diff options
Diffstat (limited to 'lib/libc/gen/sysctl.3')
| -rw-r--r-- | lib/libc/gen/sysctl.3 | 120 |
1 files changed, 67 insertions, 53 deletions
diff --git a/lib/libc/gen/sysctl.3 b/lib/libc/gen/sysctl.3 index 602b559..36f91cc 100644 --- a/lib/libc/gen/sysctl.3 +++ b/lib/libc/gen/sysctl.3 @@ -38,29 +38,30 @@ .Nm sysctl .Nd get or set system information .Sh SYNOPSIS +.Fd #include <sys/types.h> .Fd #include <sys/sysctl.h> .Ft int .Fn sysctl "int *name" "u_int namelen" "void *oldp" "size_t *oldlenp" "void *newp" "size_t newlen" .Sh DESCRIPTION The -.Nm sysctl +.Fn sysctl function retrieves system information and allows processes with appropriate privileges to set system information. The information available from -.Nm sysctl +.Fn sysctl consists of integers, strings, and tables. Information may be retrieved and set from the command interface using the -.Xr sysctl 1 +.Xr sysctl 8 utility. .Pp Unless explicitly noted below, -.Nm sysctl +.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 -.Nm sysctl +.Fn sysctl are serialized to avoid deadlock. .Pp The state is described using a ``Management Information Base'' (MIB) @@ -75,7 +76,8 @@ The information is copied into the buffer specified by 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 that location gives the amount of data copied after a successful call +and after a call that returns with the error code 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 @@ -87,7 +89,7 @@ and should be set to NULL. .Pp The size of the available data can be determined by calling -.Nm sysctl +.Fn sysctl with a NULL parameter for .Fa oldp . The size of the available data will be returned in the location pointed to by @@ -117,7 +119,7 @@ listed here, and described in separate sections below. .Bl -column CTLXMACHDEPXXX "Next level namesXXXXXX" -offset indent .It Sy Pa Name Next level names Description .It CTL\_DEBUG sys/sysctl.h Debugging -.It CTL\_FS sys/sysctl.h File system +.It CTL\_VFS sys/sysctl.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 @@ -128,22 +130,24 @@ listed here, and described in separate sections below. .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; -.sp + mib[0] = CTL_KERN; mib[1] = KERN_MAXPROC; len = sizeof(maxproc); sysctl(mib, 2, &maxproc, &len, NULL, 0); .Ed -.sp +.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; -.sp + mib[0] = CTL_USER; mib[1] = USER_CS_PATH; sysctl(mib, 2, NULL, &len, NULL, 0); @@ -153,10 +157,10 @@ sysctl(mib, 2, p, &len, NULL, 0); .Sh CTL_DEBUG The debugging variables vary from system to system. A debugging variable may be added or deleted without need to recompile -.Nm sysctl +.Fn sysctl to know about it. Each time it runs, -.Nm sysctl +.Fn sysctl gets the list of debugging variables from the kernel and displays their current values. The system defines twenty @@ -176,7 +180,7 @@ as a debugging variable, the following declaration would be used: int dospecialcheck = 1; struct ctldebug debug5 = { "dospecialcheck", &dospecialcheck }; .Ed -.Sh CTL_FS +.Sh CTL_VFS There are currently no second level names for the file system. .Sh CTL_HW The string and integer information available for the CTL_HW level @@ -192,6 +196,7 @@ privilege may change the value. .It HW\_PHYSMEM integer no .It HW\_USERMEM integer no .It HW\_PAGESIZE integer no +.It HW\_FLOATINGPOINT integer no .\".It HW\_DISKNAMES integer no .\".It HW\_DISKSTATS integer no .El @@ -211,6 +216,8 @@ The bytes of physical memory. The bytes of non-kernel memory. .It Li HW_PAGESIZE The software page size. +.It Li HW_FLOATINGPOINT +Nonzero if the floating point support is in hardware. .\".It Fa HW_DISKNAMES .