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mingw-ldd

Lists dependencies of a PE (exe/dll) file.

Features

  • Mimics ldd output
  • Allows to specify dll lookup paths
  • Has no hardcoded dll lookup paths
  • Makes sure the dependencies are of the same CPU architecture
  • Sorts the output by dll name
  • Can also print in per-dep or tree output formats
  • Uses multiprocessing to speed up the dll lookup

Note that the arguments do not mimic ldd arguments.

Usage

The script can be installed from PyPi:

pip install mingw_ldd
mingw-ldd --help

The script can be used stanalone, given you have pefile installed:

sudo apt-get install python3-pefile
./mingw_ldd/mingw_ldd.py --help

or:

sudo apt-get install virtualenv
virtualenv -p /usr/bin/python3 env
./env/bin/pip install -r requirements.txt
./env/bin/python3 ./mingw_ldd/mingw_ldd.py --help

The mingw_ldd.py script file is self-contained and can be easily copied into other project's codebase.

Example

$ mingw-ldd.py -h
usage: mingw_ldd.py [-h] [--output-format {ldd-like,per-dep-list,tree}] --dll-lookup-dirs DLL_LOOKUP_DIR [DLL_LOOKUP_DIR ...] [--disable-multiprocessing] PE_FILE

Ldd-like output:

$ ./mingw-ldd.py /home/nurupo/qtox/workspace/i686/qtox/release/libtoxcore.dll \
                 --dll-lookup-dirs /usr/lib/gcc/i686-w64-mingw32/*-posix \
                                   /usr/i686-w64-mingw32/lib \
                                   /home/nurupo/qtox/workspace/i686/qtox/release
        advapi32.dll => not found
        iphlpapi.dll => not found
        kernel32.dll => not found
        libgcc_s_sjlj-1.dll => /usr/lib/gcc/i686-w64-mingw32/9.3-posix/libgcc_s_sjlj-1.dll
        libopus-0.dll => /home/nurupo/qtox/workspace/i686/qtox/release/libopus-0.dll
        libsodium-23.dll => /home/nurupo/qtox/workspace/i686/qtox/release/libsodium-23.dll
        libvpx.dll => /home/nurupo/qtox/workspace/i686/qtox/release/libvpx.dll
        libwinpthread-1.dll => /usr/i686-w64-mingw32/lib/libwinpthread-1.dll
        msvcrt.dll => not found
        user32.dll => not found
        ws2_32.dll => not found

Per-dep-list output:

$ ./mingw-ldd.py /home/nurupo/qtox/workspace/i686/qtox/release/libtoxcore.dll \
                 --output-format per-dep-list \
                 --dll-lookup-dirs /usr/lib/gcc/i686-w64-mingw32/*-posix \
                                   /usr/i686-w64-mingw32/lib \
                                   /home/nurupo/qtox/workspace/i686/qtox/release
/home/nurupo/qtox/workspace/i686/qtox/release/libopus-0.dll
        KERNEL32.dll => not found
        libgcc_s_sjlj-1.dll => /usr/lib/gcc/i686-w64-mingw32/9.3-posix/libgcc_s_sjlj-1.dll
        msvcrt.dll => not found
/home/nurupo/qtox/workspace/i686/qtox/release/libsodium-23.dll
        ADVAPI32.dll => not found
        KERNEL32.dll => not found
        libgcc_s_sjlj-1.dll => /usr/lib/gcc/i686-w64-mingw32/9.3-posix/libgcc_s_sjlj-1.dll
        msvcrt.dll => not found
        USER32.dll => not found
/home/nurupo/qtox/workspace/i686/qtox/release/libtoxcore.dll
        IPHLPAPI.DLL => not found
        KERNEL32.dll => not found
        libgcc_s_sjlj-1.dll => /usr/lib/gcc/i686-w64-mingw32/9.3-posix/libgcc_s_sjlj-1.dll
        libopus-0.dll => /home/nurupo/qtox/workspace/i686/qtox/release/libopus-0.dll
        libsodium-23.dll => /home/nurupo/qtox/workspace/i686/qtox/release/libsodium-23.dll
        libvpx.dll => /home/nurupo/qtox/workspace/i686/qtox/release/libvpx.dll
        libwinpthread-1.dll => /usr/i686-w64-mingw32/lib/libwinpthread-1.dll
        msvcrt.dll => not found
        WS2_32.dll => not found
/home/nurupo/qtox/workspace/i686/qtox/release/libvpx.dll
        KERNEL32.dll => not found
        libgcc_s_sjlj-1.dll => /usr/lib/gcc/i686-w64-mingw32/9.3-posix/libgcc_s_sjlj-1.dll
        libwinpthread-1.dll => /usr/i686-w64-mingw32/lib/libwinpthread-1.dll
        msvcrt.dll => not found
/usr/i686-w64-mingw32/lib/libwinpthread-1.dll
        KERNEL32.dll => not found
        msvcrt.dll => not found
/usr/lib/gcc/i686-w64-mingw32/9.3-posix/libgcc_s_sjlj-1.dll
        KERNEL32.dll => not found
        libwinpthread-1.dll => /usr/i686-w64-mingw32/lib/libwinpthread-1.dll
        msvcrt.dll => not found

