xref: /freebsd/sbin/savecore/savecore.8 (revision 13464e4a44fc58490a03bb8bfc7e3c972e9c30b2)
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28.\"     From: @(#)savecore.8	8.1 (Berkeley) 6/5/93
29.\" $FreeBSD$
30.\"
31.Dd December 10, 2016
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.# .
122If the core is encrypted, it saves the dump key in
123.Ar directory Ns Pa /key.# .
124The core can be later decrypted using
125.Xr decryptcore 8 .
126For kernel textdumps generated with the
127.Xr textdump 4
128facility, output will be stored in the
129.Xr tar 5
130format and named
131.Ar directory Ns Pa /textdump.tar.# .
132The
133.Dq #
134is the number from the first line of the file
135.Ar directory Ns Pa /bounds ,
136and it is incremented and stored back into the file each time
137.Nm
138successfully runs.
139.Pp
140The
141.Nm
142utility
143also checks the available disk space before attempting to make the copies.
144If there is insufficient disk space in the file system containing
145.Ar directory ,
146or if the file
147.Ar directory Ns Pa /minfree
148exists and the number of free kilobytes (for non-superusers) in the
149file system after the copies were made would be less than the number
150in the first line of this file, the copies are not attempted.
151.Pp
152If
153.Nm
154successfully copies the kernel and the core dump, the core dump is cleared
155so that future invocations of
156.Nm
157will ignore it.
158.Pp
159The
160.Nm
161utility
162is meant to be called near the end of the initialization file
163.Pa /etc/rc
164(see
165.Xr rc 8 ) .
166.Sh SEE ALSO
167.Xr gzip 1 ,
168.Xr getbootfile 3 ,
169.Xr libxo 3 ,
170.Xr xo_parse_args 3 ,
171.Xr textdump 4 ,
172.Xr tar 5 ,
173.Xr decryptcore 8 ,
174.Xr dumpon 8 ,
175.Xr syslogd 8
176.Sh HISTORY
177The
178.Nm
179utility appeared in
180.Bx 4.1 .
181.Pp
182Support for kernel textdumps appeared in
183.Fx 7.1 .
184.Sh BUGS
185The minfree code does not consider the effect of compression or sparse files.
186