Initial commit of the options(4) man page, which documents machine
independent options available during kernel configuration. The man page is still incomplete, but there is enough in it that it should be in the repository. Next on the list: port specific versions of this page. Many thanks to the cast of thousands who helped contribute text for this.
This commit is contained in:
perry
parent
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.\" $NetBSD: options.4,v 1.1 1996/10/20 23:58:12 perry Exp $
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.\"
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.\" Copyright (c) 1996
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.\" Perry E. Metzger. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
|
||||
.\" modification, are permitted provided that the following conditions
|
||||
.\" are met:
|
||||
.\" 1. Redistributions of source code must retain the above copyright
|
||||
.\" notice, this list of conditions and the following disclaimer.
|
||||
.\" 2. Redistributions in binary form must reproduce the above copyright
|
||||
.\" notice, this list of conditions and the following disclaimer in the
|
||||
.\" documentation and/or other materials provided with the distribution.
|
||||
.\" 3. All advertising materials mentioning features or use of this software
|
||||
.\" must display the following acknowledgement:
|
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.\" This product includes software developed for the NetBSD Project
|
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.\" by Perry E. Metzger.
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.\" 4. The name of the author may not be used to endorse or promote products
|
||||
.\" derived from this software without specific prior written permission.
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||||
.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
||||
.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
||||
.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
||||
.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
||||
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
||||
.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
||||
.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
||||
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
||||
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\"
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.Dd October 20, 1996
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.Os NetBSD 1.3
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.Dt OPTIONS 4
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.Sh NAME
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.Nm options
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.Nd Miscellaneous kernel configuration options
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.Sh SYNOPSIS
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.Cd options ...
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.Sh DESCRIPTION
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This manual page describes a number of miscellaneous kernel
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configuration options that may be specified in a kernel config
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file. See
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.Xr config 8
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for information on how to configure and build kernels.
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.Em Note:
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Options are passed to the compile process as -D flags to the C
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compiler, as is the name of the kernel. This means that kernel names
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(which are set by the file name passed to
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.Xr config 8 )
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and option names must not conflict! Naming your kernel
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.Em PORTAL
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or
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.Em GATEWAY
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or other such things is the equivalent of setting an option, and can
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have unintended consequences! (Unfortunately, not all possible kernel
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options are documented here. You may find out about one the hard way.)
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.Ss Compatibility Options
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.Bl -ohang
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.It Cd options COMPAT_09
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Enable binary compatibility with
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.Nx 0.9 .
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This enables support for
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16-bit user, group, and process ids (following revisions support
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32-bit identifiers),
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It also allows the use of the deprecated getdomainname, setdomainname,
|
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and uname syscalls.
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This option also allows using numeric fileystem identifiers rather
|
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than strings. Post 0.9 versions use string identifiers.
|
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.It Cd options COMPAT_10
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Enable binary compatibility with
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.Nx 1.0 .
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This option allows the use of the filesystem name of
|
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.Dq ufs
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as an alias for
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.Dq ffs .
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The name
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.Dq ffs
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should be used post 1.0 in
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.Pa /etc/fstab
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and other files. It also adds old syscalls for the
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.At V
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shared memory interface. This was changed post 1.0 to work on 64-bit
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architectures. This option also enables
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.Dq sgtty
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compatibility, without which programs using the old interface produce
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an
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.Dq inapropriate ioctl
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error.
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.It Cd options COMPAT_11
|
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Enable binary compatibility with
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.Nx 1.1 .
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This allows binaries running on the i386 port to gain direct access to
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the io ports by opening
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.Pa /dev/io
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read/write. This functionality was
|
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replaced by
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.Xr i386_iopl 2
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post 1.1.
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On the
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.Tn Atari
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port, the location of the disk label was moved after 1.1. When the
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.Em COMPAT_11
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option is set, the kernel will read (pre) 1.1 style disk labels as a
|
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last resort. When a disklabel is re-written, the old style label will
|
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be replaced with a post 1.1 style label.
|
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.It Cd options COMPAT_12
|
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Enable binary compatibility with
|
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.Nx 1.2 .
|
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This allows the use of old syscalls for reboot. The syscall number
|
||||
was changed post 1.2 to add functionality to the reboot syscall.
|
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.It Cd options COMPAT_43
|
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Enables compatibility with
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.Bx 4.3 .
