LDCONFIG(8)             FreeBSD System Manager's Manual            LDCONFIG(8)

NAME

     ldconfig - configure the dynamic linker search path for shared libraries

SYNOPSIS

     ldconfig [-32] [-BRimr] [-f hints_file] [directory | file ...]

DESCRIPTION

     ldconfig utility is used to configure the set of paths used by the
     dynamic linker ld-elf.so.1(1) when searching for shared libraries.  The
     dynamic linker looks for libraries in a set of built-in system
     directories and any directories specified in the hints file.  This
     obviates the need for storing search paths within the executable, see the
     -rpath option for the static linker ld(1).

     The hints file is maintained by ldconfig.  The directories list to be
     stored in the hints file is supplied on the command line.

     Alternatively to the directories list on the command line, files may be
     specified; these are expected to contain directories to scan for shared
     libraries.  Each directory's pathname must start on a new line.  Blank
     lines and lines starting with the comment character `#' are ignored.

     For security reasons, directories which are world or group-writable or
     which are not owned by root produce warning messages and are skipped,
     unless the -i option is present.

     The LD_LIBRARY_PATH environment variable can be used to specify
     additional shared library search directories.  LD_LIBRARY_PATH is a `:'
     separated list of directory paths which are searched by the dynamic
     linker when it needs to load a shared library.  It can be viewed as the
     run-time equivalent of the -L switch of ld(1).

     The following options are recognized by ldconfig:

     -32     Generate the hints for 32-bit ABI shared libraries on 64-bit
             systems that support running 32-bit binaries.

     -elf    Ignored for backwards compatibility.

     -B      Force writing big-endian binary data to the hints file.  The
             default is to create hints files in little-endian byte-order on
             all architectures.  Reading of and merging into hints files
             preserves the endianness of the existing hints file.

     -R      Appends pathnames on the command line to the directory list from
             the hints file.

             This is the default action when no options are given.

     -f hints_file
             Read and/or update the specified hints file, instead of the
             standard file.  This option is provided primarily for testing.

     -i      Run in insecure mode.  The security checks will not be performed.

     -m      Instead of replacing the list of the directories to search with
             the directories specified on the command line, merge existing
             list with the specified directories, and write the result to the
             hints file.

     -r      List the current list of the directories from the hints file on
             the standard output.  The hints file is not modified.

             Scan and print all libraries found on the directories list.

     The historic options -elf, -s, and -v are accepted but ignored.

SECURITY

     Special care must be taken when loading shared libraries into the address
     space of set-user-Id programs.  Whenever such a program is run by any
     user except the owner of the program, the dynamic linker will only load
     shared libraries from paths found in the hints file.  In particular, the
     LD_LIBRARY_PATH is not used to search for libraries.  Thus, ldconfig
     serves to specify the trusted collection of directories from which shared
     objects can be safely loaded.

FILES

     /var/run/ld-elf.so.hints       Standard hints file for the ELF dynamic
                                    linker.
     /var/run/ld-elf32.so.hints     Hints file for 32 bit libraries on 64 bit
                                    architectures, processed by ldconfig when
                                    invoked with -32.
     /etc/ld-elf.so.conf            Optional file with names of directories to
                                    be included in the standard hints file
                                    when booting to multi-user mode.
     /usr/local/libdata/ldconfig/*  Additional files with names of directories
                                    provided by optional ports or packages.

SEE ALSO

     ld(1), ld-elf.so.1(1), link(5)

HISTORY

     A ldconfig utility first appeared in SunOS 4.0, it appeared in its
     current form in FreeBSD 1.1.

     The name 'hints file' is historic from the times when the file also
     contained hints to the dynamic linker.  This functionality is not
     provided for ELF.

FreeBSD 15.1-STABLE-HBSD        April 20, 2024                     LDCONFIG(8)