linux(4) manual page

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 following line in loader.conf(5):

linux_load="YES"

The linux module provides limited Linux ABI (application binary interface) compatibility, making it possible to run many unmodified Linux applications and libraries without the need for virtualization or emulation. Some of the facilities provided are:

An image activator for correctly branded elf(5) executable images
Special signal handling for activated images
Linux to native system call translation
Linux-specific system calls

Note that dynamically linked Linux executables will require a suitable environment in /compat/linux. This includes native Linux shared libraries, and Linux-specific virtual filesystems. To set it up, install the emulators/linux_base-c7 port or the linux_base-c7 package, and add the following line to the rc.conf(5) file:

linux_enable="YES"

To avoid mounting Linux-specific filesystems at startup, also add the following line:

linux_mounts_enable="NO"

The following variables are available as both sysctl(8) variables and loader(8) tunables:

compat.linux.debug
	Enable debugging messages. Set to 0 to silence them. Defaults to 1.
compat.linux.default_openfiles
	Default soft openfiles resource limit for Linux applications. Set to -1 to disable the limit. Defaults to 1024.
compat.linux.emul_path
	Path to the Linux run-time environment. Defaults to `/compat/linux`.
compat.linux.osname
	Linux kernel operating system name.
compat.linux.osrelease
	Linux kernel operating system release. Changing 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.
compat.linux.preserve_vstatus
	When set to 1, it prevents Linux applications from resetting the termios(4) VSTATUS setting. From a user perspective, this makes SIGINFO work for Linux executables. Defaults to 0.

brandelf(1), pty(4), elf(5), fdescfs(5), linprocfs(5), linsysfs(5), tmpfs(5)

`/compat/linux`	minimal Linux run-time environment
`/compat/linux/dev`	device file system, see devfs(5)
`/compat/linux/dev/fd`	file descriptor file system mounted with the linrdlnk option, see fdescfs(5)
`/compat/linux/dev/shm`
	in-memory file system, see tmpfs(5)
`/compat/linux/proc`	Linux process file system, see linprocfs(5)
`/compat/linux/sys`	Linux kernel objects file system, see linsysfs(5)

Manual Pages — LINUX

NAME

CONTENTS

SYNOPSIS

DESCRIPTION

SYSCTL VARIABLES

FILES

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