pylddwrap 1.0.2

Command-Line Tool pylddwrap

• Assume we need the dependencies of the /bin/ls. The following command gives them as a table:

pylddwrap /bin/ls

• The output of the command looks like this:

soname          | path                                  | found | mem_address          | unused
----------------+---------------------------------------+-------+----------------------+-------
linux-vdso.so.1 | None                                  | True  | (0x00007ffd8750f000) | False
libselinux.so.1 | /lib/x86_64-linux-gnu/libselinux.so.1 | True  | (0x00007f4e73dc3000) | True
libc.so.6       | /lib/x86_64-linux-gnu/libc.so.6       | True  | (0x00007f4e739f9000) | False
libpcre.so.3    | /lib/x86_64-linux-gnu/libpcre.so.3    | True  | (0x00007f4e73789000) | False
libdl.so.2      | /lib/x86_64-linux-gnu/libdl.so.2      | True  | (0x00007f4e73585000) | False
None            | /lib64/ld-linux-x86-64.so.2           | True  | (0x00007f4e73fe5000) | False
libpthread.so.0 | /lib/x86_64-linux-gnu/libpthread.so.0 | True  | (0x00007f4e73368000) | False

• To obtain the dependencies as JSON, invoke:

pylddwrap --format json /bin/ls

• The JSON output is structured like this:

[
  {
    "soname": "linux-vdso.so.1",
    "path": "None",
    "found": true,
    "mem_address": "(0x00007ffed857f000)",
    "unused": false
  },
  ...
]

ldwrap Python Module

We provide lddwrap Python module which you can integrate into your deployment scripts and other modules.

• The following example shows how to list the dependencies of /bin/ls:

import pathlib
import lddwrap

path = pathlib.Path("/bin/ls")
deps = lddwrap.list_dependencies(path=path)
for dep in deps:
    print(dep)

"""
soname: linux-vdso.so.1, path: None, found: True, mem_address: (0x00007ffe8e2fb000), unused: None
soname: libselinux.so.1, path: /lib/x86_64-linux-gnu/libselinux.so.1, found: True, mem_address: (0x00007f7759ccc000), unused: None
soname: libc.so.6, path: /lib/x86_64-linux-gnu/libc.so.6, found: True, mem_address: (0x00007f7759902000), unused: None
...
"""

• List all dependencies of the /bin/ls utility and check if the direct dependencies are used. If unused for list_dependencies is set to False then the unused variable of the dependencies will not be determined and are therefore unknown and set to None. Otherwise information about direct usage will be retrieved and added to the dependencies.

import pathlib
import lddwrap

path = pathlib.Path("/bin/ls")
deps = lddwrap.list_dependencies(path=path, unused=True)
print(deps[1])
# soname: libselinux.so.1,
# path: /lib/x86_64-linux-gnu/libselinux.so.1,
# found: True,
# mem_address: (0x00007f5a6064a000),
# unused: True

• Lddwrap operates normally with the environment variables of the caller. In cases where your dependencies are determined differently than the current environment, you pass a separate environment (in form of a dictionary) as an argument:

import os
import pathlib
import lddwrap

env = os.environ.copy()
env['LD_LIBRARY_PATH'] = "some/important/path"
path = pathlib.Path("/bin/ls")
deps = lddwrap.list_dependencies(path=path, env=env)

Pre-commit Checks

We provide a set of pre-commit checks that lint and check code for formatting.

Namely, we use:

• yapf to check the formatting.

• The style of the docstrings is checked with pydocstyle.

• Static type analysis is performed with mypy.

• Various linter checks are done with pylint.

Run the pre-commit checks locally from an activated virtual environment with development dependencies:

./precommit.py

• The pre-commit script can also automatically format the code:

./precommit.py  --overwrite