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.\" $DragonFly: src/sbin/ldconfig/ldconfig.8,v 1.2 2003/06/17 04:27:33 dillon Exp $ 32.\" 33.Dd October 3, 1993 34.Dt LDCONFIG 8 35.Os 36.Sh NAME 37.Nm ldconfig 38.Nd configure the shared library cache 39.Sh SYNOPSIS 40.Nm 41.Op Fl aout | Fl elf 42.Op Fl Rimrsv 43.Op Fl f Ar hints_file 44.Op Ar directory | Ar 45.Sh DESCRIPTION 46The 47.Nm 48utility is used to prepare a set of 49.Dq hints 50for use by the dynamic linker 51to facilitate quick lookup of shared libraries available in multiple 52directories. It scans a set of built-in system directories and any 53.Ar directories 54specified on the command line (in the given order) looking for 55shared libraries and stores the results in a system file to forestall 56the overhead that would otherwise result from the directory search 57operations the dynamic linker would have to perform to load the 58required shared libraries. 59.Pp 60Files named on the command line are expected to contain directories 61to scan for shared libraries. Each directory's pathname must start on a new 62line. Blank lines and lines starting with the comment character 63.Ql \&# 64are ignored. 65Filenames must conform to the 66.Pa lib*.so.[0-9] 67pattern in order to be added to the hints file. 68.Pp 69For security reasons, directories which are world or group-writable or which 70are not owned by root produce warning messages and are skipped, unless 71the 72.Fl i 73option is present. 74.Pp 75The shared libraries which are found will be automatically available for loading 76if needed by the program being prepared for execution. 77This obviates the need 78for storing search paths within the executable. 79.Pp 80The 81.Ev LD_LIBRARY_PATH 82environment variable can be used to override the use of 83directories (or the order thereof) from the cache or to specify additional 84directories where shared libraries might be found. 85.Ev LD_LIBRARY_PATH 86is a 87.Sq \&: 88separated list of directory paths which are searched by 89the dynamic linker 90when it needs to load a shared library. 91It can be viewed as the run-time 92equivalent of the 93.Fl L 94switch of 95.Xr ld 1 . 96.Pp 97The 98.Nm 99utility is typically run as part of the boot sequence. 100.Pp 101The following options are recognized by 102.Nm : 103.Bl -tag -width indent 104.It Fl aout 105Generate the hints for a.out format shared libraries. 106.It Fl elf 107Generate the hints for ELF format shared libraries. 108.It Fl R 109Rescan the previously configured directories. This opens the previous hints 110file and fetches the directory list from the header. Any additional pathnames 111on the command line are also processed. 112This is the default action when no parameters are given. 113.It Fl f Ar hints_file 114Read and/or update the specified hints file, instead of the standard file. 115This option is provided primarily for testing. 116.It Fl i 117Run in insecure mode. The security checks will not be performed. 118.It Fl m 119Instead of replacing the contents of the hints file 120with those found in the directories specified, 121.Dq merge 122in new entries. 123Directories recorded in the hints file by previous runs of 124.Nm 125are also rescanned for new shared libraries. 126.It Fl r 127List the current contents of the hints file 128on the standard output. 129The hints file is not modified. The list of 130directories stored in the hints file is included. 131.It Fl s 132Do not scan the built-in system directory 133.Pq Dq /usr/lib 134for shared libraries. 135.It Fl v 136Switch on verbose mode. 137.El 138.Sh SECURITY 139Special care must be taken when loading shared libraries into the address 140space of 141.Ev set-user-Id 142programs. 143Whenever such a program is run by any user except the owner of the program, 144the dynamic linker 145will only load shared libraries from the hints 146file. 147In particular, the 148.Ev LD_LIBRARY_PATH 149is not used to search for libraries. 150Thus, the role of ldconfig is dual. 151In 152addition to building a set of hints for quick lookup, it also serves to 153specify the trusted collection of directories from which shared objects can 154be safely loaded. 155.Sh ENVIRONMENT 156.Bl -tag -width OBJFORMATxxx -compact 157.It Ev OBJFORMAT 158Overrides 159.Pa /etc/objformat 160(see below) to determine whether 161.Fl aout 162or 163.Fl elf 164is the default. If set, its value should be either 165.Ql aout 166or 167.Ql elf . 168.El 169.Sh FILES 170.Bl -tag -width /var/run/ld-elf.so.hintsxxx -compact 171.It Pa /var/run/ld.so.hints 172Standard hints file for the a.out dynamic linker. 173.It Pa /var/run/ld-elf.so.hints 174Standard hints file for the ELF dynamic linker. 175.It Pa /etc/ld.so.conf 176Conventional configuration file containing directory names for 177invocations with 178.Fl aout . 179.It Pa /etc/ld-elf.so.conf 180Conventional configuration file containing directory names for 181invocations with 182.Fl elf . 183.It Pa /etc/objformat 184Determines whether 185.Fl aout 186or 187.Fl elf 188is the default. If present, it must consist of a single line 189containing either 190.Ql OBJFORMAT=aout 191or 192.Ql OBJFORMAT=elf . 193.El 194.Sh SEE ALSO 195.Xr ld 1 , 196.Xr link 5 197.Sh HISTORY 198A 199.Nm 200utility first appeared in SunOS 4.0, it appeared in its current form 201in 202.Fx 1.1 . 203.Sh BUGS 204Some security checks (for example, verifying root ownership of 205added directories) are not performed when 206.Fl aout 207is specified. 208