1.\" $NetBSD: options.4,v 1.399 2010/12/21 08:11:21 jruoho Exp $ 2.\" 3.\" Copyright (c) 1996 4.\" Perry E. Metzger. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgment: 16.\" This product includes software developed for the NetBSD Project 17.\" by Perry E. Metzger. 18.\" 4. The name of the author may not be used to endorse or promote products 19.\" derived from this software without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31.\" 32.\" 33.Dd December 21, 2010 34.Dt OPTIONS 4 35.Os 36.Sh NAME 37.Nm options 38.Nd Miscellaneous kernel configuration options 39.Sh SYNOPSIS 40.Cd cinclude ... 41.Cd config ... 42.Cd [no] file-system ... 43.Cd ident ... 44.Cd include ... 45.Cd [no] makeoptions ... 46.Cd maxusers ... 47.Cd [no] options ... 48.Cd [no] pseudo-device ... 49.Sh DESCRIPTION 50This manual page describes a number of miscellaneous kernel 51configuration options that may be specified in a kernel config 52file. 53See 54.Xr config 1 55and 56.Xr config 5 57for information on how to configure and build kernels. 58.Pp 59The 60.Ar no 61form removes a previously specified option. 62.Ss Keywords 63The following keywords are recognized in a kernel configuration file: 64.Bl -ohang 65.It Sy cinclude Qq Ar filename 66Conditionally includes another kernel configuration file whose name is 67.Ar filename , 68which may be double-quoted and may be an explicit path or relative to 69the kernel source directory. 70Failure to open the named file is ignored. 71.It Sy config Ar exec_name No root on Ar rootdev Oo type Ar fstype Oc \ 72Oo dumps on Ar dumpdev Oc 73Defines a configuration whose kernel executable is named 74.Ar exec_name , 75normally 76.Dq netbsd , 77with its root file system of type 78.Ar fstype 79on the device 80.Ar rootdev , 81and optionally specifying the location of kernel core dumps on the device 82.Ar dumpdev . 83.Ar dev 84or 85.Ar dumpdev 86and 87.Ar fstype 88may be specified as 89.Dq \&? , 90which is a wild card. 91The root 92.Ar fstype 93and 94.Ar dumpdev 95are optional and assumed to be wild carded if they are not specified. 96.It Ar device_instance No at Ar attachment \ 97Oo Ar locators value Oo ... Oc Oc Oo flags Ar value Oc 98Define an instance of the device driver 99.Ar device_instance 100that attaches to the bus or device named 101.Ar attachment . 102An 103.Ar attachment 104may require additional information on where the device can be found, such 105as an address, channel, function, offset, and/or slot, referred to as 106.Ar locators , 107whose 108.Ar value 109often may be a wild card, 110.Dq \&? . 111Some device drivers have one or more 112.Ar flags 113that can be adjusted to affect the way they operate. 114.It Sy file-system Ar fs_name Op , Ar fs_name Op ... 115Include support for the file-system 116.Ar fs_name . 117.It Sy ident Qq Ar string 118Sets the kernel identification string to 119.Ar string . 120.It Sy include Qq Ar filename 121Functions the same as 122.Ar cinclude , 123except failure to open 124.Ar filename 125produces a fatal error. 126.It Sy options Ar option_name Op , Ar option_name=value Op ... 127Specifies (or sets) the option, or comma-separated list of options, 128.Ar option_name . 129Some options expect to be assigned a value, which may be an integer, 130a double-quoted word, a bare word, or an empty string 131.Pq Qq . 132Note that those are eventually handled by the C compiler, so the rules 133of that language apply. 134.Pp 135.Em Note : 136Options that are not defined by device definition files are passed to 137the compile process as 138.Fl D 139flags to the C compiler. 140.It Sy makeoptions Ar name=value 141Defines a 142.Xr make 1 143macro 144.Ar name 145with the value 146.Ar value 147in the kernel Makefile. 148.It Sy maxusers Ar integer 149Set the maxusers variable in the kernel. 150.It Sy no Ar keyword Ar name Op Ar arguments Op ... 151For the 152.Xr config 1 153.Ar keywords 154file-system, makeoptions, options, and pseudo-device, 155.Ar no 156removes the file-system, makeoption, options, or pseudo-device, 157.Ar name . 158This is useful when a kernel configuration file includes another which 159has undesired options. 160.Pp 161For example, a local configuration file that wanted the kitchen sink, but 162not COMPAT_09 or bridging, might be: 163.Bd -literal -offset indent 164include "arch/i386/conf/GENERIC" 165no options COMPAT_09 166no pseudo-device bridge 167.Ed 168.It Sy pseudo-device Ar name Op Ar N 169Includes support for the pseudo-device 170.Ar name . 171Some pseudo-devices can have multiple or 172.Ar N 173instances. 174.El 175.Ss Compatibility Options 176.Bl -ohang 177.It Cd options COMPAT_09 178Enable binary compatibility with 179.Nx 0.9 . 180This enables support for 18116-bit user, group, and process IDs (following revisions support 18232-bit identifiers). 183It also allows the use of the deprecated 184.Xr getdomainname 3 , 185.Xr setdomainname 3 , 186and 187.Xr uname 3 188syscalls. 189This option also allows using numeric file system identifiers rather 190than strings. 191Post 192.Nx 0.9 193versions use string identifiers. 194.It Cd options COMPAT_10 195Enable binary compatibility with 196.Nx 1.0 . 197This option allows the use of the file system name of 198.Dq ufs 199as an alias for 200.Dq ffs . 201The name 202.Dq ffs 203should be used post 1.0 in 204.Pa /etc/fstab 205and other files. 206It also adds old syscalls for the 207.At V 208shared memory interface. 209This was changed post 1.0 to work on 64-bit architectures. 210This option also enables 211.Dq sgtty 212compatibility, without which programs using the old interface produce 213an 214.Dq inappropriate ioctl 215error, and 216.Pa /dev/io 217only works when this option is set in the kernel, 218see 219.Xr io 4 220on ports that support it. 221.It Cd options COMPAT_11 222Enable binary compatibility with 223.Nx 1.1 . 224This allows binaries running on the i386 port to gain direct access to 225the io ports by opening 226.Pa /dev/io 227read/write. 228This functionality was replaced by 229.Xr i386_iopl 2 230post 1.1. 231On the 232.Tn Atari 233port, the location of the disk label was moved after 1.1. 234When the 235.Em COMPAT_11 236option is set, the kernel will read (pre) 1.1 style disk labels as a 237last resort. 238When a disk label is re-written, the old style label will be replaced 239with a post 1.1 style label. 240This also enables the 241.Em EXEC_ELF_NOTELESS 242option. 243.It Cd options COMPAT_12 244Enable binary compatibility with 245.Nx 1.2 . 246This allows the use of old syscalls for 247.Fn reboot 248and 249.Fn swapon . 250The syscall numbers were changed post 1.2 to add functionality to the 251.Xr reboot 2 252syscall, and the new 253.Xr swapctl 2 254interface was introduced. 255This also enables the 256.Em EXEC_ELF_NOTELESS 257option. 258.It Cd options COMPAT_13 259Enable binary compatibility with 260.Nx 1.3 . 261This allows the use of old syscalls for 262.Fn sigaltstack , 263and also enables the old 264.Xr swapctl 2 265command 266.Dv SWAP_STATS 267(now called 268.Dv SWAP_OSTATS ) , 269which does not include the 270.Fa se_path 271member of 272.Va struct swapent . 273.It Cd options COMPAT_14 274Enable binary compatibility with 275.Nx 1.4 . 276This allows some old 277.Xr ioctl 2 278on 279.Xr wscons 4 280to be performed, and allows the 281.Dv NFSSVC_BIOD 282mode of the 283.Xr nfssvc 2 284system call to be used for compatibility with the deprecated nfsiod program. 285.It Cd options COMPAT_15 286Enable binary compatibility with 287.Nx 1.5 . 288Since there were no API changes from 289.Nx 1.5 290and 291.Nx 1.6 , 292this option does nothing. 293.It Cd options COMPAT_16 294Enable binary compatibility with 295.Nx 1.6 . 296This allows the use of old signal trampoline code which has been deprecated 297with the addition of 298.Xr siginfo 2 . 299.It Cd options COMPAT_20 300Enable binary compatibility with 301.Nx 2.0 . 302This allows the use of old syscalls for 303.Fn statfs , 304.Fn fstatfs , 305.Fn getfsstat 306and 307.Fn fhstatfs , 308which have been deprecated with the addition of the 309.Xr statvfs 2 , 310.Xr fstatvfs 2 , 311.Xr getvfsstat 2 312and 313.Xr fhstatvfs 2 314system calls. 315.It Cd options COMPAT_30 316Enable binary compatibility with 317.Nx 3.0 . 318See 319.Xr compat_30 8 320for details about the changes made after the 321.Nx 3.0 322release. 323.It Cd options COMPAT_43 324Enables compatibility with 325.Bx 4.3 . 326This adds an old syscall for 327.Xr lseek 2 . 328It also adds the ioctls for 329.Dv TIOCGETP 330and 331.Dv TIOCSETP . 332The return values for 333.Xr getpid 2 , 334.Xr getgid 2 , 335and 336.Xr getuid 2 337syscalls are modified as well, to return the parent's PID and 338UID as well as the current process's. 339It also enables the deprecated 340.Dv NTTYDISC 341terminal line discipline. 342It also provides backwards compatibility with 343.Dq old 344SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including 345binary compatibility with code written before the introduction of the 346sa_len field in sockaddrs. 347It also enables 348support for some older pre 349.Bx 4.4 350socket calls. 351.It Cd options COMPAT_BSDPTY 352This option is currently on by default and enables the pty multiplexer 353.Xr ptm 4 354and 355.Xr ptmx 4 356to find and use ptys named 357.Pa /dev/ptyXX 358(master) and 359.Pa /dev/ttyXX 360(slave). 361Eventually this option will become optional as ptyfs based pseudo-ttys become 362the default, see 363.Xr mount_ptyfs 8 . 364.It Cd options COMPAT_SVR4 365On those architectures that support it, this enables binary 366compatibility with 367.At V.4 368applications built for the same architecture. 369This currently includes the i386, m68k, and sparc ports. 370.It Cd options COMPAT_LINUX 371On those architectures that support it, this enables binary 372compatibility with Linux ELF and 373.Xr a.out 5 374applications built for the same architecture. 375This currently includes the alpha, arm, i386, m68k, mips, powerpc and 376x86_64 ports. 377.It Cd options COMPAT_LINUX32 378On those 64 bit architectures that support it, this enables binary 379compatibility with 32 bit Linux binaries. 380For now this is limited to running i386 ELF Linux binaries on amd64. 381.It Cd options COMPAT_SUNOS 382On those architectures that support it, this enables binary 383compatibility with 384.Tn SunOS 4.1 385applications built for the same architecture. 386This currently includes the sparc, sparc64 and most or all m68k ports. 387Note that the sparc64 requires the 388.Em COMPAT_NETBSD32 389option for 64-bit kernels, in addition to this option. 390.It Cd options COMPAT_ULTRIX 391On those architectures that support it, this enables binary 392compatibility with 393.Tn ULTRIX 394applications built for the same architecture. 395This currently is limited to the pmax. 396The functionality of this option is unknown. 397.It Cd options COMPAT_DARWIN 398On those architectures that support it, this enables binary compatibility with 399.Tn Darwin 400applications built for the same architecture. 401This feature is highly experimental, it requires COMPAT_MACH and 402EXEC_MACHO and it is currently limited to i386 and powerpc ports of 403.Nx . 404.It Cd options COMPAT_FREEBSD 405On those architectures that support it, this enables binary 406compatibility with 407.Fx 408applications built for the same architecture. 409At the moment this is limited to the i386 port. 410.It Cd options COMPAT_IBCS2 411On those architectures that support it, this enables binary 412compatibility with iBCS2 or SVR3 applications built for the same architecture. 413This is currently limited to the i386 and vax ports. 