.\" $NetBSD: 1.7.t,v 1.4 2013/10/06 05:45:19 dholland Exp $ .\" .\" Copyright (c) 1983, 1993, 1994 .\" 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. .\" 3. 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. .\" .\" @(#)1.7.t 8.4 (Berkeley) 5/26/94 .\" .Sh 2 19 "System operation support .LP Unless noted otherwise, the calls in this section are permitted only to a privileged user. .Sh 3 20 "Monitoring system operation .PP The .Fn sysctl function allows any process to retrieve system information and allows processes with appropriate privileges to set system configurations. .DS .Fd sysctl 6 "get or set system information sysctl(name, namelen, oldp, oldlenp, newp, newlen); int *name; u_int namelen; result void *oldp; result size_t *oldlenp; void *newp; size_t newlen; .DE The information available from .Fn sysctl consists of integers, strings, and tables. .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 object to be interrogated or set is named using a ``Management Information Base'' (MIB) style name, listed in \fIname\fP, which is a \fInamelen\fP length array of integers. This name is from a hierarchical name space, with the most significant component in the first element of the array. It is analogous to a file pathname, but with integers as components rather than slash-separated strings. .PP The information is copied into the buffer specified by \fIoldp\fP. The size of the buffer is given by the location specified by \fIoldlenp\fP before the call, and that location is filled in with the amount of data copied after a successful call. 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 an error. .PP To set a new value, \fInewp\fP is set to point to a buffer of length \fInewlen\fP from which the requested value is to be taken. If a new value is not to be set, \fInewp\fP should be set to NULL and \fInewlen\fP set to 0. .PP The top level names (those used in the first element of the \fIname\fP array) are defined with a CTL_ prefix in \fI\fP, and are as follows. The next and subsequent levels down are found in the include files listed here: .DS .TS l l l. Name Next Level Names Description _ CTL\_DEBUG sys/sysctl.h Debugging CTL\_FS sys/sysctl.h Filesystem CTL\_HW sys/sysctl.h Generic CPU, I/O CTL\_KERN sys/sysctl.h High kernel limits CTL\_MACHDEP sys/sysctl.h Machine dependent CTL\_NET sys/socket.h Networking CTL\_USER sys/sysctl.h User-level CTL\_VM vm/vm_param.h Virtual memory .TE .DE .Sh 3 20 "Bootstrap operations .LP The call: .DS .Fd mount 4 "mount a filesystem mount(type, dir, flags, data); int type; char *dir; int flags; caddr_t data; .DE extends the name space. The .Fn mount call grafts a filesystem object onto the system file tree at the point specified in \fIdir\fP. The argument \fItype\fP specifies the type of filesystem to be mounted. The argument \fIdata\fP describes the filesystem object to be mounted according to the \fItype\fP. The contents of the filesystem become available through the new mount point \fIdir\fP. Any files in or below \fIdir\fP at the time of a successful mount disappear from the name space until the filesystem is unmounted. The \fIflags\fP value specifies generic properties, such as a request to mount the filesystem read-only. .LP Information about all mounted filesystems can be obtained with the call: .DS .Fd getfsstat 3 "get list of all mounted filesystems getfsstat(buf, bufsize, flags); result struct statfs *buf; long bufsize, int flags; .DE .LP The call: .DS .Fd swapon 1 "add a swap device for interleaved paging/swapping swapon(blkdev); char *blkdev; .DE specifies a device to be made available for paging and swapping. .Sh 3 21 "Shutdown operations .LP The call: .DS .Fd unmount 2 "dismount a filesystem unmount(dir, flags); char *dir; int flags; .DE unmounts the filesystem mounted on \fIdir\fP. This call will succeed only if the filesystem is not currently being used or if the MNT_FORCE flag is specified. .LP The call: .DS .Fd sync 0 "force completion of pending disk writes (flush cache) sync(); .DE schedules I/O to flush all modified disk blocks resident in the kernel. (This call does not require privileged status.) Files can be selectively flushed to disk using the .Fn fsync call (see section .Xr 2.2.6 ). .LP The call: .DS .Fd reboot 1 "reboot system or halt processor reboot(how); int how; .DE causes a machine halt or reboot. The call may request a reboot by specifying \fIhow\fP as RB_AUTOBOOT, or that the machine be halted with RB_HALT, among other options. These constants are defined in \fI\fP. .Sh 3 21 "Accounting .PP The system optionally keeps an accounting record in a file for each process that exits on the system. The format of this record is beyond the scope of this document. The accounting may be enabled to a file \fIname\fP by doing: .DS .Fd acct 1 "enable or disable process accounting acct(path); char *path; .DE If \fIpath\fP is NULL, then accounting is disabled. Otherwise, the named file becomes the accounting file.