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diff --git a/share/man/man4/options.4 b/share/man/man4/options.4 new file mode 100644 index 00000000000..f7cb8119471 --- /dev/null +++ b/share/man/man4/options.4 @@ -0,0 +1,924 @@ +.\" $OpenBSD: options.4,v 1.1 1997/08/18 01:27:54 mickey Exp $ +.\" $NetBSD: options.4,v 1.21 1997/06/25 03:13:00 thorpej Exp $ +.\" +.\" Copyright (c) 1996 +.\" Perry E. Metzger. All rights reserved. +.\" +.\" 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: +.\" This product includes software developed for the NetBSD Project +.\" by Perry E. Metzger. +.\" 4. The name of the author may not be used to endorse or promote products +.\" derived from this software without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR +.\" 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. +.\" +.\" +.Dd October 20, 1996 +.Os NetBSD 1.3 +.Dt OPTIONS 4 +.Sh NAME +.Nm option +.Nd Miscellaneous kernel configuration options +.Sh SYNOPSIS +.Cd option ... +.Sh DESCRIPTION +This manual page describes a number of miscellaneous kernel +configuration options that may be specified in a kernel config +file. See +.Xr config 8 +for information on how to configure and build kernels. +.Em Note: +Options are passed to the compile process as -D flags to the C +compiler. +.Ss Compatibility Options +.Bl -ohang +.It Cd option COMPAT_09 +Enable binary compatibility with +.Nx 0.9 . +This enables support for +16-bit user, group, and process ids (following revisions support +32-bit identifiers), +It also allows the use of the deprecated getdomainname, setdomainname, +and uname syscalls. +This option also allows using numeric fileystem identifiers rather +than strings. Post 0.9 versions use string identifiers. +.It Cd option COMPAT_10 +Enable binary compatibility with +.Nx 1.0 . +This option allows the use of the filesystem name of +.Dq ufs +as an alias for +.Dq ffs . +The name +.Dq ffs +should be used post 1.0 in +.Pa /etc/fstab +and other files. It also adds old syscalls for the +.At V +shared memory interface. This was changed post 1.0 to work on 64-bit +architectures. This option also enables +.Dq sgtty +compatibility, without which programs using the old interface produce +an +.Dq inapropriate ioctl +error. +.It Cd option COMPAT_11 +Enable binary compatibility with +.Nx 1.1 . +This allows binaries running on the i386 port to gain direct access to +the io ports by opening +.Pa /dev/io +read/write. This functionality was +replaced by +.Xr i386_iopl 2 +post 1.1. +On the +.Tn Atari +port, the location of the disk label was moved after 1.1. When the +.Em COMPAT_11 +option is set, the kernel will read (pre) 1.1 style disk labels as a +last resort. When a disklabel is re-written, the old style label will +be replaced with a post 1.1 style label. +.It Cd option COMPAT_12 +Enable binary compatibility with +.Nx 1.2 . +This allows the use of old syscalls for +.Fn reboot , and +.Fn swapon . +The syscall numbers was changed post 1.2 to add functionality to the +reboot syscall, and the new +.Fn swapctl +interface was introduced. +.It Cd option COMPAT_43 +Enables compatibility with +.Bx 4.3 . +This adds an old syscall for lseek. It also adds the ioctls for +TIOCGETP and TIOCSETP. The return values for getpid, getgid, and +getuid syscalls are modified as well, to return the parent's pid and +uid as well as the current process's. It also enables the deprecated +NTTYDISC terminal line disipline. +It also provides backwards compatibility with +.Dq old +SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including +binary compatibility with code written before the introduction of the +sa_len field in sockaddrs. +It also enables +support for some older pre BSD 4.4 socket calls. +.It Cd option COMPAT_SVR4 +On those architectures that support it, this enables binary +compatibility with +.At V.4 +applications built for the same architecture. This currently includes +the sparc, and i386. +.It Cd option COMPAT_LINUX +On those architectures that support it, this enables binary +compatibility with Linux ELF and a.out +applications built for the same architecture. This is currently limited +to the i386. +.It Cd option COMPAT_SUNOS +On those architectures that support it, this enables binary +compatibility with SunOS 4.1 +applications built for the same architecture. This currently includes +the sparc and most or all m68k platforms. +.It Cd option COMPAT_ULTRIX +On those architectures that support it, this enables binary +compatibility with Ultrix +applications built for the same architecture. This