414.It Cd options COMPAT_IRIX 415On those architectures that support it, this enables binary 416compatibility with IRIX o32 binaries built for the same architecture. 417This feature is experimental, and it is currently limited to 418the sgimips port. 419.It Cd options COMPAT_MACH 420On those architectures that support it, this enables the emulation of 421Mach kernel traps for binaries built for the same architecture. 422This feature is highly experimental and it is currently 423limited to the i386 and powerpc ports of 424.Nx . 425.It Cd options COMPAT_OSF1 426On those architectures that support it, this enables binary 427compatibility with 428.Tn Digital 429.Ux 430.Po 431formerly 432.Tn OSF/1 433.Pc 434applications built for the same architecture. 435This is currently limited to the alpha port. 436.It Cd options COMPAT_NOMID 437Enable compatibility with 438.Xr a.out 5 439executables that lack a machine ID. 440This includes 441.Nx 0.8 Ns 's 442ZMAGIC format, and 386BSD and BSDI's 443QMAGIC, NMAGIC, and OMAGIC 444.Xr a.out 5 445formats. 446.It Cd options COMPAT_NETBSD32 447On those architectures that support it, this enables binary 448compatibility with 32-bit applications built for the same architecture. 449This is currently limited to the amd64 and sparc64 ports, and only 450applicable for 64-bit kernels. 451.It Cd options COMPAT_SVR4_32 452On those architectures that support it, this enables binary 453compatibility with 32-bit SVR4 applications built for the same architecture. 454This is currently limited to the sparc64 port, and only applicable for 45564-bit kernels. 456.It Cd options COMPAT_AOUT_M68K 457On m68k architectures which have switched to ELF, 458this enables binary compatibility with 459.Nx Ns Tn /m68k 460.Xr a.out 5 461executables on 462.Nx Ns Tn /m68k 463ELF kernels. 464This handles alignment incompatibility of m68k ABI between 465a.out and ELF which causes the structure padding differences. 466Currently only some system calls which use 467.Va struct stat 468are adjusted and some binaries which use 469.Xr sysctl 3 470to retrieve network details would not work properly. 471.It Cd options EXEC_MACHO 472On those architectures that support it, this adds support for running 473Mach-O executables. 474This is currently limited to the i386 and powerpc ports of 475.Nx . 476.It Cd options EXEC_ELF_NOTELESS 477Run unidentified ELF binaries as 478.Nx 479binaries. 480This might be needed for very old 481.Nx 482ELF binaries on some archs. 483These old binaries didn't contain an appropriate 484.Li .note.netbsd.ident 485section, and thus can't be identified by the kernel as 486.Nx 487binaries otherwise. 488Beware - if this option is on, the kernel would run 489.Em any 490unknown ELF binaries as if they were 491.Nx 492binaries. 493.It Cd options P1003_1B_SEMAPHORE 494Includes kernel support for the standard C library 495.Pq libc 496functions that implement semaphores as specified in 497.St -p1003.1-96 . 498.El 499.Ss Debugging Options 500.Bl -ohang 501.It Cd options DDB 502Compiles in a kernel debugger for diagnosing kernel problems. 503See 504.Xr ddb 4 505for details. 506.Em NOTE : 507not available on all architectures. 508.It Cd options DDB_FROMCONSOLE=integer 509If set to non-zero, DDB may be entered by sending a break on a serial 510console or by a special key sequence on a graphics console. 511A value of "0" ignores console breaks or key sequences. 512If not explicitly specified, the default value is "1". 513Note that this sets the value of the 514.Em ddb.fromconsole 515.Xr sysctl 3 516variable which may be changed at run time -- see 517.Xr sysctl 8 518for details. 519.It Cd options DDB_HISTORY_SIZE=integer 520If this is non-zero, enable history editing in the kernel debugger 521and set the size of the history to this value. 522.It Cd options DDB_ONPANIC 523The default if not specified is 524.Dq 1 525- just enter into DDB. 526If set to 527.Dq 2 528the kernel will 529attempt to print out a stack trace before entering into DDB. 530If set to 531.Dq 0 532the kernel will attempt to print out a stack trace 533and reboot the system. 534If set to 535.Dq -1 536then neither a stack trace is printed or DDB entered - 537it is as if DDB were not compiled into the kernel. 538Note that this sets the value of the 539.Em ddb.onpanic 540.Xr sysctl 3 541variable which may be changed at run time -- see 542.Xr sysctl 8 543for details. 544.It Cd options DDB_COMMANDONENTER=string 545This option specify commands which will be executed on each entry to DDB. 546This sets the default value of the 547.Em ddb.commandonenter 548.Xr sysctl 3 549variable which may be changed at run time. 550.It Cd options DDB_BREAK_CHAR=integer 551This option overrides using break to enter the kernel debugger 552on the serial console. 553The value given is the ASCII value to be used instead. 554This is currently only supported by the com driver. 555.It Cd options DDB_VERBOSE_HELP 556This option adds more verbose descriptions to the 557.Em help 558command. 559.It Cd options KGDB 560Compiles in a remote kernel debugger stub for diagnosing kernel problems 561using the 562.Dq remote target 563feature of gdb. 564See 565.Xr gdb 1 566for details. 567.Em NOTE : 568not available on all architectures. 569.It Cd options KGDB_DEV 570Device number 571.Po 572as a 573.Dv dev_t 574.Pc 575of kgdb device. 576.It Cd options KGDB_DEVADDR 577Memory address of kgdb device. 578.It Cd options KGDB_DEVMODE 579Permissions of kgdb device. 580.It Cd options KGDB_DEVNAME 581Device name of kgdb device. 582.It Cd options KGDB_DEVRATE 583Baud rate of kgdb device. 584.It Cd makeoptions DEBUG="-g" 585The 586.Fl g 587flag causes 588.Pa netbsd.gdb 589to be built in addition to 590.Pa netbsd . 591.Pa netbsd.gdb 592is useful for debugging kernel crash dumps with gdb. 593See 594.Xr gdb 1 595for details. 596This also turns on 597.Em options DEBUG 598(which see). 599.It Cd options DEBUG 600Turns on miscellaneous kernel debugging. 601Since options are turned into preprocessor defines (see above), 602.Em options DEBUG 603is equivalent to doing a 604.Em #define DEBUG 605throughout the kernel. 606Much of the kernel has 607.Em #ifdef DEBUG 608conditionalized debugging code. 609Note that many parts of the kernel (typically device drivers) include their own 610.Em #ifdef XXX_DEBUG 611conditionals instead. 612This option also turns on certain other options, 613which may decrease system performance. 614.It Cd options DIAGNOSTIC 615Adds code to the kernel that does internal consistency checks. 616This code will cause the kernel to panic if corruption of internal data 617structures is detected. 618These checks can decrease performance up to 15%. 619.It Cd options LOCKDEBUG 620Adds code to the kernel to detect incorrect use of locking primitives 621(mutex, rwlock, simplelock). 622This code will cause the kernel to check for dead lock conditions. 623It will also check for memory being freed to not contain initialised 624lock primitives. 625Functions for use in 626.Xr ddb 4 627to check lock chains etc. are also enabled. 628These checks are very expensive and can decrease performance on 629multi-processor machines by a factor of three. 630.It Cd options KSTACK_CHECK_MAGIC 631Check kernel stack usage and panic if stack overflow is detected. 632This check is performance sensitive because it scans stack on each context 633switch. 634.It Cd options KTRACE 635Add hooks for the system call tracing facility, which allows users to 636watch the system call invocation behavior of processes. 637See 638.Xr ktrace 1 639for details. 640.It Cd options MSGBUFSIZE=integer 641This option sets the size of the kernel message buffer. 642This buffer holds the kernel output of 643.Fn printf 644when not (yet) read by 645.Xr syslogd 8 . 646This is particularly useful when the system has crashed and you wish to lookup 647the kernel output from just before the crash. 648Also, since the autoconfig output becomes more and more verbose, 649it sometimes happens that the message buffer overflows before 650.Xr syslogd 8 651was able to read it. 652Note that not all systems are capable of obtaining a variable sized message 653buffer. 654There are also some systems on which memory contents are not preserved 655across reboots. 656.It Cd options MALLOCLOG 657Enables an event log for 658.Xr malloc 9 . 659Useful for tracking down 660.Dq Data modified on freelist 661and 662.Dq multiple free 663problems. 664.It Cd options MALLOCLOGSIZE=integer 665Defines the number of entries in the malloc log. 666Default is 100000 entries. 667.It Cd options UVMHIST 668Enables the UVM history logs, which create in-memory traces of 669various UVM activities. 670These logs can be displayed be calling 671.Fn uvmhist_dump 672or 673.Fn uvm_hist 674with appropriate arguments from DDB. 675See the kernel source file sys/uvm/uvm_stat.c for details. 676.It Cd options UVMHIST_PRINT 677Prints the UVM history logs on the system console as entries are added. 678Note that the output is 679.Em extremely 680voluminous, so this option is really only useful for debugging 681the very earliest parts of kernel initialization. 682.El 683.Ss File Systems 684.Bl -ohang 685.It Cd file-system FFS 686Includes code implementing the Berkeley Fast File System 687.Po Em FFS Pc . 688Most machines need this if they are not running diskless. 689.It Cd file-system EXT2FS 690Includes code implementing the Second Extended File System 691.Po Em ext2 Pc , 692revision 0 and revision 1 with the 693.Em filetype , 694.Em sparse_super 695and 696.Em large_file 697options. 698This is the most commonly used file system on the Linux operating system, 699and is provided here for compatibility. 700Some of the specific features of 701.Em ext2 702like the "behavior on errors" are not implemented. 703See 704.Xr mount_ext2fs 8 705for details. 706.It Cd file-system LFS 707.Bq Em EXPERIMENTAL 708Include the Log-structured File System 709.Po Em LFS Pc . 710See 711.Xr mount_lfs 8 712and 713.Xr newfs_lfs 8 714for details. 715.It Cd file-system MFS 716Include the Memory File System 717.Po Em MFS Pc . 718This file system stores files in swappable memory, and produces 719notable performance improvements when it is used as the file store 720for 721.Pa /tmp 722and similar file systems. 723See 724.Xr mount_mfs 8 725for details. 726.It Cd file-system NFS 727Include the client side of the Network File System 728.Pq Tn NFS 729remote file sharing protocol. 730Although the bulk of the code implementing 731.Tn NFS 732is kernel based, several user level daemons are needed for it to work. 733See 734.Xr mount_nfs 8 735for details. 736.It Cd file-system CD9660 737Includes code for the 738.Tn ISO 7399660 + Rock Ridge file system, which is the standard file system on many 740.Tn CD-ROM 741discs. 742Useful primarily if you have a 743.Tn CD-ROM 744drive. 745See 746.Xr mount_cd9660 8 747for details. 748.It Cd file-system MSDOSFS 749Includes the 750.Tn MS-DOS 751FAT file system, which is reportedly still used 752by unfortunate people who have not heard about 753.Nx . 754Also implements the 755.Tn Windows 95 756extensions to the same, which permit the use of longer, mixed case 757file names. 758See 759.Xr mount_msdos 8 760and 761.Xr fsck_msdos 8 762for details. 763.It Cd file-system NTFS 764.Bq Em EXPERIMENTAL 765Includes code for the 766.Tn Microsoft Windows NT 767file system. 768See 769.Xr mount_ntfs 8 770for details. 771.It Cd file-system FDESC 772Includes code for a file system, conventionally mounted on 773.Pa /dev/fd , 774which permits access to the per-process file descriptor space via 775special files in the file system. 