1.\" $NetBSD: sysctl.8,v 1.144 2006/03/06 00:51:48 christos Exp $ 2.\" 3.\" Copyright (c) 2004 The NetBSD Foundation, Inc. 4.\" 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 acknowledgement: 16.\" This product includes software developed by the NetBSD 17.\" Foundation, Inc. and its contributors. 18.\" 4. Neither the name of The NetBSD Foundation nor the names of its 19.\" contributors may be used to endorse or promote products derived 20.\" from this software without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 23.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 24.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 25.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 26.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 27.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 28.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 29.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 30.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 31.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 32.\" POSSIBILITY OF SUCH DAMAGE. 33.\" 34.\" 35.\" Copyright (c) 1993 36.\" The Regents of the University of California. All rights reserved. 37.\" 38.\" Redistribution and use in source and binary forms, with or without 39.\" modification, are permitted provided that the following conditions 40.\" are met: 41.\" 1. Redistributions of source code must retain the above copyright 42.\" notice, this list of conditions and the following disclaimer. 43.\" 2. Redistributions in binary form must reproduce the above copyright 44.\" notice, this list of conditions and the following disclaimer in the 45.\" documentation and/or other materials provided with the distribution. 46.\" 3. Neither the name of the University nor the names of its contributors 47.\" may be used to endorse or promote products derived from this software 48.\" without specific prior written permission. 49.\" 50.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 51.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 52.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 53.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 54.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 55.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 56.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 57.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 58.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 59.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 60.\" SUCH DAMAGE. 61.\" 62.\" @(#)sysctl.8 8.1 (Berkeley) 6/6/93 63.\" 64.Dd March 5, 2006 65.Dt SYSCTL 8 66.Os 67.Sh NAME 68.Nm sysctl 69.Nd get or set kernel state 70.Sh SYNOPSIS 71.Nm sysctl 72.Op Fl AdeMn 73.Oo 74.Fl r | 75.Fl x 76.Oc 77.Op Ar name ... 78.Nm sysctl 79.Op Fl nq 80.Oo 81.Fl r | 82.Fl x 83.Oc 84.Fl w 85.Ar name Ns Li = Ns Ar value ... 86.Nm sysctl 87.Op Fl en 88.Oo 89.Fl r | 90.Fl x 91.Oc 92.Fl a 93.Nm sysctl 94.Op Fl nq 95.Oo 96.Fl r | 97.Fl x 98.Oc 99.Fl f 100.Ar file 101.Sh DESCRIPTION 102The 103.Nm sysctl 104utility retrieves kernel state and allows processes with 105appropriate privilege to set kernel state. 106The state to be retrieved or set is described using a 107``Management Information Base'' (``MIB'') style name, 108described as a dotted set of components. 109The 110.Sq / 111character may also be used as a separator and a leading separator 112character is accepted. 113If 114.Ar name 115specifies a non-leaf node in the MIB, all the nodes underneath 116.Ar name 117will be printed. 118.Pp 119The following options are available: 120.Bl -tag -width indent 121.It Fl A 122List all the known MIB names including tables, unless any MIB 123arguments or 124.Fl f Ar file 125are given. 