.\" Copyright (c) 2003 Matthew N. Dodd <winter@jurai.net>
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.\" $FreeBSD$
.\"
.\" Note: The date here should be updated whenever a non-trivial
.\" change is made to the manual page.
.Dd April 7, 2003
.Dt LIBMAP.CONF 5
.Os
.Sh NAME
.Nm libmap.conf
.Nd "configuration file for dynamic object dependency mapping"
.Sh DESCRIPTION
The
.Em libmap
functionality of
.Nm ld-elf.so.1
allows dynamic object dependencies to be mapped to arbitrary
names.
.Pp
The configuration file consists of two whitespace separated columns; the 
left hand side containing the mapping candidate and the right hand
side containing the mapping.  Dependencies are matched against candidates
and replaced with the mappings.
.Pp
Constrained mappings may be specified by enclosing the name of the
executable or library in brackets.  All mappings following a constraint
will only be evaluated for that constraint.  Currently, constraints
are matched literally so that an executable with a fully qualified pathname 
will only match the same constraint.  This means that
.Em /usr/bin/foo
will not match a constraint for
.Em foo
and vise-versa.
.Pp
WARNING!  Constrained mappings must never appear first in the configuration
file.  While there is a way to specify the
.Dq default
constraint, its use is not recommended.
.Pp
The most common use at the date of writing is for allowing multiple
POSIX threading libraries to be used on a system without relinking or
changing symlinks.
.Pp
In order to enable this feature please see 
.Pa src/libexec/rtld-elf/Makefile .
.Sh EXAMPLE
.Bd -literal

# /etc/libmap.conf
#
# candidate		mapping
#
libc_r.so.5		libthr.so.1	# Everything uses 'libthr'
libc_r.so		libthr.so

[/usr/local/bin/mplayer]		# 'mplayer' uses libc_r.
libc_r.so.5		libc_r.so.5
libc_r.so		libc_r.so

[mplayer]
libc_r.so.5		libc_r.so.5
libc_r.so		libc_r.so

[/usr/local/sbin/httpd]			# Apache uses libkse
libc_r.so.5		libkse.so.1
libc_r.so		libkse.so

[httpd]
libc_r.so.5		libkse.so.1
libc_r.so		libkse.so
.Ed
.Sh FILES
.Bl -tag -width ".Pa /etc/libmap.conf" -compact
.It Pa /etc/libmap.conf
The libmap configuration file.
.El
.Sh SEE ALSO
.Xr rtld 1
.Xr ldd 1
.Sh HISTORY
The
.Nm
manual page and libmap.conf functionality first appeared in
.Fx 5.1 .
.Sh AUTHORS
This
manual page was written by
.An Matthew N. Dodd <winter@jurai.net> .