linux(4)

NAME

linux - Linux ABI support

SYNOPSIS

To link Linux ABI support into the kernel:
options COMPAT_LINUX
To load the Linux ABI support kernel module:
      kldload linux

DESCRIPTION

The linux module provides limited Linux ABI (application bi

nary interface) compatibility for userland applications. The module

provides the
following significant facilities:

+o An image activator for correctly branded elf(5) exe

cutable images

+o Special signal handling for activated images

+o Linux to native system call translation

It is important to note that the Linux ABI support it not

provided
through an emulator. Rather, a true (albeit limited) ABI

implementation
is provided.

The following sysctl(8) tunable variables are available:

compat.linux.osname Linux kernel operating system

name.

compat.linux.osrelease Linux kernel operating system re

lease.

compat.linux.oss_version Linux Open Sound System version.

The linux module can be linked into the kernel statically

with the
COMPAT_LINUX kernel configuration option or loaded as re

quired. The following command will load the module if it is neither linked

into the kernel nor already loaded as a module:

if ! kldstat -v | grep -E 'linux(aout|elf)' >

/dev/null; then

kldload linux > /dev/null 2>&1

fi

Note that dynamically linked Linux executables will require

a suitable
environment in /compat/linux. Specifically, the Linux run

time linker's
hints files should be correctly initialized. For this rea

son, it is common to execute the following commands to prepare the system

to correctly
run Linux executables:

if [ -x /compat/linux/sbin/ldconfig ]; then

/compat/linux/sbin/ldconfig

fi

For information on loading the linux kernel loadable module

automatically
on system startup, see rc.conf(5). This information applies

regardless
of whether the linux module is statically linked into the

kernel or
loaded as a module.

FILES

/compat/linux minimal Linux run-time environment
/compat/linux/proc limited Linux process file system

SEE ALSO

brandelf(1), elf(5), linprocfs(5)

HISTORY

Linux ABI support first appeared in FreeBSD 2.1.

BSD August 17, 2000

BSD