776See 777.Xr mount_fdesc 8 778for details. 779Note that this facility is redundant, and thus unneeded on most 780.Nx 781systems, since the 782.Xr fd 4 783pseudo-device driver already provides identical functionality. 784On most 785.Nx 786systems, instances of 787.Xr fd 4 788are mknoded under 789.Pa /dev/fd/ 790and on 791.Pa /dev/stdin , 792.Pa /dev/stdout , 793and 794.Pa /dev/stderr . 795.It Cd file-system KERNFS 796Includes code which permits the mounting of a special file system 797(normally mounted on 798.Pa /kern ) 799in which files representing various kernel variables and parameters 800may be found. 801See 802.Xr mount_kernfs 8 803for details. 804.It Cd file-system NULLFS 805Includes code for a loopback file system. 806This permits portions of the file hierarchy to be re-mounted in other places. 807The code really exists to provide an example of a stackable file system layer. 808See 809.Xr mount_null 8 810for details. 811.It Cd file-system OVERLAY 812Includes code for a file system filter. 813This permits the overlay file system to intercept all access to an underlying 814file system. 815This file system is intended to serve as an example of a stacking file 816system which has a need to interpose itself between an underlying file 817system and all other access. 818See 819.Xr mount_overlay 8 820for details. 821.It Cd file-system PROCFS 822Includes code for a special file system (conventionally mounted on 823.Pa /proc ) 824in which the process space becomes visible in the file system. 825Among 826other things, the memory spaces of processes running on the system are 827visible as files, and signals may be sent to processes by writing to 828.Pa ctl 829files in the procfs namespace. 830See 831.Xr mount_procfs 8 832for details. 833.It Cd file-system UDF 834.Bq Em EXPERIMENTAL 835Includes code for the UDF file system commonly found on CD and DVD 836media but also more and more on USB sticks. 837Useful primarily if you have a CD or a DVD drive, be it a read-only 838or a rewritable device. 839Currently only supports read-access. 840See 841.Xr mount_udf 8 842for details. 843.It Cd file-system UMAPFS 844Includes a loopback file system in which user and group IDs may be 845remapped -- this can be useful when mounting alien file systems with 846different UIDs and GIDs than the local system. 847See 848.Xr mount_umap 8 849for details. 850.It Cd file-system UNION 851.Bq Em EXPERIMENTAL 852Includes code for the union file system, which permits directories to 853be mounted on top of each other in such a way that both file systems 854remain visible -- this permits tricks like allowing writing (and the 855deleting of files) on a read-only file system like a 856.Tn CD-ROM 857by mounting a local writable file system on top of the read-only file system. 858See 859.Xr mount_union 8 860for details. 861.It Cd file-system CODA 862.Bq Em EXPERIMENTAL 863Includes code for the Coda file system. 864Coda is a distributed file system like NFS and AFS. 865It is freely available, like NFS, but it functions much like AFS in being a 866.Dq stateful 867file system. 868Both Coda and AFS cache files on your local machine to improve performance. 869Then Coda goes a step further than AFS by letting you access the cached 870files when there is no available network, viz. disconnected laptops and 871network outages. 872In Coda, both the client and server are outside the kernel which makes 873them easier to experiment with. 874Coda is available for several UNIX and non-UNIX platforms. 875See http://www.coda.cs.cmu.edu for more details. 876.Em NOTE : 877You also need to enable the pseudo-device, vcoda, for the Coda 878file system to work. 879.It Cd file-system SMBFS 880.Bq Em EXPERIMENTAL 881Includes code for the SMB/CIFS file system. 882See 883.Xr mount_smbfs 8 884for details. 885.Em NOTE : 886You also need to enable the pseudo-device, nsmb, for the SMB 887file system to work. 888.It Cd file-system PTYFS 889.Bq Em EXPERIMENTAL 890Includes code for a special file system (normally mounted on 891.Pa /dev/pts ) 892in which pseudo-terminal slave devices become visible in the file system. 893See 894.Xr mount_ptyfs 8 895for details. 896.It Cd file-system TMPFS 897Includes code for the efficient memory file system, normally used over 898.Pa /tmp . 899See 900.Xr mount_tmpfs 8 901for details. 902.It Cd file-system PUFFS 903Includes kernel support for the pass-to-userspace framework file system. 904It can be used to implement file system functionality in userspace. 905See 906.Xr puffs 3 907for more details. 908This enables for example sshfs: 909.Xr mount_psshfs 8 . 910.El 911.Ss File System Options 912.Bl -ohang 913.It Cd options MAGICLINKS 914Enables the expansion of special strings 915.Po 916beginning with 917.Dq @ 918.Pc 919when traversing symbolic links. 920See 921.Xr symlink 7 922for a list of supported strings. 923Note that this option only controls the enabling of this feature 924by the kernel at boot-up. 925This feature can still be manipulated with the 926.Xr sysctl 8 927command regardless of the setting of this option. 928.It Cd options NFSSERVER 929Include the server side of the 930.Em NFS 931(Network File System) remote file sharing protocol. 932Although the bulk of the code implementing 933.Em NFS 934is kernel based, several user level daemons are needed for it to 935work. 936See 937.Xr mountd 8 938and 939.Xr nfsd 8 940for details. 941.It Cd options QUOTA 942Enables kernel support for file system quotas. 943See 944.Xr quotaon 8 , 945.Xr edquota 8 , 946and 947.Xr quota 1 948for details. 949Note that quotas only work on 950.Dq ffs 951file systems, although 952.Xr rpc.rquotad 8 953permits them to be accessed over 954.Em NFS . 955.It Cd options FFS_EI 956Enable ``Endian-Independent'' FFS support. 957This allows a system to mount an FFS file system created for another 958architecture, at a small performance cost for all FFS file systems. 959See also 960.Xr newfs 8 , 961.Xr fsck_ffs 8 , 962.Xr dumpfs 8 963for file system byte order status and manipulation. 964.It Cd options FFS_NO_SNAPSHOT 965Disable the 966.Dq file system snapshot 967support in FFS file systems. 968Maybe useful for install media kernels, small memory systems and 969embedded systems which don't require the snapshot support. 970.It Cd options WAPBL 971Enable 972.Dq Write Ahead Physical Block Logging file system journaling . 973This provides rapid file system consistency checking after a system outage. 974It also provides better general use performance over regular FFS. 975See also 976.Xr wapbl 4 . 977.It Cd options NVNODE=integer 978This option sets the size of the cache used by the name-to-inode translation 979routines, (a.k.a. the 980.Fn namei 981cache, though called by many other names in the kernel source). 982By default, this cache has 983.Dv NPROC 984(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 985A reasonable way to derive a value of 986.Dv NVNODE , 987should you notice a large number of namei cache misses with a tool such as 988.Xr systat 1 , 989is to examine your system's current computed value with 990.Xr sysctl 8 , 991(which calls this parameter "kern.maxvnodes") and to increase this value 992until either the namei cache hit rate improves or it is determined that 993your system does not benefit substantially from an increase in the size of 994the namei cache. 995.It Cd options NAMECACHE_ENTER_REVERSE 996Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 997as well as a normal one. 998Normally, this is already done for directory vnodes, to speed up the getcwd 999operation. 1000This option will cause longer hash chains in the reverse cache, and thus 1001slow down getcwd somewhat. 1002However, it does make vnode -\*[Gt] path translations possible in some cases. 1003For now, only useful if strict /proc/#/maps emulation for Linux binaries is 1004required. 1005.It Cd options EXT2FS_SYSTEM_FLAGS 1006This option changes the behavior of the APPEND and IMMUTABLE flags 1007for a file on an 1008.Em ext2 1009file system. 1010Without this option, the superuser or owner of the file can 1011set and clear them. 1012With this option, only the superuser can set them, and 1013they can't be cleared if the securelevel is greater than 0. 1014See also 1015.Xr chflags 1 1016and 1017.Xr secmodel_securelevel 9 . 1018.It Cd options NFS_BOOT_BOOTP 1019Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1020information if NFS is used to mount the root file system. 1021See 1022.Xr diskless 8 1023for details. 1024.It Cd options NFS_BOOT_DHCP 1025Same as 1026.Dq NFS_BOOT_BOOTP , 1027but use the DHCP extensions to the 1028BOOTP protocol (RFC 1541). 1029.It Cd options NFS_BOOT_BOOTP_REQFILE 1030Specifies the string sent in the bp_file field of the BOOTP / DHCP 1031request packet. 1032.It Cd options NFS_BOOT_BOOTPARAM 1033Enable use of the BOOTPARAM protocol, consisting of RARP and 1034BOOTPARAM RPC, to get configuration information if NFS 1035is used to mount the root file system. 1036See 1037.Xr diskless 8 1038for details. 1039.It Cd options NFS_BOOT_RWSIZE=value 1040Set the initial NFS read and write sizes for diskless-boot requests. 1041The normal default is 8Kbytes. 1042This option provides a way to lower the value (e.g., to 1024 bytes) 1043as a workaround for buggy network interface cards or boot PROMs. 1044Once booted, the read and write request sizes can be increased by 1045remounting the file system. 1046See 1047.Xr mount_nfs 8 1048for details. 1049.It Cd options NFS_V2_ONLY 1050Reduce the size of the NFS client code by omitting code that's only required 1051for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1052servers. 1053.It Cd options UFS_DIRHASH 1054Increase lookup performance by maintaining in-core hash tables 1055for large directories. 1056.El 1057.Ss Buffer queue strategy options 1058The following options enable alternative buffer queue strategies. 1059.Bl -ohang 1060.It Cd options BUFQ_READPRIO 1061Enable experimental buffer queue strategy for disk I/O. 1062In the default strategy, outstanding disk requests are ordered by 1063sector number and sent to the disk, regardless of whether the 1064operation is a read or write; this option gives priority to issuing 1065read requests over write requests. 1066Although requests may therefore be issued out of sector-order, causing 1067more seeks and thus lower overall throughput, interactive system 1068responsiveness under heavy disk I/O load may be improved, as processes 1069blocking on disk reads are serviced sooner (file writes typically 1070don't cause applications to block). 1071The performance effect varies greatly depending on the hardware, drive 1072firmware, file system configuration, workload, and desired performance 1073trade-off. 1074Systems using drive write-cache (most modern IDE disks, by default) 1075are unlikely to benefit and may well suffer; such disks acknowledge 1076writes very quickly, and optimize them internally according to 1077physical layout. 1078Giving these disks as many requests to work with as possible (the 1079standard strategy) will typically produce the best results, especially 1080if the drive has a large cache; the drive will silently complete 1081writes from cache as it seeks for reads. 1082Disks that support a large number of concurrent tagged requests (SCSI 1083disks and many hardware RAID controllers) expose this internal 1084scheduling with tagged responses, and don't block for reads; such 1085disks may not see a noticeable difference with either strategy. 