\".It Fa HW_DISKSTATS .El @@ -223,36 +230,33 @@ 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 "KERNXCHOWNXRESTRICTEDXXX" "struct clockrateXXX" -offset indent +.Bl -column "KERNXMAXFILESPERPROCXXX" "struct clockrateXXX" -offset indent .It Sy Pa Second level name Type Changeable .It KERN\_ARGMAX integer no +.It KERN\_BOOTFILE string yes .It KERN\_BOOTTIME struct timeval no -.It KERN\_CHOWN\_RESTRICTED integer no .It KERN\_CLOCKRATE struct clockinfo no .It KERN\_FILE struct file no .It KERN\_HOSTID integer yes .It KERN\_HOSTNAME string yes .It KERN\_JOB\_CONTROL integer no -.It KERN\_LINK\_MAX integer no .It KERN\_MAXFILES integer yes +.It KERN\_MAXFILESPERPROC integer yes .It KERN\_MAXPROC integer yes +.It KERN\_MAXPROCPERUID integer yes .It KERN\_MAXVNODES integer yes -.It KERN\_MAX\_CANON integer no -.It KERN\_MAX\_INPUT integer no -.It KERN\_NAME\_MAX integer no .It KERN\_NGROUPS integer no -.It KERN\_NO\_TRUNC 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\_PATH\_MAX integer no -.It KERN\_PIPE\_BUF integer no .It KERN\_POSIX1 integer no .It KERN\_PROC struct proc no .It KERN\_PROF node not applicable .It KERN\_SAVED\_IDS integer no .It KERN\_SECURELVL integer raise only -.It KERN\_VDISABLE integer no +.It KERN\_UPDATEINTERVAL integer no .It KERN\_VERSION string no .It KERN\_VNODE struct vnode no .El @@ -260,16 +264,14 @@ information. .Bl -tag -width "123456" .It Li KERN_ARGMAX The maximum bytes of argument to -.Xr exec 2 . +.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_CHOWN_RESTRICTED -Return 1 if appropriate privileges are required for the -.Xr chown 2 -system call, otherwise 0. .It Li KERN_CLOCKRATE A .Va struct clockinfo @@ -289,35 +291,38 @@ Get or set the host id. 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_LINK_MAX -The maximum file link count. .It Li KERN_MAXFILES -The maximum number of open files that may be open in the system. +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 simultaneous processes the system will allow. +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_MAX_CANON -The maximum number of bytes in terminal canonical input line. -.It Li KERN_MAX_INPUT -The minimum maximum number of bytes for which space is available in -a terminal input queue. -.It Li KERN_NAME_MAX -The maximum number of bytes in a file name. .It Li KERN_NGROUPS The maximum number of supplemental groups. -.It Li KERN_NO_TRUNC -Return 1 if file names longer than KERN_NAME_MAX are truncated. +.It Li KERN_NISDOMAINNAME +The name of the current YP/NIS domain. +.It Li KERN_OSRELDATE +The system release date in YYYYMM format +(January 1996 is encoded as 199601). .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_PATH_MAX -The maximum number of bytes in a pathname. -.It Li KERN_PIPE_BUF -The maximum number of bytes which will be written atomically to a pipe. .It Li KERN_POSIX1 The version of ISO/IEC 9945 (POSIX 1003.1) with which the system attempts to comply. @@ -377,8 +382,6 @@ Returns 1 if saved set-group and saved set-user ID is available. The system security level. This level may be raised by processes with appropriate privilege. It may only be lowered by process 1. -.It Li KERN_VDISABLE -Returns the terminal character disabling value. .It Li KERN_VERSION The system version string. .It Li KERN_VNODE @@ -391,13 +394,23 @@ Each element of the array contains the kernel address of a vnode .Va struct vnode * followed by the vnode itself .Va struct vnode . +.It Li KERN_UPDATEINTERVAL +The interval between +.Xr sync 2 +calls in the +.Xr update 4 +process. .El .Sh CTL_MACHDEP The set of variables defined is architecture dependent. -Most architectures define at least the following variables. -.Bl -column "CONSOLE_DEVICEXXX" "integerXXX" -offset indent +The following variables are defined for the i386 architecture. +.Bl -column "CONSOLE_DEVICEXXX" "struct bootinfoXXX" -offset indent .It Sy Pa Second level name Type Changeable .It Li CPU_CONSDEV dev_t no +.It Li CPU_ADJKERNTZ int yes +.It Li CPU_DISRTCSET int yes +.It Li CPU_BOOTINFO struct bootinfo no +.It Li CPU_WALLCLOCK int yes .El .Sh CTL_NET The string and integer information available for the CTL_NET level @@ -580,7 +593,7 @@ The returned data consists of a .El .Sh RETURN VALUES If the call to -.Nm sysctl +.Fn sysctl is successful, 0 is returned. Otherwise \-1 is returned and .Va errno @@ -646,5 +659,6 @@ definitions for fourth level UDP identifiers .Xr sysctl 8 .Sh HISTORY The -.Nm sysctl -function first appeared in 4.4BSD. +.Fn sysctl +function first appeared in +.Bx 4.4 . |