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This adds an old syscall for lseek. It also adds the ioctls for
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TIOCGETP and TIOCSETP. The return values for getpid, getgid, and
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getuid syscalls are modified as well, to return the parent's pid and
|
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uid as well as the current process's. It also enables the deprecated
|
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NTTYDISC terminal line disipline.
|
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It also provides backwards compatibility with
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.Dq old
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SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including
|
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binary compatibility with code written before the introduction of the
|
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sa_len field in sockaddrs.
|
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It also enables
|
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support for some older pre BSD 4.4 socket calls.
|
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.It Cd options COMPAT_SVR4
|
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On those architectures that support it, this enables binary
|
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compatibility with
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.At V.4
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applications built for the same architecture.
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.El
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.Ss Debugging Options
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.Bl -ohang
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.It Cd options DDB
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Compiles in a kernel debugger for diagnosing kernel problems. See
|
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.Xr ddb 4
|
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for details.
|
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.Em NOTE:
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not available on all architectures.
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.It Cd options KGDB
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Compiles in a remote kernel debugger stub for diagnosing kernel problems
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using the
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.Dq remote target
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feature of gdb. See
|
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.Xr gdb 1
|
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for details.
|
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.Em NOTE:
|
||||
not available on all architectures.
|
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.It Cd makeoptions DEBUG="-g"
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The -g flag causes
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.Pa netbsd.gdb
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to be built in addition to
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.Pa netbsd .
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.Pa netbsd.gdb
|
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is useful for debugging kernel crash dumps with gdb.
|
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The command
|
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.Dl gdb -k
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invokes gdb in kernel debugger mode.
|
||||
See
|
||||
.Xr gdb 1
|
||||
for details. This also turns on
|
||||
.Em options DEBUG
|
||||
(which see).
|
||||
.It Cd options DEBUG
|
||||
Turns on miscellaneous kernel debugging. Since options are turned into
|
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preprocessor defines (see above),
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.Em options DEBUG
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is equivalent to doing a
|
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.Em #define DEBUG
|
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throughout the kernel. Much of the kernel has
|
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.Em #ifdef DEBUG
|
||||
conditionalized debugging code. Note that many parts of the kernel
|
||||
(typically device drivers) include their own
|
||||
.Em #ifdef XXX_DEBUG
|
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conditionals instead.
|
||||
.It Cd options DIAGNOSTIC
|
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Adds code to the kernel that does internal consistency checks. This
|
||||
code will cause the kernel to panic if corruption of internal data
|
||||
structures is detected.
|
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.It Cd options KTRACE
|
||||
Add hooks for the system call tracing facility, which allows users to
|
||||
watch the system call invokation behavior of processes. See
|
||||
.Xr ktrace 1
|
||||
for details.
|
||||
.El
|
||||
.Ss File Systems
|
||||
.Bl -ohang
|
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.It Cd options FFS
|
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Includes code implementing the Berkeley Fast File System
|
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.Em ( FFS ) .
|
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Most machines need this if they are not running diskless.
|
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.It Cd options LFS
|
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Include the log structured file system
|
||||
.Em ( LFS ) .
|
||||
See
|
||||
.Xr mount_lfs 8
|
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and
|
||||
.Xr newlfs 8
|
||||
for details.
|
||||
.It Cd options MFS
|
||||
Include the memory file system
|
||||
.Em ( MFS ) .
|
||||
This file system stores files in swappable memory, and produces
|
||||
notable performance improvements when it is used as the file store
|
||||
for
|
||||
.Pa /tmp
|
||||
and similar file systems. See
|
||||
.Xr mount_mfs 8
|
||||
for details.
|
||||
.It Cd options NFSCLIENT
|
||||
.It Cd options NFSSERVER
|
||||
Include code implementing the client and server sides of the
|
||||
.Em NFS
|
||||
(Network File System) remote file sharing protocol,
|
||||
respectively. Although the bulk of the code implementing
|
||||
.Em NFS
|
||||
is kernel based, several user level daemons are needed for it to
|
||||
work. See
|
||||
.Xr mount_nfs 8 ,
|
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.Xr mountd 8 ,
|
||||
.Xr nfsd 8 ,
|
||||
and
|
||||
.Xr nfsiod 8
|
||||
for details.
