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Diffstat (limited to 'lib/libc/gen/sysctl.3')
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diff --git a/lib/libc/gen/sysctl.3 b/lib/libc/gen/sysctl.3 new file mode 100644 index 0000000..a841545 --- /dev/null +++ b/lib/libc/gen/sysctl.3 @@ -0,0 +1,860 @@ +.\" Copyright (c) 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 4. Neither the name of the University nor the names of its contributors +.\" may be used to endorse or promote products derived from this software +.\" without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" @(#)sysctl.3 8.4 (Berkeley) 5/9/95 +.\" $FreeBSD$ +.\" +.Dd April 25, 2010 +.Dt SYSCTL 3 +.Os +.Sh NAME +.Nm sysctl , +.Nm sysctlbyname , +.Nm sysctlnametomib +.Nd get or set system information +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In sys/types.h +.In sys/sysctl.h +.Ft int +.Fn sysctl "const int *name" "u_int namelen" "void *oldp" "size_t *oldlenp" "const void *newp" "size_t newlen" +.Ft int +.Fn sysctlbyname "const char *name" "void *oldp" "size_t *oldlenp" "const void *newp" "size_t newlen" +.Ft int +.Fn sysctlnametomib "const char *name" "int *mibp" "size_t *sizep" +.Sh DESCRIPTION +The +.Fn sysctl +function retrieves system information and allows processes with +appropriate privileges to set system information. +The information available from +.Fn sysctl +consists of integers, strings, and tables. +Information may be retrieved and set from the command interface +using the +.Xr sysctl 8 +utility. +.Pp +Unless explicitly noted below, +.Fn sysctl +returns a consistent snapshot of the data requested. +Consistency is obtained by locking the destination +buffer into memory so that the data may be copied out without blocking. +Calls to +.Fn sysctl +are serialized to avoid deadlock. +.Pp +The state is described using a ``Management Information Base'' (MIB) +style name, listed in +.Fa name , +which is a +.Fa namelen +length array of integers. +.Pp +The +.Fn sysctlbyname +function accepts an ASCII representation of the name and internally +looks up the integer name vector. +Apart from that, it behaves the same +as the standard +.Fn sysctl +function. +.Pp +The information is copied into the buffer specified by +.Fa oldp . +The size of the buffer is given by the location specified by +.Fa oldlenp +before the call, +and that location gives the amount of data copied after a successful call +and after a call that returns with the error code +.Er ENOMEM . +If the amount of data available is greater +than the size of the buffer supplied, +the call supplies as much data as fits in the buffer provided +and returns with the error code +.Er ENOMEM . +If the old value is not desired, +.Fa oldp +and +.Fa oldlenp +should be set to NULL. +.Pp +The size of the available data can be determined by calling +.Fn sysctl +with the +.Dv NULL +argument for +.Fa oldp . +The size of the available data will be returned in the location pointed to by +.Fa oldlenp . +For some operations, the amount of space may change often. +For these operations, +the system attempts to round up so that the returned size is +large enough for a call to return the data shortly thereafter. +.Pp +To set a new value, +.Fa newp +is set to point to a buffer of length +.Fa newlen +from which the requested value is to be taken. +If a new value is not to be set, +.Fa newp +should be set to NULL and +.Fa newlen +set to 0. +.Pp +The +.Fn sysctlnametomib +function accepts an ASCII representation of the name, +looks up the integer name vector, +and returns the numeric representation in the mib array pointed to by +.Fa mibp . +The number of elements in the mib array is given by the location specified by +.Fa sizep +before the call, +and that location gives the number of entries copied after a successful call. +The resulting +.Fa mib +and +.Fa size +may be used in subsequent +.Fn sysctl +calls to get the data associated with the requested ASCII name. +This interface is intended for use by applications that want to +repeatedly request the same variable (the +.Fn sysctl +function runs in about a third the time as the same request made via the +.Fn sysctlbyname +function). +The +.Fn sysctlnametomib +function is also useful for fetching mib prefixes and then adding +a final component. +For example, to fetch process information +for processes with pid's less than 100: +.Pp +.Bd -literal -offset indent -compact +int i, mib[4]; +size_t len; +struct kinfo_proc kp; + +/* Fill out the first three components of the mib */ +len = 4; +sysctlnametomib("kern.proc.pid", mib, &len); + +/* Fetch and print entries for pid's < 100 */ +for (i = 0; i < 100; i++) { + mib[3] = i; + len = sizeof(kp); + if (sysctl(mib, 4, &kp, &len, NULL, 0) == -1) + perror("sysctl"); + else if (len > 0) + printkproc(&kp); +} +.Ed +.Pp +The top level names are defined with a CTL_ prefix in +.In sys/sysctl.h , +and are as follows. +The next and subsequent levels down are found in the include files +listed here, and described in separate sections below. +.Bl -column CTLXMACHDEPXXX "Next level namesXXXXXX" -offset indent +.It Sy "Name Next level names Description" +.It "CTL_DEBUG sys/sysctl.h Debugging" +.It "CTL_VFS sys/mount.h File system" +.It "CTL_HW sys/sysctl.h Generic CPU, I/O" +.It "CTL_KERN sys/sysctl.h High kernel limits" +.It "CTL_MACHDEP sys/sysctl.h Machine dependent" +.It "CTL_NET sys/socket.h Networking" +.It "CTL_USER sys/sysctl.h User-level" +.It "CTL_VM vm/vm_param.h Virtual memory" +.El +.Pp +For example, the following retrieves the maximum number of processes allowed +in the system: +.Pp +.Bd -literal -offset indent -compact +int mib[2], maxproc; +size_t len; + +mib[0] = CTL_KERN; +mib[1] = KERN_MAXPROC; +len = sizeof(maxproc); +sysctl(mib, 2, &maxproc, &len, NULL, 0); +.Ed +.Pp +To retrieve the standard search path for the system utilities: +.Pp +.Bd -literal -offset indent -compact +int mib[2]; +size_t len; +char *p; + +mib[0] = CTL_USER; +mib[1] = USER_CS_PATH; +sysctl(mib, 2, NULL, &len, NULL, 0); +p = malloc(len); +sysctl(mib, 2, p, &len, NULL, 0); +.Ed +.Ss CTL_DEBUG +The debugging variables vary from system to system. +A debugging variable may be added or deleted without need to recompile +.Fn sysctl +to know about it. +Each time it runs, +.Fn sysctl +gets the list of debugging variables from the kernel and +displays their current values. +The system defines twenty +.Pq Vt "struct ctldebug" +variables named +.Va debug0 +through +.Va debug19 . +They are declared as separate variables so that they can be +individually initialized at the location of their associated variable. +The loader prevents multiple use of the same variable by issuing errors +if a variable is initialized in more than one place. +For example, to export the variable +.Va dospecialcheck +as a debugging variable, the following declaration would be used: +.Pp +.Bd -literal -offset indent -compact +int dospecialcheck = 1; +struct ctldebug debug5 = { "dospecialcheck", &dospecialcheck }; +.Ed +.Ss CTL_VFS +A distinguished second level name, VFS_GENERIC, +is used to get general information about all file systems. +One of its third level identifiers is VFS_MAXTYPENUM +that gives the highest valid file system type number. +Its other third level identifier is VFS_CONF that +returns configuration information about the file system +type given as a fourth level identifier (see +.Xr getvfsbyname 3 +as an example of its use). +The remaining second level identifiers are the +file system type number returned by a +.Xr statfs 2 +call or from VFS_CONF. +The third level identifiers available for each file system +are given in the header file that defines the mount +argument structure for that file system. +.Ss CTL_HW +The string and integer information available for the CTL_HW level +is detailed below. +The changeable column shows whether a process with appropriate +privilege may change the value. +.Bl -column "Second level nameXXXXXX" integerXXX -offset indent +.It Sy "Second level name Type Changeable" +.It "HW_MACHINE string no" +.It "HW_MODEL string no" +.It "HW_NCPU integer no" +.It "HW_BYTEORDER integer no" +.It "HW_PHYSMEM integer no" +.It "HW_USERMEM integer no" +.It "HW_PAGESIZE integer no" +.