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 .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE)
10 .\" Do not restrict distribution.
11 .\" May be distributed under the GNU General Public License
14 .TH LDD 1 2017-07-13 "" "Linux Programmer's Manual"
16 ldd \- print shared object dependencies
18 .BR ldd " [\fIoption\fP]... \fIfile\fP..."
21 prints the shared objects (shared libraries) required by each program or
22 shared object specified on the command line.
23 An example of its use and output is the following:
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.
90 on an untrusted executable,
91 since this may result in the execution of arbitrary code.
92 A safer alternative when dealing with untrusted executables is:
96 $ \fBobjdump \-p /path/to/program | grep NEEDED\fP
100 Note, however, that this alternative shows only the direct dependencies
101 of the executable, while
103 shows the entire dependency tree of the executable.
107 Print the version number of
110 .BR \-v ", " \-\-verbose
111 Print all information, including, for example,
112 symbol versioning information.
114 .BR \-u ", " \-\-unused
115 Print unused direct dependencies.
118 .BR \-d ", " \-\-data\-relocs
119 Perform relocations and report any missing objects (ELF only).
121 .BR \-r ", " \-\-function\-relocs
122 Perform relocations for both data objects and functions, and
123 report any missing objects or functions (ELF only).
128 .\" The standard version of
130 .\" comes with glibc2.
131 .\" Libc5 came with an older version, still present
133 .\" The long options are not supported by the libc5 version.
134 .\" On the other hand, the glibc2 version does not support
136 .\" and only has the equivalent
137 .\" .BR \-\-version .
139 .\" The libc5 version of this program will use the name of a library given
140 .\" on the command line as-is when it contains a \(aq/\(aq; otherwise it
141 .\" searches for the library in the standard locations.
143 .\" on a shared library in the current directory, prefix the name with "./".
146 does not work on a.out shared libraries.
149 does not work with some extremely old a.out programs which were
152 support was added to the compiler releases.
155 on one of these programs, the program will attempt to run with
157 = 0 and the results will be unpredictable.
160 .\" Roland McGrath and Ulrich Drepper.