|
||||
.It Cd options CD9660
|
||||
Includes code for the ISO 9660 + Rock Ridge file system, which is the
|
||||
standard file system on many CD-ROMs. Useful mostly if you have a CD
|
||||
drive. See
|
||||
.Xr mount_cd9660 8
|
||||
for details.
|
||||
.It Cd options MSDOSFS
|
||||
Includes the
|
||||
.Tn MS-DOS
|
||||
FAT file system, which is reportedly still used
|
||||
by unfortunate people who have not heard about
|
||||
.Nx .
|
||||
Also implements the
|
||||
.Tn Windows 95
|
||||
extensions to the same, which permit the use of longer, mixed case
|
||||
file names. see
|
||||
.Xr mount_msdos 8
|
||||
and
|
||||
.Xr fsck_msdos 8
|
||||
for details.
|
||||
.It Cd options FDESC
|
||||
Includes code for a file system, conventionally mounted on
|
||||
.Pa /dev/fd ,
|
||||
which permits access to the per-process file descriptor space via
|
||||
special files in the file system.
|
||||
See
|
||||
.Xr mount_fdesc 8
|
||||
for details.
|
||||
Note that this facility is redundant, and thus unneeded on most
|
||||
.Nx
|
||||
systems, since the
|
||||
.Xr fd 4
|
||||
pseudodevice driver already provides identical functionality. On most
|
||||
.Nx
|
||||
systems, instances of
|
||||
.Xr fd 4
|
||||
are mknoded under
|
||||
.Pa /dev/fd/
|
||||
and on
|
||||
.Pa /dev/stdin ,
|
||||
.Pa /dev/stdout ,
|
||||
and
|
||||
.Pa /dev/stderr .
|
||||
.It Cd options KERNFS
|
||||
Includes code which permits the mounting of a special file system
|
||||
(normally mounted on
|
||||
.Pa /kern )
|
||||
in which files representing various kernel variables and parameters
|
||||
may be found.
|
||||
See
|
||||
.Xr mount_kernfs 8
|
||||
for details.
|
||||
.It Cd options NULLFS
|
||||
Includes code for a loopback file system. This permits portions of the file
|
||||
hierarchy to be re-mounted in other places. The code really exists to
|
||||
provide an example of a stackable file system layer. See
|
||||
.Xr mount_null 8
|
||||
for details.
|
||||
.It Cd options PORTAL
|
||||
Includes the (experimental) portal filesystem. This permits
|
||||
interesting tricks like opening TCP sockets by opening files in the
|
||||
file system. The portal file system is conventionally mounted on
|
||||
.Pa /p
|
||||
and is partially implemented by a special daemon. See
|
||||
.Xr mount_portal 8
|
||||
for details.
|
||||
.It Cd options PROCFS
|
||||
Includes code for a special file system (conventionally mounted on
|
||||
.Pa /proc )
|
||||
in which the process space becomes visible in the file system. Among
|
||||
other things, the memory spaces of processes running on the system are
|
||||
visible as files, and signals may be sent to processes by writing to
|
||||
.Pa ctl
|
||||
files in the procfs namespace. See
|
||||
.Xr mount_procfs 8
|
||||
for details.
|
||||
.It Cd options UMAPFS
|
||||
Includes a loopback file system in which user and group ids may be
|
||||
remapped -- this can be useful when mounting alien file systems with
|
||||
different uids and gids than the local system.
|
||||
See
|
||||
.Xr mount_umap 8
|
||||
for details.
|
||||
.It Cd options UNION
|
||||
Includes code for the union file system, which permits directories to
|
||||
be mounted on top of each other in such a way that both file systems
|
||||
remain visible -- this permits tricks like allowing writing (and the
|
||||
deleting of files) on a read-only file system like a CD-ROM by
|
||||
mounting a local writable file system on top of the read-only file
|
||||
system. See
|
||||
.Xr mount_union 8
|
||||
for details.
|
||||
.El
|
||||
.Ss File System Options
|
||||
.Bl -ohang
|
||||
.It Cd options QUOTA
|
||||
Enables kernel support for file system quotas. See
|
||||
.Xr quotaon 8 ,
|
||||
.Xr edquota 8 ,
|
||||
and
|
||||
.Xr quota 1
|
||||
for details. Note that quotas only work on
|
||||
.Dq ffs
|
||||
file systems, although
|
||||
.Xr rpc.rquotad 8
|
||||
permits them to be accessed over
|
||||
.Em NFS .