\".It "HW_DISKNAMES integer no" +.\".It "HW_DISKSTATS integer no" +.It "HW_FLOATINGPT integer no" +.It "HW_MACHINE_ARCH string no" +.It "HW_REALMEM integer no" +.El +.Bl -tag -width 6n +.It Li HW_MACHINE +The machine class. +.It Li HW_MODEL +The machine model +.It Li HW_NCPU +The number of cpus. +.It Li HW_BYTEORDER +The byteorder (4,321, or 1,234). +.It Li HW_PHYSMEM +The bytes of physical memory. +.It Li HW_USERMEM +The bytes of non-kernel memory. +.It Li HW_PAGESIZE +The software page size. +.\".It Fa HW_DISKNAMES +.\".It Fa HW_DISKSTATS +.It Li HW_FLOATINGPT +Nonzero if the floating point support is in hardware. +.It Li HW_MACHINE_ARCH +The machine dependent architecture type. +.It Li HW_REALMEM +The bytes of real memory. +.El +.Ss CTL_KERN +The string and integer information available for the CTL_KERN level +is detailed below. +The changeable column shows whether a process with appropriate +privilege may change the value. +The types of data currently available are process information, +system vnodes, the open file entries, routing table entries, +virtual memory statistics, load average history, and clock rate +information. +.Bl -column "KERNXMAXFILESPERPROCXXX" "struct clockrateXXX" -offset indent +.It Sy "Second level name Type Changeable" +.It "KERN_ARGMAX integer no" +.It "KERN_BOOTFILE string yes" +.It "KERN_BOOTTIME struct timeval no" +.It "KERN_CLOCKRATE struct clockinfo no" +.It "KERN_FILE struct xfile no" +.It "KERN_HOSTID integer yes" +.It "KERN_HOSTUUID string yes" +.It "KERN_HOSTNAME string yes" +.It "KERN_JOB_CONTROL integer no" +.It "KERN_MAXFILES integer yes" +.It "KERN_MAXFILESPERPROC integer yes" +.It "KERN_MAXPROC integer no" +.It "KERN_MAXPROCPERUID integer yes" +.It "KERN_MAXVNODES integer yes" +.It "KERN_NGROUPS integer no" +.It "KERN_NISDOMAINNAME string yes" +.It "KERN_OSRELDATE integer no" +.It "KERN_OSRELEASE string no" +.It "KERN_OSREV integer no" +.It "KERN_OSTYPE string no" +.It "KERN_POSIX1 integer no" +.It "KERN_PROC node not applicable" +.It "KERN_PROF node not applicable" +.It "KERN_QUANTUM integer yes" +.It "KERN_SAVED_IDS integer no" +.It "KERN_SECURELVL integer raise only" +.It "KERN_UPDATEINTERVAL integer no" +.It "KERN_VERSION string no" +.It "KERN_VNODE struct xvnode no" +.El +.Bl -tag -width 6n +.It Li KERN_ARGMAX +The maximum bytes of argument to +.Xr execve 2 . +.It Li KERN_BOOTFILE +The full pathname of the file from which the kernel was loaded. +.It Li KERN_BOOTTIME +A +.Va struct timeval +structure is returned. +This structure contains the time that the system was booted. +.It Li KERN_CLOCKRATE +A +.Va struct clockinfo +structure is returned. +This structure contains the clock, statistics clock and profiling clock +frequencies, the number of micro-seconds per hz tick and the skew rate. +.It Li KERN_FILE +Return the entire file table. +The returned data consists of an array of +.Va struct xfile , +whose size depends on the current number of such objects in the system. +.It Li KERN_HOSTID +Get or set the host ID. +.It Li KERN_HOSTUUID +Get or set the host's universally unique identifier (UUID). +.It Li KERN_HOSTNAME +Get or set the hostname. +.It Li KERN_JOB_CONTROL +Return 1 if job control is available on this system, otherwise 0. +.It Li KERN_MAXFILES +The maximum number of files that may be open in the system. +.It Li KERN_MAXFILESPERPROC +The maximum number of files that may be open for a single process. +This limit only applies to processes with an effective uid