126Those with string or integer values will be printed as with the 127.Fl a 128flag; for table or structure values that 129.Nm 130is not able to print, 131the name of the utility to retrieve them is given. 132Errors in retrieving or setting values will be directed to stdout 133instead of stderr. 134.It Fl a 135List all the currently available string or integer values. 136The use of a solitary separator character (either 137.Sq \&. 138or 139.Sq / ) 140by 141itself has the same effect. 142Any given 143.Ar name 144arguments are ignored if this option is specified. 145.It Fl d 146Descriptions of each of the nodes selected will be printed instead of 147their values. 148.It Fl e 149Separate the name and the value of the variable(s) with 150.Ql = . 151This is useful for producing output which can be fed back to the 152.Nm 153utility. 154This option is ignored if 155.Fl n 156is specified or a variable is being set. 157.It Fl f 158Specifies the name of a file to read and process. 159Blank lines and comments (beginning with 160.Ql # ) 161are ignored. 162Line continuations with 163.Ql \e 164are permitted. 165Remaining lines are processed similarly to 166command line arguments of the form 167.Ar name 168or 169.Ar name Ns Li = Ns Ar value . 170The 171.Fl w 172flag is implied by 173.Fl f . 174Any 175.Ar name 176arguments are ignored. 177.It Fl M 178Makes 179.Nm 180print the MIB instead of any of the actual values contained in the 181MIB. 182This causes the entire MIB to be printed unless specific MIB arguments 183or 184.Fl f Ar file 185are also given. 186.It Fl n 187Specifies that the printing of the field name should be 188suppressed and that only its value should be output. 189This flag is useful for setting shell variables. 190For example, to save the pagesize in variable psize, use: 191.Bd -literal -offset indent -compact 192set psize=`sysctl -n hw.pagesize` 193.Ed 194.It Fl q 195Used to indicate that nothing should be printed for writes unless an 196error is detected. 197.It Fl r 198Raw output form. 199Values printed are in their raw binary forms as retrieved directly 200from the kernel. 201Some additional nodes that 202.Nm 203cannot print directly can be retrieved with this flag. 204This option conflicts with the 205.Fl x 206option. 207.It Fl w 208Sets the MIB style name given to the value given. 209The MIB style name and value must be separated by 210.Ql = 211with no whitespace. 212Only integral and string values can be set via this method. 213.It Fl x 214Makes 215.Nm 216print the requested value in a hexadecimal representation instead of 217its regular form. 218If specified more than once, the output for each value resembles that of 219.Xr hexdump 1 220when given the 221.Fl C 222flag. 223This option conflicts with the 224.Fl r 225option. 226.Pp 227.El 228The 229.Ql proc 230top-level MIB has a special semantic: it represent per-process values 231and as such may differ from one process to another. 232The second-level name is the pid of the process (in decimal form), 233or the special word 234.Ql curproc . 235For variables below 236.Ql proc. Ns Ao pid Ac Ns .rlimit , 237the integer value may be replaced 238with the string 239.Ql unlimited 240if it matches the magic value used to disable 241a limit. 242.Pp 243The information available from 244.Nm sysctl 245consists of integers, strings, and tables. 246The tabular information can only be retrieved by special 247purpose programs such as 248.Nm ps , 249.Nm systat , 250and 251.Nm netstat . 252The string and integer information is summarized below. 253For a detailed description of these variable see 254.Xr sysctl 3 . 255The changeable column indicates whether a process with appropriate 256privilege can change the value. 