|
||||
.It Cd options FIFO
|
||||
Augments the system to permit the use of
|
||||
.At V
|
||||
style FIFOs (i.e.
|
||||
.Dq named pipes
|
||||
). This option is recommended.
|
||||
.El
|
||||
.Ss Miscellaneous Options
|
||||
.Bl -ohang
|
||||
.It Cd options GENERIC
|
||||
Indicates, on some ports, that code permitting booting and mounting
|
||||
root on any file system should be included. This option also allows
|
||||
the
|
||||
.Dq swap generic
|
||||
configuration file option to find the location of the swap file at
|
||||
boot time rather than having a compiled in default. Largely obsolete
|
||||
though still in use on some architectures. Most ports now include the
|
||||
necessary code regardless of this option. On a port that still cares
|
||||
about
|
||||
.Em options GENERIC ,
|
||||
it should be omitted ONLY in very special cases, such as
|
||||
a
|
||||
.Em RAMDISK
|
||||
installation kernel.
|
||||
.It Cd options LKM
|
||||
Enable loadable kernel modules. See
|
||||
.Xr lkm 4
|
||||
for details.
|
||||
.Em NOTE:
|
||||
not available on all architectures.
|
||||
.It Cd options INSECURE
|
||||
Hardwires the kernel security level at -1. This means that the system
|
||||
always runs in secure level 0 mode, even when running multiuser. See
|
||||
the manual page for
|
||||
.Xr init 8
|
||||
for details on the implications of this. The kernel secure level may
|
||||
manipulated by the superuser by altering the
|
||||
.Em kern.securelevel
|
||||
sysctl variable. (It should be noted that the secure level may only be
|
||||
lowered by a call from process id 1, i.e.
|
||||
.Em init . )
|
||||
See also
|
||||
.Xr sysctl 8
|
||||
and
|
||||
.Xr sysctl 3 .
|
||||
.It Cd options UCONSOLE
|
||||
Normally, only the superuser can execute the TIOCCONS ioctl, which
|
||||
redirects console output to a non-console tty. (See
|
||||
.Xr tty 4
|
||||
for details).
|
||||
This option permits any user to execute the ioctl. This is useful on
|
||||
machines such as personal workstations which run X servers, where one
|
||||
would prefer to permit console output to be viewed in a window without
|
||||
requiring a suid root program to do it.
|
||||
.It Cd options MACHINE_NONCONTIG
|
||||
[Does something or other with the VM subsystem. Not clear if its
|
||||
optional. Text is solicited.]
|
||||
.It Cd options NTP
|
||||
Turns on in-kernel precision timekeeping support used by software
|
||||
implementing
|
||||
.Em NTP
|
||||
(Network Time Protocol, RFC1305).
|
||||
The
|
||||
.Em NTP
|
||||
option adds an in-kernel phase-locked loop (PLL) for normal
|
||||
.Em NTP
|
||||
operation, and a frequency-locked loop (FLL) for intermittently-connected
|
||||
operation.
|
||||
.Xr xntpd 8
|
||||
will employ a user-level PLL when kernel support is unavailable,
|
||||
but the in-kernel version has lower latency and more precision, and
|
||||
so typically keeps much better time.
|
||||
The interface to the kernel
|
||||
.Em NTP
|
||||
support is provided by the
|
||||
.Xr ntp_adjtime 2
|
||||
and
|
||||
.Xr ntp_gettime 2
|
||||
system calls, which are intended for use by
|
||||
.Xr xntpd 8
|
||||
and are enabled by the option.
|
||||
On systems with sub-microsecond resolution timers, or where (HZ / 100000)
|
||||
is not an integer, the
|
||||
.Em NTP
|
||||
option also enables extended-precision arithmetic to keep track of
|
||||
fractional clock ticks at NTP time-format precision.
|
||||
.It Cd options PPS
|
||||
This option enables a kernel serial line discipline for receiving time
|
||||
phase signals from an external reference clock such as a radio clock.
|
||||
(The
|
||||
.Em NTP
|
||||
option (which see) must be on if the
|
||||
.Em PPS
|
||||
option is used.)
|
||||
Some reference clocks generate a pulse per second (PPS) signal in
|
||||
phase with their time source. The
|
||||
.Em PPS
|
||||
line discipline receives this signal on either the data leads
|
||||
or the DCD control lead of a serial port.
