LINUX(4) BSD Kernel Interfaces Manual LINUX(4)NAME
linux — Linux ABI support
SYNOPSIS
To compile support for this ABI into an i386 kernel place the following
line in your kernel configuration file:
options COMPAT_LINUX
for an amd64 kernel use:
options COMPAT_LINUX32
Alternatively, to load the ABI as a module at boot time, place the fol‐
lowing line in loader.conf(5):
linux_load="YES"
DESCRIPTION
The linux module provides limited Linux ABI (application binary inter‐
face) compatibility for userland applications. The module provides the
following significant facilities:
· An image activator for correctly branded elf(5) executable images
· Special signal handling for activated images
· 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 release. Chang‐
ing this to something else is discouraged on
non-development systems, because it may change
the way Linux programs work. Recent versions
of GNU libc are known to use different syscalls
depending on the value of this sysctl.
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 required. The fol‐
lowing command will load the module if it is neither linked into the ker‐
nel 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 reason, it is com‐
mon 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 -r /compat/linux
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
/compat/linux/sys limited Linux system file system
SEE ALSObrandelf(1), elf(5), linprocfs(5), linsysfs(5)HISTORY
Linux ABI support first appeared in FreeBSD 2.1.
BSD February 8, 2010 BSD