The output of ldd is very useful when trying to understand dynamic library resolution. However, the ldd output lacks some things that would make it even better. PDD attempts to improve on this.
Example (LDD):
$ which cmake
/sw/arch/RHEL9/EB_production/2024/software/CMake/3.29.3-GCCcore-13.3.0/bin/cmake
$ ldd `which cmake`
linux-vdso.so.1 (0x00007fff53dd5000)
/sw/arch/xalt/lib64/libxalt_init.so (0x00001527ca1ae000)
libcurl.so.4 => /sw/arch/RHEL9/EB_production/2024/software/cURL/8.7.1-GCCcore-13.3.0/lib64/libcurl.so.4 (0x00001527ca0eb000)
libarchive.so.13 => /sw/arch/RHEL9/EB_production/2024/software/libarchive/3.7.4-GCCcore-13.3.0/lib64/libarchive.so.13 (0x00001527c9fff000)
libz.so.1 => /sw/arch/RHEL9/EB_production/2024/software/zlib/1.3.1-GCCcore-13.3.0/lib64/libz.so.1 (0x00001527c9fdf000)
libstdc++.so.6 => /sw/arch/RHEL9/EB_production/2024/software/GCCcore/13.3.0/lib64/libstdc++.so.6 (0x00001527c9d7d000)
libm.so.6 => /lib64/libm.so.6 (0x00001527c9c8e000)
libgcc_s.so.1 => /sw/arch/RHEL9/EB_production/2024/software/GCCcore/13.3.0/lib64/libgcc_s.so.1 (0x00001527c9c68000)
libc.so.6 => /lib64/libc.so.6 (0x00001527c9a5f000)
libidn2.so.0 => /home/paulm/.local/easybuild/RHEL9/2024/software/libidn2/2.3.7-GCCcore-13.3.0/lib/libidn2.so.0 (0x00001527c9a05000)
libssl.so.3 => /sw/arch/RHEL9/EB_production/2024/software/OpenSSL/3/lib64/libssl.so.3 (0x00001527c995d000)
libcrypto.so.3 => /sw/arch/RHEL9/EB_production/2024/software/OpenSSL/3/lib64/libcrypto.so.3 (0x00001527c952a000)
libzstd.so.1 => /sw/arch/RHEL9/EB_production/2024/software/zstd/1.5.6-GCCcore-13.3.0/lib/libzstd.so.1 (0x00001527c9434000)
libbrotlidec.so.1 => /sw/arch/RHEL9/EB_production/2024/software/Brotli/1.1.0-GCCcore-13.3.0/lib/libbrotlidec.so.1 (0x00001527c9424000)
libacl.so.1 => /lib64/libacl.so.1 (0x00001527c9417000)
liblzma.so.5 => /sw/arch/RHEL9/EB_production/2024/software/XZ/5.4.5-GCCcore-13.3.0/lib64/liblzma.so.5 (0x00001527c93e2000)
libbz2.so.1 => /lib64/libbz2.so.1 (0x00001527c93cf000)
libxml2.so.2 => /lib64/libxml2.so.2 (0x00001527c9246000)
/lib64/ld-linux-x86-64.so.2 (0x00001527ca219000)
libbrotlicommon.so.1 => /sw/arch/RHEL9/EB_production/2024/software/Brotli/1.1.0-GCCcore-13.3.0/lib/libbrotlicommon.so.1 (0x00001527c9221000)
libattr.so.1 => /lib64/libattr.so.1 (0x00001527c9219000)
Example (PDD):
$ ./pdd `which cmake`
/sw/arch/RHEL9/EB_production/2024/software/CMake/3.29.3-GCCcore-13.3.0/bin/cmake
NEEDED entries (sorted):
libarchive.so.13 libc.so.6 libcurl.so.4 libgcc_s.so.1 libm.so.6 libstdc++.so.6 libz.so.1
RPATH entries:
/sw/arch/RHEL9/EB_production/2024/software/CMake/3.29.3-GCCcore-13.3.0/lib
/sw/arch/RHEL9/EB_production/2024/software/CMake/3.29.3-GCCcore-13.3.0/lib64
$ORIGIN
$ORIGIN/../lib
$ORIGIN/../lib64
/sw/arch/RHEL9/EB_production/2024/software/OpenSSL/3/lib64
/sw/arch/RHEL9/EB_production/2024/software/libarchive/3.7.4-GCCcore-13.3.0/lib64
/sw/arch/RHEL9/EB_production/2024/software/cURL/8.7.1-GCCcore-13.3.0/lib64
/sw/arch/RHEL9/EB_production/2024/software/bzip2/1.0.8-GCCcore-13.3.0/lib64
/sw/arch/RHEL9/EB_production/2024/software/zlib/1.3.1-GCCcore-13.3.0/lib64
