LINUX(4)	     FreeBSD/i386 Kernel Interfaces Manual	      LINUX(4)

NAME
     linux -- Linux ABI support

SYNOPSIS
     To compile support for this ABI into the kernel, place the following line
     in your kernel configuration file:

	   options COMPAT_LINUX

     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:

     o	 An image activator for correctly branded elf(5) executable 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 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 ALSO
     brandelf(1), elf(5), linprocfs(5), linsysfs(5)

HISTORY
     Linux ABI support first appeared in FreeBSD 2.1.

FreeBSD 7.2			March 17, 2008			   FreeBSD 7.2

NAME - SYNOPSIS - DESCRIPTION - FILES - SEE ALSO - HISTORY -