257.Bl -column proc.xpidx.rlimit.coredumpsize.hardxxxxxx integerxxx 258.It Sy Name Type Changeable 259.It ddb.commandonenter string yes 260.It ddb.fromconsole integer yes 261.It ddb.lines integer yes 262.It ddb.maxoff integer yes 263.It ddb.maxwidth integer yes 264.It ddb.onpanic integer yes 265.It ddb.radix integer yes 266.It ddb.tabstops integer yes 267.It ddb.tee_msgbuf integer yes 268.It hw.alignbytes integer no 269.It hw.byteorder integer no 270.It hw.cnmagic integer yes 271.It hw.disknames string no 272.It hw.diskstats struct no 273.It hw.machine string no 274.It hw.machine_arch string no 275.It hw.model string no 276.It hw.ncpu integer no 277.It hw.pagesize integer no 278.It hw.physmem integer no 279.It hw.physmem64 quad no 280.It hw.usermem integer no 281.It hw.usermem64 quad no 282.It kern.argmax integer no 283.It kern.autonicetime integer yes 284.It kern.autoniceval integer yes 285.It kern.boottime struct no 286.It kern.bufq.strategies string no 287.It kern.ccpu integer no 288.It kern.clockrate struct no 289.It kern.consdev integer no 290.It kern.cp_id struct no 291.It kern.cp_time struct no 292.It kern.cryptodevallowsoft int yes 293.It kern.defcorename string yes 294.It kern.domainname string yes 295.It kern.dump_on_panic integer yes 296.It kern.drivers struct no 297.It kern.file struct no 298.It kern.forkfsleep integer yes 299.It kern.fscale integer no 300.It kern.fsync integer no 301.It kern.hardclock_ticks integer no 302.It kern.hostid integer yes 303.It kern.hostname string yes 304.It kern.iov_max integer no 305.It kern.job_control integer no 306.It kern.labeloffset integer no 307.It kern.labelsector integer no 308.It kern.login_name_max integer no 309.It kern.logsigexit integer yes 310.It kern.mapped_files integer no 311.It kern.maxfiles integer yes 312.It kern.maxpartitions integer no 313.It kern.maxphys integer no 314.It kern.maxproc integer yes 315.It kern.maxptys integer yes, special 316.It kern.maxvnodes integer raise only 317.It kern.mbuf.mblowat integer yes 318.It kern.mbuf.mclbytes integer no 319.It kern.mbuf.mcllowat integer yes 320.It kern.mbuf.mclsize integer no 321.It kern.mbuf.msize integer no 322.It kern.mbuf.nmbclusters integer raise only 323.It kern.memlock integer no 324.It kern.memlock_range integer no 325.It kern.memory_protection integer no 326.It kern.monotonic_clock integer no 327.It kern.msgbuf integer no 328.It kern.msgbufsize integer no 329.It kern.ngroups integer no 330.It kern.ntptime struct no 331.It kern.osrelease string no 332.It kern.osrevision integer no 333.It kern.ostype string no 334.It kern.pipe.kvasize integer no 335.It kern.pipe.maxbigpipes integer yes 336.It kern.pipe.maxkvasz integer yes 337.It kern.pipe.maxloankvasz integer yes 338.It kern.pipe.nbigpipes integer no 339.It kern.posix1version integer no 340.It kern.posix_barriers integer no 341.It kern.posix_reader_writer_locks integer no 342.It kern.posix_semaphores integer no 343.It kern.posix_spin_locks integer no 344.It kern.posix_threads integer no 345.It kern.posix_timers integer no 346.It kern.proc struct no 347.It kern.proc2 struct no 348.It kern.proc_args string yes 349.It kern.prof node not applicable 350.It kern.rawpartition integer no 351.It kern.root_device string no 352.It kern.root_partition integer no 353.It kern.rtc_offset integer yes 354.It kern.saved_ids integer no 355.It kern.sbmax integer yes 356.It kern.securelevel integer raise only 357.It kern.somaxkva integer yes 358.It kern.synchronized_io integer no 359.It kern.sysvipc_info struct no 360.It kern.sysvmsg integer no 361.It kern.sysvsem integer no 362.It kern.sysvshm integer no 363.It kern.timex struct no 364.It kern.tkstat.cancc quad no 365.It kern.tkstat.nin quad no 366.It kern.tkstat.nout quad no 367.It kern.tkstat.rawcc quad no 368.It kern.urandom integer no 369.It kern.userasymcrypto int yes 370.It kern.usercrypto int yes 371.It kern.veriexec.verbose integer yes 372.It kern.veriexec.strict integer raise only 373.It kern.veriexec.algorithms string no 374.It