Updating Information for FreeBSD current users This file is maintained and copyrighted by M. Warner Losh . See end of file for further details. For commonly done items, please see the COMMON ITEMS: section later in the file. Items affecting the ports and packages system can be found in /usr/ports/UPDATING. Please read that file before running portupgrade. NOTE TO PEOPLE WHO THINK THAT FreeBSD 7.x IS SLOW: FreeBSD 7.x has many debugging features turned on, in both the kernel and userland. These features attempt to detect incorrect use of system primitives, and encourage loud failure through extra sanity checking and fail stop semantics. They also substantially impact system performance. If you want to do performance measurement, benchmarking, and optimization, you'll want to turn them off. This includes various WITNESS- related kernel options, INVARIANTS, malloc debugging flags in userland, and various verbose features in the kernel. Many developers choose to disable these features on build machines to maximize performance. 20070302: Firmwares for ipw(4) and iwi(4) are now included in the base tree. In order to use them one must agree to the respective LICENSE in share/doc/legal and define legal..license_ack=1 via loader.conf(5) or kenv(1). Make sure to deinstall the now deprecated modules from the respective firmware ports. 20070228: The name resolution/mapping functions addr2ascii(3) and ascii2addr(3) were removed from FreeBSD's libc. These originally came from INRIA IPv6. Nothing in FreeBSD ever used them. They may be regarded as deprecated in previous releases. The AF_LINK support for getnameinfo(3) was merged from NetBSD to replace it as a more portable (and re-entrant) API. 20070224: To support interrupt filtering a modification to the newbus API has occurred, ABI was broken and __FreeBSD_version was bumped to 700031. Please make sure that your kernel and modules are in sync. For more info: http://docs.freebsd.org/cgi/mid.cgi?20070221233124.GA13941 20070224: The IPv6 multicast forwarding code may now be loaded into GENERIC kernels by loading the ip_mroute.ko module. This is built into the module unless WITHOUT_INET6 or WITHOUT_INET6_SUPPORT options are set; see src.conf(5) for more information. 20070214: The output of netstat -r has changed. Without -n, we now only print a "network name" without the prefix length if the network address and mask exactly match a Class A/B/C network, and an entry exists in the nsswitch "networks" map. With -n, we print the full unabbreviated CIDR network prefix in the form "a.b.c.d/p". 0.0.0.0/0 is always printed as "default". This change is in preparation for changes such as equal-cost multipath, and to more generally assist operational deployment of FreeBSD as a modern IPv4 router. 20070210: PIM has been turned on by default in the IPv4 multicast routing code. The kernel option 'PIM' has now been removed. PIM is now built by default if option 'MROUTING' is specified. It may now be loaded into GENERIC kernels by loading the ip_mroute.ko module. 20070207: Support for IPIP tunnels (VIFF_TUNNEL) in IPv4 multicast routing has been removed. Its functionality may be achieved by explicitly configuring gif(4) interfaces and using the 'phyint' keyword in mrouted.conf. XORP does not support source-routed IPv4 multicast tunnels nor the integrated IPIP tunneling, therefore it is not affected by this change. The __FreeBSD_version macro has been bumped to 700030. 20061221: Support for PCI Message Signalled Interrupts has been re-enabled in the bge driver, only for those chips which are believed to support it properly. If there are any problems, MSI can be disabled completely by setting the 'hw.pci.enable_msi' and 'hw.pci.enable_msix' tunables to 0 in the loader. 20061214: Support for PCI Message Signalled Interrupts has been disabled again in the bge driver. Many revisions of the hardware fail to support it properly. Support can be re-enabled by removing the #define of BGE_DISABLE_MSI in "src/sys/dev/bge/if_bge.c". 20061214: Support for PCI Message Signalled Interrupts has been added to the bge driver. If there are any problems, MSI can be disabled completely by setting the 'hw.pci.enable_msi' and 'hw.pci.enable_msix' tunables to 0 in the loader. 20061205: The removal of several facets of the experimental Threading system from the kernel means that the proc and thread structures have changed quite a bit. I suggest all kernel modules that might reference these structures be recompiled.. Especially the linux module. 20061126: Sound infrastructure has been updated with various fixes and improvements. Most of the changes are pretty much transparent, with exceptions of followings: 1) All sound driver specific sysctls (hw.snd.pcm%d.*) have been moved to their own dev sysctl nodes, for example: hw.snd.pcm0.vchans -> dev.pcm.0.vchans 2) /dev/dspr%d.