1.\"	$NetBSD: dbsym.8,v 1.4 2014/08/17 19:12:59 joerg Exp $
2.\"
3.Dd August 14, 2014
4.Dt DBSYM 8
5.Os
6.Sh NAME
7.Nm dbsym
8.Nd copy kernel symbol table into db_symtab space
9.Sh SYNOPSIS
10.Nm
11.Op Fl Ppv
12.Op Fl b Ar bfdname
13.Ar kernel
14.Sh DESCRIPTION
15.Nm
16is used to copy the symbol table in a newly linked kernel into the
17.Va db_symtab
18array (in the data section) so that the
19.Xr ddb 4
20kernel debugger can find the symbols.
21This program is only used
22on systems for which the boot program does not load the symbol table
23into memory with the kernel.
24The space for these symbols is
25reserved in the data segment using a config option like:
26.Dl options		SYMTAB_SPACE=72000
27The size of the db_symtab array (the value of SYMTAB_SPACE) must be
28at least as large as the kernel symbol table.
29If insufficient space
30is reserved, dbsym will refuse to copy the symbol table.
31.Pp
32To recognize kernel executable format, the
33.Fl b
34flag specifies BFD name of kernel.
35.Pp
36If the
37.Fl P
38flag is given,
39.Nm
40will report the size of the kernel symbol table.
41.Pp
42If the
43.Fl p
44flag is given,
45.Nm
46will report the size of the kernel symbol table and the size of the
47db_symtab space.
48Two values are printed out in a line separated by a space.
49.Pp
50If the
51.Fl v
52flag is given,
53.Nm
54will print out status information as
55it is copying the symbol table.
56.Pp
57Note that debugging symbols are not useful to the
58.Xr ddb 4
59kernel debugger, so to minimize the size of the kernel, one should
60either compile the kernel without debugging symbols (no
61.Fl g
62flag) or use the
63.Xr strip 1
64command to strip debugging symbols from the kernel before
65.Nm
66is used to copy the symbol table.
67The command
68.Dl strip -d netbsd
69will strip out debugging symbols.
70.Sh SEE ALSO
71.Xr strip 1 ,
72.Xr ddb 4
73