|
||||
.Em NTP
|
||||
uses the PPS signal to discipline the local clock oscillator to a high
|
||||
degree of precision (typically less than 50 microseconds in time and
|
||||
0.1 ppm in accuracy).
|
||||
.Em PPS
|
||||
can also generate a serial output pulse when the system receives a PPS
|
||||
interrupt. This can be used to measure the system interrupt latency
|
||||
and thus calibrate
|
||||
.Em NTP
|
||||
to account for it.
|
||||
Using
|
||||
.Em PPS
|
||||
usually requires a
|
||||
gadget box
|
||||
to convert from TTL to RS-232 signal levels.
|
||||
The gadget box and PPS are described in more detail in the HTML documentation
|
||||
shipped with the xntpd distribution.
|
||||
.It Cd option SETUIDSCRIPTS
|
||||
Allows scripts with the setuid bit set to execute as the effective
|
||||
user rather than the real user, just like binary executables.
|
||||
NOTE: Using this option will also enable
|
||||
.Em option FDSCRIPTS
|
||||
.It Cd option FDSCRIPTS
|
||||
Allows execution of scripts with the execute bit set, but not the
|
||||
read bit, by opening the file and passing the file descriptor to
|
||||
the shell, rather than the filename. NOTE: Execute only (non-readable)
|
||||
scripts will have
|
||||
.Va argv[0]
|
||||
set to
|
||||
.Pa /dev/fd/* . [Quoth Curt Sampson "Is this the secure or
|
||||
non-secure version of this?]
|
||||
.It Cd options TIMEZONE=integer
|
||||
The kernel (and typically the hardware battery backed-up clock on
|
||||
those machines that have one) keeps time in
|
||||
.Em UTC
|
||||
(Universal Coordinated Time, once known as
|
||||
.Em GMT ,
|
||||
or Greenwich Mean Time)
|
||||
and not in the time of the local time zone.
|
||||
The
|
||||
.Em TIMEZONE
|
||||
option is used on some ports (such as the i386) to tell the kernel
|
||||
that the hardware clock is offset from
|
||||
.Em UTC
|
||||
by the specified number of minutes. This is typically used when a
|
||||
machine boots several operating systems and one of them wants the
|
||||
hardware clock to run in the local time zone and not in
|
||||
.Em UTC ,
|
||||
e.g.
|
||||
.Em TIMEZONE=300
|
||||
means
|
||||
the hardware clock is running US Eastern Time (300 minutes behind
|
||||
.Em UTC ) ,
|
||||
and not
|
||||
.Em UTC .
|
||||
.Bd -filled -offset indent
|
||||
.Em HISTORICAL NOTE:
|
||||
The
|
||||
.Em TIMEZONE
|
||||
option at one time was used to set the kernel's idea of what time zone
|
||||
the system was operating in -- this information was returned by
|
||||
.Xr gettimeofday 2 .
|
||||
Time zone information is now managed by user space software based
|
||||
on the contents of the
|
||||
.Pa /etc/localtime
|
||||
file or the
|
||||
.Ev TZ
|
||||
environment variable.
|
||||
(See
|
||||
.Xr zic 8 ,
|
||||
.Xr tzfile 5 ,
|
||||
and
|
||||
.Xr tzset 3
|
||||
for details).
|
||||
This usage of the
|
||||
.Em TIMEZONE
|
||||
option is now obsolete.
|
||||
.Ed
|
||||
.It Cd options DST=[0|1]
|
||||
On some ports (such as the i386) that permit offsetting the system's
|
||||
hardware real time clock with the
|
||||
.Em TIMEZONE
|
||||
option
|
||||
(see
|
||||
.Em TIMEZONE
|
||||
above) the
|
||||
.Em DST
|
||||
option being set to one indicates that the hardware clock real time
|
||||
clock is set for
|
||||
.Dq daylight savings time ,
|
||||
and that because of this 60
|
||||
minutes should be subtracted from the
|
||||
.Em TIMEZONE
|
||||
value (60 minutes being the standard DST correction.) The effect of
|
||||
this on such ports is thus identical to simply subtracting 60 from the
|
||||
value of
|
||||
.Em TIMEZONE ,
|
||||
and the use of the option is thus purely aesthetic in nature.
|
||||
.Bd -filled -offset indent
|
||||
.Em HISTORICAL NOTE:
|
||||
Long ago,
|
||||
.Dq daylight savings time
|
||||
computations were made in the kernel and not in user space.