%d has been deprecated. Each channel now has its own chardev in the form of "dsp%d.%d", where is p = playback, r = record and v = virtual, respectively. Users are encouraged to use these devs instead of (old) "/dev/dsp%d.%d". This does not affect those who are using "/dev/dsp". 20061122: The following binaries have been disconnected from the build: mount_devfs, mount_ext2fs, mount_fdescfs, mount_procfs, mount_linprocfs, and mount_std. The functionality of these programs has been moved into the mount program. For example, to mount a devfs filesystem, instead of using mount_devfs, use: "mount -t devfs". This does not affect entries in /etc/fstab, since entries in /etc/fstab are always processed with "mount -t fstype". 20061113: Support for PCI Message Signalled Interrupts on i386 and amd64 has been added to the kernel and various drivers will soon be updated to use MSI when it is available. If there are any problems, MSI can be disabled completely by setting the 'hw.pci.enable_msi' and 'hw.pci.enable_msix' tunables to 0 in the loader. 20061110: The MUTEX_PROFILING option has been renamed to LOCK_PROFILING. The lockmgr object layout has been changed as a result of having a lock_object embedded in it. As a consequence all file system kernel modules must be re-compiled. The mutex profiling man page has not yet been updated to reflect this change. 20061026: KSE in the kernel has now been made optional and turned on by default. Use 'nooption KSE' in your kernel config to turn it off. All kernel modules *must* be recompiled after this change. There-after, modules from a KSE kernel should be compatible with modules from a NOKSE kernel due to the temporary padding fields added to 'struct proc'. 20060929: mrouted and its utilities have been removed from the base system. 20060927: Some ioctl(2) command codes have changed. Full backward ABI compatibility is provided if the "options COMPAT_FREEBSD6" is present in the kernel configuration file. Make sure to add this option to your kernel config file, or recompile X.Org and the rest of ports; otherwise they may refuse to work. 20060924: tcpslice has been removed from the base system. 20060913: The sizes of struct tcpcb (and struct xtcpcb) have changed due to the rewrite of TCP syncookies. Tools like netstat, sockstat, and systat needs to be rebuilt. 20060903: libpcap updated to v0.9.4 and tcpdump to v3.9.4 20060816: The IPFIREWALL_FORWARD_EXTENDED option is gone and the behaviour for IPFIREWALL_FORWARD is now as it was before when it was first committed and for years after. The behaviour is now ON. 20060725: enigma(1)/crypt(1) utility has been changed on 64 bit architectures. Now it can decrypt files created from different architectures. Unfortunately, it is no longer able to decrypt a cipher text generated with an older version on 64 bit architectures. If you have such a file, you need old utility to decrypt it. 20060709: The interface version of the i4b kernel part has changed. So after updating the kernel sources and compiling a new kernel, the i4b user space tools in "/usr/src/usr.sbin/i4b" must also be rebuilt, and vice versa. 20060627: The XBOX kernel now defaults to the nfe(4) driver instead of the nve(4) driver. Please update your configuration accordingly. 20060514: The i386-only lnc(4) driver for the AMD Am7900 LANCE and Am79C9xx PCnet family of NICs has been removed. The new le(4) driver serves as an equivalent but cross-platform replacement with the pcn(4) driver still providing performance-optimized support for the subset of AMD Am79C971 PCnet-FAST and greater chips as before. 20060511: The machdep.* sysctls and the adjkerntz utility have been modified a bit. The new adjkerntz utility uses the new sysctl names and sysctlbyname() calls, so it may be impossible to run an old /sbin/adjkerntz utility in single-user mode with a new kernel. Replace the `adjkerntz -i' step before `make installworld' with: /usr/obj/usr/src/sbin/adjkerntz/adjkerntz -i and proceed as usual with the rest of the installworld-stage steps. Otherwise, you risk installing binaries with their timestamp set several hours in the future, especially if you are running with local time set to GMT+X hours. 20060412: The ip6fw utility has been removed. The behavior provided by ip6fw has been in ipfw2 for a good while and the rc.d scripts have been updated to deal with it. There are some rules that might not migrate cleanly. Use rc.firewall6 as a template to rewrite rules. 20060428: The puc(4) driver has been overhauled. The ebus(4) and sbus(4) attachments have been removed. Make sure to configure scc(4) on sparc64. Note also that by default puc(4) will use uart(4) and not sio(4) for serial ports because interrupt handling has been optimized for multi-port serial cards and only uart(4) implements the interface to support it. 20060330: The scc(4) driver replaces puc(4) for Serial Communications Controllers (SCCs) like the Siemens SAB82532 and the Zilog Z8530. On sparc64, it is advised to add scc(4) to the kernel configuration to make sure that the serial ports remain functional. 