Build an embedded filesystem (QNX)


mkefs [-Ddnv] [-c cache_dir] [-l inputline] [-o directory]
      [-p patch_file] [-t ffs2 | ffs3] [buildfile] [directory] [outputfile]

Runs on:

Linux, Microsoft Windows


-c cache_dir
Cache compressed files in cache_dir.
Treat undeclared intermediate directories as errors. If there's a target filesystem entry of /x/y, and /x has never occurred explicitly in the buildfile, the input directory, or as a child of a recursively included directory, then /x is considered an undeclared intermediate directory.
Display warnings for undeclared intermediate directories.
-l inputline
("el") Process inputline before interpretation of the buildfile begins. Input lines given to mkefs should be quoted to prevent interpretation by the shell (as mkefs input lines often contain spaces). Multiple -l options are processed in the order specified. No default.
Don't use timestamps in the files. Using the -n option permits identical images in binary format. Specifying additional -n options strips all time information from files.
-o directory
("oh") Specify a directory to be used for all permanent build artifacts, other than the output image itself.
-p patchfile
Apply patching instructions from this file (see "Patch files," below).
-t ffs2 | -t ffs3
Set the type of output filesystem. Use -t ffs2 to make a version 2 flash filesystem image (no longer supported; for backward compatibility only). Use -t ffs3 to make a version 3 flash filesystem image. The default is ffs3.
Operate verbosely. Specifying additional -v options increases verbosity. Default is quiet operation.


The mkefs utility reads a text buildfile describing an embedded filesystem and produces a binary image file containing the embedded filesystem. You can copy this file to flash at a later stage, or use mkimage to combine it with an OS image before downloading.

Note: Don't confuse this command with mkifs, which builds an OS image filesystem, or mketfs, which builds an embedded transaction filesystem (ETFS).

You specify the input and output on the command line:

The filename of the buildfile that describes the contents of the embedded filesystem; use "-" to specify standard input (the default).
The root of a directory hierarchy to be appended to the file list specified in buildfile (if any). The default is no directory.
The filename of the image file containing the embedded filesystem; use "-" to specify standard output (the default). Note that you can specify the outputfile only if you specified a buildfile.

If you don't specify either a buildfile or a directory, a buildfile is expected as input from standard input. The output is always an image file; if you don't specify outputfile, image-file data will be produced on standard output.

Note: QNX Neutrino flash filesystem version 3 no longer provides built-in decompression. The flash filesystem's decompression functionality has moved into the inflator resource manager. You should now use the deflate utility to compress files.


The buildfile uses the same grammar as the mkifs command, but supports different attributes.

The buildfile is basically just a list of files that you want to be included in the embedded filesystem image file when it's built by mkefs. As well as the files to be included, you can specify various attributes that are used to set parameters of the filesystem and the files in it. For example, you can specify the maximum size of the filesystem, or the user and group IDs of the individual files.

Note: You can't use a backslash (\) to break long lines into smaller pieces.

In a buildfile, a pound sign (#) indicates a comment; anything between it and the end of the line is ignored. There must be a space between a buildfile command and the pound sign.

Each line is in the form:

[attributes] file_specification

where the attributes (with the enclosing square brackets) and the file specification are both optional.

You can use an attribute:

Attributes provide information about the file following the attribute. They're enclosed in square brackets; when combining attributes (e.g., to specify both the user ID and the group ID), enclose both attribute tokens in the same pair of square brackets. For example:

# correct way
[uid=5 gid=5] filename

# incorrect way
[uid=5] [gid=5] filename

There are two types of attributes:

boolean attributes
Those prefixed with a plus ("+") or minus ("-") sign.
value attributes
Those ending with an equals sign ("=") followed by a value. Don't put any spaces around the equals sign.

A question mark (?) before an attribute makes the setting conditional. The attribute is set only if it hasn't already been set. For example, ?+bigendian sets the +bigendian attribute only if +bigendian or -bigendian hasn't already been set.

The file_specification takes one of the following forms:
The file is copied from the host to the location in the image defined by the prefix attribute. If path isn't absolute, mkefs looks for it in the locations identified by the search attribute.
The specified file or contents of the specified directory are fetched from the host filesystem and placed into the image.
An inline definition. The contents of the file are listed within the buildfile itself, enclosed in braces ({ }); the file doesn't exist on the host system anywhere. The contents of the inline file can't be on the same line as the opening or closing brace.
Note: The mkefs utility doesn't parse the contents of an inline file for anything but the closing brace. For example, mkefs doesn't interpret a pound sign (#) in an inline file as the beginning of a comment. The syntax of the inline file depends on what it's used for on the target system.

Closing braces (}) and backslashes (\) in an inline file must be escaped with a backslash.

You can enclose a filename in double quotes ("") if it includes spaces or unusual characters.


The mkefs command supports the following attributes:

Note: An OR-bar indicates that either the first element or the second element must be present, but not both (e.g., +|- bigendian means either +bigendian or -bigendian, but not +-bigendian).

bigendian attribute (boolean)


Set the byte order for the embedded filesystem to either big (via +bigendian) or little (via -bigendian) endian. The default is little endian.

block_size attribute


Set the block size for the embedded filesystem. The block size depends on what memory devices you have in your target hardware and how they're arranged. For example, two interleaved 64 KB × 8-bit devices configured for a 16-bit interface have a block size of 128 KB. The default block size is 64 KB.

cd attribute


Set the current working directory to the specified pathname before attempting to open the host file. Default is the directory from which mkefs was invoked.

dperms attribute


Set the access permissions of the directory. The dperms_spec can be one of the following:

The default dperms_spec is *.

