.\" Copyright (c) 2003 Matthew N. Dodd <winter@jurai.net>
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.\" $FreeBSD$
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.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
.Nm libmap
functionality of
.Xr ld-elf.so.1 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
.Pa /usr/bin/foo
will not match a constraint for
.Pa 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
.Tn 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 ldd 1 ,
.Xr rtld 1
.Sh HISTORY
The
.Nm
manual page and
.Nm libmap
functionality first appeared in
.Fx 5.1 .
.Sh AUTHORS
This manual page was written by
.An Matthew N. Dodd Aq winter@jurai.net .