1086However, if IDE disks are run with write-cache disabled for safety, 1087writes are not acknowledged until actually completed, and only one 1088request can be outstanding; a large number of small writes in one 1089locality can keep the disk busy, starving reads elsewhere on the disk. 1090Such systems are likely to see the most benefit from this option. 1091Finally, the performance interaction of this option with ffs soft 1092dependencies can be subtle, as that mechanism can drastically alter 1093the workload for file system metadata writes. 1094.It Cd options BUFQ_PRIOCSCAN 1095Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1096.It Cd options NEW_BUFQ_STRATEGY 1097Synonym of 1098.Em BUFQ_READPRIO . 1099.El 1100.Ss Miscellaneous Options 1101.Bl -ohang 1102.It Cd options MEMORY_DISK_DYNAMIC 1103This option makes the 1104.Xr md 4 1105.Tn RAM 1106disk size dynamically sized. 1107It is incompatible with 1108.Xr mdsetimage 8 . 1109.It Cd options MEMORY_DISK_HOOKS 1110This option allows for some machine dependent functions to be called when 1111the 1112.Xr md 4 1113.Tn RAM 1114disk driver is configured. 1115This can result in automatically loading a 1116.Tn RAM 1117disk from floppy on open (among other things). 1118.It Cd options MEMORY_DISK_IS_ROOT 1119Forces the 1120.Xr md 4 1121.Tn RAM 1122disk to be the root device. 1123This can only be overridden when 1124the kernel is booted in the 'ask-for-root' mode. 1125.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1126Allocates the given number of 512 byte blocks as memory for the 1127.Xr md 4 1128.Tn RAM 1129disk, to be populated with 1130.Xr mdsetimage 8 . 1131.It Cd options MEMORY_DISK_SERVER=0 1132Do not include the interface to a userland memory disk server process. 1133Per default, this option is set to 1, including the support code. 1134Useful for install media kernels. 1135.It Cd options MEMORY_DISK_RBFLAGS=value 1136This option sets the 1137.Xr reboot 2 1138flags used when booting with a memory disk as root file system. 1139Possible values include 1140.Dv RB_AUTOBOOT 1141(boot in the usual fashion - default value), and 1142.Dv RB_SINGLE 1143(boot in single-user mode). 1144.It Cd options MODULAR 1145Enables the framework for kernel modules (see 1146.Xr module 7 ) . 1147.It Cd options VND_COMPRESSION 1148Enables the 1149.Xr vnd 4 1150driver to also handle compressed images. 1151See 1152.Xr vndcompress 1 , 1153.Xr vnd 4 1154and 1155.Xr vnconfig 8 1156for more information. 1157.It Cd options SPLDEBUG 1158Help the kernel programmer find bugs related to the interrupt priority 1159level. 1160When 1161.Fn spllower 1162or 1163.Fn splraise 1164changes the current CPU's interrupt priority level to or from 1165.Dv IPL_HIGH , 1166record a backtrace. 1167Read 1168.Xr return_address 9 1169for caveats about collecting backtraces. 1170This feature is experimental, and it is only available on i386. 1171See 1172.Pa sys/kern/subr_spldebug.c . 1173.It Cd options TFTPROOT 1174Download the root memory disk through TFTP at root mount time. 1175This enables the use of a root 1176.Tn RAM 1177disk without requiring it to be embedded in the kernel using 1178.Xr mdsetimage 8 . 1179The 1180.Tn RAM 1181disk name is obtained using DHCP's filename parameter. 1182This option requires 1183.Em MEMORY_DISK_HOOKS , 1184.Em MEMORY_DISK_DYNAMIC , 1185and 1186.Em MEMORY_DISK_IS_ROOT . 1187It is incompatible with 1188.Em MEMORY_DISK_ROOT_SIZE . 1189.It Cd options MALLOC_NOINLINE 1190Time critical fixed size memory allocation is performed with 1191.Fn MALLOC 1192and 1193.Fn FREE . 1194Normally these expand to inline code, but with 1195.Em MALLOC_NOINLINE 1196these call the normal 1197.Fn malloc 1198and 1199.Fn free 1200functions. 1201Useful for install media kernels, small memory systems and embedded systems. 1202.It Cd options HZ=integer 1203On ports that support it, set the system clock frequency (see 1204.Xr hz 9 ) 1205to the supplied value. 1206Handle with care. 1207.It Cd options NTP 1208Turns on in-kernel precision timekeeping support used by software 1209implementing 1210.Em NTP 1211(Network Time Protocol, RFC 1305). 1212The 1213.Em NTP 1214option adds an in-kernel Phase-Locked Loop (PLL) for normal 1215.Em NTP 1216operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1217operation. 1218.Xr ntpd 8 1219will employ a user-level PLL when kernel support is unavailable, 1220but the in-kernel version has lower latency and more precision, and 1221so typically keeps much better time. 1222The interface to the kernel 1223.Em NTP 1224support is provided by the 1225.Xr ntp_adjtime 2 1226and 1227.Xr ntp_gettime 2 1228system calls, which are intended for use by 1229.Xr ntpd 8 1230and are enabled by the option. 1231On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1232is not an integer, the 1233.Em NTP 1234option also enables extended-precision arithmetic to keep track of 1235fractional clock ticks at NTP time-format precision. 1236.It Cd options PPS_SYNC 1237This option enables a kernel serial line discipline for receiving time 1238phase signals from an external reference clock such as a radio clock. 1239(The 1240.Em NTP 1241option (which see) must be on if the 1242.Em PPS_SYNC 1243option is used.) 1244Some reference clocks generate a Pulse Per Second (PPS) signal in 1245phase with their time source. 1246The 1247.Em PPS 1248line discipline receives this signal on either the data leads 1249or the DCD control lead of a serial port. 1250.Em NTP 1251uses the PPS signal to discipline the local clock oscillator to a high 1252degree of precision (typically less than 50 microseconds in time and 12530.1 ppm in accuracy). 1254.Em PPS 1255can also generate a serial output pulse when the system receives a PPS 1256interrupt. 1257This can be used to measure the system interrupt latency and thus calibrate 1258.Em NTP 1259to account for it. 1260Using 1261.Em PPS 1262usually requires a 1263gadget box 1264to convert from TTL to RS-232 signal levels. 1265The gadget box and PPS are described in more detail in the HTML documentation 1266for 1267.Xr ntpd 8 1268in 1269.Pa /usr/share/doc/html/ntp . 1270.It Cd options SETUIDSCRIPTS 1271Allows scripts with the setuid bit set to execute as the effective 1272user rather than the real user, just like binary executables. 1273.Pp 1274.Em NOTE : 1275Using this option will also enable 1276.Em options FDSCRIPTS 1277.It Cd options FDSCRIPTS 1278Allows execution of scripts with the execute bit set, but not the 1279read bit, by opening the file and passing the file descriptor to 1280the shell, rather than the filename. 1281.Pp 1282.Em NOTE : 1283Execute only (non-readable) scripts will have 1284.Va argv[0] 1285set to 1286.Pa /dev/fd/* . 1287What this option allows as far as security is 1288concerned, is the ability to safely ensure that the correct script 1289is run by the interpreter, as it is passed as an already open file. 1290.It Cd options PUCCN 1291Enables treating serial ports found on PCI boards 1292.Xr puc 4 1293as potential console devices. 1294The method for choosing such a console device is port dependent. 1295.It Cd options RTC_OFFSET=integer 1296The kernel (and typically the hardware battery backed-up clock on 1297those machines that have one) keeps time in 1298.Em UTC 1299(Universal Coordinated Time, once known as 1300.Em GMT , 1301or Greenwich Mean Time) 1302and not in the time of the local time zone. 1303The 1304.Em RTC_OFFSET 1305option is used on some ports (such as the i386) to tell the kernel 1306that the hardware clock is offset from 1307.Em UTC 1308by the specified number of minutes. 1309This is typically used when a machine boots several operating 1310systems and one of them wants the hardware clock to run in the 1311local time zone and not in 1312.Em UTC , 1313e.g. 1314.Em RTC_OFFSET=300 1315means 1316the hardware clock is set to US Eastern Time (300 minutes behind 1317.Em UTC ) , 1318and not 1319.Em UTC . 1320(Note: 1321.Em RTC_OFFSET 1322is used to initialize a kernel variable named 1323.Va rtc_offset 1324which is the source actually used to determine the clock offset, and 1325which may be accessed via the kern.rtc_offset sysctl variable. 1326See 1327.Xr sysctl 8 1328and 1329.Xr sysctl 3 1330for details. 1331Since the kernel clock is initialized from the hardware clock very 1332early in the boot process, it is not possible to meaningfully change 1333.Va rtc_offset 1334in system initialization scripts. 1335Changing this value currently may only be done at kernel compile 1336time or by patching the kernel and rebooting). 1337.Pp 1338.Em NOTE : 1339Unfortunately, in many cases where the hardware clock 1340is kept in local time, it is adjusted for Daylight Savings 1341Time; this means that attempting to use 1342.Em RTC_OFFSET 1343to let 1344.Nx 1345coexist with such an operating system, like Windows, 1346would necessitate changing 1347.Em RTC_OFFSET 1348twice a year. 1349As such, this solution is imperfect. 1350.It Cd options KMEMSTATS 1351The kernel memory allocator, 1352.Xr malloc 9 , 1353will keep statistics on its performance if this option is enabled. 1354Unfortunately, this option therefore essentially disables the 1355.Fn MALLOC 1356and 1357.Fn FREE 1358forms of the memory allocator, which are used to enhance the performance 1359of certain critical sections of code in the kernel. 1360This option therefore can lead to a significant decrease in the 1361performance of certain code in the kernel if enabled. 1362Examples of such code include the 1363.Fn namei 1364routine, the 1365.Xr ccd 4 1366driver, 1367and much of the networking code. 1368.It Cd options MAXUPRC=integer 1369Sets the soft 1370.Dv RLIMIT_NPROC 1371resource limit, which specifies the maximum number of simultaneous 1372processes a user is permitted to run, for process 0; 1373this value is inherited by its child processes. 1374It defaults to 1375.Em CHILD_MAX , 1376which is currently defined to be 160. 1377Setting 1378.Em MAXUPRC 1379to a value less than 1380.Em CHILD_MAX 1381is not permitted, as this would result in a violation of the semantics of 1382.St -p1003.1-90 . 1383.It Cd options NOFILE=integer 1384Sets the soft 1385.Dv RLIMIT_NOFILE 1386resource limit, which specifies the maximum number of open 1387file descriptors for each process; 1388this value is inherited by its child processes. 1389It defaults to 1390.Em OPEN_MAX , 1391which is currently defined to be 64. 1392.It Cd options MAXFILES=integer 1393Sets the default value of the 1394.Em kern.maxfiles 1395sysctl variable, which indicates the maximum number of files that may 1396be open in the system. 1397.It Cd options DEFCORENAME=string 1398Sets the default value of the 1399.Em kern.defcorename 1400sysctl variable, otherwise it is set to 1401.Nm %n.core . 1402See 1403.Xr sysctl 8 1404and 1405.Xr sysctl 3 1406for details. 1407.It Cd options RASOPS_CLIPPING 1408Enables clipping within the 1409.Nm rasops 1410raster-console output system. 1411.Em NOTE : 1412only available on architectures that use 1413.Nm rasops 1414for console output. 1415.It Cd options RASOPS_SMALL 1416Removes optimized character writing code from the 1417.Nm rasops 1418raster-console output system. 1419.Em NOTE : 1420only available on architectures that use 1421.Nm rasops 1422for console output. 1423.It Cd options INCLUDE_CONFIG_FILE 1424Embeds the kernel config file used to define the kernel in the kernel 1425binary itself. 1426The embedded data also includes any files directly included by the config 1427file itself, e.g. 1428.Pa GENERIC.local 1429or 1430.Pa std.$MACHINE . 