20060317: Most world/kernel related NO_* build options changed names. New knobs have common prefixes WITHOUT_*/WITH_* (modelled after FreeBSD ports) and should be set in /etc/src.conf (the src.conf(5) manpage is provided). Full backwards compatibility is maintained for the time being though it's highly recommended to start moving old options out of the system-wide /etc/make.conf file into the new /etc/src.conf while also properly renaming them. More conversions will likely follow. Posting to current@: http://lists.freebsd.org/pipermail/freebsd-current/2006-March/061725.html 20060305: The NETSMBCRYPTO kernel option has been retired because its functionality is always included in NETSMB and smbfs.ko now. 20060303: The TDFX_LINUX kernel option was retired and replaced by the tdfx_linux device. The latter can be loaded as the 3dfx_linux.ko kernel module. Loading it alone should suffice to get 3dfx support for Linux apps because it will pull in 3dfx.ko and linux.ko through its dependencies. 20060204: The 'audit' group was added to support the new auditing functionality in the base system. Be sure to follow the directions for updating, including the requirement to run mergemaster -p. 20060201: The kernel ABI to file system modules was changed on i386. Please make sure that your kernel and modules are in sync. 20060118: This actually occured some time ago, but installing the kernel now also installs a bunch of symbol files for the kernel modules. This increases the size of /boot/kernel to about 67Mbytes. You will need twice this if you will eventually back this up to kernel.old on your next install. If you have a shortage of room in your root partition, you should add -DINSTALL_NODEBUG to your make arguments or add INSTALL_NODEBUG="yes" to your /etc/make.conf. 20060113: libc's malloc implementation has been replaced. This change has the potential to uncover application bugs that previously went unnoticed. See the malloc(3) manual page for more details. 20060112: The generic netgraph(4) cookie has been changed. If you upgrade kernel passing this point, you also need to upgrade userland and netgraph(4) utilities like ports/net/mpd or ports/net/mpd4. 20060106: si(4)'s device files now contain the unit number. Uses of {cua,tty}A[0-9a-f] should be replaced by {cua,tty}A0[0-9a-f]. 20060106: The kernel ABI was mostly destroyed due to a change in the size of struct lock_object which is nested in other structures such as mutexes which are nested in all sorts of other structures. Make sure your kernel and modules are in sync. 20051231: The page coloring algorithm in the VM subsystem was converted from tuning with kernel options to autotuning. Please remove any PQ_* option except PQ_NOOPT from your kernel config. 20051211: The net80211-related tools in the tools/tools/ath directory have been moved to tools/tools/net80211 and renamed with a "wlan" prefix. Scripts that use them should be adjusted accordingly. 20051202: Scripts in the local_startup directories (as defined in /etc/defaults/rc.conf) that have the new rc.d semantics will now be run as part of the base system rcorder. If there are errors or problems with one of these local scripts, it could cause boot problems. If you encounter such problems, boot in single user mode, remove that script from the */rc.d directory. Please report the problem to the port's maintainer, and the freebsd-ports@freebsd.org mailing list. 20051129: The nodev mount option was deprecated in RELENG_6 (where it was a no-op), and is now unsupported. If you have nodev or dev listed in /etc/fstab, remove it, otherwise it will result in a mount error. 20051129: ABI between ipfw(4) and ipfw(8) has been changed. You need to rebuild ipfw(8) when rebuilding kernel. 20051108: rp(4)'s device files now contain the unit number. Uses of {cua,tty}R[0-9a-f] should be replaced by {cua,tty}R0[0-9a-f]. 20051029: /etc/rc.d/ppp-user has been renamed to /etc/rc.d/ppp. Its /etc/rc.conf.d configuration file has been `ppp' from the beginning, and hence there is no need to touch it. 20051014: Now most modules get their build-time options from the kernel configuration file. A few modules still have fixed options due to their non-conformant implementation, but they will be corrected eventually. You may need to review the options of the modules in use, explicitly specify the non-default options in the kernel configuration file, and rebuild the kernel and modules afterwards. 20051001: kern.polling.enable sysctl MIB is now deprecated. Use ifconfig(8) to turn polling(4) on your interfaces. 