|
||||
The
|
||||
.Em DST
|
||||
option was used at that time to set the kernel's idea of whether DST
|
||||
information should be returned by
|
||||
.Xr gettimeofday 2 .
|
||||
As with
|
||||
.Em TIMEZONE
|
||||
(which see), the moving of timezone handling from the kernel to user
|
||||
space libraries has obsoleted the old usage of this option.
|
||||
.Ed
|
||||
.El
|
||||
.Ss Networking Options
|
||||
.Bl -ohang
|
||||
.It Cd options GATEWAY
|
||||
Enables
|
||||
.Em IPFORWARDING
|
||||
(which see)
|
||||
and (on most ports) increases the size of
|
||||
.Em NMBCLUSTERS
|
||||
(which see). In general,
|
||||
.Em GATEWAY
|
||||
is used to indicate that a system should act as a router, and
|
||||
.Em IPFORWARDING
|
||||
is not invoked directly.
|
||||
(Note that
|
||||
.Em GATEWAY
|
||||
has no impact on protocols other than IP, such as CLNP or XNS.)
|
||||
.It Cd options IPFORWARDING
|
||||
Enables IP routing behavior. With this option enabled, the machine
|
||||
will forward IP datagrams between its interfaces that are destined for
|
||||
other machines. Note that even without this option, the kernel will
|
||||
still forward some packets (such as source routed packets) -- removing
|
||||
.Em GATEWAY
|
||||
and
|
||||
.Em IPFORWARDING
|
||||
is insufficient to stop all routing through a bastion host on a
|
||||
firewall -- source routing is controlled independently.
|
||||
To turn off source routing, use
|
||||
.Em options IPFORWSRCRT=0
|
||||
(which see).
|
||||
Note that IP forwarding may be turned on and off independently of the
|
||||
setting of the
|
||||
.Em IPFORWARDING
|
||||
option through the use of the
|
||||
.Em net.inet.ip.forwarding
|
||||
sysctl variable. If
|
||||
.Em net.inet.ip.forwarding
|
||||
is 1, IP forwarding is on. See
|
||||
.Xr sysctl 8
|
||||
and
|
||||
.Xr sysctl 3
|
||||
for details.
|
||||
.It Cd options IPFORWSRCRT=value
|
||||
If
|
||||
.Em value
|
||||
is set to zero, source routing of IP datagrams is turned off. If
|
||||
.Em value
|
||||
is set to one (the default) or the option is absent, source routed IP
|
||||
datagrams are forwarded by the machine. Note that source routing of
|
||||
IP packets may be turned on and off independently of the setting of
|
||||
the
|
||||
.Em IPFORWSRCRT
|
||||
option through the use of the
|
||||
.Em net.inet.ip.forwsrcrt
|
||||
sysctl variable. If
|
||||
.Em net.inet.ip.forwsrcrt
|
||||
is 1, forwarding of source routed IP datagrams is on. See
|
||||
.Xr sysctl 8
|
||||
and
|
||||
.Xr sysctl 3
|
||||
for details.
|
||||
.It Cd options INET
|
||||
Includes support for the TCP/IP protocol stack. You almost certainly
|
||||
want this. See
|
||||
.Xr inet 4
|
||||
for details.
|
||||
[Is this option required, though? Can you save space on a
|
||||
standalone machine by nuking it, or will the kernel compile croak?]
|
||||
.It Cd options NS
|
||||
Include support for the Xerox XNS protocol stack. See
|
||||
.Xr ns 4
|
||||
for details.
|
||||
.It Cd options ISO,TPIP
|
||||
Include support for the ubiquitous OSI protocol stack. See
|
||||
.Xr iso 4
|
||||
for details.
|
||||
.It Cd options EON
|
||||
Include support for OSI tunneling over IP. [Do we have any
|
||||
documentation on this at all?]
|
||||
.It Cd options CCITT,LLC,HDLC
|
||||
Include support for the X.25 protocol stack. [Really? What is this
|
||||
thing? Does anything actually drive it? Do we have any documentation?]