of nonzero +at the time of the open request. +Files that have already been opened are not affected if the limit +or the effective uid is changed. +.It Li KERN_MAXPROC +The maximum number of concurrent processes the system will allow. +.It Li KERN_MAXPROCPERUID +The maximum number of concurrent processes the system will allow +for a single effective uid. +This limit only applies to processes with an effective uid of nonzero +at the time of a fork request. +Processes that have already been started are not affected if the limit +is changed. +.It Li KERN_MAXVNODES +The maximum number of vnodes available on the system. +.It Li KERN_NGROUPS +The maximum number of supplemental groups. +.It Li KERN_NISDOMAINNAME +The name of the current YP/NIS domain. +.It Li KERN_OSRELDATE +The kernel release version in the format +.Ar M Ns Ar mm Ns Ar R Ns Ar xx , +where +.Ar M +is the major version, +.Ar mm +is the two digit minor version, +.Ar R +is 0 if release branch, otherwise 1, +and +.Ar xx +is updated when the available APIs change. +.Pp +The userland release version is available from +.In osreldate.h ; +parse this file if you need to get the release version of +the currently installed userland. +.It Li KERN_OSRELEASE +The system release string. +.It Li KERN_OSREV +The system revision string. +.It Li KERN_OSTYPE +The system type string. +.It Li KERN_POSIX1 +The version of +.St -p1003.1 +with which the system +attempts to comply. +.It Li KERN_PROC +Return selected information about specific running processes. +.Pp +For the following names, an array of +.Va struct kinfo_proc +structures is returned, +whose size depends on the current number of such objects in the system. +.Bl -column "Third level nameXXXXXX" "Fourth level is:XXXXXX" -offset indent +.It "Third level name Fourth level is:" +.It "KERN_PROC_ALL None" +.It "KERN_PROC_PID A process ID" +.It "KERN_PROC_PGRP A process group" +.It "KERN_PROC_TTY A tty device" +.It "KERN_PROC_UID A user ID" +.It "KERN_PROC_RUID A real user ID" +.El +.Pp +If the third level name is +.Dv KERN_PROC_ARGS +then the command line argument +array is returned in a flattened form, i.e., zero-terminated arguments +follow each other. +The total size of array is returned. +It is also possible for a process to set its own process title this way. +If the third level name is +.Dv KERN_PROC_PATHNAME , +the path of the +process' text file is stored. +For +.Dv KERN_PROC_PATHNAME , +a process ID of +.Li \-1 +implies the current process. +.Bl -column "Third level nameXXXXXX" "Fourth level is:XXXXXX" -offset indent +.It Sy "Third level name Fourth level is:" +.It Dv KERN_PROC_ARGS Ta "A process ID" +.It Dv KERN_PROC_PATHNAME Ta "A process ID" +.El +.It Li KERN_PROF +Return profiling information about the kernel. +If the kernel is not compiled for profiling, +attempts to retrieve any of the KERN_PROF values will +fail with +.Er ENOENT . +The third level names for the string and integer profiling information +is detailed below. +The changeable column shows whether a process with appropriate +privilege may change the value. +.Bl -column "GPROFXGMONPARAMXXX" "struct gmonparamXXX" -offset indent +.It Sy "Third level name Type Changeable" +.It "GPROF_STATE integer yes" +.It "GPROF_COUNT u_short[\|] yes" +.It "GPROF_FROMS u_short[\|] yes" +.It "GPROF_TOS struct tostruct yes" +.It "GPROF_GMONPARAM struct gmonparam no" +.El +.Pp +The variables are as follows: +.Bl -tag -width 6n +.It Li GPROF_STATE +Returns GMON_PROF_ON or GMON_PROF_OFF to show that profiling +is running or stopped. +.It Li GPROF_COUNT +Array of statistical program counter counts. +.It Li GPROF_FROMS +Array indexed by program counter of call-from points. +.It Li GPROF_TOS +Array of +.Va struct tostruct +describing destination of calls and their counts. +.It Li GPROF_GMONPARAM +Structure giving the sizes of the above arrays. +.El +.It Li KERN_QUANTUM +The maximum period