1431The embedded config file can be extracted from the resulting kernel with 1432.Xr config 1 1433.Fl x , 1434or by the following command: 1435.Bd -literal -offset indent 1436strings netbsd | sed -n 's/^_CFG_//p' | unvis 1437.Ed 1438.It Cd options INCLUDE_JUST_CONFIG 1439Similar to the above option, but includes just the actual config file, 1440not any included files. 1441.It Cd options PIPE_SOCKETPAIR 1442Use slower, but smaller socketpair(2)-based pipe implementation instead 1443of default faster, but bigger one. 1444Primarily useful for installation kernels. 1445.It Cd options USERCONF 1446Compiles in the in-kernel device configuration manager. 1447See 1448.Xr userconf 4 1449for details. 1450.It Cd options PERFCTRS 1451Compiles in kernel support for CPU performance-monitoring counters. 1452See 1453.Xr pmc 1 1454for details. 1455.Em NOTE : 1456not available on all architectures. 1457.It Cd options SYSCALL_STATS 1458Count the number of times each system call number is called. 1459The values can be read through the sysctl interface and displayed using 1460.Xr systat 1 . 1461.Em NOTE : 1462not yet available on all architectures. 1463.It Cd options SYSCALL_TIMES 1464Count the time spent (using 1465.Fn cpu_counter32 ) 1466in each system call. 1467.Em NOTE : 1468Using this option will also enable 1469.Cd options SYSCALL_STATS . 1470.It Cd options SYSCALL_TIMES_HASCOUNTER 1471Force use of 1472.Fn cpu_counter32 1473even if 1474.Fn cpu_hascounter 1475reports false. 1476Useful for systems where the cycle counter doesn't run at a constant rate 1477(e.g. Soekris boxes). 1478.It Cd options XSERVER_DDB 1479A supplement to XSERVER that adds support for entering 1480.Xr ddb 4 1481while in 1482.Tn X11 . 1483.It Cd options FILEASSOC 1484Support for 1485.Xr fileassoc 9 . 1486.It Cd options FILEASSOC_NHOOKS=integer 1487Number of storage slots per file for 1488.Xr fileassoc 9 . 1489Default is 4. 1490.It Cd options I2C_SCAN 1491Scan each i2c bus to determine which addresses respond. 1492.Pp 1493.Em WARNING ! 1494Using this option can access some devices in such a 1495manner as to leave them in an unstable or unuseable state, and 1496can prevent those devices from being properly matched and/or 1497attached. 1498It can also lock up the entire 1499.Xr iic 4 1500bus and even prevent a machine from completing the boot process. 1501Don't use this option unless you know what you're doing and can 1502accept all sorts of unforeseen consequences. 1503.El 1504.Ss Networking Options 1505.Bl -ohang 1506.It Cd options GATEWAY 1507Enables 1508.Em IPFORWARDING 1509(which see) 1510and (on most ports) increases the size of 1511.Em NMBCLUSTERS 1512(which see). 1513In general, 1514.Em GATEWAY 1515is used to indicate that a system should act as a router, and 1516.Em IPFORWARDING 1517is not invoked directly. 1518(Note that 1519.Em GATEWAY 1520has no impact on protocols other than 1521.Tn IP , 1522such as 1523.Tn CLNP ) . 1524.Em GATEWAY 1525option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1526.It Cd options ICMPPRINTFS 1527The 1528.Em ICMPPRINTFS 1529option will enable debugging information to be printed about 1530the 1531.Xr icmp 4 1532protocol. 1533.It Cd options IPFORWARDING=value 1534If 1535.Em value 1536is 1 this enables IP routing behavior. 1537If 1538.Em value 1539is 0 (the default), it disables it. 1540The 1541.Em GATEWAY 1542option sets this to 1 automatically. 1543With this option enabled, the machine will forward IP datagrams destined 1544for other machines between its interfaces. 1545Note that even without this option, the kernel will 1546still forward some packets (such as source routed packets) -- removing 1547.Em GATEWAY 1548and 1549.Em IPFORWARDING 1550is insufficient to stop all routing through a bastion host on a 1551firewall -- source routing is controlled independently. 1552To turn off source routing, use 1553.Em options IPFORWSRCRT=0 1554(which see). 1555Note that IP forwarding may be turned on and off independently of the 1556setting of the 1557.Em IPFORWARDING 1558option through the use of the 1559.Em net.inet.ip.forwarding 1560sysctl variable. 1561If 1562.Em net.inet.ip.forwarding 1563is 1, IP forwarding is on. 1564See 1565.Xr sysctl 8 1566and 1567.Xr sysctl 3 1568for details. 1569.It Cd options IPFORWSRCRT=value 1570If 1571.Em value 1572is set to zero, source routing of IP datagrams is turned off. 1573If 1574.Em value 1575is set to one (the default) or the option is absent, source routed IP 1576datagrams are forwarded by the machine. 1577Note that source routing of IP packets may be turned on and off 1578independently of the setting of the 1579.Em IPFORWSRCRT 1580option through the use of the 1581.Em net.inet.ip.forwsrcrt 1582sysctl variable. 1583If 1584.Em net.inet.ip.forwsrcrt 1585is 1, forwarding of source routed IP datagrams is on. 1586See 1587.Xr sysctl 8 1588and 1589.Xr sysctl 3 1590for details. 1591.It Cd options IFA_STATS 1592Tells the kernel to maintain per-address statistics on bytes sent 1593and received over (currently) Internet and AppleTalk addresses. 1594.\"This can be a fairly expensive operation, so you probably want to 1595.\"keep this disabled. 1596The option is not recommended as it degrades system stability. 1597.It Cd options IFQ_MAXLEN=value 1598Increases the allowed size of the network interface packet queues. 1599The default queue size is 50 packets, and you do not normally need 1600to increase it. 1601.It Cd options IPSELSRC 1602Includes support for source-address selection policies. 1603See 1604.Xr in_getifa 9 . 1605.It Cd options MROUTING 1606Includes support for IP multicast routers. 1607You certainly want 1608.Em INET 1609with this. 1610Multicast routing is controlled by the 1611.Xr mrouted 8 1612daemon. 1613See also option 1614.Cd PIM . 1615.It Cd options PIM 1616Includes support for Protocol Independent Multicast (PIM) routing. 1617You need 1618.Em MROUTING 1619and 1620.Em INET 1621with this. 1622Software using this can be found e.g. in 1623.Pa pkgsrc/net/xorp . 1624.It Cd options INET 1625Includes support for the 1626.Tn TCP/IP 1627protocol stack. 1628You almost certainly want this. 1629See 1630.Xr inet 4 1631for details. 1632.It Cd options INET6 1633Includes support for the 1634.Tn IPv6 1635protocol stack. 1636See 1637.Xr inet6 4 1638for details. 1639Unlike 1640.Em INET , 1641.Em INET6 1642enables multicast routing code as well. 1643This option requires 1644.Em INET 1645at this moment, but it should not. 1646.It Cd options ND6_DEBUG 1647The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1648for debugging IPv6 neighbor discovery protocol handling. 1649See 1650.Xr sysctl 3 1651for details. 1652.It Cd options IPSEC 1653Includes support for the 1654.Tn IPsec 1655protocol, using the KAME implementation. 1656See 1657.Xr ipsec 4 1658for details. 1659.It Cd options IPSEC_DEBUG 1660Enables debugging code in 1661.Tn IPsec 1662stack. 1663See 1664.Xr ipsec 4 1665for details. 1666.It Cd options IPSEC_ESP 1667Includes support for 1668.Tn IPsec 1669.Tn ESP 1670protocol, using the KAME implementation. 1671See 1672.Xr ipsec 4 1673for details. 1674.It Cd options FAST_IPSEC 1675Includes support for the 1676.Tn IPsec 1677protocol, using the implementation derived from 1678.Ox , 1679relaying on 1680.Xr opencrypto 9 1681to carry out cryptographic operations. 1682See 1683.Xr fast_ipsec 4 1684for details. 1685.It Cd options IPSEC_NAT_T 1686Includes support for 1687.Tn IPsec 1688Network Address Translator traversal (NAT-T), as described in RFCs 3947 1689and 3948. 1690This feature might be patent-encumbered in some countries. 1691.It Cd options ALTQ 1692Enabled ALTQ (Alternate Queueing). 1693For simple rate-limiting, use 1694.Xr tbrconfig 8 1695to set up the interface transmission rate. 1696To use queueing disciplines, their appropriate kernel options should also 1697be defined (documented below). 1698Queueing disciplines are managed by 1699.Xr altqd 8 . 1700See 1701.Xr altq 9 1702for details. 1703.It Cd options ALTQ_HFSC 1704Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1705module. 1706HFSC supports both link-sharing and guaranteed real-time services. 1707HFSC employs a service curve based QoS model, and its unique feature 1708is an ability to decouple delay and bandwidth allocation. 1709Requires 1710.Em ALTQ_RED 1711to use the RED queueing discipline on HFSC classes, or 1712.Em ALTQ_RIO 1713to use the RIO queueing discipline on HFSC classes. 1714This option assumes 1715.Em ALTQ . 1716.It Cd options ALTQ_PRIQ 1717Include support for ALTQ-implemented PRIQ (Priority Queueing). 1718PRIQ implements a simple priority-based queueing discipline. 1719A higher priority class is always served first. 1720Requires 1721.Em ALTQ_RED 1722to use the RED queueing discipline on HFSC classes, or 1723.Em ALTQ_RIO 1724to use the RIO queueing discipline on HFSC classes. 1725This option assumes 1726.Em ALTQ . 1727.It Cd options ALTQ_WFQ 1728Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1729WFQ implements a weighted-round robin scheduler for a set of queues. 1730A weight can be assigned to each queue to give a different proportion 1731of the link capacity. 1732A hash function is used to map a flow to one of a set of queues. 1733This option assumes 1734.Em ALTQ . 1735.It Cd options ALTQ_FIFOQ 1736Include support for ALTQ-implemented FIFO queueing. 1737FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1738This option assumes 1739.Em ALTQ . 1740.It Cd options ALTQ_RIO 1741Include support for ALTQ-implemented RIO (RED with In/Out). 1742The original RIO has 2 sets of RED parameters; one for in-profile 1743packets and the other for out-of-profile packets. 1744At the ingress of the network, profile meters tag packets as IN or 1745OUT based on contracted profiles for customers. 1746Inside the network, IN packets receive preferential treatment by 1747the RIO dropper. 1748ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1749PHB of DiffServ (RFC 2597). 1750This option assumes 1751.Em ALTQ . 1752.It Cd options ALTQ_BLUE 1753Include support for ALTQ-implemented Blue buffer management. 1754Blue is another active buffer management mechanism. 1755This option assumes 1756.Em ALTQ . 1757.It Cd options ALTQ_FLOWVALVE 1758Include support for ALTQ-implemented Flowvalve. 1759Flowvalve is a simple implementation of a RED penalty box that identifies 1760and punishes misbehaving flows. 1761This option requires 1762.Em ALTQ_RED 1763and assumes 1764.Em ALTQ . 1765.It Cd options ALTQ_CDNR 1766Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1767packet marking/manipulation. 1768Traffic conditioners are components to meter, mark, or drop incoming 1769packets according to some rules. 1770As opposed to queueing disciplines, traffic conditioners handle incoming 1771packets at an input interface. 1772This option assumes 1773.Em ALTQ . 1774.It Cd options ALTQ_NOPCC 1775Disables use of processor cycle counter to measure time in ALTQ. 1776This option should be defined for a non-Pentium i386 CPU which does not 1777have TSC, SMP (per-CPU counters are not in sync), or power management 1778which affects processor cycle counter. 1779This option assumes 1780.Em ALTQ . 1781.It Cd options ALTQ_IPSEC 1782Include support for IPsec in IPv4 ALTQ. 1783This option assumes 1784.Em ALTQ . 1785.It Cd options ALTQ_JOBS 1786Include support for ALTQ-implemented JoBS (Joint Buffer Management 1787and Scheduling). 1788This option assumes 1789.Em ALTQ . 1790.It Cd options ALTQ_AFMAP 1791Include support for an undocumented ALTQ feature that is used to map an IP 1792flow to an ATM VC (Virtual Circuit). 1793This option assumes 1794.Em ALTQ . 1795.It Cd options ALTQ_LOCALQ 1796Include support for ALTQ-implemented local queues. 1797Its practical use is undefined. 1798Assumes 1799.Em ALTQ . 