kern.veriexec.count.dev_\*[Lt]id\*[Gt] quad no 375.It kern.version string no 376.It kern.vnode struct no 377.It machdep.console_device dev_t no 378.It net.bpf.maxbufsize integer yes 379.It net.bpf.stats struct no 380.It net.bpf.peers struct no 381.It net.inet.arp.prune integer yes 382.It net.inet.arp.keep integer yes 383.It net.inet.arp.down integer yes 384.It net.inet.arp.refresh integer yes 385.It net.inet.icmp.maskrepl integer yes 386.It net.inet.icmp.errppslimit integer yes 387.It net.inet.icmp.rediraccept integer yes 388.It net.inet.icmp.redirtimeout integer yes 389.It net.inet.icmp.returndatabytes integer yes 390.It net.inet.ip.allowsrcrt integer yes 391.It net.inet.ip.anonportmax integer yes 392.It net.inet.ip.anonportmin integer yes 393.It net.inet.ip.checkinterface integer yes 394.It net.inet.ip.directed-broadcast integer yes 395.It net.inet.ip.do_loopback_cksum integer yes 396.It net.inet.ip.forwarding integer yes 397.It net.inet.ip.forwsrcrt integer yes 398.It net.inet.ip.gifttl integer yes 399.It net.inet.ip.grettl integer yes 400.It net.inet.ip.hostzerobroadcast integer yes 401.It net.inet.ip.maxfragpackets integer yes 402.It net.inet.ip.lowportmax integer yes 403.It net.inet.ip.lowportmin integer yes 404.It net.inet.ip.mtudisc integer yes 405.It net.inet.ip.mtudisctimeout integer yes 406.It net.inet.ip.random_id integer yes 407.It net.inet.ip.redirect integer yes 408.It net.inet.ip.subnetsarelocal integer yes 409.It net.inet.ip.ttl integer yes 410.It net.inet.ip.ifq.drops integer no 411.It net.inet.ip.ifq.len integer no 412.It net.inet.ip.ifq.maxlen integer yes 413.It net.inet.ipsec.ah_cleartos integer yes 414.It net.inet.ipsec.ah_net_deflev integer yes 415.It net.inet.ipsec.ah_offsetmask integer yes 416.It net.inet.ipsec.ah_trans_deflev integer yes 417.It net.inet.ipsec.def_policy integer yes 418.It net.inet.ipsec.dfbit integer yes 419.It net.inet.ipsec.ecn integer yes 420.It net.inet.ipsec.esp_net_deflev integer yes 421.It net.inet.ipsec.esp_trans_deflev integer yes 422.It net.inet.ipsec.inbound_call_ike integer yes 423.It net.inet.tcp.ack_on_push integer yes 424.It net.inet.tcp.compat_42 integer yes 425.It net.inet.tcp.cwm integer yes 426.It net.inet.tcp.cwm_burstsize integer yes 427.It net.inet.tcp.delack_ticks integer yes 428.It net.inet.tcp.do_lookback_cksum integer yes 429.It net.inet.tcp.init_win integer yes 430.It net.inet.tcp.init_win_local integer yes 431.It net.inet.tcp.keepcnt integer yes 432.It net.inet.tcp.keepidle integer yes 433.It net.inet.tcp.keepintvl integer yes 434.It net.inet.tcp.log_refused integer yes 435.It net.inet.tcp.mss_ifmtu integer yes 436.It net.inet.tcp.mssdflt integer yes 437.It net.inet.tcp.newreno integer yes 438.It net.inet.tcp.recvspace integer yes 439.It net.inet.tcp.rfc1323 integer yes 440.It net.inet.tcp.rstppslimit integer yes 441.It net.inet.tcp.sack.enable integer yes 442.It net.inet.tcp.sack.globalholes integer no 443.It net.inet.tcp.sack.globalmaxholes integer yes 444.It net.inet.tcp.sack.maxholes integer yes 445.It net.inet.tcp.sendspace integer yes 446.It net.inet.tcp.slowhz integer no 447.It net.inet.tcp.syn_bucket_limit integer yes 448.It net.inet.tcp.syn_cache_interval integer yes 449.It net.inet.tcp.syn_cache_limit integer yes 450.It net.inet.tcp.timestamps integer yes 451.It net.inet.tcp.win_scale integer yes 452.It net.inet.tcp.ident struct no 453.It net.inet.tcp.debug struct no 454.It net.inet.tcp.debx integer no 455.It net.inet.udp.checksum integer yes 456.It net.inet.udp.do_loopback_cksum integer yes 457.It net.inet.udp.recvspace integer yes 458.It net.inet.udp.sendspace integer yes 459.It net.ns.spp.debug struct yes 460.It net.ns.spp.debx integer yes 461.It net.inet6.icmp6.errppslimit integer yes 462.It net.inet6.icmp6.mtudisc_hiwat integer yes 463.It net.inet6.icmp6.mtudisc_lowat integer yes 464.It net.inet6.icmp6.nd6_debug integer yes 465.It net.inet6.icmp6.nd6_delay integer yes 466.It net.inet6.icmp6.nd6_maxnudhint integer yes 467.It net.inet6.icmp6.nd6_mmaxtries integer yes 468.It net.inet6.icmp6.nd6_prune integer yes 469.It net.inet6.icmp6.nd6_umaxtries integer yes 470.It net.inet6.icmp6.nd6_useloopback integer yes 471.It net.inet6.icmp6.nodeinfo integer yes 472.It net.inet6.icmp6.rediraccept integer yes 473.It net.inet6.icmp6.redirtimeout integer yes 474.It net.inet6.ip6.accept_rtadv integer yes 475.It net.inet6.ip6.anonportmax integer yes 476.It net.inet6.ip6.anonportmin integer yes 477.It net.inet6.ip6.auto_flowlabel integer yes 478.It net.inet6.ip6.dad_count integer yes 479.It net.inet6.ip6.defmcasthlim integer yes 480.It net.inet6.ip6.forwarding integer yes 481.It net.inet6.ip6.gifhlim integer yes 482.It net.inet6.ip6.hdrnestlimit integer yes 483.It net.inet6.ip6.hlim integer yes 484.It net.inet6.ip6.kame_version string no 485.It net.inet6.ip6.keepfaith integer yes 486.It net.inet6.ip6.log_interval integer yes 487.It net.inet6.ip6.lowportmax integer yes 488.It net.inet6.ip6.lowportmin integer yes 489.It net.inet6.ip6.maxfragpackets integer yes 490.It net.inet6.ip6.maxfrags integer yes 491.It net.inet6.ip6.redirect integer yes 492.It net.inet6.ip6.rr_prune integer yes 493.It net.inet6.ip6.use_deprecated integer yes 494.It net.inet6.ip6.v6only integer yes 495.It net.inet6.ip6.ifq.drops integer no 496.It net.inet6.ip6.ifq.len integer no 497.It net.inet6.ip6.ifq.maxlen integer yes 498.It net.inet6.ipsec6.ah_net_deflev integer yes 499.It net.inet6.ipsec6.ah_trans_deflev integer yes 500.It net.inet6.ipsec6.def_policy integer yes 501.It net.inet6.ipsec6.ecn integer yes 502.It net.inet6.ipsec6.esp_net_deflev integer yes 503.It net.inet6.ipsec6.esp_trans_deflev integer yes 504.It net.inet6.ipsec6.inbound_call_ike integer yes 505.It net.inet6.udp6.do_loopback_cksum integer yes 506.It net.inet6.udp6.recvspace integer yes 507.It net.inet6.udp6.sendspace integer yes 508.It net.key.ah_keymin integer yes 509.It net.key.debug integer yes 510.It net.key.esp_auth integer yes 511.It net.key.esp_keymin integer yes 512.It net.key.kill_int integer yes 513.It net.key.spi_max_value integer yes 514.It net.key.spi_min_value integer yes 515.It net.key.spi_try integer yes 516.It proc.\*[Lt]pid\*[Gt].corename string yes 517.It proc.\*[Lt]pid\*[Gt].rlimit.coredumpsize.hard integer yes 518.It proc.\*[Lt]pid\*[Gt].rlimit.coredumpsize.soft integer yes 519.It proc.\*[Lt]pid\*[Gt].rlimit.cputime.hard integer yes 520.It proc.\*[Lt]pid\*[Gt].rlimit.cputime.soft integer yes 521.It proc.\*[Lt]pid\*[Gt].rlimit.datasize.hard integer yes 522.It proc.\*[Lt]pid\*[Gt].rlimit.datasize.soft integer yes 523.It proc.\*[Lt]pid\*[Gt].rlimit.filesize.hard integer yes 524.It proc.\*[Lt]pid\*[Gt].rlimit.filesize.soft integer yes 525.It proc.\*[Lt]pid\*[Gt].rlimit.maxproc.hard integer yes 526.It proc.\*[Lt]pid\*[Gt].rlimit.maxproc.soft integer yes 527.It proc.\*[Lt]pid\*[Gt].rlimit.memorylocked.hard integer yes 528.It proc.\*[Lt]pid\*[Gt].rlimit.memorylocked.soft integer yes 529.It proc.\*[Lt]pid\*[Gt].rlimit.memoryuse.hard integer yes 530.It proc.\*[Lt]pid\*[Gt].rlimit.memoryuse.soft integer yes 531.It proc.\*[Lt]pid\*[Gt].rlimit.stacksize.hard integer yes 532.It proc.\*[Lt]pid\*[Gt].rlimit.stacksize.soft integer yes 533.It proc.\*[Lt]pid\*[Gt].stopexec int yes 534.It proc.\*[Lt]pid\*[Gt].stopfork int yes 535.It security.curtain integer yes 536.It security.setid_core node not applicable 537.It security.setid_core.dump integer yes 538.It security.setid_core.group integer yes 539.It security.setid_core.mode integer yes 540.It security.setid_core.owner integer yes 541.It security.setid_core.path string yes 542.It user.bc_base_max integer no 543.It user.bc_dim_max integer no 544.It user.bc_scale_max integer no 545.It user.bc_string_max integer no 546.It user.coll_weights_max integer no 547.It user.cs_path string no 548.It user.expr_nest_max integer no 549.It user.line_max integer no 550.It user.posix2_c_bind integer no 551.It user.posix2_c_dev integer no 552.It user.posix2_char_term integer no 553.It user.posix2_fort_dev integer no 554.It user.posix2_fort_run integer no 555.It user.posix2_localedef integer no 556.It user.posix2_sw_dev integer no 557.It user.posix2_upe integer no 558.It user.posix2_version integer no 559.It user.re_dup_max integer no 560.It vendor.\*[Lt]vendor\*[Gt].* ? vendor specific 561.It vfs.generic.usermount integer yes 562.It vfs.generic.fstypes string yes 563.It vfs.ffs.doasyncfree integer yes 564.It vfs.ffs.log_changeopt integer yes 565.It vfs.nfs.iothreads integer yes 566.It vfs.cd9660.utf8_joliet integer yes 567.It vfs.sync.delay integer yes 568.It vfs.sync.filedelay integer yes 569.It vfs.sync.dirdelay integer yes 570.It vfs.sync.metadelay integer yes 571.It vm.anonmax integer yes 572.It vm.anonmin integer yes 573.It vm.bufcache integer yes 574.It vm.bufmem integer no 575.It vm.bufmem_hiwater integer yes 576.It vm.bufmem_lowater integer yes 577.It vm.execmax integer yes 578.It vm.execmin integer yes 579.It vm.filemax integer yes 580.It vm.filemin integer yes 581.It vm.idlezero integer yes 582.It vm.inactivepct integer yes 583.It vm.loadavg struct no 584.It vm.maxslp integer no 585.It vm.nkmempages integer no 586.It vm.uspace integer no 587.It vm.uvmexp struct no 588.It vm.uvmexp2 struct no 589.It vm.vmmeter struct no 590.El 591.Pp 592Entries found under 593.Dq vendor. Ns Aq vendor 594are left to be specified (and used) by vendors 595using the 596.Nx 597operating system in their products. 598Values and structure are vendor-defined, and no registry 599exists right now. 600.Sh CREATION AND DELETION 601New nodes are allowed to be created by the superuser when the kernel 602is running at security level 0. 603These new nodes may refer to existing kernel data or to new data that 604is only instrumented by 605.Xr sysctl 3 606itself. 607.Pp 608The syntax for creating new nodes is 609.Dq //create=new.node.path 610followed by one or more of the following attributes separated by 611commas. 612The use of a double separator (both 613.Sq / 614and 615.Sq \&. 616can be used as 617separators) as the prefix tells sysctl that the first series of tokens 618is not a MIB name, but a command. 619It is recommended that the double separator preceding the command not 620be the same as the separator used in naming the MIB entry so as to 621avoid possible parse conflicts. 622The 623.Dq value 624assigned, if one is given, must be last. 625.Pp 626.Bl -bullet -compact 627.It 628.Ar type= Ns Aq Ar T 629where 630.Ar T 631must be one of 632.Dq node , 633.Dq int , 634.Dq string , 635.Dq quad , 636or 637.Dq struct . 638If the type is omitted, the 639.Dq node 640type is assumed. 641.It 642.Ar size= Ns Aq Ar S 643here, 644.Ar S 645asserts the size of the new node. 646Nodes of type 647.Dq node 648should not have a size set. 649The size may be omitted for nodes of types 650.Dq int 651or 652.Dq quad . 653If the size is omitted for a node of type 654.Dq string , 655the size will be determined by the length of the given value, or by 656the kernel for kernel strings. 657Nodes of type 658.Dq struct 659must have their size explicitly set. 660.It 661.Ar addr= Ns Aq Ar A 662or 663.Ar symbol= Ns Aq Ar A 664The kernel address of the data being instrumented. 665If 666.Dq symbol 667is used, the symbol must be globally visible to the in-kernel 668.Xr ksyms 4 669driver. 670.It 671.Ar n= Ns Aq Ar N 672The MIB number to be assigned to the new node. 673If no number is specified, the kernel will assign a value. 674.It 675.Ar flags= Ns Aq Ar F 676A concatenated string of single letters that govern the behavior of 677the node. 678Flags currently available are: 679.Bl -tag -width www 680.It a 681Allow anyone to write to the node, if it is writable. 682.It h 683.Dq Hidden . 684.Nm 685must be invoked with 686.Fl A 687or the hidden node must be specifically requested in order to see it 688.It i 689.Dq Immediate . 690Makes the node store data in itself, rather than allocating new space 691for it. 692This is the default for nodes of type 693.Dq int 694and 695.Dq quad . 696This is the opposite of owning data. 697.It o 698.Dq Own . 699When the node is created, separate space will be allocated to store 700the data to be instrumented. 701This is the default for nodes of type 702.Dq string 703and 704.Dq struct 705where it is not possible to guarantee sufficient space to store the 706data in the node itself. 707.It p 708.Dq Private . 709Nodes that are marked private, and children of nodes so marked, are 710only viewable by the superuser. 711Be aware that the immediate data that some nodes may store is not 712necessarily protected by this. 713.It x 714.Dq Hexadecimal . 715Make 716.Nm 717default to hexadecimal display of the retrieved value 718.It r 719.Dq Read-only . 720The data instrumented by the given node is read-only. 721Note that other mechanisms may still exist for changing the data. 722This is the default for nodes that instrument data. 723.It w 724.Dq Writable . 725The data instrumented by the given node is writable at any time. 726This is the default for nodes that can have children. 727.It 1 728.Dq Read-only at securelevel 1 . 729The data instrumented by this node is writable until the securelevel 730reaches or passes securelevel 1. 731Examples of this include some network tunables. 732.It 2 733.Dq Read-only at securelevel 2 . 734The data instrumented by this node is writable until the securelevel 735reaches or passes securelevel 2. 736An example of this is the per-process core filename setting. 737.El 738.Pp 739.It 740.Ar value= Ns Aq Ar V 741An initial starting value for a new node that does not reference 742existing kernel data. 743Initial values can only be assigned for nodes of the 744.Dq int , 745.Dq quad , 746and 747.Dq string 748types. 749.El 750.Pp 751New nodes must fit the following set of criteria: 752.Pp 753.Bl -bullet -compact 754.It 755If the new node is to address an existing kernel object, only one of the 756.Dq symbol 757or 758.Dq addr 759arguments may be given. 760.It 761The size for a 762.Dq struct 763type node must be specified; no initial value is expected or permitted. 764.It 765Either the size or the initial value for a 766.Dq string 767node must be given. 768.It 769The node which will be the parent of the new node must be writable. 770.El 771.Pp 772If any of the given parameters describes an invalid configuration, 773.Nm 774will emit a diagnostic message to the standard error and exit. 775.Pp 776Descriptions can be added by the super-user to any node that does not 777have one, provided that the node is not marked with the 778.Dq PERMANENT 779flag. 780The syntax is similar to the syntax for creating new nodes with the 781exception of the keyword that follows the double separator at the 782start of the command: 783.Dq //describe=new.node.path=new node description . 784Once a description has been added, it cannot be changed or removed. 785.Pp 786When destroying nodes, only the path to the node is necessary, i.e., 787.Dq //destroy=old.node.path . 788No other parameters are expected or permitted. 789Nodes being destroyed must have no children, and their parent must be 790writable. 791Nodes that are marked with the 792.Dq Dv PERMANENT 793flag (as assigned by the kernel) may not be deleted. 794.Pp 795In all cases, the initial 796.Sq = 797that follows the command (eg, 798.Dq create , 799.Dq destroy , 800or 801.Dq describe ) 802may be replaced with another instance of the separator character, 803provided that the same separator character is used for the length of 804the name specification. 805.Sh FILES 806.Bl -tag -width xnetinet6/udp6Xvar.hx -compact 807.It Pa /etc/sysctl.conf 808.Nm 809variables set at boot time 810.It Aq Pa sys/sysctl.h 811definitions for top level identifiers, second level kernel, hardware, 812and security identifiers, and user level identifiers 813.It Aq Pa sys/socket.h 814definitions for second level network identifiers 815.It Aq Pa sys/gmon.h 816definitions for third level profiling identifiers 817.It Aq Pa uvm/uvm_param.h 818definitions for second level virtual memory identifiers 819.It Aq Pa netinet/in.h 820definitions for third level IPv4/v6 identifiers and 821fourth level IPv4/v6 identifiers 822.It Aq Pa netinet/icmp_var.h 823definitions for fourth level ICMP identifiers 824.It Aq Pa netinet/icmp6.h 825definitions for fourth level ICMPv6 identifiers 826.It Aq Pa netinet/tcp_var.h 827definitions for fourth level TCP identifiers 828.It Aq Pa netinet/udp_var.h 829definitions for fourth level UDP identifiers 830.It Aq Pa netinet6/udp6_var.h 831definitions for fourth level IPv6 UDP identifiers 832.It Aq Pa netinet6/ipsec.h 833definitions for fourth level IPsec identifiers 834.It Aq Pa netkey/key_var.h 835definitions for third level PF_KEY identifiers 836.It Aq Pa sys/verified_exec.h 837definitions for third level verified exec identifiers 838.El 839.Sh EXAMPLES 840For example, to retrieve the maximum number of processes allowed 841in the system, one would use the following request: 842.Bd -literal -offset indent -compact 843sysctl kern.maxproc 844.Ed 845.Pp 846To set the maximum number of processes allowed 847in the system to 1000, one would use the following request: 848.Bd -literal -offset indent -compact 849sysctl -w kern.maxproc=1000 850.Ed 851.Pp 852Information about the system clock rate may be obtained with: 853.Bd -literal -offset indent -compact 854sysctl kern.clockrate 855.Ed 856.Pp 857Information about the load average history may be obtained with: 858.Bd -literal -offset indent -compact 859sysctl vm.loadavg 860.Ed 861.Pp 862To view the values of the per-process variables of the current shell, 863the request: 864.Bd -literal -offset indent -compact 865sysctl proc.$$ 866.Ed 867can be used if the shell interpreter replaces $$ with its pid (this is true 868for most shells). 869.Pp 870To redirect core dumps to the 871.Pa /var/tmp/ Ns Aq username 872directory, 873.Bd -literal -offset indent -compact 874sysctl -w proc.$$.corename=/var/tmp/%u/%n.core 875.Ed 876should be used. 877.Bd -literal -offset indent -compact 878sysctl -w proc.curproc.corename=/var/tmp/%u/%n.core 879.Ed 880changes the value for the sysctl process itself, and will not have the desired 881effect. 882.Pp 883To create the root of a new sub-tree called 884.Dq local 885add some children to the new node, and some descriptions: 886.Bd -literal -offset indent -compact 887sysctl -w //create=local 888sysctl -w //describe=local=my local sysctl tree 889sysctl -w //create=local.esm_debug,type=int,symbol=esm_debug,flags=w 890sysctl -w //describe=local.esm_debug=esm driver debug knob 891sysctl -w //create=local.audiodebug,type=int,symbol=audiodebug,flags=w 892sysctl -w //describe=local.audiodebug=generic audio debug knob 893.Ed 894Note that the children are made writable so that the two debug 895settings in question can be tuned arbitrarily. 896.Pp 897To destroy that same subtree: 898.Bd -literal -offset indent -compact 899sysctl -w //destroy=local.esm_debug 900sysctl -w //destroy=local.audiodebug 901sysctl -w //destroy=local 902.Ed 903.Sh SEE ALSO 904.Xr sysctl 3 , 905.Xr ksyms 4 906.Sh HISTORY 907.Nm sysctl 908first appeared in 909.Bx 4.4 . 910