of time, in microseconds, for which a process is allowed +to run without being preempted if other processes are in the run queue. +.It Li KERN_SAVED_IDS +Returns 1 if saved set-group and saved set-user ID is available. +.It Li KERN_SECURELVL +The system security level. +This level may be raised by processes with appropriate privilege. +It may not be lowered. +.It Li KERN_VERSION +The system version string. +.It Li KERN_VNODE +Return the entire vnode table. +Note, the vnode table is not necessarily a consistent snapshot of +the system. +The returned data consists of an array whose size depends on the +current number of such objects in the system. +Each element of the array consists of a +.Va struct xvnode . +.El +.Ss CTL_NET +The string and integer information available for the CTL_NET level +is detailed below. +The changeable column shows whether a process with appropriate +privilege may change the value. +.Bl -column "Second level nameXXXXXX" "routing messagesXXX" -offset indent +.It Sy "Second level name Type Changeable" +.It "PF_ROUTE routing messages no" +.It "PF_INET IPv4 values yes" +.It "PF_INET6 IPv6 values yes" +.El +.Bl -tag -width 6n +.It Li PF_ROUTE +Return the entire routing table or a subset of it. +The data is returned as a sequence of routing messages (see +.Xr route 4 +for the header file, format and meaning). +The length of each message is contained in the message header. +.Pp +The third level name is a protocol number, which is currently always 0. +The fourth level name is an address family, which may be set to 0 to +select all address families. +The fifth and sixth level names are as follows: +.Bl -column "Fifth level nameXXXXXX" "Sixth level is:XXX" -offset indent +.It Sy "Fifth level name Sixth level is:" +.It "NET_RT_FLAGS rtflags" +.It "NET_RT_DUMP None" +.It "NET_RT_IFLIST 0 or if_index" +.It "NET_RT_IFMALIST 0 or if_index" +.El +.Pp +The +.Dv NET_RT_IFMALIST +name returns information about multicast group memberships on all interfaces +if 0 is specified, or for the interface specified by +.Va if_index . +.It Li PF_INET +Get or set various global information about the IPv4 +(Internet Protocol version 4). +The third level name is the protocol. +The fourth level name is the variable name. +The currently defined protocols and names are: +.Bl -column ProtocolXX VariableXX TypeXX ChangeableXX +.It Sy "Protocol Variable Type Changeable" +.It "icmp bmcastecho integer yes" +.It "icmp maskrepl integer yes" +.It "ip forwarding integer yes" +.It "ip redirect integer yes" +.It "ip ttl integer yes" +.It "udp checksum integer yes" +.El +.Pp +The variables are as follows: +.Bl -tag -width 6n +.It Li icmp.bmcastecho +Returns 1 if an ICMP echo request to a broadcast or multicast address is +to be answered. +.It Li icmp.maskrepl +Returns 1 if ICMP network mask requests are to be answered. +.It Li ip.forwarding +Returns 1 when IP forwarding is enabled for the host, +meaning that the host is acting as a router. +.It Li ip.redirect +Returns 1 when ICMP redirects may be sent by the host. +This option is ignored unless the host is routing IP packets, +and should normally be enabled on all systems. +.It Li ip.ttl +The maximum time-to-live (hop count) value for an IP packet sourced by +the system. +This value applies to normal transport protocols, not to ICMP. +.It Li udp.checksum +Returns 1 when UDP checksums are being computed and checked. +Disabling UDP checksums is strongly discouraged. +.Pp +For variables net.inet.*.ipsec, please refer to +.Xr ipsec 4 . +.El +.It Li PF_INET6 +Get or set various global information about the IPv6 +(Internet Protocol version 6). +The third level name is the protocol. +The fourth level name is the variable name. +.Pp +For variables net.inet6.* please refer to +.Xr inet6 4 . +For variables net.inet6.