1800.It Cd options SUBNETSARELOCAL 1801Sets default value for net.inet.ip.subnetsarelocal variable, which 1802controls whether non-directly-connected subnets of connected networks 1803are considered "local" for purposes of choosing the MSS for a TCP 1804connection. 1805This is mostly present for historic reasons and completely irrelevant if 1806you enable Path MTU discovery. 1807.It Cd options HOSTZEROBROADCAST 1808Sets default value for net.inet.ip.hostzerobroadcast variable, which 1809controls whether the zeroth host address of each connected subnet is 1810also considered a broadcast address. 1811Default value is "1", for compatibility with old systems; if this is 1812set to zero on all hosts on a subnet, you should be able to fit an extra 1813host per subnet on the 1814".0" address. 1815.It Cd options MCLSHIFT=value 1816This option is the base-2 logarithm of the size of mbuf clusters. 1817The 1818.Bx 1819networking stack keeps network packets in a linked 1820list, or chain, of kernel buffer objects called mbufs. 1821The system provides larger mbuf clusters as an optimization for 1822large packets, instead of using long chains for large packets. 1823The mbuf cluster size, 1824or 1825.Em MCLBYTES , 1826must be a power of two, and is computed as two raised to the power 1827.Em MCLSHIFT . 1828On systems with Ethernet network adapters, 1829.Em MCLSHIFT 1830is often set to 11, giving 2048-byte mbuf clusters, large enough to 1831hold a 1500-byte 1832.Tn Ethernet 1833frame in a single cluster. 1834Systems with network interfaces supporting larger frame sizes like 1835.Tn ATM , 1836.Tn FDDI , 1837or 1838.Tn HIPPI 1839may perform better with 1840.Em MCLSHIFT 1841set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1842respectively. 1843.It Cd options ISO,TPIP 1844Include support for the ubiquitous 1845.Tn OSI 1846protocol stack. 1847See 1848.Xr iso 4 1849for details. 1850This option assumes 1851.Em INET . 1852.It Cd options EON 1853Include support for tunneling 1854.Tn OSI 1855protocols over 1856.Tn IP . 1857Known to be broken, or at least very fragile, and undocumented. 1858.It Cd options NETATALK 1859Include support for the 1860.Tn AppleTalk 1861protocol stack. 1862The kernel provides provision for the 1863.Em Datagram Delivery Protocol 1864(DDP), providing SOCK_DGRAM support and 1865.Tn AppleTalk 1866routing. 1867This stack is used by the 1868.Em NETATALK 1869package, which adds support for 1870.Tn AppleTalk 1871server services via user libraries and applications. 1872.It Cd options BLUETOOTH 1873Include support for the 1874.Tn Bluetooth 1875protocol stack. 1876See 1877.Xr bluetooth 4 1878for details. 1879.It Cd options IPNOPRIVPORTS 1880Normally, only root can bind a socket descriptor to a so-called 1881.Dq privileged 1882.Tn TCP 1883port, that is, a port number in the range 0-1023. 1884This option eliminates those checks from the kernel. 1885This can be useful if there is a desire to allow daemons without 1886privileges to bind those ports, e.g., on firewalls. 1887The security tradeoffs in doing this are subtle. 1888This option should only be used by experts. 1889.It Cd options TCP_COMPAT_42 1890.Tn TCP 1891bug compatibility with 1892.Bx 4.2 . 1893In 1894.Bx 4.2 , 1895.Tn TCP 1896sequence numbers were 32-bit signed values. 1897Modern implementations of TCP use unsigned values. 1898This option clamps the initial sequence number to start in 1899the range 2^31 rather than the full unsigned range of 2^32. 1900Also, under 1901.Bx 4.2 , 1902keepalive packets must contain at least one byte or else 1903the remote end would not respond. 1904.It Cd options TCP_DEBUG 1905Record the last 1906.Em TCP_NDEBUG 1907TCP packets with SO_DEBUG set, and decode to the console if 1908.Em tcpconsdebug 1909is set. 1910.It Cd options TCP_NDEBUG 1911Number of packets to record for 1912.Em TCP_DEBUG . 1913Defaults to 100. 1914.It Cd options TCP_SENDSPACE=value 1915.It Cd options TCP_RECVSPACE=value 1916These options set the max TCP window size to other sizes than the default. 1917The TCP window sizes can be altered via 1918.Xr sysctl 8 1919as well. 1920.It Cd options TCP_INIT_WIN=value 1921This option sets the initial TCP window size for non-local connections, 1922which is used when the transmission starts. 1923The default size is 1, but if the machine should act more aggressively, 1924the initial size can be set to some other value. 1925The initial TCP window size can be set via 1926.Xr sysctl 8 1927as well. 1928.It Cd options PFIL_HOOKS 1929This option turns on the packet filter interface hooks. 1930See 1931.Xr pfil 9 1932for details. 1933This option assumes 1934.Em INET . 1935.It Cd options IPFILTER_LOG 1936This option, in conjunction with 1937.Em pseudo-device ipfilter , 1938enables logging of IP packets using IP-Filter. 1939.It Cd options IPFILTER_LOOKUP 1940This option enables the 1941IP-Filter 1942.Xr ippool 8 1943functionality to be enabled. 1944.It Cd options IPFILTER_COMPAT 1945This option enables older IP-Filter binaries to work. 1946.It Cd options IPFILTER_DEFAULT_BLOCK 1947This option sets the default policy of IP-Filter. 1948If it is set, IP-Filter will block packets by default. 1949.It Cd options BRIDGE_IPF 1950This option causes 1951.Em bridge 1952devices to use the IP and/or IPv6 filtering hooks, forming 1953a link-layer filter that uses protocol-layer rules. 1954This option assumes the presence of 1955.Em pseudo-device ipfilter . 1956.It Cd options MBUFTRACE 1957This option can help track down mbuf leaks. 1958When enabled, mbufs are tagged with the devices and protocols using them, 1959which slightly decreases network performance. 1960This additional information can be viewed with 1961.Xr netstat 1 : 1962.Dl Ic netstat Fl mssv 1963Not all devices or protocols support this option. 1964.El 1965.Ss Sysctl Related Options 1966.Bl -ohang 1967.It Cd options SYSCTL_DISALLOW_CREATE 1968Disallows the creation or deletion of nodes from the sysctl tree, as 1969well as the assigning of descriptions to nodes that lack them, by any 1970process. 1971These operations are still available to kernel sub-systems, including 1972loadable kernel modules. 1973.It Cd options SYSCTL_DISALLOW_KWRITE 1974Prevents processes from adding nodes to the sysctl tree that make 1975existing kernel memory areas writable. 1976Sections of kernel memory can still be read and new nodes that own 1977their own data may still be writable. 1978.It Cd options SYSCTL_DEBUG_SETUP 1979Causes the SYSCTL_SETUP routines to print a brief message when they 1980are invoked. 1981This is merely meant as an aid in determining the order in which 1982sections of the tree are created. 1983.It Cd options SYSCTL_DEBUG_CREATE 1984Prints a message each time 1985.Fn sysctl_create , 1986the function that adds nodes to the tree, is called. 1987.It Cd options SYSCTL_INCLUDE_DESCR 1988Causes the kernel to include short, human readable descriptions for 1989nodes in the sysctl tree. 1990The descriptions can be retrieved programmatically (see 1991.Xr sysctl 3 ) , 1992or by the sysctl binary itself (see 1993.Xr sysctl 8 ) . 1994The descriptions are meant to give an indication of the purpose and/or 1995effects of a given node's value, not replace the documentation for the 1996given subsystem as a whole. 1997.El 1998.Ss System V IPC Options 1999.Bl -ohang 2000.It Cd options SYSVMSG 2001Includes support for 2002.At V 2003style message queues. 2004See 2005.Xr msgctl 2 , 2006.Xr msgget 2 , 2007.Xr msgrcv 2 , 2008.Xr msgsnd 2 . 2009.It Cd options SYSVSEM 2010Includes support for 2011.At V 2012style semaphores. 2013See 2014.Xr semctl 2 , 2015.Xr semget 2 , 2016.Xr semop 2 . 2017.It Cd options SEMMNI=value 2018Sets the number of 2019.At V 2020style semaphore identifiers. 2021The GENERIC config file for your port will have the default. 2022.It Cd options SEMMNS=value 2023Sets the number of 2024.At V 2025style semaphores in the system. 2026The GENERIC config file for your port will have the default. 2027.It Cd options SEMUME=value 2028Sets the maximum number of undo entries per process for 2029.At V 2030style semaphores. 2031The GENERIC config file for your port will have the default. 2032.It Cd options SEMMNU=value 2033Sets the number of undo structures in the system for 2034.At V 2035style semaphores. 2036The GENERIC config file for your port will have the default. 2037.It Cd options SYSVSHM 2038Includes support for 2039.At V 2040style shared memory. 2041See 2042.Xr shmat 2 , 2043.Xr shmctl 2 , 2044.Xr shmdt 2 , 2045.Xr shmget 2 . 2046.It Cd options SHMMAXPGS=value 2047Sets the maximum number of 2048.At V 2049style shared memory pages that are available through the 2050.Xr shmget 2 2051system call. 2052Default value is 1024 on most ports. 2053See 2054.Pa /usr/include/machine/vmparam.h 2055for the default. 2056.El 2057.Ss VM Related Options 2058.Bl -ohang 2059.It Cd options NMBCLUSTERS=value 2060The number of mbuf clusters the kernel supports. 2061Mbuf clusters are MCLBYTES in size (usually 2k). 2062This is used to compute the size of the kernel VM map 2063.Em mb_map , 2064which maps mbuf clusters. 2065Default on most ports is 1024 (2048 with 2066.Dq options GATEWAY 2067). 2068See 2069.Pa /usr/include/machine/param.h 2070for exact default information. 2071Increase this value if you get 2072.Dq mclpool limit reached 2073messages. 2074.It Cd options NKMEMPAGES=value 2075.It Cd options NKMEMPAGES_MIN=value 2076.It Cd options NKMEMPAGES_MAX=value 2077Size of kernel VM map 2078.Em kmem_map , 2079in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2080from the 2081.Xr sysctl 8 2082variable 2083.Em hw.pagesize 2084). 2085This VM map is used to map the kernel malloc arena. 2086The kernel attempts to auto-size this map based on the amount of 2087physical memory in the system. 2088Platform-specific code may place bounds on this computed size, 2089which may be viewed with the 2090.Xr sysctl 8 2091variable 2092.Em vm.nkmempages . 2093See 2094.Pa /usr/include/machine/param.h 2095for the default upper and lower bounds. 2096The related options 2097.Sq NKMEMPAGES_MIN 2098and 2099.Sq NKMEMPAGES_MAX 2100allow the bounds to be overridden in the kernel configuration file. 2101These options are provided in the event the computed value is 2102insufficient resulting in an 2103.Dq out of space in kmem_map 2104panic. 2105.It Cd options SB_MAX=value 2106Sets the max size in bytes that a socket buffer is allowed to occupy. 2107The default is 256k, but sometimes it needs to be increased, for example 2108when using large TCP windows. 2109This option can be changed via 2110.Xr sysctl 8 2111as well. 2112.It Cd options SOMAXKVA=value 2113Sets the maximum size of kernel virtual memory that the socket buffers 2114are allowed to use. 2115The default is 16MB, but in situations where for example large TCP 2116windows are used this value must also be increased. 2117This option can be changed via 2118.Xr sysctl 8 2119as well. 2120.It Cd options BUFCACHE=value 2121Size of the buffer cache as a percentage of total available 2122.Tn RAM . 2123Ignored if BUFPAGES is also specified. 2124.It Cd options NBUF=value 2125Sets the number of buffer headers available, i.e., the number of 2126open files that may have a buffer cache entry. 2127Each buffer header 2128requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2129The default value is machine dependent, but is usually equal to the 2130value of BUFPAGES. 2131If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2132then NBUF may be reduced at run time so that the storage allocated 2133for buffer headers doesn't exceed that limit. 2134.It Cd options BUFPAGES=value 2135These options set the number of pages available for the buffer cache. 