Binfmt misc
Encyclopedia
binfmt_misc is a capability of the Linux kernel
which allows arbitrary executable file formats to be recognized and passed to certain user space
applications, such as emulator
s and virtual machine
s.
The executable formats are registered through a special purpose file system interface (similar to /proc). Debian
-based distributions provide the functionality through an extra binfmt-support package.
:name:type:offset:magic:mask:interpreter:
Each format has a corresponding file entry in the /proc/sys/fs/binfmt_misc directory which can be read to get information about a given file format.
programs to be passed directly to the Java virtual machine
.
Another common usage is to execute PE executables (compiled for MS-DOS
or Microsoft Windows
) through Wine
. For example, the following line will run DOS and Windows EXE
files (identified by the "MZ" type code
) using Wine
:
:DOSWin:M::MZ::/usr/bin/wine:
To run EXE (.NET) files with Mono
:
:CLR:M::MZ::/usr/bin/mono:
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
which allows arbitrary executable file formats to be recognized and passed to certain user space
User space
A conventional computer operating system usually segregates virtual memory into kernel space and user space. Kernel space is strictly reserved for running the kernel, kernel extensions, and most device drivers...
applications, such as emulator
Emulator
In computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...
s and virtual machine
Virtual machine
A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...
s.
The executable formats are registered through a special purpose file system interface (similar to /proc). Debian
Debian
Debian is a computer operating system composed of software packages released as free and open source software primarily under the GNU General Public License along with other free software licenses. Debian GNU/Linux, which includes the GNU OS tools and Linux kernel, is a popular and influential...
-based distributions provide the functionality through an extra binfmt-support package.
Registration
The register file contains lines which define executable types to be handled. Each line is of the form::name:type:offset:magic:mask:interpreter:
- name is the name of the binary format.
- type is either E or M
- If it is E, the executable file format is identified by its filename extensionFilename extensionA filename extension is a suffix to the name of a computer file applied to indicate the encoding of its contents or usage....
: magic is the file extension to be associated with the binary format; offset and mask are ignored. - If it is M, the format is identified by magic number at an absolute offset in the file and mask is a bitmask indicating which bits in the number are significant.
- If it is E, the executable file format is identified by its filename extension
- interpreter is a program that is to be run with the matching file as an argument.
Each format has a corresponding file entry in the /proc/sys/fs/binfmt_misc directory which can be read to get information about a given file format.
Common usage
binfmt_misc allows JavaJava (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
programs to be passed directly to the Java virtual machine
Java Virtual Machine
A Java virtual machine is a virtual machine capable of executing Java bytecode. It is the code execution component of the Java software platform. Sun Microsystems stated that there are over 4.5 billion JVM-enabled devices.-Overview:...
.
Another common usage is to execute PE executables (compiled for MS-DOS
MS-DOS
MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
or Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
) through Wine
Wine (software)
Wine is a free software application that aims to allow computer programs written for Microsoft Windows to run on Unix-like operating systems. Wine also provides a software library, known as Winelib, against which developers can compile Windows applications to help port them to Unix-like...
. For example, the following line will run DOS and Windows EXE
EXE
EXE is the common filename extension denoting an executable file in the DOS, OpenVMS, Microsoft Windows, Symbian, and OS/2 operating systems....
files (identified by the "MZ" type code
Type code
A type code is the only mechanism used in pre-Mac OS X versions of the Macintosh operating system to denote a file's format, in a manner similar to file extensions in other operating systems. Codes are four-byte OSTypes...
) using Wine
Wine (software)
Wine is a free software application that aims to allow computer programs written for Microsoft Windows to run on Unix-like operating systems. Wine also provides a software library, known as Winelib, against which developers can compile Windows applications to help port them to Unix-like...
:
:DOSWin:M::MZ::/usr/bin/wine:
To run EXE (.NET) files with Mono
Mono (software)
Mono, pronounced , is a free and open source project led by Xamarin to create an Ecma standard compliant .NET-compatible set of tools including, among others, a C# compiler and a Common Language Runtime....
:
:CLR:M::MZ::/usr/bin/mono: