1.\" $NetBSD: sysctl.3,v 1.89 2002/02/10 01:21:38 ross Exp $ 2.\" 3.\" Copyright (c) 1993 4.\" The Regents of the University of California. 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 University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)sysctl.3 8.4 (Berkeley) 5/9/95 35.\" 36.Dd June 24, 1999 37.Dt SYSCTL 3 38.Os 39.Sh NAME 40.Nm sysctl 41.Nd get or set system information 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include \*[Lt]sys/param.h\*[Gt] 46.Fd #include \*[Lt]sys/sysctl.h\*[Gt] 47.Ft int 48.Fn sysctl "int *name" "u_int namelen" "void *oldp" "size_t *oldlenp" "void *newp" "size_t newlen" 49.Sh DESCRIPTION 50The 51.Nm 52function retrieves system information and allows processes with 53appropriate privileges to set system information. 54The information available from 55.Nm 56consists of integers, strings, and tables. 57Information may be retrieved and set from the command interface 58using the 59.Xr sysctl 8 60utility. 61.Pp 62Unless explicitly noted below, 63.Nm 64returns a consistent snapshot of the data requested. 65Consistency is obtained by locking the destination 66buffer into memory so that the data may be copied out without blocking. 67Calls to 68.Nm 69are serialized to avoid deadlock. 70.Pp 71The state is described using a ``Management Information Base'' (MIB) 72style name, listed in 73.Fa name , 74which is a 75.Fa namelen 76length array of integers. 77.Pp 78The information is copied into the buffer specified by 79.Fa oldp . 80The size of the buffer is given by the location specified by 81.Fa oldlenp 82before the call, 83and that location gives the amount of data copied after a successful call. 84If the amount of data available is greater 85than the size of the buffer supplied, 86the call supplies as much data as fits in the buffer provided 87and returns with the error code ENOMEM. 88If the old value is not desired, 89.Fa oldp 90and 91.Fa oldlenp 92should be set to NULL. 93.Pp 94The size of the available data can be determined by calling 95.Nm 96with a NULL parameter for 97.Fa oldp . 98The size of the available data will be returned in the location pointed to by 99.Fa oldlenp . 100For some operations, the amount of space may change often. 101For these operations, 102the system attempts to round up so that the returned size is 103large enough for a call to return the data shortly thereafter. 104.Pp 105To set a new value, 106.Fa newp 107is set to point to a buffer of length 108.Fa newlen 109from which the requested value is to be taken. 110If a new value is not to be set, 111.Fa newp 112should be set to NULL and 113.Fa newlen 114set to 0. 115.Pp 116The top level names are defined with a CTL_ prefix in 117.Pa Aq sys/sysctl.h , 118and are as follows. 119The next and subsequent levels down are found in the include files 120listed here, and described in separate sections below. 121.Pp 122.Bl -column CTLXMACHDEPXXX "Next level namesXXXXXX" -offset indent 123.It Sy Pa Name Next level names Description 124.It CTL\_KERN sys/sysctl.h High kernel limits 125.It CTL\_VM uvm/uvm_param.h Virtual memory 126.It CTL\_VFS sys/mount.h Filesystem 127.It CTL\_NET sys/socket.h Networking 128.It CTL\_DEBUG sys/sysctl.h Debugging 129.It CTL\_HW sys/sysctl.h Generic CPU, I/O 130.It CTL\_MACHDEP sys/sysctl.h Machine dependent 131.It CTL\_USER sys/sysctl.h User-level 132.It CTL\_DDB sys/sysctl.h In-kernel debugger 133.It CTL\_PROC sys/sysctl.h Per-process 134.It CTL\_VENDOR ? Vendor specific 135.El 136.Pp 137For example, the following retrieves the maximum number of processes allowed 138in the system: 139.Bd -literal -offset indent -compact 140int mib[2], maxproc; 141size_t len; 142.sp 143mib[0] = CTL_KERN; 144mib[1] = KERN_MAXPROC; 145len = sizeof(maxproc); 146sysctl(mib, 2, \*[Am]maxproc, \*[Am]len, NULL, 0); 147.Ed 148.sp 149To retrieve the standard search path for the system utilities: 150.Bd -literal -offset indent -compact 151int mib[2]; 152size_t len; 153char *p; 154.sp 155mib[0] = CTL_USER; 156mib[1] = USER_CS_PATH; 157sysctl(mib, 2, NULL, \*[Am]len, NULL, 0); 158p = malloc(len); 159sysctl(mib, 2, p, \*[Am]len, NULL, 0); 160.Ed 161.Sh CTL_DEBUG 162The debugging variables vary from system to system. 163A debugging variable may be added or deleted without need to recompile 164.Nm 165to know about it. 166Each time it runs, 167.Nm 168gets the list of debugging variables from the kernel and 169displays their current values. 170The system defines twenty 171.Ns ( Va struct ctldebug ) 172variables named 173.Dv debug0 174through 175.Dv debug19 . 176They are declared as separate variables so that they can be 177individually initialized at the location of their associated variable. 178The loader prevents multiple use of the same variable by issuing errors 179if a variable is initialized in more than one place. 180For example, to export the variable 181.Dv dospecialcheck 182as a debugging variable, the following declaration would be used: 183.Bd -literal -offset indent -compact 184int dospecialcheck = 1; 185struct ctldebug debug5 = { "dospecialcheck", \*[Am]dospecialcheck }; 186.Ed 187.Sh CTL_VFS 188A distinguished second level name, VFS_GENERIC, 189is used to get general information about all filesystems. 190One of its third level identifiers is VFS_MAXTYPENUM 191that gives the highest valid filesystem type number. 192Its other third level identifier is VFS_CONF that 193returns configuration information about the filesystem 194type given as a fourth level identifier. 195The remaining second level identifiers are the 196filesystem type number returned by a 197.Xr statfs 2 198call or from VFS_CONF. 199The third level identifiers available for each filesystem 200are given in the header file that defines the mount 201argument structure for that filesystem. 202.Sh CTL_HW 203The string and integer information available for the CTL_HW level 204is detailed below. 205The changeable column shows whether a process with appropriate 206privilege may change the value. 207.Bl -column "Second level nameXXXXXX" "struct disk_sysctlXXX" -offset indent 208.It Sy Pa Second level name Type Changeable 209.It HW\_MACHINE string no 210.It HW\_MODEL string no 211.It HW\_NCPU integer no 212.It HW\_BYTEORDER integer no 213.It HW\_PHYSMEM integer no 214.It HW\_USERMEM integer no 215.It HW\_PAGESIZE integer no 216.\".It HW\_DISKNAMES struct no 217.\".It HW\_DISKSTATS struct no 218.It HW\_MACHINE\_ARCH string no 219.It HW\_ALIGNBYTES integer no 220.It HW\_DISKNAMES string no 221.It HW\_DISKSTATS struct disk_sysctl no 222.El 223.Pp 224.Bl -tag -width "123456" 225.It Li HW_MACHINE 226The machine class. 227.It Li HW_MODEL 228The machine model 229.It Li HW_NCPU 230The number of cpus. 231.ne 1i 232.It Li HW_BYTEORDER 233The byteorder (4,321, or 1,234). 234.It Li HW_PHYSMEM 235The bytes of physical memory. 236.It Li HW_USERMEM 237The bytes of non-kernel memory. 238.It Li HW_PAGESIZE 239The software page size. 240.It Li HW_DISKNAMES 241The list of (space separated) disk device names on the system. 242.It Li HW_DISKSTATS 243Return statistical information on the disk devices on the system. 244An array of 245.Va struct disk_sysctl 246structures is returned, 247whose size depends on the current number of such objects in the system. 248The third level name is the size of the 249.Va struct disk_sysctl . 250.It Li HW_MACHINE_ARCH 251The machine cpu class. 252.It Li HW_ALIGNBYTES 253Alignment constraint for all possible data types. 254This shows the value 255.Dv ALIGNBYTES 256in 257.Pa /usr/include/machine/param.h , 258at the kernel compilation time. 259.El 260.Sh CTL_KERN 261The string and integer information available for the CTL_KERN level 262is detailed below. 263The changeable column shows whether a process with appropriate 264privilege may change the value. 265The types of data currently available are process information, 266system vnodes, the open file entries, routing table entries, 267virtual memory statistics, load average history, and clock rate 268information. 269.Bl -column "KERNXCHOWNXRESTRICTEDXXX" "struct clockrateXXX" -offset indent 270.It Sy Pa Second level name Type Changeable 271.It KERN\_ARGMAX integer no 272.It KERN\_AUTONICETIME integer yes 273.It KERN\_AUTONICEVAL integer yes 274.It KERN\_BOOTTIME struct timeval no 275.It KERN\_CCPU integer no 276.It KERN\_CLOCKRATE struct clockinfo no 277.It KERN\_CP\_TIME long[\|] no 278.It KERN\_DEFCORENAME string yes 279.It KERN\_DOMAINNAME string yes 280.It KERN\_FILE struct file no 281.It KERN\_FSCALE integer no 282.It KERN\_FSYNC integer no 283.It KERN\_HOSTID integer yes 284.It KERN\_HOSTNAME string yes 285.It KERN\_IOV\_MAX integer no 286.It KERN\_JOB\_CONTROL integer no 287.It KERN\_LOGIN\_NAME\_MAX integer no 288.It KERN\_LOGSIGEXIT integer yes 289.It KERN\_MAPPED\_FILES integer no 290.It KERN\_MAXFILES integer yes 291.It KERN\_MAXPARTITIONS integer no 292.It KERN\_MAXPROC integer yes 293.It KERN\_MAXPTYS integer yes 294.It KERN\_MAXVNODES integer yes 295.It KERN\_MBUF node not applicable 296.It KERN\_MEMLOCK integer no 297.It KERN\_MEMLOCK\_RANGE integer no 298.It KERN\_MEMORY\_PROTECTION integer no 299.It KERN\_MONOTONIC\_CLOCK integer no 300.It KERN\_MSGBUF char[\|] no 301.It KERN\_MSGBUFSIZE integer no 302.It KERN\_NGROUPS integer no 303.It KERN\_NTPTIME struct ntptimeval no 304.It KERN\_OSRELEASE string no 305.It KERN\_OSREV integer no 306.It KERN\_OSTYPE string no 307.It KERN\_POSIX1 integer no 308.It KERN\_PROC struct kinfo_proc no 309.It KERN\_PROC2 struct kinfo_proc2 no 310.It KERN\_PROC\_ARGS string no 311.It KERN\_PROF node not applicable 312.It KERN\_RAWPARTITION integer no 313.It KERN\_ROOT\_DEVICE string no 314.It KERN\_RTC\_OFFSET integer no 315.It KERN\_SAVED\_IDS integer no 316.It KERN\_SECURELVL integer raise only 317.It KERN\_SYNCHRONIZED\_IO integer no 318.It KERN\_SYSVIPC\_INFO node not applicable 319.It KERN\_SYSVMSG integer no 320.It KERN\_SYSVSEM integer no 321.It KERN\_SYSVSHM integer no 322.It KERN\_TKSTAT node not applicable 323.It KERN\_VERSION string no 324.It KERN\_VNODE struct vnode no 325.El 326.ne 1i 327.Pp 328.Bl -tag -width "123456" 329.It Li KERN_ARGMAX 330The maximum bytes of argument to 331.Xr execve 2 . 332.It Li KERN_AUTONICETIME 333The number of seconds of cpu-time a non-root process may accumulate before 334having its priority lowered from the default to the value of KERN_AUTONICEVAL. 335If set to 0, automatic lowering of priority is not performed, and if set to -1 336all non-root processes are immediately lowered. 337.It Li KERN_AUTONICEVAL 338The priority assigned for automatically niced processes. 339.It Li KERN_BOOTTIME 340A 341.Va struct timeval 342structure is returned. 343This structure contains the time that the system was booted. 344.It Li KERN_CCPU 345The scheduler exponential decay value. 346.It Li KERN_CLOCKRATE 347A 348.Va struct clockinfo 349structure is returned. 350This structure contains the clock, statistics clock and profiling clock 351frequencies, the number of micro-seconds per hz tick, and the clock 352skew rate. 353.It Li KERN_CP_TIME 354Return an array if CPUSTATES longs is returned. This array contains the 355number of clock ticks spent in different CPU states. 356.It Li KERN_DEFCORENAME 357Default template for the name of core dump files (see also PROC_PID_CORENAME 358in the per-process variables CTL_PROC, and 359.Xr core 5 360for format of this template). The default value is 361.Nm %n.core 362and can be changed with the kernel configuration option 363.Cd options DEFCORENAME 364(see 365.Xr options 4 366). 367.It Li KERN_DOMAINNAME 368Get or set the YP domain name. 369.It Li KERN_FILE 370Return the entire file table. 371The returned data consists of a single 372.Va struct filehead 373followed by an array of 374.Va struct file , 375whose size depends on the current number of such objects in the system. 376.It Li KERN_FSCALE 377The kernel fixed-point scale factor. 378.It Li KERN_FSYNC 379Return 1 if the POSIX 1003.1b File Synchronization Option is available 380on this system, 381otherwise 0. 382.It Li KERN_HOSTID 383Get or set the host id. 384.It Li KERN_HOSTNAME 385Get or set the hostname. 386.It Li KERN_IOV_MAX 387Return the maximum number of 388.Va iovec 389structures that a process has available for use with 390.Xr preadv 2 , 391.Xr pwritev 2 , 392.Xr readv 2 , 393.Xr recvmsg 2 , 394.Xr sendmsg 2 395and 396.Xr writev 2 . 397.It Li KERN_JOB_CONTROL 398Return 1 if job control is available on this system, otherwise 0. 399.It Li KERN_LOGIN_NAME_MAX 400The size of the storage required for a login name, in bytes, 401including the terminating NUL. 402.It Li KERN_LOGSIGEXIT 403If this flag is non-zero, the kernel will 404.Xr log 9 405all process exits due to signals which create a 406.Xr core 5 407file, and whether the coredump was created. 408.It Li KERN_MAPPED_FILES 409Returns 1 if the POSIX 1003.1b Memory Mapped Files Option is available 410on this system, 411otherwise 0. 412.It Li KERN_MAXFILES 413The maximum number of open files that may be open in the system. 414.It Li KERN_MAXPARTITIONS 415The maximum number of partitions allowed per disk. 416.It Li KERN_MAXPROC 417The maximum number of simultaneous processes the system will allow. 418.It Li KERN_MAXPTYS 419The maximum number of pseudo terminals. This value can be both 420raised and lowered, though it cannot 421be set lower than number of currently used ptys. See also 422.Xr pty 4 . 423.It Li KERN_MAXVNODES 424The maximum number of vnodes available on the system. This can only 425be raised. 426.It Li KERN_MBUF 427Return information about the mbuf control variables. 428the third level names for the mbuf variables are detailed below. 429The changeable column shows whether a process with appropriate 430privilege may change the value. 431.Bl -column "MBUFXNMBCLUSTERSXXX" "struct integerXXX" -offset indent 432.It Sy Pa Third level name Type Changeable 433.It MBUF\_MSIZE integer yes 434.It MBUF\_MCLBYTES integer yes 435.It MBUF\_NMBCLUSTERS integer yes 436.It MBUF\_MBLOWAT integer yes 437.It MBUF\_MCLLOWAT integer yes 438.El 439.Pp 440The variables are as follows: 441.Bl -tag -width "123456" 442.It Li MBUF_MSIZE 443The mbuf base size. 444.It Li MBUF_MCLBYTES 445The mbuf cluster size. 446.It Li MBUF_NMBCLUSTERS 447The limit on the number of mbuf clusters. 448The variable can only be increased, and only increased on machines with 449direct-mapped pool pages 450.It Li MBUF_MBLOWAT 451The mbuf low water mark. 452.It Li MBUF_MCLLOWAT 453The mbuf cluster low water mark. 454.El 455.It Li KERN_MEMLOCK 456Returns 1 if the POSIX 1003.1b Process Memory Locking Option is available 457on this system, 458otherwise 0. 459.It Li KERN_MEMLOCK_RANGE 460Returns 1 if the POSIX 1003.1b Range Memory Locking Option is available 461on this system, 462otherwise 0. 463.It Li KERN_MEMORY_PROTECTION 464Returns 1 if the POSIX 1003.1b Memory Protection Option is available 465on this system, 466otherwise 0. 467.It Li KERN_MONOTONIC_CLOCK 468Returns the standard version the implementation of the POSIX 1003.1b 469Monotonic Clock Option conforms to, 470otherwise 0. 471.It Li KERN_MSGBUF 472The kernel message buffer, rotated so that the head of the circular kernel 473message buffer is returned at the start of the buffer specified by 474.Fa oldp . 475The returned data may contain NUL bytes. 476.It Li KERN_MSGBUFSIZE 477The maximum number of characters that the kernel message buffer can hold. 478.It Li KERN_NGROUPS 479The maximum number of supplemental groups. 480.It Li KERN_NO_TRUNC 481Return 1 if file names longer than KERN_NAME_MAX are truncated. 482.It Li KERN_NTPTIME 483A 484.Va struct ntptimeval 485structure is returned. 486This structure contains data used by the 487.Xr ntpd 8 488program. 489.It Li KERN_OSRELEASE 490The system release string. 491.It Li KERN_OSREV 492The system revision string. 493.It Li KERN_OSTYPE 494The system type string. 495.It Li KERN_PATH_MAX 496The maximum number of bytes in a pathname. 497.It Li KERN_POSIX1 498The version of ISO/IEC 9945 (POSIX 1003.1) with which the system 499attempts to comply. 500.It Li KERN_PROC 501Return the entire process table, or a subset of it. 502An array of 503.Va struct kinfo_proc 504structures is returned, 505whose size depends on the current number of such objects in the system. 506The third and fourth level names are as follows: 507.Bl -column "Third level nameXXXXXX" "Fourth level is:XXXXXX" -offset indent 508.It Pa Third level name Fourth level is: 509.It KERN\_PROC\_ALL None 510.It KERN\_PROC\_PID A process ID 511.It KERN\_PROC\_PGRP A process group 512.It KERN\_PROC\_SESSION A session ID 513.It KERN\_PROC\_TTY A tty device 514.It KERN\_PROC\_UID A user ID 515.It KERN\_PROC\_RUID A real user ID 516.It KERN\_PROC\_GID A group ID 517.It KERN\_PROC\_RGID A real group ID 518.El 519.It Li KERN_PROC2 520As for KERN_PROC, but an array of 521.Va struct kinfo_proc2 522structures are returned. The fifth level name is the size of the 523.Va struct kinfo_proc2 524and the sixth level name is the number of structures to return. 525.It Li KERN_PROC_ARGS 526Return the argv or environment strings (or the number thereof) 527of a process. Multiple strings are returned separated by NUL 528characters. The third level name is the process ID. The fourth 529level name is as follows: 530.Bl -column "Third level nameXXXXXX" -offset indent 531.It KERN\_PROC\_ARGV The argv strings 532.It KERN\_PROC\_NARGV The number of argv strings 533.It KERN\_PROC\_ENV The environ strings 534.It KERN\_PROC\_NENV The number of environ strings 535.El 536.It Li KERN_PROF 537Return profiling information about the kernel. 538If the kernel is not compiled for profiling, 539attempts to retrieve any of the KERN_PROF values will 540fail with EOPNOTSUPP. 541The third level names for the string and integer profiling information 542is detailed below. 543The changeable column shows whether a process with appropriate 544privilege may change the value. 545.Bl -column "GPROFXGMONPARAMXXX" "struct gmonparamXXX" -offset indent 546.It Sy Pa Third level name Type Changeable 547.It GPROF\_STATE integer yes 548.It GPROF\_COUNT u_short[\|] yes 549.It GPROF\_FROMS u_short[\|] yes 550.It GPROF\_TOS struct tostruct yes 551.It GPROF\_GMONPARAM struct gmonparam no 552.El 553.Pp 554The variables are as follows: 555.Bl -tag -width "123456" 556.It Li GPROF_STATE 557Returns GMON_PROF_ON or GMON_PROF_OFF to show that profiling 558is running or stopped. 559.It Li GPROF_COUNT 560Array of statistical program counter counts. 561.It Li GPROF_FROMS 562Array indexed by program counter of call-from points. 563.It Li GPROF_TOS 564Array of 565.Va struct tostruct 566describing destination of calls and their counts. 567.It Li GPROF_GMONPARAM 568Structure giving the sizes of the above arrays. 569.El 570.It Li KERN_RAWPARTITION 571The raw partition of a disk (a == 0). 572.It Li KERN_ROOT_DEVICE 573The name of the root device. 574.It Li KERN_RTC_OFFSET 575Return the offset of real time clock from UTC in minutes. 576.It Li KERN_SAVED_IDS 577Returns 1 if saved set-group and saved set-user ID is available. 578.It Li KERN_SECURELVL 579The system security level. 580This level may be raised by processes with appropriate privilege. 581It may only be lowered by process 1. 582.It Li KERN_SYNCHRONIZED_IO 583Returns 1 if the POSIX 1003.1b Synchronized I/O Option is available 584on this system, 585otherwise 0. 586.It Li KERN_SYSVIPC_INFO 587Return System V style IPC configuration and run-time information. 588The third level name selects the System V style IPC facility. 589.Bl -column "KERN_SYSVIPC_MSG_INFOXXX" "struct shm_sysctl_infoXXX" -offset indent 590.It Sy Pa Third level name Type 591.It KERN\_SYSVIPC\_MSG\_INFO struct msg_sysctl_info 592.It KERN\_SYSVIPC\_SEM\_INFO struct sem_sysctl_info 593.It KERN\_SYSVIPC\_SHM\_INFO struct shm_sysctl_info 594.El 595.Pp 596.Bl -tag -width "123456" 597.It Li KERN_SYSVIPC_MSG_INFO 598Return information on the System V style message facility. The 599.Sy msg_sysctl_info 600structure is defined in 601.Aq Pa sys/msg.h . 602.It Li KERN_SYSVIPC_SEM_INFO 603Return information on the System V style semaphore facility. The 604.Sy sem_sysctl_info 605structure is defined in 606.Aq Pa sys/sem.h . 607.It Li KERN_SYSVIPC_SHM_INFO 608Return information on the System V style shared memory facility. The 609.Sy shm_sysctl_info 610structure is defined in 611.Aq Pa sys/shm.h . 612.El 613.It Li KERN_SYSVMSG 614Returns 1 if System V style message queue functionality is available 615on this system, 616otherwise 0. 617.It Li KERN_SYSVSEM 618Returns 1 if System V style semaphore functionality is available 619on this system, 620otherwise 0. 621.It Li KERN_SYSVSHM 622Returns 1 if System V style share memory functionality is available 623on this system, 624otherwise 0. 625.It Li KERN_TKSTAT 626Return information about the number of characters sent and received 627on ttys. The third level names for the tty statistic variables 628are detailed below. The changeable column shows whether a process 629with appropriate privilege may change the value. 630.Bl -column "KERNXTKSTATXRAWCCXXX" "struct integerXXX" -offset indent 631.It Sy Pa Third level name Type Changeable 632.It KERN\_TKSTAT\_NIN quad no 633.It KERN\_TKSTAT\_NOUT quad no 634.It KERN\_TKSTAT\_CANCC quad no 635.It KERN\_TKSTAT\_RAWCC quad no 636.El 637.Pp 638The variables are as follows: 639.Bl -tag -width "123456" 640.It Li KERN_TKSTAT_NIN 641The total number of input characters. 642.It Li KERN_TKSTAT_NOUT 643The total number of output characters. 644.It Li KERN_TKSTAT_CANCC 645The number of canonical input characters. 646.It Li KERN_TKSTAT_RAWCC 647The number of raw input characters. 648.El 649.It Li KERN_VERSION 650The system version string. 651.It Li KERN_VNODE 652Return the entire vnode table. 653Note, the vnode table is not necessarily a consistent snapshot of 654the system. 655The returned data consists of an array whose size depends on the 656current number of such objects in the system. 657Each element of the array contains the kernel address of a vnode 658.Va struct vnode * 659followed by the vnode itself 660.Va struct vnode . 661.El 662.Sh CTL_MACHDEP 663The set of variables defined is architecture dependent. 664Most architectures define at least the following variables. 665.Bl -column "CONSOLE_DEVICEXXX" "integerXXX" -offset indent 666.It Sy Pa Second level name Type Changeable 667.It Li CPU_CONSDEV dev_t no 668.El 669.Sh CTL_NET 670The string and integer information available for the CTL_NET level 671is detailed below. 672The changeable column shows whether a process with appropriate 673privilege may change the value. 674.Bl -column "Second level nameXXXXXX" "routing messagesXXX" -offset indent 675.It Sy Pa Second level name Type Changeable 676.It PF\_ROUTE routing messages no 677.It PF\_INET IPv4 values yes 678.It PF\_INET6 IPv6 values yes 679.El 680.Pp 681.Bl -tag -width "123456" 682.It Li PF_ROUTE 683Return the entire routing table or a subset of it. 684The data is returned as a sequence of routing messages (see 685.Xr route 4 686for the header file, format and meaning). 687The length of each message is contained in the message header. 688.Pp 689The third level name is a protocol number, which is currently always 0. 690The fourth level name is an address family, which may be set to 0 to 691select all address families. 692The fifth and sixth level names are as follows: 693.Bl -column "Fifth level nameXXXXXX" "Sixth level is:XXX" -offset indent 694.It Pa Fifth level name Sixth level is: 695.It NET\_RT\_FLAGS rtflags 696.It NET\_RT\_DUMP None 697.It NET\_RT\_IFLIST None 698.El 699.It Li PF_INET 700Get or set various global information about the IPv4 701.Pq Internet Protocol version 4 . 702The third level name is the protocol. 703The fourth level name is the variable name. 704The currently defined protocols and names are: 705.Bl -column "Protocol name" "Variable nameXX" "integer" "yes" -offset indent 706.It Pa Protocol name Variable name Type Changeable 707.It ip forwarding integer yes 708.It ip redirect integer yes 709.It ip ttl integer yes 710.It ip forwsrcrt integer yes 711.It ip directed-broadcast integer yes 712.It ip allowsrcrt integer yes 713.It ip subnetsarelocal integer yes 714.It ip mtudisc integer yes 715.It ip anonportmin integer yes 716.It ip anonportmax integer yes 717.It ip mtudisctimeout integer yes 718.It ip gifttl integer yes 719.It ip lowportmin integer yes 720.It ip lowportmax integer yes 721.It ip maxfragpacket integer yes 722.It icmp maskrepl integer yes 723.It icmp errppslimit integer yes 724.It icmp rediraccept integer yes 725.It icmp redirtimeout integer yes 726.It tcp rfc1323 integer yes 727.It tcp sendspace integer yes 728.It tcp recvspace integer yes 729.It tcp mssdflt integer yes 730.It tcp syn_cache_limit integer yes 731.It tcp syn_bucket_limit integer yes 732.It tcp syn_cache_interval integer yes 733.It tcp init_win integer yes 734.It tcp mss_ifmtu integer yes 735.It tcp sack integer yes 736.It tcp win_scale integer yes 737.It tcp timestamps integer yes 738.It tcp compat_42 integer yes 739.It tcp cwm integer yes 740.It tcp cwm_burstsize integer yes 741.It tcp ack_on_push integer yes 742.It tcp keepidle integer yes 743.It tcp keepintvl integer yes 744.It tcp keepcnt integer yes 745.It tcp slowhz integer no 746.It tcp newreno integer yes 747.It tcp log_refused integer yes 748.It tcp rstppslimit integer yes 749.It udp checksum integer yes 750.It udp sendspace integer yes 751.It udp recvspace integer yes 752.El 753.Pp 754The variables are as follows: 755.Bl -tag -width "123456" 756.It Li ip.forwarding 757Returns 1 when IP forwarding is enabled for the host, 758meaning that the host is acting as a router. 759.It Li ip.redirect 760Returns 1 when ICMP redirects may be sent by the host. 761This option is ignored unless the host is routing IP packets, 762and should normally be enabled on all systems. 763.It Li ip.ttl 764The maximum time-to-live (hop count) value for an IP packet sourced by 765the system. 766This value applies to normal transport protocols, not to ICMP. 767.It Li ip.forwsrcrt 768Returns 1 when forwarding of source-routed packets is enabled for 769the host. This value may only be changed if the kernel security 770level is less than 1. 771.It Li ip.directed-broadcast 772Returns 1 if directed broadcast behavior is enabled for the host. 773.It Li ip.allowsrcrt 774Returns 1 if the host accepts source routed packets. 775.It Li ip.subnetsarelocal 776Returns 1 if subnets are to be considered local addresses. 777.It Li ip.mtudisc 778Returns 1 if Path MTU Discovery is enabled. 779.It Li ip.anonportmin 780The lowest port number to use for TCP and UDP ephemeral port allocation. 781This cannot be set to less than 1024 or greater than 65535. 782.It Li ip.anonportmax 783The highest port number to use for TCP and UDP ephemeral port allocation. 784This cannot be set to less than 1024 or greater than 65535, and must 785be greater than 786.Li ip.anonportmin . 787.It Li ip.mtudisctimeout 788Returns the number of seconds in which a route added by the Path MTU 789Discovery engine will time out. When the route times out, the Path 790MTU Discovery engine will attempt to probe a larger path MTU. 791.It Li ip.gifttl 792The maximum time-to-live (hop count) value for an IPv4 packet generated by 793.Xr gif 4 794tunnel interface. 795.It Li ip.lowportmin 796The lowest port number to use for TCP and UDP reserved port allocation. 797This cannot be set to less than 0 or greater than 1024, and must 798be smaller than 799.Li ip.lowportmax . 800.It Li ip.lowportmax 801The highest port number to use for TCP and UDP reserved port allocation. 802This cannot be set to less than 0 or greater than 1024, and must 803be greater than 804.Li ip.lowportmin . 805.It Li ip.maxfragpackets 806The maximum number of fragmented packets the node will accept. 8070 means that the node will not accept any fragmented packets. 808-1 means that the node will accept as many fragmented packets as it receives. 809The flag is provided basically for avoiding possible DoS attacks. 810.It Li icmp.maskrepl 811Returns 1 if ICMP network mask requests are to be answered. 812.It Li icmp.errppslimit 813The variable specifies the maximum number of outgoing ICMP error messages, 814per second. 815ICMP error messages that exceeded the value are subject to rate limitation 816and will not go out from the node. 817Negative value disables rate limitation. 818.It Li icmp.rediraccept 819If set to non-zero, the host will accept ICMP redirect packets. 820Note that routers will never accept ICMP redirect packets, 821and the variable is meaningful on IP hosts only. 822.It Li icmp.redirtimeout 823The variable specifies lifetime of routing entries generated by incoming 824ICMP redirect. This defaults to zero; if the system is not running 825a routing daemon like 826.Xr routed 8 827than this value can be set to remove the routes added by redirect. 828A reasonable value to use would be 600 seconds. 829.It Li tcp.rfc1323 830Returns 1 if RFC1323 extensions to TCP are enabled. 831.It Li tcp.sendspace 832Returns the default TCP send buffer size. 833.It Li tcp.recvspace 834Returns the default TCP receive buffer size. 835.It Li tcp.mssdflt 836Returns the default maximum segment size both advertsized to the peer 837and to use when the peer does not advertize a maximum segment size to 838us during connection setup. Do not change this value unless you really 839know what you are doing. 840.It Li tcp.syn_cache_limit 841Returns the maximum number of entries allowed in the TCP compressed state 842engine. 843.It Li tcp.syn_bucket_limit 844Returns the maximum number of entries allowed per hash bucket in the TCP 845compressed state engine. 846.It Li tcp.syn_cache_interval 847Returns the TCP compressed state engine's timer interval. 848.It Li tcp.init_win 849Returns a value indicating the TCP initial congestion window. If this 850value is 0, an auto-tuning algorithm designed to use an initial window 851of approximately 4K bytes is in use. Otherwise, this value indicates 852a fixed number of packets. 853.It Li tcp.mss_ifmtu 854Returns 1 if TCP calculates the outgoing maximum segment size based on 855the MTU of the appropriate interface. Otherwise, it is calculated based on 856the greater of the MTU of the interface, and the largest (non-loopback) 857interface MTU on the system. 858.It Li tcp.sack 859TCP Selective ACKnowledgement (RFC 2018) is not implemented in 860.Nx 861at this time. 862Changing this value will have no effect. 863.It Li tcp.win_scale 864If rfc1323 is enabled, a value of 1 indicates RFC1323 window scale options, 865for increasing the TCP window size, are enabled. 866.It Li tcp.timestamps 867If rfc1323 is enabled, a value of 1 indicates RFC1323 time stamp options, 868used for measuring TCP round trip times, are enabled. 869.It Li tcp.compat_42 870Returns 1 if work-arounds for bugs in the 4.2BSD TCP implementation are 871enabled. Use of this option is not recommended, although it may be 872required in order to communicate with extremely old TCP implementations. 873.It Li tcp.cwm 874Returns 1 if use of the Hughes/Touch/Heidemann Congestion Window Monitoring 875algorithm is enabled. This algorithm prevents line-rate bursts of packets 876that could otherwise occur when data begins flowing on an idle TCP 877connection. These line-rate bursts can contribute to network and router 878congestion. This can be particularly useful on World Wide Web servers 879which support HTTP/1.1, which has lingering connections. 880.It Li tcp.cwm_burstsize 881Returns the Congestion Window Monitoring allowed burst size, in terms 882of packet count. 883.It Li tcp.ack_on_push 884Returns 1 if TCP is to immediately transmit an ACK upon reception of 885a packet with PUSH set. This can avoid losing a round trip time in some 886rare situations, but has the caveat of potentially defeating TCP's delayed 887ACK algorithm. Use of this option is generally not recommended, but 888the variable exists in case your configuration really needs it. 889.It Li tcp.keepidle 890Time a connection must be idle before keepalives are sent (if keepalives 891are enabled for the connection). See also tcp.slowhz. 892.It Li tcp.keepintvl 893Time after a keepalive probe is sent until, in the absence of any response, 894another probe is sent. See also tcp.slowhz. 895.It Li tcp.keepcnt 896Number of keepalive probes sent before declaring a connection dead. If 897set to zero, there is no limit; keepalives will be sent until some kind of 898response is received from the peer. 899.It Li tcp.slowhz 900The units for tcp.keepidle and tcp.keepintvl; those variables are in ticks 901of a clock that ticks tcp.slowhz times per second. (That is, their values 902must be divided by the tcp.slowhz value to get times in seconds.) 903.It Li tcp.newreno 904Returns 1 if the use of J. Hoe's NewReno congestion control algorithm is 905enabled. This algorithm improves the start-up behavior of TCP connections. 906.It Li tcp.log_refused 907Returns 1 if refused TCP connections to the host will be logged. 908.It Li tcp.rstppslimit 909The variable specifies the maximum number of outgoing TCP RST packets, 910per second. 911TCP RST packet that exceeded the value are subject to rate limitation 912and will not go out from the node. 913Negative value disables rate limitation. 914.It Li udp.checksum 915Returns 1 when UDP checksums are being computed and checked. 916Disabling UDP checksums is strongly discouraged. 917.It Li udp.sendspace 918Returns the default UDP send buffer size. 919.It Li udp.recvspace 920Returns the default UDP receive buffer size. 921.El 922.Pp 923For variables net.*.ipsec, please refer to 924.Xr ipsec 4 . 925.It Li PF_INET6 926Get or set various global information about the IPv6 927.Pq Internet Protocol version 6 . 928The third level name is the protocol. 929The fourth level name is the variable name. 930The currently defined protocols and names are: 931.Bl -column "Protocol name" "Variable nameXX" "integer" "yes" -offset indent 932.It Pa Protocol name Variable name Type Changeable 933.It ip6 forwarding integer yes 934.It ip6 redirect integer yes 935.It ip6 hlim integer yes 936.It ip6 maxfragpackets integer yes 937.It ip6 accept_rtadv integer yes 938.It ip6 keepfaith integer yes 939.It ip6 log_interval integer yes 940.It ip6 hdrnestlimit integer yes 941.It ip6 dad_count integer yes 942.It ip6 auto_flowlabel integer yes 943.It ip6 defmcasthlim integer yes 944.It ip6 gif_hlim integer yes 945.It ip6 kame_version string no 946.It ip6 use_deprecated integer yes 947.It ip6 rr_prune integer yes 948.It ip6 bindv6only integer yes 949.It ip6 anonportmin integer yes 950.It ip6 anonportmax integer yes 951.It ip6 lowportmin integer yes 952.It ip6 lowportmax integer yes 953.It icmp6 rediraccept integer yes 954.It icmp6 redirtimeout integer yes 955.It icmp6 nd6_prune integer yes 956.It icmp6 nd6_delay integer yes 957.It icmp6 nd6_umaxtries integer yes 958.It icmp6 nd6_mmaxtries integer yes 959.It icmp6 nd6_useloopback integer yes 960.It icmp6 nodeinfo integer yes 961.It icmp6 errppslimit integer yes 962.It icmp6 nd6_maxnudhint integer yes 963.It icmp6 mtudisc_hiwat integer yes 964.It icmp6 mtudisc_lowat integer yes 965.It icmp6 nd6_debug integer yes 966.It udp6 sendspace integer yes 967.It udp6 recvspace integer yes 968.El 969.Pp 970The variables are as follows: 971.Bl -tag -width "123456" 972.It Li ip6.forwarding 973Returns 1 when IPv6 forwarding is enabled for the node, 974meaning that the node is acting as a router. 975Returns 0 when IPv6 forwarding is disabled for the node, 976meaning that the node is acting as a host. 977IPv6 specification defines node behavior for 978.Dq router 979case and 980.Dq host 981case quite differently, and changing this variable during operation 982may cause serious trouble. 983It is recommended to configure the variable at bootstrap time, 984and bootstrap time only. 985.It Li ip6.redirect 986Returns 1 when ICMPv6 redirects may be sent by the node. 987This option is ignored unless the node is routing IP packets, 988and should normally be enabled on all systems. 989.It Li ip6.hlim 990The default hop limit value for an IPv6 unicast packet sourced by the node. 991This value applies to all the transport protocols on top of IPv6. 992There are APIs to override the value, as documented in 993.Xr ip6 4 . 994.It Li ip6.maxfragpackets 995The maximum number of fragmented packets the node will accept. 9960 means that the node will not accept any fragmented packets. 997-1 means that the node will accept as many fragmented packets as it receives. 998The flag is provided basically for avoiding possible DoS attacks. 999.It Li ip6.accept_rtadv 1000If set to non-zero, the node will accept ICMPv6 router advertisement packets 1001and autoconfigures address prefixes and default routers. 1002The node must be a host 1003.Pq not a router 1004for the option to be meaningful. 1005.It Li ip6.keepfaith 1006If set to non-zero, it enables 1007.Dq FAITH 1008TCP relay IPv6-to-IPv4 translator code in the kernel. 1009Refer 1010.Xr faith 4 1011and 1012.Xr faithd 8 1013for detail. 1014.It Li ip6.log_interval 1015The variable controls amount of logs generated by IPv6 packet 1016forwarding engine, by seting interval between log output 1017.Pq in seconds . 1018.It Li ip6.hdrnestlimit 1019The number of IPv6 extension headers permitted on incoming IPv6 packets. 1020If set to 0, the node will accept as many extension headers as possible. 1021.It Li ip6.dad_count 1022The variable cofigures number of IPv6 DAD 1023.Pq duplicated address detection 1024probe packets. 1025The packets will be generated when IPv6 interface addresses are configured. 1026.It Li ip6.auto_flowlabel 1027On connected transport protocol packets, 1028fill IPv6 flowlabel field to help intermediate routers to identify packet flows. 1029.It Li ip6.defmcasthlim 1030The default hop limit value for an IPv6 multicast packet sourced by the node. 1031This value applies to all the transport protocols on top of IPv6. 1032There are APIs to override the value, as documented in 1033.Xr ip6 4 . 1034.It Li ip6.gif_hlim 1035The maximum hop limit value for an IPv6 packet generated by 1036.Xr gif 4 1037tunnel interface. 1038.It Li ip6.kame_version 1039The string identifies the version of KAME IPv6 stack implemented in the kernel. 1040.It Li ip6.use_deprecated 1041The variable controls use of deprecated address, specified in RFC2462 5.5.4. 1042.It Li ip6.rr_prune 1043The variable specifies interval between IPv6 router renumbering prefix 1044babysitting, in seconds. 1045.It Li ip6.bindv6only 1046The variable specifies initial value for 1047.Dv IPV6_BINDV6ONLY 1048socket option for 1049.Dv AF_INET6 1050socket. 1051Please refer to 1052.Xr ip6 4 1053for detail. 1054.It Li ip6.anonportmin 1055The lowest port number to use for TCP and UDP ephemeral port allocation. 1056This cannot be set to less than 1024 or greater than 65535. 1057.It Li ip6.anonportmax 1058The highest port number to use for TCP and UDP ephemeral port allocation. 1059This cannot be set to less than 1024 or greater than 65535, and must 1060be greater than 1061.Li ip6.anonportmin . 1062.It Li ip6.lowportmin 1063The lowest port number to use for TCP and UDP reserved port allocation. 1064This cannot be set to less than 0 or greater than 1024, and must 1065be smaller than 1066.Li ip6.lowportmax . 1067.It Li ip6.lowportmax 1068The highest port number to use for TCP and UDP reserved port allocation. 1069This cannot be set to less than 0 or greater than 1024, and must 1070be greater than 1071.Li ip6.lowportmin . 1072.It Li icmp6.rediraccept 1073If set to non-zero, the host will accept ICMPv6 redirect packets. 1074Note that IPv6 routers will never accept ICMPv6 redirect packets, 1075and the variable is meaningful on IPv6 hosts 1076.Pq non-router 1077only. 1078.It Li icmp6.redirtimeout 1079The variable specifies lifetime of routing entries generated by incoming 1080ICMPv6 redirect. 1081.It Li icmp6.nd6_prune 1082The variable specifies interval between IPv6 neighbor cache babysitting, 1083in seconds. 1084.It Li icmp6.nd6_delay 1085The variable specifies 1086.Dv DELAY_FIRST_PROBE_TIME 1087timing constant in IPv6 neighbor discovery specification 1088.Pq RFC2461 , 1089in seconds. 1090.It Li icmp6.nd6_umaxtries 1091The variable specifies 1092.Dv MAX_UNICAST_SOLICIT 1093constant in IPv6 neighbor discovery specification 1094.Pq RFC2461 . 1095.It Li icmp6.nd6_mmaxtries 1096The variable specifies 1097.Dv MAX_MULTICAST_SOLICIT 1098constant in IPv6 neighbor discovery specification 1099.Pq RFC2461 . 1100.It Li icmp6.nd6_useloopback 1101If set to non-zero, kernel IPv6 stack will use loopback interface for 1102local traffic. 1103.It Li icmp6.nodeinfo 1104The variable enables responses to ICMPv6 node information queries. 1105If you set the variable to 0, reponses will not be generated for 1106ICMPv6 node information queries. 1107Since node information queries can have a security impact, it is 1108possible to fine tune which responses should be answered. 1109Two separate bits can be set. 1110.Bl -tag -width "12345" 1111.It 1 1112Respond to ICMPv6 FQDN queries, e.g. 1113.Li ping6 -w . 1114.It 2 1115Respond to ICMPv6 node addresses queries, e.g. 1116.Li ping6 -a . 1117.El 1118.It Li icmp6.errppslimit 1119The variable specifies the maximum number of outgoing ICMPv6 error messages, 1120per second. 1121ICMPv6 error messages that exceeded the value are subject to rate limitation 1122and will not go out from the node. 1123Negative value disables rate limitation. 1124.It Li icmp6.nd6_maxnudhint 1125IPv6 neighbor discovery permits upper layer protocols to supply reachability 1126hints, to avoid unnecessary neighbor discovery exchanges. 1127The variable defines the number of consecutive hints the neighbor discovery 1128layer will take. 1129For example, by setting the variable to 3, neighbor discovery layer 1130will take 3 consecutive hints in maximum. 1131After receiving 3 hints, neighbor discovery layer will perform 1132normal neighbor discovery process. 1133.It Li icmp6.mtudisc_hiwat 1134.It Li icmp6.mtudisc_lowat 1135The variables define the maximum number of routing table entries, 1136created due to path MTU discovery 1137.Pq prevents denial-of-service attacks with ICMPv6 too big messages . 1138When IPv6 path MTU discovery happens, we keep path MTU information into 1139the routing table. 1140If the number of routing table entries exceed the value, 1141the kernel will not attempt to keep the path MTU information. 1142.Li icmp6.mtudisc_hiwat 1143is used when we have verified ICMPv6 too big messages. 1144.Li icmp6.mtudisc_lowat 1145is used when we have unverified ICMPv6 too big messages. 1146Verification is performed by using address/port pairs kept in connected pcbs. 1147Negative value disables the upper limit. 1148.It Li icmp6.nd6_debug 1149If set to non-zero, kernel IPv6 neighbor discovery code will generate 1150debugging messages. 1151The debug outputs are useful to diagnose IPv6 interoperability issues. 1152The flag must be set to 0 for normal operation. 1153.El 1154.Pp 1155We reuse net.*.tcp for 1156.Tn TCP 1157over 1158.Tn IPv6 , 1159and therefore we do not have variables net.*.tcp6. 1160Variables net.inet6.udp6 have identical meaning to net.inet.udp. 1161Please refer to 1162.Li PF_INET 1163section above. 1164For variables net.*.ipsec6, please refer to 1165.Xr ipsec 4 . 1166.El 1167.Sh CTL_PROC 1168The string and integer information available for the CTL_PROC 1169is detailed below. 1170The changeable column shows whether a process with appropriate 1171privilege may change the value. 1172These values are per-process, and as such may change from one process 1173to another. When a process is created, the default values are inherited from 1174its parent. When a set-user-ID or set-group-ID binary is executed, the 1175value of PROC_PID_CORENAME is reset to the system default value. 1176The second level name is either the magic value PROC_CURPROC, which 1177points to the current process, or the PID of the target process. 1178.Bl -column "USER_COLL_WEIGHTS_MAXXXX" "integerXXX" "yes" -offset indent 1179.It Sy Pa Third level name Type Changeable 1180.It PROC\_PID\_CORENAME string yes 1181.It PROC\_PID\_LIMIT node not applicable 1182.El 1183.Bl -tag -width "123456" 1184.Pp 1185.It Li PROC_PID_CORENAME 1186The template used for the core dump file name (see 1187.Xr core 5 1188for details). The base name must either be 1189.Nm core 1190or end with the suffix ``.core'' (the super-user may set arbitrary names). By 1191default it points to KERN_DEFCORENAME. 1192.It Li PROC_PID_LIMIT 1193Return resources limits, as defined for the 1194.Xr getrlimit 2 1195and 1196.Xr setrlimit 2 1197system calls. 1198The fourth level name is one of: 1199.Bl -tag -width PROC_PID_LIMIT_MEMLOCKAA 1200.It Li PROC_PID_LIMIT_CPU 1201The maximum amount of cpu time (in seconds) to be used by each process. 1202.It Li PROC_PID_LIMIT_FSIZE 1203The largest size (in bytes) file that may be created. 1204.It Li PROC_PID_LIMIT_DATA 1205The maximum size (in bytes) of the data segment for a process; 1206this defines how far a program may extend its break with the 1207.Xr sbrk 2 1208system call. 1209.It Li PROC_PID_LIMIT_STACK 1210The maximum size (in bytes) of the stack segment for a process; 1211this defines how far a program's stack segment may be extended. 1212Stack extension is performed automatically by the system. 1213.It Li PROC_PID_LIMIT_CORE 1214The largest size (in bytes) 1215.Pa core 1216file that may be created. 1217.It Li PROC_PID_LIMIT_RSS 1218The maximum size (in bytes) to which a process's resident set size may 1219grow. 1220This imposes a limit on the amount of physical memory to be given to 1221a process; if memory is tight, the system will prefer to take memory 1222from processes that are exceeding their declared resident set size. 1223.It Li PROC_PID_LIMIT_MEMLOCK 1224The maximum size (in bytes) which a process may lock into memory 1225using the 1226.Xr mlock 2 1227function. 1228.It Li PROC_PID_LIMIT_NPROC 1229The maximum number of simultaneous processes for this user id. 1230.It Li PROC_PID_LIMIT_NOFILE 1231The maximum number of open files for this process. 1232.El 1233.Pp 1234The fifth level name is one of PROC_PID_LIMIT_TYPE_SOFT or 1235PROC_PID_LIMIT_TYPE_HARD, to select respectively the soft or hard limit. 1236Both are of type integer. 1237.El 1238.Sh CTL_USER 1239The string and integer information available for the CTL_USER level 1240is detailed below. 1241The changeable column shows whether a process with appropriate 1242privilege may change the value. 1243.Bl -column "USER_COLL_WEIGHTS_MAXXXX" "integerXXX" -offset indent 1244.It Sy Pa Second level name Type Changeable 1245.It USER\_BC\_BASE\_MAX integer no 1246.It USER\_BC\_DIM\_MAX integer no 1247.It USER\_BC\_SCALE\_MAX integer no 1248.It USER\_BC\_STRING\_MAX integer no 1249.It USER\_COLL\_WEIGHTS\_MAX integer no 1250.It USER\_CS\_PATH string no 1251.It USER\_EXPR\_NEST\_MAX integer no 1252.It USER\_LINE\_MAX integer no 1253.It USER\_POSIX2\_CHAR\_TERM integer no 1254.It USER\_POSIX2\_C\_BIND integer no 1255.It USER\_POSIX2\_C\_DEV integer no 1256.It USER\_POSIX2\_FORT\_DEV integer no 1257.It USER\_POSIX2\_FORT\_RUN integer no 1258.It USER\_POSIX2\_LOCALEDEF integer no 1259.It USER\_POSIX2\_SW\_DEV integer no 1260.It USER\_POSIX2\_UPE integer no 1261.It USER\_POSIX2\_VERSION integer no 1262.It USER\_RE\_DUP\_MAX integer no 1263.It USER\_STREAM\_MAX integer no 1264.It USER\_TZNAME\_MAX integer no 1265.El 1266.Bl -tag -width "123456" 1267.Pp 1268.It Li USER_BC_BASE_MAX 1269The maximum ibase/obase values in the 1270.Xr bc 1 1271utility. 1272.It Li USER_BC_DIM_MAX 1273The maximum array size in the 1274.Xr bc 1 1275utility. 1276.It Li USER_BC_SCALE_MAX 1277The maximum scale value in the 1278.Xr bc 1 1279utility. 1280.It Li USER_BC_STRING_MAX 1281The maximum string length in the 1282.Xr bc 1 1283utility. 1284.It Li USER_COLL_WEIGHTS_MAX 1285The maximum number of weights that can be assigned to any entry of 1286the LC_COLLATE order keyword in the locale definition file. 1287.It Li USER_CS_PATH 1288Return a value for the 1289.Ev PATH 1290environment variable that finds all the standard utilities. 1291.It Li USER_EXPR_NEST_MAX 1292The maximum number of expressions that can be nested within 1293parenthesis by the 1294.Xr expr 1 1295utility. 1296.It Li USER_LINE_MAX 1297The maximum length in bytes of a text-processing utility's input 1298line. 1299.It Li USER_POSIX2_CHAR_TERM 1300Return 1 if the system supports at least one terminal type capable of 1301all operations described in POSIX 1003.2, otherwise 0. 1302.It Li USER_POSIX2_C_BIND 1303Return 1 if the system's C-language development facilities support the 1304C-Language Bindings Option, otherwise 0. 1305.It Li USER_POSIX2_C_DEV 1306Return 1 if the system supports the C-Language Development Utilities Option, 1307otherwise 0. 1308.It Li USER_POSIX2_FORT_DEV 1309Return 1 if the system supports the FORTRAN Development Utilities Option, 1310otherwise 0. 1311.It Li USER_POSIX2_FORT_RUN 1312Return 1 if the system supports the FORTRAN Runtime Utilities Option, 1313otherwise 0. 