2136Their default value is a machine dependent value, often calculated as 2137between 5% and 10% of total available 2138.Tn RAM . 2139.It Cd options MAXTSIZ=bytes 2140Sets the maximum size limit of a process' text segment. 2141See 2142.Pa /usr/include/machine/vmparam.h 2143for the port-specific default. 2144.It Cd options DFLDSIZ=bytes 2145Sets the default size limit of a process' data segment, the value that 2146will be returned as the soft limit for 2147.Dv RLIMIT_DATA 2148(as returned by 2149.Xr getrlimit 2 ) . 2150See 2151.Pa /usr/include/machine/vmparam.h 2152for the port-specific default. 2153.It Cd options MAXDSIZ=bytes 2154Sets the maximum size limit of a process' data segment, the value that 2155will be returned as the hard limit for 2156.Dv RLIMIT_DATA 2157(as returned by 2158.Xr getrlimit 2 ) . 2159See 2160.Pa /usr/include/machine/vmparam.h 2161for the port-specific default. 2162.It Cd options DFLSSIZ=bytes 2163Sets the default size limit of a process' stack segment, the value that 2164will be returned as the soft limit for 2165.Dv RLIMIT_STACK 2166(as returned by 2167.Xr getrlimit 2 ) . 2168See 2169.Pa /usr/include/machine/vmparam.h 2170for the port-specific default. 2171.It Cd options MAXSSIZ=bytes 2172Sets the maximum size limit of a process' stack segment, the value that 2173will be returned as the hard limit for 2174.Dv RLIMIT_STACK 2175(as returned by 2176.Xr getrlimit 2 ) . 2177See 2178.Pa /usr/include/machine/vmparam.h 2179for the port-specific default. 2180.It Cd options DUMP_ON_PANIC=integer 2181Defaults to one. 2182If set to zero, the kernel will not dump to the dump device when 2183it panics, though dumps can still be forced via 2184.Xr ddb 4 2185with the 2186.Dq sync 2187command. 2188Note that this sets the value of the 2189.Em kern.dump_on_panic 2190.Xr sysctl 3 2191variable which may be changed at run time -- see 2192.Xr sysctl 8 2193for details. 2194.It Cd options USE_TOPDOWN_VM 2195User space memory allocations (as made by 2196.Xr mmap 2 ) 2197will be arranged in a 2198.Dq top down 2199fashion instead of the traditional 2200.Dq upwards from MAXDSIZ \&+ vm_daddr 2201method. 2202This includes the placement of 2203.Xr ld.so 1 . 2204Arranging memory in this manner allows either (or both of) the heap or 2205.Xr mmap 2 2206allocated space to grow larger than traditionally possible. 2207This option is not available on all ports, but is instead expected to be 2208offered on a port-by-port basis, after which some ports will commit to 2209using it by default. 2210See the files 2211.Pa /usr/include/uvm/uvm_param.h 2212for some implementation details, and 2213.Pa /usr/include/machine/vmparam.h 2214for port specific details including availability. 2215.It Cd options VMSWAP 2216Enable paging device/file support. 2217This option is on by default. 2218.It Cd options PDPOLICY_CLOCKPRO 2219Use CLOCK-Pro, an alternative page replace policy. 2220.El 2221.Ss Security Options 2222.Bl -ohang 2223.It Cd options INSECURE 2224Hardwires the kernel security level at \-1. 2225This means that the system 2226always runs in secure level \-1 mode, even when running multiuser. 2227See the manual page for 2228.Xr init 8 2229for details on the implications of this. 2230The kernel secure level may manipulated by the superuser by altering the 2231.Em kern.securelevel 2232.Xr sysctl 3 2233variable (the secure level may only be lowered by a call from process ID 1, 2234i.e., 2235.Xr init 8 ) . 2236See also 2237.Xr secmodel_securelevel 9 , 2238.Xr sysctl 8 2239and 2240.Xr sysctl 3 . 2241.It Cd options VERIFIED_EXEC_FP_MD5 2242Enables support for MD5 hashes in Veriexec. 2243.It Cd options VERIFIED_EXEC_FP_SHA1 2244Enables support for SHA1 hashes in Veriexec. 2245.It Cd options VERIFIED_EXEC_FP_RMD160 2246Enables support for RMD160 hashes in Veriexec. 2247.It Cd options VERIFIED_EXEC_FP_SHA256 2248Enables support for SHA256 hashes in Veriexec. 2249.It Cd options VERIFIED_EXEC_FP_SHA384 2250Enables support for SHA384 hashes in Veriexec. 2251.It Cd options VERIFIED_EXEC_FP_SHA512 2252Enables support for SHA512 hashes in Veriexec. 2253.It Cd options PAX_MPROTECT=value 2254Enables PaX MPROTECT, 2255.Xr mprotect 2 2256restrictions from the PaX project. 2257.Pp 2258The 2259.Ar value 2260is the default value for the 2261.Em global 2262knob, see 2263.Xr sysctl 3 . 2264If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2265using 2266.Xr paxctl 8 . 2267If 1, PaX MPROTECT will be enabled for all programs. 2268Programs can be exempted using 2269.Xr paxctl 8 . 2270.Pp 2271See 2272.Xr security 8 2273for more details. 2274.It Cd options PAX_SEGVGUARD=value 2275Enables PaX Segvguard. 2276.Pp 2277The 2278.Ar value 2279is the default value for the 2280.Em global 2281knob, see 2282.Xr sysctl 3 . 2283If 0, PaX Segvguard will be enabled only if explicitly set on programs 2284using 2285.Xr paxctl 8 . 2286If 1, PaX Segvguard will be enabled to all programs, and exemption can 2287be done using 2288.Xr paxctl 8 . 2289.Pp 2290See 2291.Xr security 8 2292for more details. 2293.It Cd options PAX_ASLR=value 2294Enables PaX ASLR. 2295.Pp 2296The 2297.Ar value 2298is the default value for the 2299.Em global 2300knob, see 2301.Xr sysctl 3 . 2302If 0, PaX ASLR will be enabled only if explicitly set on programs 2303using 2304.Xr paxctl 8 . 2305If 1, PaX ASLR will be enabled to all programs, and exemption can 2306be done using 2307.Xr paxctl 8 . 2308.Pp 2309See 2310.Xr security 8 2311for more details. 2312.It Cd options USER_VA0_DISABLE_DEFAULT=value 2313Sets the initial value of the flag which controls whether user programs 2314can map virtual address 0. 2315The flag can be changed at runtime by 2316.Xr sysctl 3 . 2317.El 2318.Ss amiga-specific Options 2319.Bl -ohang 2320.It Cd options BB060STUPIDROM 2321When the bootloader (which passes 2322.Tn AmigaOS 2323.Tn ROM 2324information) claims we have a 68060 2325.Tn CPU 2326without 2327.Tn FPU , 2328go look into the Processor Configuration Register (PCR) to find out. 2329You need this with 2330.Tn Amiga 2331.Tn ROM Ns s 2332up to (at least) V40.xxx (OS3.1), 2333when you boot via the bootblocks and don't have a DraCo. 2334.It Cd options IOBZCLOCK=frequency 2335The IOBlix boards come with two different serial master clocks: older ones 2336use 24 MHz, newer ones use 22.1184 MHz. 2337The driver normally assumes the latter. 2338If your board uses 24 MHz, you can recompile your kernel with 2339options IOBZCLOCK=24000000 2340or patch the kernel variable 2341.Tn iobzclock 2342to the same value. 2343.It Cd options LIMITMEM=value 2344If there, limit the part of the first memory bank used by 2345.Nx 2346to value megabytes. 2347Default is unlimited. 2348.It Cd options NKPTADD=addvalue 2349.It Cd options NKPTADDSHIFT=shiftvalue 2350The 2351.Tn CPU 2352specific 2353.Tn MMU 2354table for the kernel is pre-allocated at kernel startup time. 2355Part of it is scaled with 2356.Va maxproc , 2357to have enough room to hold the user program 2358.Tn MMU 2359tables; the second part is a fixed amount for the kernel itself. 2360.Pp 2361The third part accounts for the size of the file buffer cache. 2362Its size is either 2363.Dv NKPTADD 2364pages (if defined) or memory size in bytes divided by two to 2365the power of 2366.Dv NKPTADDSHIFT . 2367The default is undefined 2368.Dv NKPTADD 2369and 2370.Dv NKPTADDSHIFT=24 , 2371allowing for 16 buffers per megabyte of main memory (while 2372a GENERIC kernel allocates about half of that). 2373When you get "can't get KPT page" panics, you should increase 2374.Dv NKPTADD 2375(if defined), or decrease 2376.Dv NKPTADDSHIFT 2377by one. 2378.It Cd options P5PPC68KBOARD 2379Add special support for Phase5 mixed 68k+PPC boards. 2380Currently, this only affects rebooting from 2381.Nx 2382and is only needed on 68040+PPC, not on 238368060+PPC; without this, affected machines will hang after 2384.Nx 2385has shut 2386down and will only restart after a keyboard reset or a power cycle. 2387.El 2388.Ss arm32-specific Options 2389.Bl -ohang 2390.It Cd options FRENCH_KBD 2391Include translation for French keyboards when using 2392.Em pccons 2393on a Shark. 2394.It Cd options FINNISH_KBD 2395Include translation for Finnish keyboards when using 2396.Em pccons 2397on a Shark. 2398.It Cd options GERMAN_KBD 2399Include translation for German keyboards when using 2400.Em pccons 2401on a Shark. 2402.It Cd options NORWEGIAN_KBD 2403Include translation for French keyboards when using 2404.Em pccons 2405on a Shark. 2406.El 2407.Ss amd64-specific Options 2408.Bl -ohang 2409.It Cd options ENHANCED_SPEEDSTEP 2410Include support for the 2411.Dq Enhanced SpeedStep Technology . 2412Note that new systems supporting 2413.Xr acpi 4 2414should prefer 2415.Xr acpicpu 4 2416instead. 2417.It Cd options EST_FREQ_USERWRITE 2418Allow any user to change the frequency of an 2419.Dq Enhanced SpeedStep Technology . 2420capable 2421.Tn CPU . 2422.It Cd options INTEL_ONDEMAND_CLOCKMOD 2423This enables the On Demand Clock Modulation by software 2424on Intel 2425.Tn CPUs 2426supporting the Thermal Monitor feature (TM). 2427You can select the duty cycle with 2428.Xr sysctl 8 2429in the node 2430.Em machdep.clockmod 2431if supported. 2432.It Cd options POWERNOW_K8 2433Include support for AMD Athlon 64 PowerNow! and Cool`n'Quiet 2434Technology, used to change the CPU voltage and frequency 2435on the fly. 2436Note that new systems supporting 2437.Xr acpi 4 2438should prefer 2439.Xr acpicpu 4 2440instead. 2441.El 2442.Ss atari-specific Options 2443.Bl -ohang 2444.It Cd options DISKLABEL_AHDI 2445Include support for AHDI (native Atari) disklabels. 2446.It Cd options DISKLABEL_NBDA 2447Include support for 2448.Nx Ns Tn /atari 2449labels. 2450If you don't set this option, it will be set automatically. 2451.Nx Ns Tn /atari 2452will not work without it. 2453.It Cd options FALCON_SCSI 2454Include support for the 5380-SCSI configuration as found on the Falcon. 2455.It Cd options RELOC_KERNEL 2456If set, the kernel will relocate itself to TT-RAM, if possible. 2457This will give you a slightly faster system. 2458.Em Beware 2459that on some TT030 systems, 2460the system will frequently dump with MMU-faults with this option enabled. 2461.It Cd options SERCONSOLE 2462Allow the modem1-port to act as the system-console. 2463A carrier should be active on modem1 during system boot to active 2464the console functionality. 2465.It Cd options TT_SCSI 2466Include support for the 5380-SCSI configuration as found on the TT030 2467and Hades. 2468.El 2469.Ss i386-specific Options 2470.Bl -ohang 2471.It Cd options ENHANCED_SPEEDSTEP 2472Include support for the 2473.Dq Enhanced SpeedStep Technology . 2474Note that new systems supporting 2475.Xr acpi 4 2476should prefer 2477.Xr acpicpu 4 2478instead. 2479.It Cd options EST_FREQ_USERWRITE 2480Allow any user to change the frequency of an 2481.Dq Enhanced SpeedStep Technology 2482capable 2483.Tn CPU . 2484.It Cd options INTEL_ONDEMAND_CLOCKMOD 2485This enables the On Demand Clock Modulation by software 2486on Intel 2487.Tn CPUs 2488supporting the Thermal Monitor feature (TM). 2489You can select the duty cycle with 2490.Xr sysctl 8 2491in the node 2492.Em machdep.clockmod 2493if supported. 2494.It Cd options POWERNOW_K7 2495Include support for the AMD 2496.Tn PowerNow! Technology 2497present in AMD Athlon Mobile processors. 2498.It Cd options VIA_PADLOCK 2499Include support for the 2500.Tn AES 2501encryption instructions of the 2502.Tn VIA PadLock Security engine , 2503which is attached as a provider to the opencrypto framework. 