|
||||
.It Cd options IPNOPRIVPORTS
|
||||
Normally, only root can bind a socket descriptor to a so-called
|
||||
.Dq privileged
|
||||
TCP
|
||||
port, that is, a port number in the range 0-1023. This option
|
||||
eliminates those checks from the kernel. This can be useful if there
|
||||
is a desire to allow daemons without privileges to bind those ports,
|
||||
e.g. on firewalls. The security tradeoffs in doing this are subtle.
|
||||
This option should only be used by experts.
|
||||
.It Cd options TCP_COMPAT_42
|
||||
TCP bug compatibility with 4.2BSD. In 4.2BSD, TCP sequence numbers
|
||||
were 32-bit signed values. Modern implementations of TCP use unsigned
|
||||
values. This option clamps the initial sequence number to start in
|
||||
the range 2^31 rather than the full unsigned range of 2^32. Also,
|
||||
under 4.2BSD, keepalive packets must contain at least one byte or else
|
||||
the remote end would not respond.
|
||||
.El
|
||||
.Ss System V IPC Options
|
||||
.Bl -ohang
|
||||
.It Cd options SYSVMSG
|
||||
Includes support for
|
||||
.At V
|
||||
style message queues. See
|
||||
.Xr msgctl 2 ,
|
||||
.Xr msgget 2 ,
|
||||
.Xr msgrcv 2 ,
|
||||
.Xr msgsnd 2 .
|
||||
.It Cd options SYSVSEM
|
||||
Includes support for
|
||||
.At V
|
||||
style semaphores. See
|
||||
.Xr semctl 2 ,
|
||||
.Xr semget 2 ,
|
||||
.Xr semop 2 .
|
||||
.It Cd options SYSVSHM
|
||||
Includes support for
|
||||
.At V
|
||||
style shared memory. See
|
||||
.Xr shmat 2 ,
|
||||
.Xr shmctl 2 ,
|
||||
.Xr shmdt 2 ,
|
||||
.Xr shmget 2 .
|
||||
.It Cd options SHMPAXPGS=value
|
||||
Sets the maximum number of
|
||||
.At V
|
||||
style shared memory pages that are available through the
|
||||
.Xr shmget 2
|
||||
system call. Default value is 1024 on most ports. See
|
||||
.Pa /usr/include/machine/vmparam.h
|
||||
for the default.
|
||||
.El
|
||||
.Ss VM Related Options
|
||||
.Bl -ohang
|
||||
.It Cd options SWAPPAGER
|
||||
Turns on paging. (To be specific, this enables the virtual memory
|
||||
module responsible for handling page faults for
|
||||
.Dq anonymous
|
||||
objects (i.e. BSS pages)).
|
||||
.Em MANDATORY
|
||||
-- you cannot actually run without
|
||||
this
|
||||
.Dq option .
|
||||
[If its mandatory, why is it an option at all?]
|
||||
.It Cd options VNODEPAGER
|
||||
Support for mmap()ing of files. (Specifically, this enables the
|
||||
virtual memory module responsible for handling page faults on mapped
|
||||
files (
|
||||
.Dq plain file
|
||||
vnodes)).
|
||||
.Em MANDATORY
|
||||
-- you cannot actually run without
|
||||
this
|
||||
.Dq option .
|
||||
[If its mandatory, why is it an option at all?]
|
||||
.It Cd options DEVPAGER
|
||||
Support for mmap()ing of devices. (Specifically, this enables the
|
||||
virtual memory module responsible for handling page faults on mapped
|
||||
devices (
|
||||
.Dq cdev
|
||||
vnodes)).
|
||||
.Em MANDATORY
|
||||
-- you cannot actually run without
|
||||
this
|
||||
.Dq option .
|
||||
[If its mandatory, why is it an option at all?]
|
||||
.It Cd options NMBCLUSTERS=value
|
||||
Size of kernel [Something, what? mbuf pool?] in CLBYTES-sized logical
|
||||
pages. This region is covered by the kernel submap
|
||||
.Em mb_map .
|
||||
[Better description, please? What does this do EXACTLY.] Default on
|
||||
most ports is 256 (512 with GATEWAY). See
|
||||
.Pa /usr/include/machine/param.h
|
||||
for exact default information. Increase this value if you get
|
||||
.Dq mb_map full
|
||||
messages.
|
||||
.It Cd options NKMEMCLUSTERS=value
|
||||
Size of kernel malloc arena in CLBYTES-sized logical pages. This area
|
||||
is covered by the kernel submap
|
||||
.Em kmem_map .
