.\" Copyright (c) 1980, 1991 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. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 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.
.\"
.\"     @(#)savecore.8	6.6 (Berkeley) 3/16/91
.\"
.Dd March 16, 1991
.Dt SAVECORE 8
.Os BSD 4
.Sh NAME
.Nm savecore
.Nd "save the details of a crash of the operating system"
.Sh SYNOPSIS
.Nm savecore
.Ar dirname
.Op Ar system
.Sh DESCRIPTION
.Nm Savecore
is meant to be called near the end of the initialization file
.Pa /etc/rc
(see
.Xr rc 8 ) .
Its function
is to detect the presence and save the state of the operating
system's previous abnormal termination, assuming the state was recorded
for this purpose. If this state information is found,
.Nm savecore
will also write a reboot message in the shutdown log.
The state information is a snapshot of all RAM memory at the time
of abnormal termination, untranslated by the processor's memory management
unit, in physical rather than virtual order (like the memory device, see
.Xr mem 4 ).
.Pp
Operands supported by
.Nm savecore :
.Bl -tag -width Ar
.It Ar dirname
The directory name where the core dump will be written.
.It Ar system
If the core dump was from a system other than
.Pa /386bsd ,
the name
of that system must be supplied as
.Ar system .
.El
.Pp
.Nm Savecore
looks for a physical RAM memory image of the current system
(currently recorded during system crashes in the
system's swap space) and it checks the image for veracity.
If the saved memory image is valid, it saves this in
.Ar dirname Ns Pa /ram.n
and the current version of the operating system's executable file
in
.Ar dirname Ns Pa /system.n
Sequence numbers are incremented and appended to the end of the pathnames
each time
.Nm savecore
is run in the directory.
.Pp
Before savecore writes out a memory image, it reads a number from the file
.Ar dirname Ns Pa /minfree .
If the number of free kilobytes on the filesystem which contains
.Ar dirname
is less than the number obtained from the minfree file,
the core dump is not saved.
If the minfree file does not exist, savecore always writes out the core
file (assuming that a core dump was taken).
.Pp
.Nm Savecore
also logs a reboot message using facility
.Dv LOG_AUTH
(see
.Xr syslog 3 )
If the system crashed as a result of a panic,
.Nm savecore
logs the panic string too.
.Sh FILES
.Bl -tag -width /386bsd -compact
.It Pa /386bsd
current
.Tn system executable file
.El
.Sh BUGS
Can be fooled into thinking a core dump is the wrong size.
.Sh HISTORY
The
.Nm
command appeared in
.Bx 4.1 .