS initialization is performed, the application's initialization
will be performed. Part of initialization is a call to
``rtems_filesystem_initialize()``. This routine will mount the 'In Memory File
System' as the base filesystem. Mounting the base filesystem consists of the
following:
- Initialization of mount table chain control structure
- Allocation of a ``jnode`` structure that will server as the root node
of the 'In Memory Filesystem'
- Allocation of a ``jnode`` structure that will server as the root node of the
'In Memory Filesystem'
- Initialization of the allocated ``jnode`` with the appropriate OPS,
directory handlers and pathconf limits and options.
- Initialization of the allocated ``jnode`` with the appropriate OPS, directory
handlers and pathconf limits and options.
- Allocation of a memory region for filesystem specific global
management variables
- Allocation of a memory region for filesystem specific global management
variables
- Creation of first mount table entry for the base filesystem
- Initialization of the first mount table chain entry to indicate that
the mount point is NULL and the mounted filesystem is the base file
system
- Initialization of the first mount table chain entry to indicate that the
mount point is NULL and the mounted filesystem is the base file system
After the base filesystem has been mounted, the following operations are
performed under its directory structure:
@ -38,10 +41,11 @@ Base Filesystem
RTEMS initially mounts a RAM based file system known as the base file system.
The root directory of this file system tree serves as the logical root of the
directory hierarchy (Figure 3). Under the root directory a '/dev' directory
is created under which all I/O device directories and files are registered as
part of the file system hierarchy.
.. code:: c
directory hierarchy (Figure 3). Under the root directory a '/dev' directory is
created under which all I/O device directories and files are registered as part
of the file system hierarchy.
.. code-block:: shell
Figure of the tree structure goes here.
@ -65,37 +69,29 @@ Base Filesystem Mounting
At present, the first file system to be mounted is the 'In Memory File
System'. It is mounted using a standard MOUNT() command in which the mount
point is NULL. This flags the mount as the first file system to be
registered under the operating system and appropriate initialization of file
system management information is performed (See figures 4 and 5). If a
different file system type is desired as the base file system, alterations
must be made to base_fs.c. This routine handles the mount of the base file
system.
point is NULL. This flags the mount as the first file system to be registered
under the operating system and appropriate initialization of file system
management information is performed (See figures 4 and 5). If a different file
system type is desired as the base file system, alterations must be made to
base_fs.c. This routine handles the mount of the base file system.
.. code:: c
.. code-block:: shell
Figure of the mount table chain goes here.
Once the root of the base file system has been established and it has been
recorded as the mount point of the base file system, devices are integrated
into the base file system. For every device that is configured into the
system (See ioman.c) a device registration process is performed. Device
registration produces a unique dev_t handle that consists of a major and
minor device number. In addition, the configuration information for each
device contains a text string that represents the fully qualified pathname to
that device's place in the base file system's hierarchy. A file system node
is created for the device along the specified registration path.
into the base file system. For every device that is configured into the system
(See ioman.c) a device registration process is performed. Device registration
produces a unique dev_t handle that consists of a major and minor device
number. In addition, the configuration information for each device contains a
text string that represents the fully qualified pathname to that device's place
in the base file system's hierarchy. A file system node is created for the
device along the specified registration path.
.. code:: c
.. code-block:: shell
Figure of the Mount Table Processing goes here.
Note: Other file systems can be mounted but they are mounted onto points
(directory mount points) in the base file system.
.. COMMENT: COPYRIGHT (c) 1988-2002.
.. COMMENT: On-Line Applications Research Corporation (OAR).
.. COMMENT: All rights reserved.

5
filesystem/trivial_ftp.rst
View File

@ -5,6 +5,5 @@ Trivial FTP Client Filesystem
This chapter describes the Trivial FTP (TFTP) Client Filesystem.
This chapter should be written after the IMFS chapter is completed
and describe the implementation of the TFTP.
This chapter should be written after the IMFS chapter is completed and describe
the implementation of the TFTP.