LIBMAP.CONF(5) FreeBSD File Formats Manual LIBMAP.CONF(5)


libmap.confconfiguration file for dynamic object dependency mapping


The libmap functionality of ld-elf.so.1(1) allows dynamic object dependencies to be mapped to arbitrary names.

Each line in /etc/libmap.conf can have one of five forms:

origin target
Whenever a dependency on origin is encountered while loading a dynamic object, use target instead of searching for origin in the normal library search paths.
path1 path2
When iterating through a library search path, replace any element that matches path1 exactly with path2.
[ constraint]
Apply constraint to all subsequent mappings until the next constraint line or the end of the file. See the Constraints section for details.
include file
Parse the contents of file before continuing with the current file. Nesting depth is limited only by available memory, but each file encountered is processed only once, and loops are silently ignored.
includedir dir
Recurse through dir and parse the contents of any file that ends in .conf before continuing with the current file. Nesting depth is limited only by available memory, but each directory or file encountered is processed only once, and loops are silently ignored.


Constrained mappings only apply when processing binaries or libraries that satisfy the constraint. There are three types of constraints:
The constraint is matched literally so that only an executable with an identical fully qualified pathname will satisfy the constraint. This means that the executable /usr/bin/foo will not satisfy the constraint [ /usr/bin/./foo], and vice-versa. This is the default constraint type.
A constraint with no path is matched against the basename of the executable. For instance, the constraint [ foo] will match /bin/foo, /usr/local/sbin/foo, or any other executable named foo, no matter what directory it is in.
A constraint with a trailing slash is satisfied if the full pathname begins with the constraint string. For instance, the constraint [ /usr/bin/] will match any executable with a path starting with /usr/bin/.

Note that the constraints are matched against the path that was passed as the first argument to whichever exec(3) function was used to execute the binary in question. Most programs executed from a shell are run without a full path, via execvp(3) or similar, so the basename constraint type is the most useful.

WARNING! Constraints apply to all mappings until the next constraint or the end of the file. Hence, unconstrained mappings must be placed at the top of the file.

ABI compatibility

On 64-bit architectures that provide 32-bit binary compatibility, the mappings in /etc/libmap.conf apply only to 64-bit binaries. Mappings for 32-bit binaries must be placed in /etc/libmap32.conf.


The libmap configuration file.
The libmap configuration file for 32-bit binaries on 64-bit system.


# origin  target 
libc_r.so.6  libpthread.so.2 # Everything that uses 'libc_r' 
libc_r.so  libpthread.so # now uses 'libpthread' 
[/tmp/mplayer]  # Test version of mplayer uses libc_r 
libpthread.so.2  libc_r.so.6 
libpthread.so  libc_r.so 
[/usr/local/jdk1.4.1/] # All Java 1.4.1 programs use libthr 
   # This works because "javavms" executes 
   # programs with the full pathname 
libpthread.so.2  libthr.so.2 
libpthread.so  libthr.so 
# Glue for Linux-only EPSON printer .so to be loaded into cups, etc. 
libc.so.6  pluginwrapper/pips.so 
libdl.so.2  pluginwrapper/pips.so


ldd(1), rtld(1)


The libmap mechanism first appeared in FreeBSD 5.1.


This manual page was written by Matthew N. Dodd <winter@jurai.net> and extensively rewritten by Dag-Erling Smørgrav <des@FreeBSD.org>.
September 16, 2013 FreeBSD