Filesystem Configuration

Macros
#define	CONFIGURE_APPLICATION_DISABLE_FILESYSTEM
	This configuration option is a boolean feature define.
#define	CONFIGURE_FILESYSTEM_ALL
	This configuration option is a boolean feature define.
#define	CONFIGURE_FILESYSTEM_DOSFS
	This configuration option is a boolean feature define.
#define	CONFIGURE_FILESYSTEM_FTPFS
	This configuration option is a boolean feature define.
#define	CONFIGURE_FILESYSTEM_IMFS
	This configuration option is a boolean feature define.
#define	CONFIGURE_FILESYSTEM_JFFS2
	This configuration option is a boolean feature define.
#define	CONFIGURE_FILESYSTEM_NFS
	This configuration option is a boolean feature define.
#define	CONFIGURE_FILESYSTEM_RFS
	This configuration option is a boolean feature define.
#define	CONFIGURE_FILESYSTEM_TFTPFS
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_CHMOD
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_CHOWN
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_LINK
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_MKNOD
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_MKNOD_DEVICE
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_MKNOD_FILE
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_MOUNT
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_READDIR
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_READLINK
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_RENAME
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_RMNOD
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_SYMLINK
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_UNMOUNT
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_DISABLE_UTIME
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_ENABLE_MKFIFO
	This configuration option is a boolean feature define.
#define	CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK
	This configuration option is an integer define.
#define	CONFIGURE_JFFS2_DELAYED_WRITE_TASK_PRIORITY
	This configuration option is an integer define.
#define	CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM
	This configuration option is a boolean feature define.
#define	CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM
	This configuration option is a boolean feature define.

Detailed Description

This section describes configuration options related to filesytems. By default, the In-Memory Filesystem (IMFS) is used as the base filesystem (also known as root filesystem). In order to save some memory for your application, you can disable the filesystem support with the CONFIGURE_APPLICATION_DISABLE_FILESYSTEM configuration option. Alternatively, you can strip down the features of the base filesystem with the CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM and CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM configuration options. These three configuration options are mutually exclusive. They are intended for an advanced application configuration.

Features of the IMFS can be disabled and enabled with the following configuration options:

• CONFIGURE_IMFS_DISABLE_CHMOD
• CONFIGURE_IMFS_DISABLE_CHOWN
• CONFIGURE_IMFS_DISABLE_LINK
• CONFIGURE_IMFS_DISABLE_MKNOD
• CONFIGURE_IMFS_DISABLE_MKNOD_FILE
• CONFIGURE_IMFS_DISABLE_MOUNT
• CONFIGURE_IMFS_DISABLE_READDIR
• CONFIGURE_IMFS_DISABLE_READLINK
• CONFIGURE_IMFS_DISABLE_RENAME
• CONFIGURE_IMFS_DISABLE_RMNOD
• CONFIGURE_IMFS_DISABLE_SYMLINK
• CONFIGURE_IMFS_DISABLE_UNMOUNT
• CONFIGURE_IMFS_DISABLE_UTIME
• CONFIGURE_IMFS_ENABLE_MKFIFO

Macro Definition Documentation

CONFIGURE_APPLICATION_DISABLE_FILESYSTEM

#define CONFIGURE_APPLICATION_DISABLE_FILESYSTEM

This configuration option is a boolean feature define.

In case this configuration option is defined, then no base filesystem is initialized during system initialization and no filesystems are configured.

Default Configuration

If this configuration option is undefined, then a base filesystem and the configured filesystems are initialized during system initialization.

Notes

Filesystems shall be initialized to support file descriptor based device drivers and basic input/output functions such as printf(). Filesystems can be disabled to reduce the memory footprint of an application.

CONFIGURE_FILESYSTEM_ALL

#define CONFIGURE_FILESYSTEM_ALL

This configuration option is a boolean feature define.

In case this configuration option is defined, then the following configuration options will be defined as well

• CONFIGURE_FILESYSTEM_DOSFS,
• CONFIGURE_FILESYSTEM_FTPFS,
• CONFIGURE_FILESYSTEM_IMFS,
• CONFIGURE_FILESYSTEM_JFFS2,
• CONFIGURE_FILESYSTEM_NFS,
• CONFIGURE_FILESYSTEM_RFS, and
• CONFIGURE_FILESYSTEM_TFTPFS.

Default Configuration

If this configuration option is undefined, then the described feature is not enabled.

CONFIGURE_FILESYSTEM_DOSFS

#define CONFIGURE_FILESYSTEM_DOSFS

This configuration option is a boolean feature define.

In case this configuration option is defined, then the DOS (FAT) filesystem is registered, so that instances of this filesystem can be mounted by the application.

Default Configuration

If this configuration option is undefined, then the described feature is not enabled.

Notes

This filesystem requires a Block Device Cache configuration, see CONFIGURE_APPLICATION_NEEDS_LIBBLOCK.

