savecore.8

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)savecore.8	8.1	9/11/90
.TH savecore 8
.SH Name
savecore \- save a core dump of the operating system
.SH Syntax
.B /etc/savecore
[ \fIoptions\fR ]
.I dirname
[
.I system
]
[
.I corename
]
.SH Description
.NXR "savecore command"
.NXR "core dump" "saving"
The 
.PN savecore 
command
is meant to be called near the end of the 
.PN /etc/rc.local  
file.  The 
.PN savecore
command 
saves the core dump of the system (assuming one was made) and
writes a reboot message in the shutdown log.
.PP
The 
.PN savecore
command checks the core dump to be certain it corresponds with the
current running ULTRIX.  If it does, it saves the core image in the file
\fIdirname\f(CW/vmcore.\fIn\fR
and saves the namelist in the file \fIdirname\f(CW/vmunix.\fIn\fR.
The trailing \fI.n\fR in the pathnames is replaced by a number which
increments each time
.PN savecore
is run in that directory.
.PP
After saving the core and namelist images, 
.PN savecore
will save the error logger buffer into a predetermined file.  The error
logger buffer contains information about why the crash occurred.  After 
.PN savecore
completes, the 
.PN elcsd 
daemon will extract the error logger file and
translate its contents into a form familiar to the 
.MS uerf 8
program.
.PP
Before 
.PN savecore 
writes out a core image, it reads a number from the file
\fIdirname\f(CW/minfree\fR.
If there are fewer free blocks on the filesystem
that contains
.I dirname
than the number obtained from the 
.PN minfree
file, a core dump is not done.
If the
.PN minfree
file does not exist, savecore always writes out the core
file (assuming that a core dump was taken).
.PP
The 
.PN savecore 
command
also writes a reboot message in the shut down log.
If the system crashed
as a result of a panic,
.PN savecore
also records the panic string in the shut down log.
.PP
For partial crash dumps,
.PN savecore
creates a sparse core image file in
\fIdirname\f(CW/vmcore.\fIn\fR.
If this sparse core image file is
copied or moved to another location, the file expands to its true size
which can take too much file system space.  Hence, to copy or move
sparse core image files, you must use the
.PN dd
command. The
.PN dd
command has a conversion option to create sparse output files.
.SH Options
.IP \-c 5
Clears the core dump.  
This option is useful when the core
dump is corrupted in a way that will not allow
.PN savecore
to save it safely.  Use the 
.PN \-c
option with caution, because once it clears the core dump, the core
dump cannot be retrieved.
.IP "\-d \fIdumpdev dumplo\fP"
Specifies the dump device and the dump offset when running
.PN savecore
on a system image other than the currently running
system image. 
The 
.PN savecore 
program assumes that the running system image is
.PN /vmunix
and it reads the dump device and dump device offset are different 
in the system image that crashed, the 
.PN \-d
option provides the 
correct dump device and dump device offset.
.IP \-e 
Saves only the error logger buffer into a file.  If
used, core or namelist images are not saved.
.IP "\-f \fIcorename\fR"
Takes the i
.I corefile
name as the file from which to extract the the crash dump data
instead of the default dump device.  This option is used only for
diskless workstations.
.PP
If the core dump was from a system other than \f(CW/vmunix\fR, the name
of that system must be supplied as
.IR system .
The
.PN savecore
program assumes that the running image is
.PN /vmunix .
.PP
After successful completion, the core dump is cleared.  Also, a message
is written in the file 
.PN /usr/adm/shutdownlog
which tells whether the dump succeeded or failed.
.SH Files
.TP 20
.PN /usr/adm/shutdownlog 
Shut down log
.TP 
.PN /vmunix 
Current running ULTRIX system
.SH See Also
dd(1), uerf(8)