1 .\" Copyright 1995-2000 David Engel (david@ods.com)
2 .\" Copyright 1995 Rickard E. Faith (faith@cs.unc.edu)
3 .\" Copyright 2000 Ben Collins (bcollins@debian.org)
4 .\" Redone for GLibc 2.2
5 .\" Copyright 2000 Jakub Jelinek (jakub@redhat.com)
7 .\" and Copyright (C) 2012, 2016, Michael Kerrisk <mtk.manpages@gmail.com>
9 .\" SPDX-License-Identifier: GPL-1.0-or-later
11 .TH LDD 1 (date) "Linux man-pages (unreleased)"
13 ldd \- print shared object dependencies
16 .BR ldd " [\fIoption\fP]... \fIfile\fP..."
20 prints the shared objects (shared libraries) required by each program or
21 shared object specified on the command line.
22 An example of its use and output
28 linux\-vdso.so.1 (0x00007ffcc3563000)
29 libselinux.so.1 => /lib64/libselinux.so.1 (0x00007f87e5459000)
30 libcap.so.2 => /lib64/libcap.so.2 (0x00007f87e5254000)
31 libc.so.6 => /lib64/libc.so.6 (0x00007f87e4e92000)
32 libpcre.so.1 => /lib64/libpcre.so.1 (0x00007f87e4c22000)
33 libdl.so.2 => /lib64/libdl.so.2 (0x00007f87e4a1e000)
34 /lib64/ld\-linux\-x86\-64.so.2 (0x00005574bf12e000)
35 libattr.so.1 => /lib64/libattr.so.1 (0x00007f87e4817000)
36 libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f87e45fa000)
42 invokes the standard dynamic linker (see
45 .B LD_TRACE_LOADED_OBJECTS
46 environment variable set to 1.
47 This causes the dynamic linker to inspect the program's dynamic dependencies,
48 and find (according to the rules described in
50 and load the objects that satisfy those dependencies.
53 displays the location of the matching object
54 and the (hexadecimal) address at which it is loaded.
59 shared dependencies are special; see
65 Be aware that in some circumstances
66 (e.g., where the program specifies an ELF interpreter other than
68 .\" The circumstances are where the program has an interpreter
69 .\" other than ld-linux.so. In this case, ldd tries to execute the
70 .\" program directly with LD_TRACE_LOADED_OBJECTS=1, with the
71 .\" result that the program interpreter gets control, and can do
72 .\" what it likes, or pass control to the program itself.
73 .\" Much more detail at
74 .\" http://www.catonmat.net/blog/ldd-arbitrary-code-execution/
77 may attempt to obtain the dependency information
78 by attempting to directly execute the program,
79 which may lead to the execution of whatever code is defined
80 in the program's ELF interpreter,
81 and perhaps to execution of the program itself.
82 .\" Mainline glibc's ldd allows this possibility (the line
84 .\" in glibc 2.15, for example), but many distro versions of
85 .\" ldd seem to remove that code path from the script.
86 (In glibc versions before 2.27,
87 .\" glibc commit eedca9772e99c72ab4c3c34e43cc764250aa3e3c
90 implementation did this for example,
91 although most distributions provided a modified version that did not.)
97 on an untrusted executable,
98 since this may result in the execution of arbitrary code.
99 A safer alternative when dealing with untrusted executables is:
103 $ \fBobjdump \-p /path/to/program | grep NEEDED\fP
107 Note, however, that this alternative shows only the direct dependencies
108 of the executable, while
110 shows the entire dependency tree of the executable.
114 Print the version number of
117 .BR \-v ", " \-\-verbose
118 Print all information, including, for example,
119 symbol versioning information.
121 .BR \-u ", " \-\-unused
122 Print unused direct dependencies.
125 .BR \-d ", " \-\-data\-relocs
126 Perform relocations and report any missing objects (ELF only).
128 .BR \-r ", " \-\-function\-relocs
129 Perform relocations for both data objects and functions, and
130 report any missing objects or functions (ELF only).
135 .\" The standard version of
137 .\" comes with glibc2.
138 .\" Libc5 came with an older version, still present
140 .\" The long options are not supported by the libc5 version.
141 .\" On the other hand, the glibc2 version does not support
143 .\" and only has the equivalent
144 .\" .BR \-\-version .
146 .\" The libc5 version of this program will use the name of a library given
147 .\" on the command line as-is when it contains a \(aq/\(aq; otherwise it
148 .\" searches for the library in the standard locations.
150 .\" on a shared library in the current directory, prefix the name with "./".
153 does not work on a.out shared libraries.
156 does not work with some extremely old a.out programs which were
159 support was added to the compiler releases.
162 on one of these programs, the program will attempt to run with
164 = 0 and the results will be unpredictable.
167 .\" Roland McGrath and Ulrich Drepper.