1.\" 2.\" Copyright (c) 1993 Paul Kranenburg 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. All advertising materials mentioning features or use of this software 14.\" must display the following acknowledgement: 15.\" This product includes software developed by Paul Kranenburg. 16.\" 3. The name of the author may not be used to endorse or promote products 17.\" derived from this software without specific prior written permission 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29.\" 30.\" $FreeBSD: src/sbin/ldconfig/ldconfig.8,v 1.19.2.10 2003/05/13 19:25:19 trhodes Exp $ 31.\" 32.Dd October 3, 1993 33.Dt LDCONFIG 8 34.Os 35.Sh NAME 36.Nm ldconfig 37.Nd configure the shared library cache 38.Sh SYNOPSIS 39.Nm 40.Op Fl aout | Fl elf 41.Op Fl Rimrsv 42.Op Fl f Ar hints_file 43.Op Ar directory | Ar 44.Sh DESCRIPTION 45The 46.Nm 47utility is used to prepare a set of 48.Dq hints 49for use by the dynamic linker 50to facilitate quick lookup of shared libraries available in multiple 51directories. It scans a set of built-in system directories and any 52.Ar directories 53specified on the command line (in the given order) looking for 54shared libraries and stores the results in a system file to forestall 55the overhead that would otherwise result from the directory search 56operations the dynamic linker would have to perform to load the 57required shared libraries. 58.Pp 59Files named on the command line are expected to contain directories 60to scan for shared libraries. Each directory's pathname must start on a new 61line. Blank lines and lines starting with the comment character 62.Ql \&# 63are ignored. 64Filenames must conform to the 65.Pa lib*.so.[0-9] 66pattern in order to be added to the hints file. 67.Pp 68For security reasons, directories which are world or group-writable or which 69are not owned by root produce warning messages and are skipped, unless 70the 71.Fl i 72option is present. 73.Pp 74The shared libraries which are found will be automatically available for loading 75if needed by the program being prepared for execution. 76This obviates the need 77for storing search paths within the executable. 78.Pp 79The 80.Ev LD_LIBRARY_PATH 81environment variable can be used to override the use of 82directories (or the order thereof) from the cache or to specify additional 83directories where shared libraries might be found. 84.Ev LD_LIBRARY_PATH 85is a 86.Sq \&: 87separated list of directory paths which are searched by 88the dynamic linker 89when it needs to load a shared library. 90It can be viewed as the run-time 91equivalent of the 92.Fl L 93switch of 94.Xr ld 1 . 95.Pp 96The 97.Nm 98utility is typically run as part of the boot sequence. 99.Pp 100The following options are recognized by 101.Nm : 102.Bl -tag -width indent 103.It Fl aout 104Generate the hints for a.out format shared libraries. 105.It Fl elf 106Generate the hints for ELF format shared libraries. 107.It Fl R 108Rescan the previously configured directories. This opens the previous hints 109file and fetches the directory list from the header. Any additional pathnames 110on the command line are also processed. 111This is the default action when no parameters are given. 112.It Fl f Ar hints_file 113Read and/or update the specified hints file, instead of the standard file. 114This option is provided primarily for testing. 115.It Fl i 116Run in insecure mode. The security checks will not be performed. 117.It Fl m 118Instead of replacing the contents of the hints file 119with those found in the directories specified, 120.Dq merge 121in new entries. 122Directories recorded in the hints file by previous runs of 123.Nm 124are also rescanned for new shared libraries. 125.It Fl r 126List the current contents of the hints file 127on the standard output. 128The hints file is not modified. The list of 129directories stored in the hints file is included. 130.It Fl s 131Do not scan the built-in system directory 132.Pq Dq /usr/lib 133for shared libraries. 134.It Fl v 135Switch on verbose mode. 136.El 137.Sh SECURITY 138Special care must be taken when loading shared libraries into the address 139space of 140.Ev set-user-Id 141programs. 142Whenever such a program is run by any user except the owner of the program, 143the dynamic linker 144will only load shared libraries from the hints 145file. 146In particular, the 147.Ev LD_LIBRARY_PATH 148is not used to search for libraries. 149Thus, the role of ldconfig is dual. 150In 151addition to building a set of hints for quick lookup, it also serves to 152specify the trusted collection of directories from which shared objects can 153be safely loaded. 154.Sh ENVIRONMENT 155.Bl -tag -width OBJFORMATxxx -compact 156.It Ev OBJFORMAT 157Overrides 158.Pa /etc/objformat 159(see below) to determine whether 160.Fl aout 161or 162.Fl elf 163is the default. If set, its value should be either 164.Ql aout 165or 166.Ql elf . 167.El 168.Sh FILES 169.Bl -tag -width /var/run/ld-elf.so.hintsxxx -compact 170.It Pa /var/run/ld.so.hints 171Standard hints file for the a.out dynamic linker. 172.It Pa /var/run/ld-elf.so.hints 173Standard hints file for the ELF dynamic linker. 174.It Pa /etc/ld.so.conf 175Conventional configuration file containing directory names for 176invocations with 177.Fl aout . 178.It Pa /etc/ld-elf.so.conf 179Conventional configuration file containing directory names for 180invocations with 181.Fl elf . 182.It Pa /etc/objformat 183Determines whether 184.Fl aout 185or 186.Fl elf 187is the default. If present, it must consist of a single line 188containing either 189.Ql OBJFORMAT=aout 190or 191.Ql OBJFORMAT=elf . 192.El 193.Sh SEE ALSO 194.Xr ld 1 , 195.Xr link 5 196.Sh HISTORY 197A 198.Nm 199utility first appeared in SunOS 4.0, it appeared in its current form 200in 201.Fx 1.1 . 202.Sh BUGS 203Some security checks (for example, verifying root ownership of 204added directories) are not performed when 205.Fl aout 206is specified. 207