xref: /freebsd/share/man/man5/core.5 (revision 17ee9d00bc1ae1e598c38f25826f861e4bc6c3ce)
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32.\"     @(#)core.5	8.3 (Berkeley) 12/11/93
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34.Dd December 11, 1993
35.Dt CORE 5
36.Os BSD 4
37.Sh NAME
38.Nm core
39.Nd memory image file format
40.Sh SYNOPSIS
41.Fd #include <sys/param.h>
42.Sh DESCRIPTION
43A small number of signals which cause abnormal termination of a process
44also cause a record of the process's in-core state to be written
45to disk for later examination by one of the available debuggers.
46(See
47.Xr sigaction 2 . )
48This memory image is written to a file named
49.Nm programname.core
50in the working directory;
51provided the terminated process had write permission in the directory,
52and provided the abnormality did not cause
53a system crash.
54(In this event, the decision to save the core file is arbitrary, see
55.Xr savecore 8 . )
56.Pp
57The maximum size of a
58.Nm programname.core
59file is limited by
60.Xr setrlimit 2 .
61Files which would be larger than the limit are not created.
62.Pp
63The
64.Nm programname.core
65file consists of the
66.Fa u .
67area, whose size (in pages) is
68defined by the
69.Dv UPAGES
70manifest in the
71.Aq Pa sys/param.h
72file.  The
73.Fa u .
74area starts with a
75.Fa user
76structure as given in
77.Aq Pa sys/user.h .
78The remainder of the
79.Nm programname.core
80file consists of the data pages followed by
81the stack pages of the process image.
82The amount of data space image in the
83.Nm programname.core
84file is given (in pages) by the
85variable
86.Fa u_dsize
87in the
88.Fa u .
89area.
90The amount of stack image in the core file is given (in pages) by the
91variable
92.Fa u_ssize
93in the
94.Ar u .
95area.
96The size of a ``page'' is given by the constant
97.Dv NBPG
98(also from
99.Aq Pa sys/param.h ) .
100.Sh SEE ALSO
101.Xr adb 1 ,
102.Xr dbx 1 ,
103.Xr gdb 1 ,
104.Xr kgdb 1 ,
105.Xr sigaction 2 ,
106.Xr setrlimit 2
107.Sh HISTORY
108A
109.Nm core
110file format appeared in
111.At v6 .
112