サーバーのよく使うコマンドメモ| ldd

2016年3月2日

コマンド サーバー

Summery

モジュールの依存関係を調べる

Construction

$ldd [option] [module-path]

Option

-u : 使われていない依存関係を表示 -v : 詳細表示 -d : 見つからないオブジェクトを表示 -r : 見つからないオブジェクトや関数を表示

Sample

## ls $ ldd /bin/ls linux-gate.so.1 (0xb770d000) libselinux.so.1 => /lib/i386-linux-gnu/libselinux.so.1 (0xb76dc000) libacl.so.1 => /lib/i386-linux-gnu/libacl.so.1 (0xb76d2000) libc.so.6 => /lib/i386-linux-gnu/i686/cmov/libc.so.6 (0xb7527000) libpcre.so.3 => /lib/i386-linux-gnu/libpcre.so.3 (0xb74b6000) libdl.so.2 => /lib/i386-linux-gnu/i686/cmov/libdl.so.2 (0xb74b1000) /lib/ld-linux.so.2 (0xb7710000) libattr.so.1 => /lib/i386-linux-gnu/libattr.so.1 (0xb74ab000) libpthread.so.0 => /lib/i386-linux-gnu/i686/cmov/libpthread.so.0 (0xb748f000) $ ldd -u /bin/ls Unused direct dependencies: /lib/i386-linux-gnu/libselinux.so.1 /lib/i386-linux-gnu/libacl.so.1 ## tar $ ldd /bin/tar linux-gate.so.1 (0xb773f000) libacl.so.1 => /lib/i386-linux-gnu/libacl.so.1 (0xb772c000) libselinux.so.1 => /lib/i386-linux-gnu/libselinux.so.1 (0xb7704000) libc.so.6 => /lib/i386-linux-gnu/i686/cmov/libc.so.6 (0xb7559000) libattr.so.1 => /lib/i386-linux-gnu/libattr.so.1 (0xb7553000) libpcre.so.3 => /lib/i386-linux-gnu/libpcre.so.3 (0xb74e2000) libdl.so.2 => /lib/i386-linux-gnu/i686/cmov/libdl.so.2 (0xb74dd000) /lib/ld-linux.so.2 (0xb7742000) libpthread.so.0 => /lib/i386-linux-gnu/i686/cmov/libpthread.so.0 (0xb74c1000) ## rsync $ which rsync /usr/bin/rsync $ ldd /usr/bin/rsync linux-gate.so.1 (0xb779f000) libattr.so.1 => /lib/i386-linux-gnu/libattr.so.1 (0xb76fd000) libacl.so.1 => /lib/i386-linux-gnu/libacl.so.1 (0xb76f3000) libpopt.so.0 => /lib/i386-linux-gnu/libpopt.so.0 (0xb76e4000) libc.so.6 => /lib/i386-linux-gnu/i686/cmov/libc.so.6 (0xb753a000) /lib/ld-linux.so.2 (0xb77a2000)

Discription

LDD(1) Linux Programmer's Manual LDD(1) NAME ldd - print shared library dependencies SYNOPSIS ldd [option]... file... DESCRIPTION ldd prints the shared libraries required by each program or shared library specified on the command line. Security In the usual case, ldd invokes the standard dynamic linker (see ld.so(8)) with the LD_TRACE_LOADED_OBJECTS environment variable set to 1, which causes the linker to dis‐ play the library dependencies. Be aware, however, that in some circumstances, some ver‐ sions of ldd may attempt to obtain the dependency information by directly executing the program. Thus, you should never employ ldd on an untrusted executable, since this may result in the execution of arbitrary code. A safer alternative when dealing with untrusted executables is: $ objdump -p /path/to/program | grep NEEDED OPTIONS --version Print the version number of ldd. -v --verbose Print all information, including, for example, symbol versioning information. -u --unused Print unused direct dependencies. (Since glibc 2.3.4.) -d --data-relocs Perform relocations and report any missing objects (ELF only). -r --function-relocs Perform relocations for both data objects and functions, and report any missing objects or functions (ELF only). --help Usage information. BUGS ldd does not work on a.out shared libraries. ldd does not work with some extremely old a.out programs which were built before ldd support was added to the compiler releases. If you use ldd on one of these programs, the program will attempt to run with argc = 0 and the results will be unpredictable. SEE ALSO sprof(1), pldd(1), ld.so(8), ldconfig(8) COLOPHON This page is part of release 3.74 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at http://www.kernel.org/doc/man-pages/. 2014-10-02 LDD(1)

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