CONFIGURE_FILESYSTEM_FTPFS

#define CONFIGURE_FILESYSTEM_FTPFS

This configuration option is a boolean feature define.

In case this configuration option is defined, then the FTP filesystem (FTP client) is registered, so that instances of this filesystem can be mounted by the application.

Default Configuration

If this configuration option is undefined, then the described feature is not enabled.

CONFIGURE_FILESYSTEM_IMFS

#define CONFIGURE_FILESYSTEM_IMFS

This configuration option is a boolean feature define.

In case this configuration option is defined, then the In-Memory Filesystem (IMFS) is registered, so that instances of this filesystem can be mounted by the application.

Default Configuration

If this configuration option is undefined, then the described feature is not enabled.

Notes

Applications will rarely need this configuration option. This configuration option is intended for test programs. You do not need to define this configuration option for the base filesystem (also known as root filesystem).

CONFIGURE_FILESYSTEM_JFFS2

#define CONFIGURE_FILESYSTEM_JFFS2

This configuration option is a boolean feature define.

In case this configuration option is defined, then the JFFS2 filesystem is registered, so that instances of this filesystem can be mounted by the application.

Default Configuration

If this configuration option is undefined, then the described feature is not enabled.

CONFIGURE_FILESYSTEM_NFS

#define CONFIGURE_FILESYSTEM_NFS

This configuration option is a boolean feature define.

In case this configuration option is defined, then the Network Filesystem (NFS) client is registered, so that instances of this filesystem can be mounted by the application.

Default Configuration

If this configuration option is undefined, then the described feature is not enabled.

CONFIGURE_FILESYSTEM_RFS

#define CONFIGURE_FILESYSTEM_RFS

This configuration option is a boolean feature define.

In case this configuration option is defined, then the RTEMS Filesystem (RFS) is registered, so that instances of this filesystem can be mounted by the application.

Default Configuration

If this configuration option is undefined, then the described feature is not enabled.

Notes

This filesystem requires a Block Device Cache configuration, see CONFIGURE_APPLICATION_NEEDS_LIBBLOCK.

CONFIGURE_FILESYSTEM_TFTPFS

#define CONFIGURE_FILESYSTEM_TFTPFS

This configuration option is a boolean feature define.

In case this configuration option is defined, then the TFTP filesystem (TFTP client) is registered, so that instances of this filesystem can be mounted by the application.

Default Configuration

If this configuration option is undefined, then the described feature is not enabled.

CONFIGURE_IMFS_DISABLE_CHMOD

#define CONFIGURE_IMFS_DISABLE_CHMOD

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support changing the mode of files (no support for chmod()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports changing the mode of files.

CONFIGURE_IMFS_DISABLE_CHOWN

#define CONFIGURE_IMFS_DISABLE_CHOWN

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support changing the ownership of files (no support for chown()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports changing the ownership of files.

CONFIGURE_IMFS_DISABLE_LINK

#define CONFIGURE_IMFS_DISABLE_LINK

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support hard links (no support for link()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports hard links.

CONFIGURE_IMFS_DISABLE_MKNOD

#define CONFIGURE_IMFS_DISABLE_MKNOD

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support making files (no support for mknod()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports making files.

CONFIGURE_IMFS_DISABLE_MKNOD_DEVICE

#define CONFIGURE_IMFS_DISABLE_MKNOD_DEVICE

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support making device files.

Default Configuration

If this configuration option is undefined, then the root IMFS supports making device files.

CONFIGURE_IMFS_DISABLE_MKNOD_FILE

#define CONFIGURE_IMFS_DISABLE_MKNOD_FILE

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support making regular files.

Default Configuration

If this configuration option is undefined, then the root IMFS supports making regular files.

CONFIGURE_IMFS_DISABLE_MOUNT

#define CONFIGURE_IMFS_DISABLE_MOUNT

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support mounting other filesystems (no support for mount()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports mounting other filesystems.

CONFIGURE_IMFS_DISABLE_READDIR

#define CONFIGURE_IMFS_DISABLE_READDIR

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support reading directories (no support for readdir()). It is still possible to open files in a directory.

Default Configuration

If this configuration option is undefined, then the root IMFS supports reading directories.

CONFIGURE_IMFS_DISABLE_READLINK

#define CONFIGURE_IMFS_DISABLE_READLINK

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support reading symbolic links (no support for readlink()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports reading symbolic links.

CONFIGURE_IMFS_DISABLE_RENAME

#define CONFIGURE_IMFS_DISABLE_RENAME

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support renaming files (no support for rename()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports renaming files.

CONFIGURE_IMFS_DISABLE_RMNOD

#define CONFIGURE_IMFS_DISABLE_RMNOD

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support removing files (no support for rmnod()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports removing files.

CONFIGURE_IMFS_DISABLE_SYMLINK

#define CONFIGURE_IMFS_DISABLE_SYMLINK

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support creating symbolic links (no support for symlink()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports creating symbolic links.