/sw/arch/RHEL9/EB_production/2024/software/ncurses/6.5-GCCcore-13.3.0/lib64
/sw/arch/RHEL9/EB_production/2024/software/binutils/2.42-GCCcore-13.3.0/lib64
/sw/arch/RHEL9/EB_production/2024/software/GCCcore/13.3.0/lib64
/sw/arch/RHEL9/EB_production/2024/software/GCCcore/13.3.0/lib
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/GCCcore/13.3.0/bin/../lib/gcc/x86_64-pc-linux-gnu/13.3.0
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/GCCcore/13.3.0/bin/../lib/gcc
/sw/arch/RHEL9/EB_production/2024/software/XZ/5.4.5-GCCcore-13.3.0/lib/../lib64
/sw/arch/RHEL9/EB_production/2024/software/XZ/5.4.5-GCCcore-13.3.0/lib
Dependencies:
libcurl.so.4 => /sw/arch/RHEL9/EB_production/2024/software/cURL/8.7.1-GCCcore-13.3.0/lib64/libcurl.so.4 [RPATH]
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/cURL/8.7.1-GCCcore-13.3.0/lib/libcurl.so.4.8.0 (real path)
libidn2.so.0 => /home/paulm/.local/easybuild/RHEL9/2024/software/libidn2/2.3.7-GCCcore-13.3.0/lib/libidn2.so.0 [LD_LIBRARY_PATH]
/gpfs/home4/paulm/.local/easybuild/RHEL9/2024/software/libidn2/2.3.7-GCCcore-13.3.0/lib/libidn2.so.0.4.0 (real path)
libm.so.6 => /lib64/libm.so.6 [default]
/usr/lib64/libm.so.6 (real path)
libc.so.6 => /lib64/libc.so.6 [default]
/usr/lib64/libc.so.6 (real path)
ld-linux-x86-64.so.2 => /lib64/ld-linux-x86-64.so.2 [default]
/usr/lib64/ld-linux-x86-64.so.2 (real path)
libssl.so.3 => /sw/arch/RHEL9/EB_production/2024/software/OpenSSL/3/lib64/libssl.so.3 [Parent RPATH]
/usr/lib64/libssl.so.3.0.7 (real path)
libcrypto.so.3 => /sw/arch/RHEL9/EB_production/2024/software/OpenSSL/3/lib64/libcrypto.so.3 [Parent RPATH]
/usr/lib64/libcrypto.so.3.0.7 (real path)
libz.so.1 => /sw/arch/RHEL9/EB_production/2024/software/zlib/1.3.1-GCCcore-13.3.0/lib64/libz.so.1 [Parent RPATH]
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/zlib/1.3.1-GCCcore-13.3.0/lib/libz.so.1.3.1 (real path)
libzstd.so.1 => /sw/arch/RHEL9/EB_production/2024/software/zstd/1.5.6-GCCcore-13.3.0/lib/libzstd.so.1 [LD_LIBRARY_PATH]
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/zstd/1.5.6-GCCcore-13.3.0/lib/libzstd.so.1.5.6 (real path)
libbrotlidec.so.1 => /sw/arch/RHEL9/EB_production/2024/software/Brotli/1.1.0-GCCcore-13.3.0/lib/libbrotlidec.so.1 [LD_LIBRARY_PATH]
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/Brotli/1.1.0-GCCcore-13.3.0/lib64/libbrotlidec.so.1.1.0 (real path)
libbrotlicommon.so.1 => /sw/arch/RHEL9/EB_production/2024/software/Brotli/1.1.0-GCCcore-13.3.0/lib/libbrotlicommon.so.1 [RPATH]
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/Brotli/1.1.0-GCCcore-13.3.0/lib64/libbrotlicommon.so.1.1.0 (real path)
libarchive.so.13 => /sw/arch/RHEL9/EB_production/2024/software/libarchive/3.7.4-GCCcore-13.3.0/lib64/libarchive.so.13 [RPATH]
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/libarchive/3.7.4-GCCcore-13.3.0/lib/libarchive.so.13.7.4 (real path)
libacl.so.1 => /lib64/libacl.so.1 [default]
/usr/lib64/libacl.so.1.1.2301 (real path)
libattr.so.1 => /lib64/libattr.so.1 [default]
/usr/lib64/libattr.so.1.1.2501 (real path)