*.ipsec6, please refer to +.Xr ipsec 4 . +.El +.Ss CTL_USER +The string and integer information available for the CTL_USER level +is detailed below. +The changeable column shows whether a process with appropriate +privilege may change the value. +.Bl -column "USER_COLL_WEIGHTS_MAXXXX" "integerXXX" -offset indent +.It Sy "Second level name Type Changeable" +.It "USER_BC_BASE_MAX integer no" +.It "USER_BC_DIM_MAX integer no" +.It "USER_BC_SCALE_MAX integer no" +.It "USER_BC_STRING_MAX integer no" +.It "USER_COLL_WEIGHTS_MAX integer no" +.It "USER_CS_PATH string no" +.It "USER_EXPR_NEST_MAX integer no" +.It "USER_LINE_MAX integer no" +.It "USER_POSIX2_CHAR_TERM integer no" +.It "USER_POSIX2_C_BIND integer no" +.It "USER_POSIX2_C_DEV integer no" +.It "USER_POSIX2_FORT_DEV integer no" +.It "USER_POSIX2_FORT_RUN integer no" +.It "USER_POSIX2_LOCALEDEF integer no" +.It "USER_POSIX2_SW_DEV integer no" +.It "USER_POSIX2_UPE integer no" +.It "USER_POSIX2_VERSION integer no" +.It "USER_RE_DUP_MAX integer no" +.It "USER_STREAM_MAX integer no" +.It "USER_TZNAME_MAX integer no" +.El +.Bl -tag -width 6n +.It Li USER_BC_BASE_MAX +The maximum ibase/obase values in the +.Xr bc 1 +utility. +.It Li USER_BC_DIM_MAX +The maximum array size in the +.Xr bc 1 +utility. +.It Li USER_BC_SCALE_MAX +The maximum scale value in the +.Xr bc 1 +utility. +.It Li USER_BC_STRING_MAX +The maximum string length in the +.Xr bc 1 +utility. +.It Li USER_COLL_WEIGHTS_MAX +The maximum number of weights that can be assigned to any entry of +the LC_COLLATE order keyword in the locale definition file. +.It Li USER_CS_PATH +Return a value for the +.Ev PATH +environment variable that finds all the standard utilities. +.It Li USER_EXPR_NEST_MAX +The maximum number of expressions that can be nested within +parenthesis by the +.Xr expr 1 +utility. +.It Li USER_LINE_MAX +The maximum length in bytes of a text-processing utility's input +line. +.It Li USER_POSIX2_CHAR_TERM +Return 1 if the system supports at least one terminal type capable of +all operations described in +.St -p1003.2 , +otherwise 0. +.It Li USER_POSIX2_C_BIND +Return 1 if the system's C-language development facilities support the +C-Language Bindings Option, otherwise 0. +.It Li USER_POSIX2_C_DEV +Return 1 if the system supports the C-Language Development Utilities Option, +otherwise 0. +.It Li USER_POSIX2_FORT_DEV +Return 1 if the system supports the FORTRAN Development Utilities Option, +otherwise 0. +.It Li USER_POSIX2_FORT_RUN +Return 1 if the system supports the FORTRAN Runtime Utilities Option, +otherwise 0. +.It Li USER_POSIX2_LOCALEDEF +Return 1 if the system supports the creation of locales, otherwise 0. +.It Li USER_POSIX2_SW_DEV +Return 1 if the system supports the Software Development Utilities Option, +otherwise 0. +.It Li USER_POSIX2_UPE +Return 1 if the system supports the User Portability Utilities Option, +otherwise 0. +.It Li USER_POSIX2_VERSION +The version of +.St -p1003.2 +with which the system attempts to comply. +.It Li USER_RE_DUP_MAX +The maximum number of repeated occurrences of a regular expression +permitted when using interval notation. +.It Li USER_STREAM_MAX +The minimum maximum number of streams that a process may have open +at any one time. +.It Li USER_TZNAME_MAX +The minimum maximum number of types supported for the name of a +timezone. +.El +.Ss CTL_VM +The string and integer information available for the CTL_VM level +is detailed below. +The changeable column shows whether a process with appropriate +privilege may change the value. +.Bl -column "Second level nameXXXXXX" "struct loadavgXXX" -offset indent +.It Sy "Second level name Type Changeable" +.It "VM_LOADAVG struct loadavg no" +.It "VM_TOTAL struct vmtotal no" +.It "VM_PAGEOUT_ALGORITHM integer yes" +.It "VM_SWAPPING_ENABLED integer maybe" +.It "VM_V_CACHE_MAX integer yes" +.It "VM_V_CACHE_MIN integer yes" +.It "VM_V_FREE_MIN integer yes" +.It "VM_V_FREE_RESERVED integer yes" +.It "VM_V_FREE_TARGET integer yes" +.It "VM_V_INACTIVE_TARGET integer yes" +.It "VM_V_PAGEOUT_FREE_MIN integer yes" +.El +.Bl -tag -width 6n +.It Li VM_LOADAVG +Return the load average history. +The returned data consists of a +.Va struct loadavg . +.It Li VM_TOTAL +Return the system wide virtual memory statistics. +The returned data consists of a +.Va struct vmtotal . +.It Li VM_PAGEOUT_ALGORITHM +0 if the statistics-based page management algorithm is in use +or 1 if the near-LRU algorithm is in use. +.It Li VM_SWAPPING_ENABLED +1 if process swapping is enabled or 0 if disabled. +This variable is +permanently set to 0 if the kernel was built with swapping disabled. +.It Li VM_V_CACHE_MAX +Maximum desired size of the cache queue. +.It Li VM_V_CACHE_MIN +Minimum desired size of the cache queue. +If the cache queue size +falls very far below this value, the pageout daemon is awakened. +.It Li VM_V_FREE_MIN +Minimum amount of memory (cache memory plus free memory) +required to be available before a process waiting on memory will be +awakened. +.It Li VM_V_FREE_RESERVED +Processes will awaken the pageout daemon and wait for memory if the +number of free and cached pages drops below this value. +.It Li VM_V_FREE_TARGET +The total amount of free memory (including cache memory) that the +pageout daemon tries to maintain. +.It Li VM_V_INACTIVE_TARGET +The desired number of inactive pages that the pageout daemon should +achieve when it runs. +Inactive pages can be quickly inserted into +process address space when needed. +.It Li VM_V_PAGEOUT_FREE_MIN +If the amount of free and cache memory falls below this value, the +pageout daemon will enter "memory conserving mode" to avoid deadlock. +.El +.Sh RETURN VALUES +.Rv -std +.Sh FILES +.Bl -tag -width <netinet/icmpXvar.h> -compact +.It In sys/sysctl.h +definitions for top level identifiers, second level kernel and hardware +identifiers, and user level identifiers +.It In sys/socket.h +definitions for second level network identifiers +.It In sys/gmon.h +definitions for third level profiling identifiers +.It In vm/vm_param.h +definitions for second level virtual memory identifiers +.It In netinet/in.h +definitions for third level IPv4/IPv6 identifiers and +fourth level IPv4/v6 identifiers +.It In netinet/icmp_var.h +definitions for fourth level ICMP identifiers +.It In netinet/icmp6.h +definitions for fourth level ICMPv6 identifiers +.It In netinet/udp_var.h +definitions for fourth level UDP identifiers +.El +.Sh ERRORS +The following errors may be reported: +.Bl -tag -width Er +.It Bq Er EFAULT +The buffer +.Fa name , +.Fa oldp , +.Fa newp , +or length pointer +.Fa oldlenp +contains an invalid address. +.It Bq Er EINVAL +The +.Fa name +array is less than two or greater than CTL_MAXNAME. +.It Bq Er EINVAL +A non-null +.Fa newp +is given and its specified length in +.Fa newlen +is too large or too small. +.It Bq Er ENOMEM +The length pointed to by +.Fa oldlenp +is too short to hold the requested value. +.It Bq Er ENOMEM +The smaller of either the length pointed to by +.Fa oldlenp +or the estimated size of the returned data exceeds the +system limit on locked memory. +.It Bq Er ENOMEM +Locking the buffer +.Fa oldp , +or a portion of the buffer if the estimated size of the data +to be returned is smaller, +would cause the process to exceed its per-process locked memory limit. +.It Bq Er ENOTDIR +The +.Fa name +array specifies an intermediate rather than terminal name. +.It Bq Er EISDIR +The +.Fa name +array specifies a terminal name, but the actual name is not terminal. +.It Bq Er ENOENT +The +.Fa name +array specifies a value that is unknown. +.It Bq Er EPERM +An attempt is made to set a read-only value. +.It Bq Er EPERM +A process without appropriate privilege attempts to set a value. +.El +.Sh SEE ALSO +.Xr confstr 3 , +.Xr kvm 3 , +.Xr sysconf 3 , +.Xr sysctl 8 +.Sh HISTORY +The +.Fn sysctl +function first appeared in +.Bx 4.4 . |
