FreeBSD Man Pages

libmap.conf(5)

NAME

     libmap.conf -- configuration file for dynamic object dependency mapping

DESCRIPTION

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

     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.

     Constrained mappings may be specified by enclosing the name of the exe-
     cutable or library in brackets.  All mappings following a constraint will
     only be evaluated for that constraint.  Constraints can be one of three
     types:

     Exact   The constraint is matched literally so that only an executable
	     with an identical fully qualified pathname will match the con-
	     straint.  This means that the executable /usr/bin/foo will not
	     match a constraint for /usr/bin/./foo and vice-versa.  This is
	     the default constraint type.

     Basename
	     A constraint with no path is matched against the basename of the
	     executable.  foo will match /bin/foo, /usr/local/sbin/foo, or any
	     other executable named foo, no matter what its path is.

     Directory
	     A constraint with a trailing slash is prefix-matched against the
	     full pathname of the executable.  /usr/bin/ will match any exe-
	     cutable with a path starting with /usr/bin.

     Note that the executable path matched against is the path parameter in an
     exec*() function call.  The Directory or Exact constraints can only match
     when the executable is called with a full pathname.  Most programs exe-
     cuted from a shell are run without a full path, via exec*p(), so the
     Basename constraint type is the most useful.

     WARNING!  Constrained mappings must never appear first in the configura-
     tion file.  While there is a way to specify the ``default'' constraint,
     its use is not recommended.

     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.

EXAMPLES

     # /etc/libmap.conf
     #
     # candidate	     mapping
     #
     libpthread.so.1	     libpthread.so.1 # Everything uses 'libpthread'
     libpthread.so	     libpthread.so

     libc_r.so.5	     libpthread.so.1 # Everything that uses 'libc_r'
     libc_r.so		     libpthread.so   # now uses 'libpthread'

     [/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.1	     libthr.so.1
     libpthread.so	     libthr.so

FILES

     /etc/libmap.conf  The libmap configuration file.

SEE ALSO

     ldd(1), rtld(1)

HISTORY

     The libmap.conf manual page and libmap functionality first appeared in
     FreeBSD 5.1.

AUTHORS

     This manual page was written by Matthew N. Dodd <winter@jurai.net>.

FreeBSD 5.4		       January 31, 2004 		   FreeBSD 5.4

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