liblzma.so.5 => /sw/arch/RHEL9/EB_production/2024/software/XZ/5.4.5-GCCcore-13.3.0/lib/../lib64/liblzma.so.5 [Parent RPATH]
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/XZ/5.4.5-GCCcore-13.3.0/lib/liblzma.so.5.4.5 (real path)
libbz2.so.1 => /lib64/libbz2.so.1 [default]
/usr/lib64/libbz2.so.1.0.8 (real path)
libxml2.so.2 => /lib64/libxml2.so.2 [default]
/usr/lib64/libxml2.so.2.9.13 (real path)
libstdc++.so.6 => /sw/arch/RHEL9/EB_production/2024/software/GCCcore/13.3.0/lib64/libstdc++.so.6 [RPATH]
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/GCCcore/13.3.0/lib64/libstdc++.so.6.0.32 (real path)
libgcc_s.so.1 => /sw/arch/RHEL9/EB_production/2024/software/GCCcore/13.3.0/lib64/libgcc_s.so.1 [Parent RPATH]
/gpfs/admin/_hpc/sw/arch/AMD-ZEN4/RHEL9/EB_production/2024/software/GCCcore/13.3.0/lib64/libgcc_s.so.1 (real path)
/home/paulm/.local/easybuild/RHEL9/2024/software/libidn2/2.3.7-GCCcore-13.3.0/lib:
libidn2.so.0
/lib64:
ld-linux-x86-64.so.2 libacl.so.1 libattr.so.1 libbz2.so.1 libc.so.6 libm.so.6 libxml2.so.2
/sw/arch/RHEL9/EB_production/2024/software/Brotli/1.1.0-GCCcore-13.3.0/lib:
libbrotlicommon.so.1 libbrotlidec.so.1
/sw/arch/RHEL9/EB_production/2024/software/GCCcore/13.3.0/lib64:
libgcc_s.so.1 libstdc++.so.6
/sw/arch/RHEL9/EB_production/2024/software/OpenSSL/3/lib64:
libcrypto.so.3 libssl.so.3
/sw/arch/RHEL9/EB_production/2024/software/XZ/5.4.5-GCCcore-13.3.0/lib64:
liblzma.so.5
/sw/arch/RHEL9/EB_production/2024/software/cURL/8.7.1-GCCcore-13.3.0/lib64:
libcurl.so.4
/sw/arch/RHEL9/EB_production/2024/software/libarchive/3.7.4-GCCcore-13.3.0/lib64:
libarchive.so.13
/sw/arch/RHEL9/EB_production/2024/software/zlib/1.3.1-GCCcore-13.3.0/lib64:
libz.so.1
/sw/arch/RHEL9/EB_production/2024/software/zstd/1.5.6-GCCcore-13.3.0/lib:
libzstd.so.1
Dependencies (files):
ld-linux-x86-64.so.2 libacl.so.1 libarchive.so.13 libattr.so.1 libbrotlicommon.so.1 libbrotlidec.so.1 libbz2.so.1 libc.so.6
libcrypto.so.3 libcurl.so.4 libgcc_s.so.1 libidn2.so.0 liblzma.so.5 libm.so.6 libssl.so.3 libstdc++.so.6
libxml2.so.2 libz.so.1 libzstd.so.1
This adds the following information:
NEEDEDandRPATHentries in the file being queried- The dependencies of the file as a tree, so you can see clearly relate the final dependencies to how they where resolved (i.e. directly versus indirectly, and from where they came)
- Symlinks used in dependency paths are resolved, with both values shown. In the example above
lddresolveslibssl.so.3to a path that is actually a symlink back to/usr/lib64/libssl.so.3.0.7, but this isn't immediately clear. - The sets of resolved dependencies grouped by location. This makes it easier to spot dependencies not in the place where you expect them.
- Python 3.x
- The
lddcommand (see below)
PDD does "manual" dependency resolution, in effect replaying the resolution steps that ld.so performs when ldd is invoked. This resolution is somewhat complex, so currently PDD also runs ldd separately, and then checks the results against its own dependency resolution results. In case there is a mismatch these are marked as >>> ldd says ... <<< in the dependency tree and such cases should be considered a bug in PDD.