CONFIGURE_IMFS_DISABLE_UNMOUNT

#define CONFIGURE_IMFS_DISABLE_UNMOUNT

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support unmounting other filesystems (no support for unmount()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports unmounting other filesystems.

CONFIGURE_IMFS_DISABLE_UTIME

#define CONFIGURE_IMFS_DISABLE_UTIME

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS does not support changing file times (no support for utime()).

Default Configuration

If this configuration option is undefined, then the root IMFS supports changing file times.

CONFIGURE_IMFS_ENABLE_MKFIFO

#define CONFIGURE_IMFS_ENABLE_MKFIFO

This configuration option is a boolean feature define.

In case this configuration option is defined, then the root IMFS supports making FIFOs.

Default Configuration

If this configuration option is undefined, then the root IMFS does not support making FIFOs (no support for mkfifo()).

CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK

#define CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK

This configuration option is an integer define.

The value of this configuration option defines the block size for in-memory files managed by the IMFS.

Default Value

The default value is 128.

Constraints

The value of the configuration option shall be equal to 16, 32, 64, 128, 256, or 512.

Notes

The configured block size has two impacts. The first is the average amount of unused memory in the last block of each file. For example, when the block size is 512, on average one-half of the last block of each file will remain unused and the memory is wasted. In contrast, when the block size is 16, the average unused memory per file is only 8 bytes. However, it requires more allocations for the same size file and thus more overhead per block for the dynamic memory management.

Second, the block size has an impact on the maximum size file that can be stored in the IMFS. With smaller block size, the maximum file size is correspondingly smaller. The following shows the maximum file size possible based on the configured block size:

• when the block size is 16 bytes, the maximum file size is 1,328 bytes.
• when the block size is 32 bytes, the maximum file size is 18,656 bytes.
• when the block size is 64 bytes, the maximum file size is 279,488 bytes.
• when the block size is 128 bytes, the maximum file size is 4,329,344 bytes.
• when the block size is 256 bytes, the maximum file size is 68,173,568 bytes.
• when the block size is 512 bytes, the maximum file size is 1,082,195,456 bytes.

CONFIGURE_JFFS2_DELAYED_WRITE_TASK_PRIORITY

#define CONFIGURE_JFFS2_DELAYED_WRITE_TASK_PRIORITY

This configuration option is an integer define.

The value of this configuration option defines the JFFS2 delayed write task priority.

Default Value

The default value is 15.

Constraints

The following constraints apply to this configuration option:

• The configuration option is not included in the pre-qualified feature set of RTEMS. Applications which are restricted to only use interfaces of the pre-qualified feature set of RTEMS shall not use the configuration option.
• The value of the configuration option shall be a valid Classic API task priority. The set of valid task priorities depends on the scheduler configuration.

CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM

#define CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM

This configuration option is a boolean feature define.

In case this configuration option is defined, then an IMFS with a reduced feature set will be the base filesystem (also known as root filesystem).

Default Configuration

If this configuration option is undefined, then the described feature is not enabled.

Notes

In case this configuration option is defined, then the following configuration options will be defined as well

• CONFIGURE_IMFS_DISABLE_CHMOD,
• CONFIGURE_IMFS_DISABLE_CHOWN,
• CONFIGURE_IMFS_DISABLE_LINK,
• CONFIGURE_IMFS_DISABLE_MKNOD_FILE,
• CONFIGURE_IMFS_DISABLE_MOUNT,
• CONFIGURE_IMFS_DISABLE_READDIR,
• CONFIGURE_IMFS_DISABLE_READLINK,
• CONFIGURE_IMFS_DISABLE_RENAME,
• CONFIGURE_IMFS_DISABLE_RMNOD,
• CONFIGURE_IMFS_DISABLE_SYMLINK,
• CONFIGURE_IMFS_DISABLE_UTIME, and
• CONFIGURE_IMFS_DISABLE_UNMOUNT.

In addition, a simplified path evaluation is enabled. It allows only a look up of absolute paths.

This configuration of the IMFS is basically a device-only filesystem. It is comparable in functionality to the pseudo-filesystem name space provided before RTEMS release 4.5.0.

CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM

#define CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM

This configuration option is a boolean feature define.

In case this configuration option is defined, then an IMFS with a reduced feature set will be the base filesystem (also known as root filesystem).

Default Configuration

If this configuration option is undefined, then the described feature is not enabled.

Notes

In case this configuration option is defined, then the following configuration options will be defined as well

• CONFIGURE_IMFS_DISABLE_CHMOD,
• CONFIGURE_IMFS_DISABLE_CHOWN,
• CONFIGURE_IMFS_DISABLE_LINK,
• CONFIGURE_IMFS_DISABLE_READLINK,
• CONFIGURE_IMFS_DISABLE_RENAME,
• CONFIGURE_IMFS_DISABLE_SYMLINK,
• CONFIGURE_IMFS_DISABLE_UTIME, and
• CONFIGURE_IMFS_DISABLE_UNMOUNT.