20050927: The old bridge(4) implementation was retired. The new if_bridge(4) serves as a full functional replacement. 20050722: The ai_addrlen of a struct addrinfo was changed to a socklen_t to conform to POSIX-2001. This change broke an ABI compatibility on 64 bit architecture. You have to recompile userland programs that use getaddrinfo(3) on 64 bit architecture. 20050711: RELENG_6 branched here. 20050629: The pccard_ifconfig rc.conf variable has been removed and a new variable, ifconfig_DEFAULT has been introduced. Unlike pccard_ifconfig, ifconfig_DEFAULT applies to ALL interfaces that do not have ifconfig_ifn entries rather than just those in removable_interfaces. 20050616: Some previous versions of PAM have permitted the use of non-absolute paths in /etc/pam.conf or /etc/pam.d/* when referring to third party PAM modules in /usr/local/lib. A change has been made to require the use of absolute paths in order to avoid ambiguity and dependence on library path configuration, which may affect existing configurations. 20050610: Major changes to network interface API. All drivers must be recompiled. Drivers not in the base system will need to be updated to the new APIs. 20050609: Changes were made to kinfo_proc in sys/user.h. Please recompile userland, or commands like `fstat', `pkill', `ps', `top' and `w' will not behave correctly. The API and ABI for hwpmc(4) have changed with the addition of sampling support. Please recompile lib/libpmc(3) and usr.sbin/{pmcstat,pmccontrol}. 20050606: The OpenBSD dhclient was imported in place of the ISC dhclient and the network interface configuration scripts were updated accordingly. If you use DHCP to configure your interfaces, you must now run devd. Also, DNS updating was lost so you will need to find a workaround if you use this feature. The '_dhcp' user was added to support the OpenBSD dhclient. Be sure to run mergemaster -p (like you are supposed to do every time anyway). 20050605: if_bridge was added to the tree. This has changed struct ifnet. Please recompile userland and all network related modules. 20050603: The n_net of a struct netent was changed to an uint32_t, and 1st argument of getnetbyaddr() was changed to an uint32_t, to conform to POSIX-2001. These changes broke an ABI compatibility on 64 bit architecture. With these changes, shlib major of libpcap was bumped. You have to recompile userland programs that use getnetbyaddr(3), getnetbyname(3), getnetent(3) and/or libpcap on 64 bit architecture. 20050528: Kernel parsing of extra options on '#!' first lines of shell scripts has changed. Lines with multiple options likely will fail after this date. For full details, please see http://people.freebsd.org/~gad/Updating-20050528.txt 20050503: The packet filter (pf) code has been updated to OpenBSD 3.7 Please note the changed anchor syntax and the fact that authpf(8) now needs a mounted fdescfs(5) to function. 20050415: The NO_MIXED_MODE kernel option has been removed from the i386 amd64 platforms as its use has been superceded by the new local APIC timer code. Any kernel config files containing this option should be updated. 20050227: The on-disk format of LC_CTYPE files was changed to be machine independent. Please make sure NOT to use NO_CLEAN buildworld when crossing this point. Crossing this point also requires recompile or reinstall of all locale depended packages. 20050225: The ifi_epoch member of struct if_data has been changed to contain the uptime at which the interface was created or the statistics zeroed rather then the wall clock time because wallclock time may go backwards. This should have no impact unless an snmp implementation is using this value (I know of none at this point.) 20050224: The acpi_perf and acpi_throttle drivers are now part of the acpi(4) main module. They are no longer built separately. 20050223: The layout of struct image_params has changed. You have to recompile all compatibility modules (linux, svr4, etc) for use with the new kernel. 20050223: The p4tcc driver has been merged into cpufreq(4). This makes "options CPU_ENABLE_TCC" obsolete. Please load cpufreq.ko or compile in "device cpufreq" to restore this functionality. 20050220: The responsibility of recomputing the file system summary of a SoftUpdates-enabled dirty volume has been transferred to the background fsck. A rebuild of fsck(8) utility is recommended if you have updated the kernel. To get the old behavior (recompute file system summary at mount time), you can set vfs.ffs.compute_summary_at_mount=1 before mounting the new volume. 20050206: The cpufreq import is complete. As part of this, the sysctls for acpi(4) throttling have been removed. The power_profile script has been updated, so you can use performance/economy_cpu_freq in rc.conf(5) to set AC on/offline cpu frequencies. 