xref: /freebsd/sbin/savecore/savecore.8 (revision a70cba95822f662d3f9da5119b6a0c433e8f70af)
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28.\"     From: @(#)savecore.8	8.1 (Berkeley) 6/5/93
29.\" $FreeBSD$
30.\"
31.Dd December 1, 2015
32.Dt SAVECORE 8
33.Os
34.Sh NAME
35.Nm savecore
36.Nd "save a core dump of the operating system"
37.Sh SYNOPSIS
38.Nm
39.Fl c
40.Op Fl v
41.Op Ar device ...
42.Nm
43.Fl C
44.Op Fl v
45.Op Ar device ...
46.Nm
47.Op Fl -libxo
48.Op Fl fkvz
49.Op Fl m Ar maxdumps
50.Op Ar directory Op Ar device ...
51.Sh DESCRIPTION
52The
53.Nm
54utility
55copies a core dump into
56.Ar directory ,
57or the current working directory if no
58.Ar directory
59argument is given,
60and enters a reboot message and information about the core dump into
61the system log.
62.Pp
63The options are as follows:
64.Bl -tag -width ".Fl m Ar maxdumps"
65.It Fl -libxo
66Generate output via
67.Xr libxo 3
68in a selection of different human and machine readable formats.
69See
70.Xr xo_parse_args 3
71for details on command line arguments.
72.It Fl C
73Check to see if a dump exists,
74and display a brief message to indicate the status.
75An exit status of 0 indicates that a dump is there,
761 indicates that none exists.
77This option is compatible only with the
78.Op Fl v
79option.
80.It Fl c
81Clear the dump, so that future invocations of
82.Nm
83will ignore it.
84.It Fl f
85Force a dump to be taken even if either the dump was cleared or if the
86dump header information is inconsistent.
87.It Fl k
88Do not clear the dump after saving it.
89.It Fl m Ar maxdumps
90Maximum number of dumps to store.
91Once the number of stored dumps is equal to
92.Ar maxdumps
93the counter will restart from
94.Dv 0 .
95.It Fl v
96Print out some additional debugging information.
97Specify twice for more information.
98.It Fl z
99Compress the core dump and kernel (see
100.Xr gzip 1 ) .
101.El
102.Pp
103The
104.Nm
105utility
106looks for dumps on each device specified by the
107.Ar device
108argument(s), or on each device in
109.Pa /etc/fstab
110marked as
111.Dq dump
112or
113.Dq swap .
114The
115.Nm
116utility
117checks the core dump in various ways to make sure that it is complete.
118If it passes these checks, it saves the core image in
119.Ar directory Ns Pa /vmcore.#
120and information about the core in
121.Ar directory Ns Pa /info.# .
122For kernel textdumps generated with the
123.Xr textdump 4
124facility, output will be stored in the
125.Xr tar 5
126format and named
127.Ar directory Ns Pa /textdump.tar.# .
128The
129.Dq #
130is the number from the first line of the file
131.Ar directory Ns Pa /bounds ,
132and it is incremented and stored back into the file each time
133.Nm
134successfully runs.
135.Pp
136The
137.Nm
138utility
139also checks the available disk space before attempting to make the copies.
140If there is insufficient disk space in the file system containing
141.Ar directory ,
142or if the file
143.Ar directory Ns Pa /minfree
144exists and the number of free kilobytes (for non-superusers) in the
145file system after the copies were made would be less than the number
146in the first line of this file, the copies are not attempted.
147.Pp
148If
149.Nm
150successfully copies the kernel and the core dump, the core dump is cleared
151so that future invocations of
152.Nm
153will ignore it.
154.Pp
155The
156.Nm
157utility
158is meant to be called near the end of the initialization file
159.Pa /etc/rc
160(see
161.Xr rc 8 ) .
162.Sh SEE ALSO
163.Xr gzip 1 ,
164.Xr getbootfile 3 ,
165.Xr libxo 3 ,
166.Xr xo_parse_args 3 ,
167.Xr textdump 4 ,
168.Xr tar 5 ,
169.Xr dumpon 8 ,
170.Xr syslogd 8
171.Sh HISTORY
172The
173.Nm
174utility appeared in
175.Bx 4.1 .
176.Pp
177Support for kernel textdumps appeared in
178.Fx 7.1 .
179.Sh BUGS
180The minfree code does not consider the effect of compression or sparse files.
181