|
||||
See
|
||||
.Pa /usr/include/machine/param.h
|
||||
for the default value, which is port specific. Increase this value if
|
||||
you get
|
||||
.Dq out of space in kmem_map
|
||||
panics, which mean you have run out of mallocable kernel memory. [Is
|
||||
this last bit right?]
|
||||
.It Cd options NBUF=value
|
||||
[Quoth CGD: "Don't forget NBUF and BUFPAGES, which can be set to
|
||||
influence buffer cache size calculations." Can anyone fill in text?]
|
||||
.It Cd options BUFPAGES=value
|
||||
[Quoth CGD: "Don't forget NBUF and BUFPAGES, which can be set to
|
||||
influence buffer cache size calculations." Can anyone fill in text?]
|
||||
.It Cd options NKPDE=value
|
||||
.Em [ NOTE :
|
||||
This option may be i386 specific.]
|
||||
The i386 architecture uses a two-level page table; page directories
|
||||
contain entries for page tables, which contain entries for pages.
|
||||
The value of NKPDE indicates how many page tables (page directory entries)
|
||||
to reserve for use by the kernel. This option should
|
||||
not be necessary, but the kernel cannot currently initialize this value at
|
||||
boot time and the default of 12 page directory entries is not large enough
|
||||
for the kernel if a very large buffer cache is used, either by default on
|
||||
machines with large memories or by modifying the value of BUFPAGES. This
|
||||
limitation could be removed by changing NKPDE from a preprocessor symbol
|
||||
to a kernel global variable (nkpde) and modifying locore.s to compute nkpde
|
||||
from the values of the kernel global variables physmem and bufpages
|
||||
(as defined or computed) at boot time.
|
||||
.El
|
||||
.\" The following requests should be uncommented and used where appropriate.
|
||||
.\" .Sh FILES
|
||||
.\" .Sh EXAMPLES
|
||||
.Sh SEE ALSO
|
||||
.Xr config 8 ,
|
||||
.Xr init 8 ,
|
||||
.Xr gettimeofday 2 ,
|
||||
.Xr tzset 3 ,
|
||||
.Xr zic 8 ,
|
||||
.Xr tzfile 5 ,
|
||||
.Xr sysctl 8 ,
|
||||
.Xr sysctl 3 ,
|
||||
.Xr xntpd 8 ,
|
||||
.Xr ntp_adjtime 2 ,
|
||||
.Xr ntp_gettime 2 ,
|
||||
.Xr i386_iopl 2 ,
|
||||
.Xr msgctl 2 ,
|
||||
.Xr msgget 2 ,
|
||||
.Xr msgrcv 2 ,
|
||||
.Xr msgsnd 2 ,
|
||||
.Xr semctl 2 ,
|
||||
.Xr semget 2 ,
|
||||
.Xr semop 2 ,
|
||||
.Xr shmat 2 ,
|
||||
.Xr shmctl 2 ,
|
||||
.Xr shmdt 2 ,
|
||||
.Xr shmget 2 ,
|
||||
.Xr ddb 4 ,
|
||||
.Xr lkm 4 ,
|
||||
.Xr inet 4 ,
|
||||
.Xr ns 4 ,
|
||||
.Xr iso 4 ,
|
||||
.Xr mount_lfs 8 ,
|
||||
.Xr newlfs 8 ,
|
||||
.Xr mount_mfs 8 ,
|
||||
.Xr mount_nfs 8 ,
|
||||
.Xr mount_cd9660 8 ,
|
||||
.Xr mount_msdos 8 ,
|
||||
.Xr mount_fdesc 8 ,
|
||||
.Xr mount_kernfs 8 ,
|
||||
.Xr mount_null 8 ,
|
||||
.Xr mount_portal 8 ,
|
||||
.Xr mount_procfs 8 ,
|
||||
.Xr mount_umap 8 ,
|
||||
.Xr mount_union 8 ,
|
||||
.Xr edquota 8 ,
|
||||
.Xr quotaon 8 ,
|
||||
.Xr quota 1 ,
|
||||
.Xr rpc.rquotad 8 ,
|
||||
.Xr ktrace 1 ,
|
||||
.Xr gdb 1
|
||||
.Sh HISTORY
|
||||
The
|
||||
.Nm
|
||||
man page first appeared in
|
||||
.Nx 1.3 .
|
||||
Loading…
Reference in New Issue