Note: When running on a Windows host, mkefs might guess at the permissions, so you should use the dperms attribute to specify them explicitly. You might also have to use the uid and gid attributes to set the ownership correctly.

ecc_on attribute


Control error-correcting code (ECC) support:

Specify value as: To:
0 Disable ECC (the default)
1 Enable 64-byte alignment ECC
2 Enable 32-byte alignment ECC
Note: Don't mix ECC-enabled partitions and ECC-disabled partitions; the devf-* drivers don't support this.

The mkefs utility automatically handles the formatting alignment, but you have to use the -b option for flashctl to specify the appropriate alignment.

filter attribute


Run the host file through the filter program specified, presenting the host file data as standard input to the program and using the standard output from the program as the data to be placed into the embedded filesystem. Default is no filter.

The most common filter you're likely to use with the embedded filesystem is deflate. This compresses the file before copying it to the embedded filesystem. For example:


You can specify a filter_spec of none. This is useful if you need to override a global filter specification.


Whether to resolve any symbolic links and include the target files or directories instead of the links.

If you specify +followlink or omit it, whenever an item taken from the host filesystem is a symbolic link, mkefs resolves the link and includes its target file or directory.

If you specify -followlink, then:

gid attribute


Set the group ID number for the file. The value of this attribute may be either a number or an asterisk (*). If it's an asterisk, the group ID is taken from the host file; for an inline file, the group ID is the group of the user running mkefs. The default value for this attribute is *.

max_size attribute


Set the maximum size of the embedded filesystem. You can set this attribute if you don't want the filesystem to exceed a maximum size. If this occurs while mkefs is building the filesystem, you'll see a warning message. The default is 4 GB.

min_size attribute


Set the minimum size of the embedded filesystem. If the size of the filesystem is less than this size after all the specified files have been added, then the filesystem is padded to the required size. If you don't specify this attribute, no padding occurs.

mount attribute


Specify the mountpoint for the embedded filesystem. You can override the mountpoint with the -n option to the flashctl command.

The default is "", which makes the flash filesystem drivers (devf-*) use the appropriate default, usually /fs1p1.

mountperms attribute


Set the access permissions for mountpoints. The perms_spec can be one of the following:

The default perms_spec is "0777".

mtime attribute


Set the timestamps of the files or directories to the specified time. The time_spec must be either:

Timestamps specified with the mtime attribute aren't affected by the -n option.

optional attribute (boolean)


If true, and the host file can't be found, output a warning and continue building the embedded filesystem. If false, and the host file can't be found, output an error message and exit mkefs. The default is true.

perms attribute


Set the access permissions of the file. The perms_spec can be one of the following:

The default perms_spec is *.

Note: When running on a Windows host, mkefs can't get the setuid ("set user ID") or setgid ("set group ID") permissions from the file, and it might guess at the read, write, and execute permissions, so you should use the perms attribute to specify the permissions explicitly. You might also have to use the uid and gid attributes to set the ownership correctly. To determine whether or not a utility needs to have the setuid or setgid permission set, see its entry in the Utilities Reference.

prefix attribute


Set the prefix on the target file names. The default is the empty string.


This attribute specifies that mkefs should search for the file in the named locations on the host system. The search directory portion of the host file name isn't included in the name that's stored in the image file system.

Note: Colon separators and forward slashes in the paths are the standard Unix conventions, but for Windows searches, you must use the standard Windows conventions, such as semicolon separators and backslashes in the paths.

spare_blocks attribute


Set the number of spare blocks to be used by the embedded filesystem. If you want the embedded filesystem to be able to reclaim the space taken up by deleted files, set the number of spare blocks to 1 or more. The default is 1.

type attribute


Sets the type of the files being created in the embedded filesystem. Allowable types are:

Note: Specifying [type=dir] tells mkefs to make the named file a directory; you don't need to specify the type when you're copying the contents of a directory. For example, this command:

creates an empty directory named /usr/bin, with the same owner and permissions as for the host directory. To recursively copy /usr/nto/x86/bin to /usr/bin, you just need to specify:


uid attribute


Set the user ID number for the file. The value of this attribute may be either a number or an asterisk (*). If it's an asterisk, the user ID is taken from the host file; for an inline file, the user ID is the user running mkefs. The default value for this attribute is *.

Patch files

Patch files let you override the user ID, group ID, and permissions of certain files, depending on their location and filename pattern. Patches are applied after all files have been collected (from the buildfile and/or the specified directory). Consequently, patch files can override settings specified in the buildfile.

Patch files must contain only lines of the form:




In comment lines, # must be the very first character. The entire line is regarded as a comment and is ignored.

The type is either d or f, optionally followed by r. Type d patches are applied only to directories, and type f patches are applied only to files. An r indicates that the patch should be applied recursively within path; without r, the patch is applied to path only.

The pattern is a filename pattern that specifies which files to apply the patch to. The uid and gid must be decimal numbers, while perms must be an octal number (see chmod). Note that it isn't possible to set only the user ID, group ID, or permissions; for each match, all three are affected.


Here's a sample buildfile, my_efs.bld:

# A sample buildfile for mkefs

[block_size=128k spare_blocks=1]

In this example, we've specified a block size of 128 KB and one spare block. The files and subdirectories from the /home/jwall/nto_flash directory on the host system are to be recursively copied into the root directory of the embedded filesystem.

To create an embedded filesystem image file using the above buildfile, invoke mkefs as follows:

mkefs my_efs.bld my_image.efs

This creates the my_image.efs file containing the embedded filesystem, which can then be copied to the target system.

Exit status:

Successful completion.
An error occurred.