better calculation of freespace

[unix-history] / usr / src / sbin / savecore / savecore.8

.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"	@(#)savecore.8	6.1 (Berkeley) %G%
.\"
.TH SAVECORE 8 ""
.UC 4
.SH NAME
savecore \- save a core dump of the operating system
.SH SYNOPSIS
.B /etc/savecore
.I dirname
[
.I system
]
.SH DESCRIPTION
.I Savecore
is meant to be called near the end of the /etc/rc file.  Its function
is to save the core dump of the system (assuming one was made) and to
write a reboot message in the shutdown log.
.PP
Savecore checks the core dump to be certain it corresponds with the
current running unix.  If it does it saves the core image in the file
.IR dirname /vmcore.n
and it's brother, the namelist,
.IR dirname /vmunix.n
The trailing ".n" in the pathnames is replaced by a number which grows
every time
.I savecore
is run in that directory.
.PP
Before savecore writes out a core image, it reads a number from the file
.IR dirname /minfree.
If the number of free bytes on the filesystem which contains
.I dirname
is less than the number obtained from the minfree file times 1024,
the core dump is not done.
If the minfree file does not exist, savecore always writes out the core
file (assuming that a core dump was taken).
.PP
.I Savecore
also writes a reboot message in the shut down log.  If the system crashed
as a result of a panic,
.I savecore
records the panic string in the shut down log too.
.PP
If the core dump was from a system other than /vmunix, the name
of that system must be supplied as
.IR sysname .
.SH FILES
.DT
/usr/adm/shutdownlog	shut down log
.br
/vmunix		current UNIX
.SH BUGS
Can be fooled into thinking a core dump is the wrong size.