20050206: NG_VERSION has been increased. Recompiling kernel (or ng_socket.ko) requires recompiling libnetgraph and userland netgraph utilities. 20050114: Support for abbreviated forms of a number of ipfw options is now deprecated. Warnings are printed to stderr indicating the correct full form when a match occurs. Some abbreviations may be supported at a later date based on user feedback. To be considered for support, abbreviations must be in use prior to this commit and unlikely to be confused with current key words. 20041221: By a popular demand, a lot of NOFOO options were renamed to NO_FOO (see bsd.compat.mk for a full list). The old spellings are still supported, but will cause annoying warnings on stderr. Make sure you upgrade properly (see the COMMON ITEMS: section later in this file). 20041219: Auto-loading of ancillary wlan modules such as wlan_wep has been temporarily disabled; you need to statically configure the modules you need into your kernel or explicitly load them prior to use. Specifically, if you intend to use WEP encryption with an 802.11 device load/configure wlan_wep; if you want to use WPA with the ath driver load/configure wlan_tkip, wlan_ccmp, and wlan_xauth as required. 20041213: The behaviour of ppp(8) has changed slightly. If lqr is enabled (``enable lqr''), older versions would revert to LCP ECHO mode on negotiation failure. Now, ``enable echo'' is required for this behaviour. The ppp version number has been bumped to 3.4.2 to reflect the change. 20041201: The wlan support has been updated to split the crypto support into separate modules. For static WEP you must configure the wlan_wep module in your system or build and install the module in place where it can be loaded (the kernel will auto-load the module when a wep key is configured). 20041201: The ath driver has been updated to split the tx rate control algorithm into a separate module. You need to include either ath_rate_onoe or ath_rate_amrr when configuring the kernel. 20041116: Support for systems with an 80386 CPU has been removed. Please use FreeBSD 5.x or earlier on systems with an 80386. 20041110: We have had a hack which would mount the root filesystem R/W if the device were named 'md*'. As part of the vnode work I'm doing I have had to remove this hack. People building systems which use preloaded MD root filesystems may need to insert a "/sbin/mount -u -o rw /dev/md0 /" in their /etc/rc scripts. 20041104: FreeBSD 5.3 shipped here. 20041102: The size of struct tcpcb has changed again due to the removal of RFC1644 T/TCP. You have to recompile userland programs that read kmem for tcp sockets directly (netstat, sockstat, etc.) 20041022: The size of struct tcpcb has changed. You have to recompile userland programs that read kmem for tcp sockets directly (netstat, sockstat, etc.) 20041016: RELENG_5 branched here. For older entries, please see updating in the RELENG_5 branch. COMMON ITEMS: General Notes ------------- Avoid using make -j when upgrading. From time to time in the past there have been problems using -j with buildworld and/or installworld. This is especially true when upgrading between "distant" versions (eg one that cross a major release boundary or several minor releases, or when several months have passed on the -current branch). Sometimes, obscure build problems are the result of environment poisoning. This can happen because the make utility reads its environment when searching for values for global variables. To run your build attempts in an "environmental clean room", prefix all make commands with 'env -i '. See the env(1) manual page for more details. When upgrading from one major version to another it is generally best to upgrade to the latest code in the currently installed branch first, then do an upgrade to the new branch. This is the best-tested upgrade path, and has the highest probability of being successful. Please try this approach before reporting problems with a major version upgrade. To build a kernel ----------------- If you are updating from a prior version of FreeBSD (even one just a few days old), you should follow this procedure. It is the most failsafe as it uses a /usr/obj tree with a fresh mini-buildworld, make kernel-toolchain make -DALWAYS_CHECK_MAKE buildkernel KERNCONF=YOUR_KERNEL_HERE make -DALWAYS_CHECK_MAKE installkernel KERNCONF=YOUR_KERNEL_HERE To test a kernel once --------------------- If you just want to boot a kernel once (because you are not sure if it works, or if you want to boot a known bad kernel to provide debugging information) run make installkernel KERNCONF=YOUR_KERNEL_HERE KODIR=/boot/testkernel nextboot -k testkernel To just build a kernel when you know that it won't mess you up -------------------------------------------------------------- This assumes you are already running a 5.X system. Replace ${arch} with the architecture of your machine (e.g. "i386", "alpha", "amd64", "ia64", "pc98", "sparc64", etc). cd src/sys/${arch}/conf config KERNEL_NAME_HERE cd ../compile/KERNEL_NAME_HERE make depend make make install If this fails, go to the "To build a kernel" section. To rebuild everything and install it on the current system. ----------------------------------------------------------- # Note: sometimes if you are running current you gotta do more than # is listed here if you are upgrading from a really old current. make buildworld make kernel KERNCONF=YOUR_KERNEL_HERE [1] [3] mergemaster -p [5] make installworld make delete-old mergemaster [4] To cross-install current onto a separate partition -------------------------------------------------- # In this approach we use a separate partition to hold # current's root, 'usr', and 'var' directories. A partition # holding "/", "/usr" and "/var" should be about 2GB in # size. make buildworld make buildkernel KERNCONF=YOUR_KERNEL_HERE make installworld DESTDIR=${CURRENT_ROOT} make distribution DESTDIR=${CURRENT_ROOT} # if newfs'd make installkernel KERNCONF=YOUR_KERNEL_HERE DESTDIR=${CURRENT_ROOT} cp /etc/fstab ${CURRENT_ROOT}/etc/fstab # if newfs'd To upgrade in-place from 5.x-stable to current ---------------------------------------------- make buildworld [9] make kernel KERNCONF=YOUR_KERNEL_HERE [8] [1] [3] mergemaster -p [5] make installworld make delete-old mergemaster -i [4] Make sure that you've read the UPDATING file to understand the tweaks to various things you need. At this point in the life cycle of current, things change often and you are on your own to cope. The defaults can also change, so please read ALL of the UPDATING entries. Also, if you are tracking -current, you must be subscribed to freebsd-current@freebsd.org. Make sure that before you update your sources that you have read and understood all the recent messages there. If in doubt, please track -stable which has much fewer pitfalls. [1] If you have third party modules, such as vmware, you should disable them at this point so they don't crash your system on reboot. [3] From the bootblocks, boot -s, and then do fsck -p mount -u / mount -a cd src adjkerntz -i # if CMOS is wall time Also, when doing a major release upgrade, it is required that you boot into single user mode to do the installworld. [4] Note: This step is non-optional. Failure to do this step can result in a significant reduction in the functionality of the system. Attempting to do it by hand is not recommended and those that pursue this avenue should read this file carefully, as well as the archives of freebsd-current and freebsd-hackers mailing lists for potential gotchas. [5] Usually this step is a noop. However, from time to time you may need to do this if you get unknown user in the following step. It never hurts to do it all the time. You may need to install a new mergemaster (cd src/usr.sbin/mergemaster && make install) after the buildworld before this step if you last updated from current before 20020224 or from -stable before 20020408. [8] In order to have a kernel that can run the 4.x binaries needed to do an installworld, you must include the COMPAT_FREEBSD4 option in your kernel. Failure to do so may leave you with a system that is hard to boot to recover. A similar kernel option COMPAT_FREEBSD5 is required to run the 5.x binaries on more recent kernels. Make sure that you merge any new devices from GENERIC since the last time you updated your kernel config file. [9] When checking out sources, you must include the -P flag to have cvs prune empty directories. If CPUTYPE is defined in your /etc/make.conf, make sure to use the "?=" instead of the "=" assignment operator, so that buildworld can override the CPUTYPE if it needs to. MAKEOBJDIRPREFIX must be defined in an environment variable, and not on the command line, or in /etc/make.conf. buildworld will warn if it is improperly defined. FORMAT: This file contains a list, in reverse chronological order, of major breakages in tracking -current. Not all things will be listed here, and it only starts on October 16, 2004. Updating files can found in previous releases if your system is older than this. Copyright information: Copyright 1998-2005 M. Warner Losh. All Rights Reserved. Redistribution, publication, translation and use, with or without modification, in full or in part, in any form or format of this document are permitted without further permission from the author. THIS DOCUMENT IS PROVIDED BY WARNER LOSH ``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 WARNER LOSH 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. If you find this document useful, and you want to, you may buy the author a beer. Contact Warner Losh if you have any questions about your use of this document. $FreeBSD$