1314.It Li USER_POSIX2_LOCALEDEF 1315Return 1 if the system supports the creation of locales, otherwise 0. 1316.It Li USER_POSIX2_SW_DEV 1317Return 1 if the system supports the Software Development Utilities Option, 1318otherwise 0. 1319.It Li USER_POSIX2_UPE 1320Return 1 if the system supports the User Portability Utilities Option, 1321otherwise 0. 1322.It Li USER_POSIX2_VERSION 1323The version of POSIX 1003.2 with which the system attempts to comply. 1324.It Li USER_RE_DUP_MAX 1325The maximum number of repeated occurrences of a regular expression 1326permitted when using interval notation. 1327.ne 1i 1328.It Li USER_STREAM_MAX 1329The minimum maximum number of streams that a process may have open 1330at any one time. 1331.It Li USER_TZNAME_MAX 1332The minimum maximum number of types supported for the name of a 1333timezone. 1334.El 1335.Sh CTL_VM 1336The string and integer information available for the CTL_VM level 1337is detailed below. 1338The changeable column shows whether a process with appropriate 1339privilege may change the value. 1340.Bl -column "Second level nameXXXXXX" "struct loadavgXXX" -offset indent 1341.It Sy Pa Second level name Type Changeable 1342.It VM\_ANONMAX int yes 1343.It VM\_ANONMIN int yes 1344.It VM\_EXECMAX int yes 1345.It VM\_EXECMIN int yes 1346.It VM\_FILEMAX int yes 1347.It VM\_FILEMIN int yes 1348.It VM\_LOADAVG struct loadavg no 1349.It VM\_MAXSLP int no 1350.It VM\_METER struct vmtotal no 1351.It VM\_NKMEMPAGES int no 1352.It VM\_USPACE int no 1353.It VM\_UVMEXP struct uvmexp no 1354.It VM\_UVMEXP2 struct uvmexp_sysctl no 1355.El 1356.Pp 1357.Bl -tag -width "123456" 1358.It Li VM_ANONMAX 1359The percentage of physical memory which will be reclaimed 1360from other types of memory usage to store anonymous application data. 1361.It Li VM_ANONMIN 1362The percentage of physical memory which will be always be available for 1363anonymous application data. 1364.It Li VM_EXECMAX 1365The percentage of physical memory which will be reclaimed 1366from other types of memory usage to store cached executable data. 1367.It Li VM_EXECMIN 1368The percentage of physical memory which will be always be available for 1369cached executable data. 1370.It Li VM_FILEMAX 1371The percentage of physical memory which will be reclaimed 1372from other types of memory usage to store cached file data. 1373.It Li VM_FILEMIN 1374The percentage of physical memory which will be always be available for 1375cached file data. 1376.It Li VM_LOADAVG 1377Return the load average history. 1378The returned data consists of a 1379.Va struct loadavg . 1380.It Li VM_MAXSLP 1381The value of the maxslp kernel global variable. 1382.It Li VM_METER 1383Return system wide virtual memory statistics. 1384The returned data consists of a 1385.Va struct vmtotal . 1386.It Li VM_USPACE 1387The number of bytes allocated for each kernel stack. 1388.It Li VM_UVMEXP 1389Return system wide virtual memory statistics. 1390The returned data consists of a 1391.Va struct uvmexp . 1392.It Li VM_UVMEXP2 1393Return system wide virtual memory statistics. 1394The returned data consists of a 1395.Va struct uvmexp_sysctl . 1396.El 1397.Sh CTL_DDB 1398The integer information available for the CTL_DDB level is detailed below. 1399The changeable column shows whether a process with appropriate 1400privilege may change the value. 1401.Bl -column "DBCTL_TABSTOPSXXX" "integerXXX" -offset indent 1402.It Sy Pa Second level name Type Changeable 1403.It DBCTL\_RADIX integer yes 1404.It DBCTL\_MAXOFF integer yes 1405.It DBCTL\_LINES integer yes 1406.It DBCTL\_TABSTOPS integer yes 1407.It DBCTL\_ONPANIC integer yes 1408.It DBCTL\_FROMCONSOLE integer yes 1409.El 1410.Pp 1411.Bl -tag -width "123456" 1412.It Li DBCTL_RADIX 1413The input and output radix. 1414.It Li DBCTL_MAXOFF 1415The maximum symbol offset. 1416.It Li DBCTL_LINES 1417Number of display lines. 1418.It Li DBCTL_TABSTOPS 1419Tab width. 1420.It Li DBCTL_ONPANIC 1421If non-zero, DDB will be entered when the kernel panics. 1422.It Li DBCTL_FROMCONSOLE 1423If not zero, DDB may be entered by sending a break on a serial 1424console or by a special key sequence on a graphics console. 1425.El 1426.Pp 1427These MIB nodes are also available as variables from within the 1428DDB. See 1429.Xr ddb 4 1430for more details. 1431.Sh CTL_VENDOR 1432The "vendor" toplevel name is reserved to be used by vendors who wish to 1433have their own private MIB tree. Intended use is to store values under 1434.Dq vendor.\*[Lt]yourname\*[Gt].* . 1435.Sh RETURN VALUES 1436If the call to 1437.Nm 1438is successful, the number of bytes copied out is returned. 1439Otherwise \-1 is returned and 1440.Va errno 1441is set appropriately. 1442.Sh FILES 1443.Bl -tag -width \*[Lt]netinet6/udp6Xvar.h\*[Gt] -compact 1444.It Pa Aq sys/sysctl.h 1445definitions for top level identifiers, second level kernel and hardware 1446identifiers, and user level identifiers 1447.It Pa Aq sys/socket.h 1448definitions for second level network identifiers 1449.It Pa Aq sys/gmon.h 1450definitions for third level profiling identifiers 1451.It Pa Aq uvm/uvm_param.h 1452definitions for second level virtual memory identifiers 1453.It Pa Aq netinet/in.h 1454definitions for third level IPv4/v6 identifiers and 1455fourth level IPv4/v6 identifiers 1456.It Pa Aq netinet/icmp_var.h 1457definitions for fourth level ICMP identifiers 1458.It Pa Aq netinet/icmp6.h 1459definitions for fourth level ICMPv6 identifiers 1460.It Pa Aq netinet/tcp_var.h 1461definitions for fourth level TCP identifiers 1462.It Pa Aq netinet/udp_var.h 1463definitions for fourth level UDP identifiers 1464.It Pa Aq netinet6/udp6_var.h 1465definitions for fourth level IPv6 UDP identifiers 1466.It Pa Aq netinet6/ipsec.h 1467definitions for fourth level IPsec identifiers 1468.El 1469.Sh ERRORS 1470The following errors may be reported: 1471.Bl -tag -width Er 1472.It Bq Er EFAULT 1473The buffer 1474.Fa name , 1475.Fa oldp , 1476.Fa newp , 1477or length pointer 1478.Fa oldlenp 1479contains an invalid address. 1480.It Bq Er EINVAL 1481The 1482.Fa name 1483array is less than two or greater than CTL_MAXNAME. 1484.It Bq Er EINVAL 1485A non-null 1486.Fa newp 1487is given and its specified length in 1488.Fa newlen 1489is too large or too small. 1490.It Bq Er ENOMEM 1491The length pointed to by 1492.Fa oldlenp 1493is too short to hold the requested value. 1494.It Bq Er ENOTDIR 1495The 1496.Fa name 1497array specifies an intermediate rather than terminal name. 1498.It Bq Er EOPNOTSUPP 1499The 1500.Fa name 1501array specifies a value that is unknown. 1502.It Bq Er EPERM 1503An attempt is made to set a read-only value. 1504.It Bq Er EPERM 1505A process without appropriate privilege attempts to set a value. 1506.It Bq Er EPERM 1507An attempt to change a value protected by the current kernel security 1508level is made. 1509.El 1510.Sh SEE ALSO 1511.Xr ipsec 4 , 1512.Xr sysctl 8 1513.Sh HISTORY 1514The 1515.Nm 1516function first appeared in 1517.Bx 4.4 . 1518