currently is limited +to the pmax. The functionality of this option is unknown. +.It Cd option COMPAT_FREEBSD +On those architectures that support it, this enables binary +compatibility with FreeBSD +applications built for the same architecture. This is obviously limited +to the i386. +.It Cd option COMPAT_HPUX +On those architectures that support it, this enables binary +compatibility with HP/UX +applications built for the same architecture. This is limited to the +hp300 port, and has some known bugs. A limited set of programs do work. +.It Cd option COMPAT_IBCS2 +On those architectures that support it, this enables binary +compatibility with iBCS2 +applications built for the same architecture. This is currently +limited to the i386. +.It Cd option COMPAT_OSF1 +On those architectures that support it, this enables binary +compatibility with Digital UNIX (formerly OSF/1) +applications built for the same architecture. This is currently +limited to the alpha, and may not even work. +.It Cd option COMPAT_NOMID +Enable compatibility with a.out executables that lack a machine id. +This includes NetBSD 0.8's ZMAGIC format, and 386BSD and BSDI's +QMAGIC, NMAGIC, and OMAGIC a.out formats. +.El +.Ss Debugging Options +.Bl -ohang +.It Cd option DDB +Compiles in a kernel debugger for diagnosing kernel problems. See +.Xr ddb 4 +for details. +.Em NOTE: +not available on all architectures. +.It Cd option DDB_ONPANIC +If set to non-zero, the DDB will be entered upon kernel panic. The +default if not specified is "1". Note that this sets the value of +the +.Em ddb.onpanic +sysctl variable which may be changed at run time -- see +.Xr sysctl 8 +for details. +.It Cd option KGDB +Compiles in a remote kernel debugger stub for diagnosing kernel problems +using the +.Dq remote target +feature of gdb. See +.Xr gdb 1 +for details. +.Em NOTE: +not available on all architectures. +.It Cd makeoptions DEBUG="-g" +The -g flag causes +.Pa netbsd.gdb +to be built in addition to +.Pa netbsd . +.Pa netbsd.gdb +is useful for debugging kernel crash dumps with gdb. +The command +.Dl gdb -k +invokes gdb in kernel debugger mode. +See +.Xr gdb 1 +for details. This also turns on +.Em option DEBUG +(which see). +.It Cd option DEBUG +Turns on miscellaneous kernel debugging. Since options are turned into +preprocessor defines (see above), +.Em option DEBUG +is equivalent to doing a +.Em #define DEBUG +throughout the kernel. Much of the kernel has +.Em #ifdef DEBUG +conditionalized debugging code. Note that many parts of the kernel +(typically device drivers) include their own +.Em #ifdef XXX_DEBUG +conditionals instead. +This option also turns on certain other options, notably the +.Em KMEMSTATS +option, which may decrease system performance. +.It Cd option DIAGNOSTIC +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. +.It Cd option 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 +.It Cd file-system FFS +Includes code implementing the Berkeley Fast File System +.Em ( FFS ) . +Most machines need this if they are not running diskless. +.It Cd file-system EXT2FS +Includes code implementing the Second Extended File System +.Em ( EXT2FS ) . +This is the most commonly used file system on the Linux operating system, +and is provided here for compatibility. Some of the specific features +of +.Em EXT2FS +like the "behavior on errors" are not implemented. This file system can't be +used with UID or GID greather than 65535. See +.Xr mount_ext2fs 8 +for details. +.It Cd file-system LFS +Include the log structured file system +.Em ( LFS ) . +See +.Xr mount_lfs 8 +and +.Xr newlfs 8 +for details. +.It Cd file-system 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 file-system NFS +Include the client side of the +.Em NFS +(Network File System) remote file sharing protocol. +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 +and +.Xr nfsiod 8 +for details. +.It Cd file-system 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 file-system 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 file-system 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 file-system 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 file-system 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 file-system 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 file-system 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 file-system 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 file-system 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 option NFSSERVER +Include the server side of the +.Em NFS +(Network File System) remote file sharing protocol. +Although the bulk of the code implementing +.Em NFS +is kernel based, several user level daemons are needed for it to +work. See +.Xr mountd 8 +and +.Xr nfsd 8 +for details. +.It Cd option 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 option FIFO +Augments the system to permit the use of +.At V +style FIFOs (i.e. +.Dq named pipes +). This option is recommended. +.It Cd option NVNODE=integer +This option sets the size of the cache used by the name-to-inode translation +routines, (a.k.a. the +.Fn namei +cache, though called by many other names in the kernel source). By default, +this cache has NPROC (set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. +A reasonable way to derive a value of NVNODE, should you notice a large +number of namei cache misses with a tool such as +.Xr systat 1 , +is to examine your system's current computed value with +.Xr sysctl 1 , +(which calls this parameter "kern.maxvnodes") and to increase this value +until either the namei cache hit rate improves or it is determined that +your system does not benefit substantially from an increase in the size of +the namei cache. +.It Cd option EXT2FS_SYSTEM_FLAGS +This option changes the behavior of the APPEND and IMMUTABLE flags +for a file on an +.Em EXT2FS +filesystem. Without this option, the superuser or owner of the file can +set and clear them. With this option, only the superuser can set them, and +they can't be cleared if the securelevel is greather than 0. See also +.Xr chflags 1 . +.El +.Ss Miscellaneous Options +.Bl -ohang +.It Cd option LKM +Enable loadable kernel modules. See +.Xr lkm 4 +for details. +.Em NOTE: +not available on all architectures. +.It Cd option 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 option 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 option MACHINE_NONCONTIG +This option changes part of the VM/pmap interface, to allow for +non-contiguous memory. On some ports it is not an option. These +ports typically only use one of the interfaces. +.It Cd option MEMORY_DISK_HOOKS +This option allows for some machine dependent functions to be called when +the ramdisk driver is configured. This can result in automatically loading +a ramdisk from floppy on open (among other things). +.It Cd option MEMORY_DISK_IS_ROOT +Forces the ramdisk to be the root device. This can only be overridden when +the kernel is booted in the 'ask-for-root' mode. +.It Cd option 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 option 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/* . +What this option allows as far as security is +concerned, is the ability to safely ensure that the correct script +it run by the interpreter, as it is passed as an already open file. +.It Cd option RTC_OFFSET=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 RTC_OFFSET +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 RTC_OFFSET=300 +means +the hardware clock is set to US Eastern Time (300 minutes behind +.Em UTC ) , +and not +.Em UTC . +(Note: +.Em RTC_OFFSET +is used to initialize a kernel variable named +.Va rtc_offset +which is the source actually used to determine the clock offset, and +which may be accessed via the kern.rtc_offset sysctl variable. +See +.Xr sysctl 8 +and +.Xr sysctl 3 +for details. Since the kernel clock is initialized from the hardware +clock very early in the boot process, it is not possible to meaningfully change +.Va rtc_offset +in system initialization scripts. Changing this value currently may +only be done at kernel compile time or by patching the kernel and +rebooting.) +.It Cd option CCDNBUF=integer +The +.Xr ccd 4 +device driver uses "component buffers" to distribute I/O requests to the +components of a concatenated disk. It keeps a freelist of buffer headers +in order to reduce use of the kernel memory allocator. +.Em CCDNBUF +is the number of buffer headers allocated on the freelist for +each component buffer. It defaults to 8. +.It Cd option KMEMSTATS +The kernel memory allocator, +.Xr malloc 9 , +will keep statistics on its performance if this option is enabled. +Unfortunately, this option therefore essentially disables +.Fn MALLOC +and +.Fn FREE +forms of the memory allocator, which are used to enhance the performance +of certain critical sections of code in the kernel. +This option therefore can +lead to a significant decrease in the performance of certain code in the kernel +if enabled. Examples of such code include the +.Fn namei +routine, the +.Xr ccd 4 +driver, +the +.Xr ncr 4 +driver, +and much of the networking code. +.Em N.B. This option is silently +.Em turned on by the DEBUG option. +.El +.Ss Networking Options +.Bl -ohang +.It Cd option 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 option 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 option 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 option 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 option MROUTING +Includes support for IP multicast routers. You certainly want +.Em INET +with this. Multicast routing is controlled by the +.Xr mrouted 8 +daemon. +.It Cd option INET +Includes support for the TCP/IP protocol stack. You almost certainly +want this. See +.Xr inet 4 +for details. +This option is currently required. +.It Cd option MCLSHIFT=value +This option is the base-2 logarithm of the size of mbuf clusters. +The BSD networking stack keeps network packets in a linked +list, or chain, of kernel buffer objects called mbufs. The system +provides larger mbuf clusters as an optimization for large packets, +instead of using long chains for large packets. +The mbuf cluster size, +or +.Em MCLBYTES, +must be a power of two, and is computed as two raised to the power +.Em MCLSHIFT. +On systems with Ethernet network adaptors, +.Em MCLSHIFT +is often set to 11, giving 2048-byte mbuf clusters, large enough to +hold a 1500-byte Ethernet frame in a single cluster. Systems with +networks supporting larger frame sizes like ATM, FDDI, or HIPPI may +perform better with MCLSHIFT set to 12 or 13, giving mbuf cluster +sizes of 4096 and 8192 bytes, respectively. +.It Cd option NS +Include support for the Xerox XNS protocol stack. See +.Xr ns 4 +for details. +.It Cd option ISO,TPIP +Include support for the ubiquitous OSI protocol stack. See +.Xr iso 4 +for details. +.It Cd option EON +Include support for OSI tunneling over IP. +.It Cd option CCITT,LLC,HDLC +Include support for the X.25 protocol stack. +The state of this code is currently unknown, and probably contains +bugs. +.It Cd option IPX,IPXIP +Include support for Internetwork Packet Exchange protocol. +.It Cd option NETATALK +Include support for AppleTalk. +.It Cd option 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 option 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. +.It Cd option PFIL_HOOKS +This option turns on the packet filter interface hooks. See +.Xr pfil 9 +for details. +.It Cd option IPFILTER +This option enables the IP filtering on the packet level using the +ip-filter package. This option requies that the +.Em PFIL_HOOK +option also be included. +.It Cd option IPFILTER_LOG +This option, in conjuction with +.Em IPFILTER , +enables logging of IP packets using ip-filter. +.It Cd option IPFILTER_DEFAULT_BLOCK +This option sets the default policy of ip-filter. If it is set, +ip-filter will block packets by default. +.It Cd option PPP_FILTER +This option turns on +.Xr pcap 3 +based filtering for ppp connections. This option is used by +.Xr pppd 8 +which needs to be compiled with +.Em PPP_FILTER +defined (the current default). +.El +.Ss System V IPC Options +.Bl -ohang +.It Cd option SYSVMSG +Includes support for +.At V +style message queues. See +.Xr msgctl 2 , +.Xr msgget 2 , +.Xr msgrcv 2 , +.Xr msgsnd 2 . +.It Cd option SYSVSEM +Includes support for +.At V +style semaphores. See +.Xr semctl 2 , +.Xr semget 2 , +.Xr semop 2 . +.It Cd option SYSVSHM +Includes support for +.At V +style shared memory. See +.Xr shmat 2 , +.Xr shmctl 2 , +.Xr shmdt 2 , +.Xr shmget 2 . +.It Cd option 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 option 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 . +.It Cd option 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 . +.It Cd option 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 . +.It Cd option NMBCLUSTERS=value +Size of kernel mbuf cluster map, +.Em mb_map , +in CLBYTES-sized logical +pages. Default on most ports is 256 (512 with +.Dq option 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 option 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. +.It Cd option NBUF=value +.It Cd option BUFPAGES=value +These option set the number of pages available for the buffer cache. +Their default value is a machine depedant value, often calculated as +between 5% and 10% of total available RAM. +.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 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 mrouted 8 , +.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 . +.Sh BUGS +The +.Em INET +and the +.Em VNODEPAGER +options should not be required. |