2504.It Cd options CPURESET_DELAY=value 2505Specifies the time (in millisecond) to wait before doing a hardware reset 2506in the last phase of a reboot. 2507This gives the user a chance to see error messages from the shutdown 2508operations (like NFS unmounts, buffer cache flush, etc ...). 2509Setting this to 0 will disable the delay. 2510Default is 2 seconds. 2511.It Cd options VM86 2512Include support for virtual 8086 mode, used by 2513.Tn DOS 2514emulators and X servers to run BIOS code, e.g., for some VESA routines. 2515.It Cd options USER_LDT 2516Include i386-specific system calls for modifying the local descriptor table, 2517used by Windows emulators. 2518.It Cd options PAE 2519Enable 2520.Tn PAE (Physical Address Extension) 2521mode. 2522.Tn PAE 2523permits up to 36 bits physical addressing (64GB of physical memory), and 2524turns physical addresses to 64 bits entities in the memory management 2525subsystem. 2526Userland virtual address space remains at 32 bits (4GB). 2527.Tn PAE 2528mode is required to enable the 2529.Tn NX/XD (No-eXecute/eXecute Disable) 2530bit for pages, which allows marking certain ones as not being executable. 2531Any attempt to execute code from such a page will raise an exception. 2532.It Cd options REALBASEMEM=integer 2533Overrides the base memory size passed in from the boot block. 2534(Value given in kilobytes.) 2535Use this option only if the boot block reports the size incorrectly. 2536(Note that some 2537.Tn BIOS Ns es 2538put the extended 2539.Tn BIOS 2540data area at the top of base memory, and therefore report a smaller 2541base memory size to prevent programs overwriting it. 2542This is correct behavior, and you should not use the 2543.Em REALBASEMEM 2544option to access this memory). 2545.It Cd options REALEXTMEM=integer 2546Overrides the extended memory size passed in from the boot block. 2547(Value given in kilobytes. 2548Extended memory does not include the first megabyte.) 2549Use this option only if the boot block reports the size incorrectly. 2550.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2551Select a non-US keyboard layout for the 2552.Em pccons 2553console driver. 2554.It Cd options CYRIX_CACHE_WORKS 2555Relevant only to the Cyrix 486DLC CPU. 2556This option is used to turn on the cache in hold-flush mode. 2557It is not turned on by default because it is known to have problems in 2558certain motherboard implementations. 2559.It Cd options CYRIX_CACHE_REALLY_WORKS 2560Relevant only to the Cyrix 486DLC CPU. 2561This option is used to turn on the cache in write-back mode. 2562It is not turned on by default because it is known to have problems in 2563certain motherboard implementations. 2564In order for this option to take effect, option 2565.Em CYRIX_CACHE_WORKS 2566must also be specified. 2567.It Cd options PCIBIOS 2568Enable support for initializing the 2569.Tn PCI 2570bus using information from the 2571.Tn BIOS . 2572See 2573.Xr pcibios 4 2574for details. 2575.It Cd options KSTACK_CHECK_DR0 2576Detect kernel stack overflow using DR0 register. 2577This option uses DR0 register exclusively so you can't use DR0 register for 2578other purpose (e.g., hardware breakpoint) if you turn this on. 2579.It Cd options MTRR 2580Include support for accessing MTRR registers from user-space. 2581See 2582.Xr i386_get_mtrr 2 . 2583.It Cd options BEEP_ONHALT 2584Make the system speaker emit several beeps when it is completely safe to 2585power down the computer after a 2586.Xr halt 8 2587command. 2588Requires 2589.Xr sysbeep 4 2590support. 2591.It Cd options BEEP_ONHALT_COUNT=times 2592Number of times to beep the speaker when 2593.Cd options BEEP_ONHALT 2594is enabled. 2595Defaults to 3. 2596.It Cd options BEEP_ONHALT_PITCH=hz 2597The tone frequency used when 2598.Cd options BEEP_ONHALT 2599option, in hertz. 2600Defaults to 1500. 2601.It Cd options BEEP_ONHALT_PERIOD=msecs 2602The duration of each beep when 2603.Cd options BEEP_ONHALT 2604is enabled, in milliseconds. 2605Defaults to 250. 2606.It Cd options MULTIBOOT 2607Makes the kernel Multiboot-compliant, allowing it to be booted through 2608a Multiboot-compliant boot manager such as GRUB. 2609See 2610.Xr multiboot 8 2611for more information. 2612.It Cd options SPLASHSCREEN 2613Display a splash screen during boot. 2614.It Cd options SPLASHSCREEN_PROGRESS 2615Display a progress bar at the splash screen during boot. 2616This option requires 2617.Em SPLASHSCREEN . 2618.El 2619.Ss isa-specific Options 2620Options specific to 2621.Xr isa 4 2622busses. 2623.Bl -ohang 2624.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2625Control the section of IO bus space used for PCMCIA bus space mapping. 2626Ideally the probed defaults are satisfactory, however in practice 2627that is not always the case. 2628See 2629.Xr pcmcia 4 2630for details. 2631.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2632Controls the allowable interrupts that may be used for 2633.Tn PCMCIA 2634devices. 2635This mask is a logical-or of power-of-2s of allowable interrupts: 2636.Bd -literal -offset 04n 2637.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2638 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2639 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2640 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2641 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2642.Ed 2643.It Cd options PCKBC_CNATTACH_SELFTEST 2644Perform a self test of the keyboard controller before attaching it as a 2645console. 2646This might be necessary on machines where we boot on cold iron, and 2647pckbc refuses to talk until we request a self test. 2648Currently only the netwinder port uses it. 2649.It Cd options PCKBD_CNATTACH_MAY_FAIL 2650If this option is set the PS/2 keyboard will not be used as the console 2651if it cannot be found during boot. 2652This allows other keyboards, like USB, to be the console keyboard. 2653.It Cd options PCKBD_LAYOUT=layout 2654Sets the default keyboard layout, see 2655.Xr pckbd 4 . 2656.El 2657.Ss m68k-specific Options 2658.Bl -ohang 2659.It Cd options FPU_EMULATE 2660Include support for MC68881/MC68882 emulator. 2661.It Cd options FPSP 2662Include support for 68040 floating point. 2663.It Cd options M68020,M68030,M68040,M68060 2664Include support for a specific 2665.Tn CPU , 2666at least one (the one you are using) should be specified. 2667.It Cd options M060SP 2668Include software support for 68060. 2669This provides emulation of unimplemented 2670integer instructions as well as emulation of unimplemented floating point 2671instructions and data types and software support for floating point traps. 2672.El 2673.Ss powerpc-specific Options (OEA Only) 2674.Bl -ohang 2675.It Cd options PMAP_MEMLIMIT=value 2676Limit the amount of memory seen by the kernel to 2677.Ar value 2678bytes. 2679.It Cd options PTEGCOUNT=value 2680Specify the size of the page table as 2681.Ar value 2682PTE groups. 2683Normally, one PTEG is allocated per physical page frame. 2684.El 2685.Ss sparc-specific Options 2686.Bl -ohang 2687.It Cd options AUDIO_DEBUG 2688Enable simple event debugging of the logging of the 2689.Xr audio 4 2690device. 2691.It Cd options BLINK 2692Enable blinking of LED. 2693Blink rate is full cycle every N seconds for 2694N \*[Lt] then current load average. 2695See 2696.Xr getloadavg 3 . 2697.\" .It Cd options COLORFONT_CACHE 2698.\" What does this do? 2699.It Cd options COUNT_SW_LEFTOVERS 2700Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2701sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2702variables accessible from 2703.Xr ddb 4 . 2704See 2705.Xr sw 4 . 2706.It Cd options DEBUG_ALIGN 2707Adds debugging messages calls when user-requested alignment fault 2708handling happens. 2709.It Cd options DEBUG_EMUL 2710Adds debugging messages calls for emulated floating point and 2711alignment fixing operations. 2712.It Cd options DEBUG_SVR4 2713Prints registers messages calls for emulated SVR4 getcontext and 2714setcontext operations. 2715See 2716.Em options COMPAT_SVR4 . 2717.It Cd options EXTREME_DEBUG 2718Adds debugging functions callable from 2719.Xr ddb 4 . 2720The debug_pagetables, test_region and print_fe_map 2721functions print information about page tables for the SUN4M 2722platforms only. 2723.It Cd options EXTREME_EXTREME_DEBUG 2724Adds extra info to 2725.Em options EXTREME_DEBUG . 2726.It Cd options FPU_CONTEXT 2727Make 2728.Em options COMPAT_SVR4 2729getcontext and setcontext include floating point registers. 2730.It Cd options MAGMA_DEBUG 2731Adds debugging messages to the 2732.Xr magma 4 2733device. 2734.It Cd options RASTERCONS_FULLSCREEN 2735Use the entire screen for the console. 2736.It Cd options RASTERCONS_SMALLFONT 2737Use the Fixed font on the console, instead of the normal font. 2738.It Cd options SUN4 2739Support sun4 class machines. 2740.It Cd options SUN4C 2741Support sun4c class machines. 2742.It Cd options SUN4M 2743Support sun4m class machines. 2744.It Cd options SUN4_MMU3L 2745.\" XXX ??? 2746Enable support for sun4 3-level MMU machines. 2747.It Cd options V9 2748Enable SPARC V9 assembler in 2749.Xr ddb 4 . 2750.El 2751.Ss sparc64-specific Options 2752.Bl -ohang 2753.It Cd options AUDIO_DEBUG 2754Enable simple event debugging of the logging of the 2755.Xr audio 4 2756device. 2757.It Cd options BLINK 2758Enable blinking of LED. 2759Blink rate is full cycle every N seconds for 2760N \*[Lt] then current load average. 2761See 2762.Xr getloadavg 3 . 2763.El 2764.Ss x68k-specific Options 2765.Bl -ohang 2766.It Cd options EXTENDED_MEMORY 2767Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2768.It Cd options JUPITER 2769Include support for Jupiter-X MPU accelerator 2770.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2771Use the built-in serial port as the system-console. 2772Speed is specified in bps, defaults to 9600. 2773.It Cd options ITE_KERNEL_ATTR=value 2774Set the kernel message attribute for ITE. 2775Value, an integer, is a logical or of the following values: 2776.Bl -tag -width 4n -compact -offset indent 2777.It 1 2778color inversed 2779.It 2 2780underlined 2781.It 4 2782bolded 2783.El 2784.El 2785.\" The following requests should be uncommented and used where appropriate. 2786.\" .Sh FILES 2787.\" .Sh EXAMPLES 2788.Sh SEE ALSO 2789.Xr config 1 , 2790.Xr gdb 1 , 2791.Xr ktrace 1 , 2792.Xr pmc 1 , 2793.Xr quota 1 , 2794.Xr vndcompress 1 , 2795.Xr gettimeofday 2 , 2796.Xr i386_get_mtrr 2 , 2797.Xr i386_iopl 2 , 2798.Xr msgctl 2 , 2799.Xr msgget 2 , 2800.Xr msgrcv 2 , 2801.Xr msgsnd 2 , 2802.Xr ntp_adjtime 2 , 2803.Xr ntp_gettime 2 , 2804.Xr reboot 2 , 2805.Xr semctl 2 , 2806.Xr semget 2 , 2807.Xr semop 2 , 2808.Xr shmat 2 , 2809.Xr shmctl 2 , 2810.Xr shmdt 2 , 2811.Xr shmget 2 , 2812.Xr sysctl 3 , 2813.Xr apm 4 , 2814.Xr ddb 4 , 2815.Xr inet 4 , 2816.Xr iso 4 , 2817.Xr md 4 , 2818.Xr pcibios 4 , 2819.Xr pcmcia 4 , 2820.Xr ppp 4 , 2821.Xr userconf 4 , 2822.Xr vnd 4 , 2823.Xr wscons 4 , 2824.Xr config 5 , 2825.Xr edquota 8 , 2826.Xr init 8 , 2827.Xr mdsetimage 8 , 2828.Xr mount_cd9660 8 , 2829.Xr mount_fdesc 8 , 2830.Xr mount_kernfs 8 , 2831.Xr mount_lfs 8 , 2832.Xr mount_mfs 8 , 2833.Xr mount_msdos 8 , 2834.Xr mount_nfs 8 , 2835.Xr mount_ntfs 8 , 2836.Xr mount_null 8 , 2837.Xr mount_portal 8 , 2838.Xr mount_procfs 8 , 2839.Xr mount_udf 8 , 2840.Xr mount_umap 8 , 2841.Xr mount_union 8 , 2842.Xr mrouted 8 , 2843.Xr newfs_lfs 8 , 2844.Xr ntpd 8 , 2845.Xr quotaon 8 , 2846.Xr rpc.rquotad 8 , 2847.Xr sysctl 8 , 2848.Xr in_getifa 9 2849.Sh HISTORY 2850The 2851.Nm 2852man page first appeared in 2853.Nx 1.3 . 2854.Sh BUGS 2855The 2856.Em EON 2857option should be a pseudo-device, and is also very fragile. 2858