xref: /freebsd/sbin/ddb/ddb.8 (revision cbb3ec25236ba72f91cbdf23f8b78b9d1af0cedf)
1.\"-
2.\" Copyright (c) 2007-2008 Robert N. M. Watson
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26.Dd December 24, 2008
27.Dt DDB 8
28.Os
29.Sh NAME
30.Nm ddb
31.Nd "configure DDB kernel debugger properties"
32.Sh SYNOPSIS
33.Nm
34.Cm capture
35.Op Fl M core
36.Op Fl N system
37.Cm print
38.Nm
39.Cm capture
40.Op Fl M core
41.Op Fl N system
42.Cm status
43.Nm
44.Cm script
45.Ar scriptname
46.Nm
47.Cm script
48.Ar scriptname Ns = Ns Ar script
49.Nm
50.Cm scripts
51.Nm
52.Cm unscript
53.Ar scriptname
54.Nm
55.Ar pathname
56.Sh DESCRIPTION
57The
58.Nm
59utility configures certain aspects of the
60.Xr ddb 4
61kernel debugger from user space that are not configured at compile-time or
62easily via
63.Xr sysctl 8
64MIB entries.
65.Pp
66To ease configuration, commands can be put in a file which is processed using
67.Nm
68as shown in the last synopsis line.
69An absolute
70.Ar pathname
71must be used.
72The file will be read line by line and applied as arguments to the
73.Nm
74utility.
75Whitespace at the beginning of lines will be ignored as will lines where the
76first non-whitespace character is
77.Ql # .
78.Sh OUTPUT CAPTURE
79The
80.Nm
81utility can be used to extract the contents of the
82.Xr ddb 4
83output capture buffer of the current live kernel, or from the crash dump of a
84kernel on disk.
85The following debugger commands are available from the command line:
86.Bl -tag -width indent
87.It Xo
88.Cm capture
89.Op Fl M Ar core
90.Op Fl N Ar system
91.Cm print
92.Xc
93Print the current contents of the
94.Xr ddb 4
95output capture buffer.
96.It Xo
97.Cm capture
98.Op Fl M Ar core
99.Op Fl N Ar system
100.Cm status
101.Xc
102Print the current status of the
103.Xr ddb 4
104output capture buffer.
105.El
106.Sh SCRIPTING
107The
108.Nm
109utility can be used to configure aspects of
110.Xr ddb 4
111scripting from user space; scripting support is described in more detail in
112.Xr ddb 4 .
113Each of the debugger commands is available from the command line:
114.Bl -tag -width indent
115.It Cm script Ar scriptname
116Print the script named
117.Ar scriptname .
118.It Cm script Ar scriptname Ns = Ns Ar script
119Define a script named
120.Ar scriptname .
121As many scripts contain characters interpreted in special ways by the shell,
122it is advisable to enclose
123.Ar script
124in quotes.
125.It Cm scripts
126List currently defined scripts.
127.It Cm unscript Ar scriptname
128Delete the script named
129.Ar scriptname .
130.El
131.Sh EXIT STATUS
132.Ex -std
133.Sh EXAMPLES
134The following example defines a script that will execute when the kernel
135debugger is entered as a result of a break signal:
136.Bd -literal -offset indent
137ddb script kdb.enter.break="show pcpu; bt"
138.Ed
139.Pp
140The following example will delete the script:
141.Pp
142.Dl "ddb unscript kdb.enter.break"
143.Pp
144For further examples, see the
145.Xr ddb 4
146and
147.Xr textdump 4
148manual pages.
149.Sh SEE ALSO
150.Xr ddb 4 ,
151.Xr mac_ddb 4 ,
152.Xr textdump 4 ,
153.Xr sysctl 8
154.Sh HISTORY
155The
156.Nm
157utility first appeared in
158.Fx 7.1 .
159.Sh AUTHORS
160.An Robert N M Watson
161.Sh BUGS
162Ideally,
163.Nm
164would not exist, as all pertinent aspects of
165.Xr ddb 4
166could be configured directly via
167.Xr sysctl 8 .
168