Tree output:

$ ./mingw-ldd.py /home/nurupo/qtox/workspace/i686/qtox/release/libtoxcore.dll \
                 --output-format tree \
                 --dll-lookup-dirs /usr/lib/gcc/i686-w64-mingw32/*-posix \
                                   /usr/i686-w64-mingw32/lib \
                                   /home/nurupo/qtox/workspace/i686/qtox/release
/home/nurupo/qtox/workspace/i686/qtox/release/libtoxcore.dll
├── IPHLPAPI.DLL => not found
├── KERNEL32.dll => not found
├── libgcc_s_sjlj-1.dll => /usr/lib/gcc/i686-w64-mingw32/9.3-posix/libgcc_s_sjlj-1.dll
│   ├── KERNEL32.dll => not found
│   ├── libwinpthread-1.dll => /usr/i686-w64-mingw32/lib/libwinpthread-1.dll
│   │   ├── KERNEL32.dll => not found
│   │   └── msvcrt.dll => not found
│   └── msvcrt.dll => not found
├── libopus-0.dll => /home/nurupo/qtox/workspace/i686/qtox/release/libopus-0.dll
│   ├── KERNEL32.dll => not found
│   ├── libgcc_s_sjlj-1.dll => /usr/lib/gcc/i686-w64-mingw32/9.3-posix/libgcc_s_sjlj-1.dll
│   │   ├── KERNEL32.dll => not found
│   │   ├── libwinpthread-1.dll => /usr/i686-w64-mingw32/lib/libwinpthread-1.dll
│   │   │   ├── KERNEL32.dll => not found
│   │   │   └── msvcrt.dll => not found
│   │   └── msvcrt.dll => not found
│   └── msvcrt.dll => not found
├── libsodium-23.dll => /home/nurupo/qtox/workspace/i686/qtox/release/libsodium-23.dll
│   ├── ADVAPI32.dll => not found
│   ├── KERNEL32.dll => not found
│   ├── libgcc_s_sjlj-1.dll => /usr/lib/gcc/i686-w64-mingw32/9.3-posix/libgcc_s_sjlj-1.dll
│   │   ├── KERNEL32.dll => not found
│   │   ├── libwinpthread-1.dll => /usr/i686-w64-mingw32/lib/libwinpthread-1.dll
│   │   │   ├── KERNEL32.dll => not found
│   │   │   └── msvcrt.dll => not found
│   │   └── msvcrt.dll => not found
│   ├── msvcrt.dll => not found
│   └── USER32.dll => not found
├── libvpx.dll => /home/nurupo/qtox/workspace/i686/qtox/release/libvpx.dll
│   ├── KERNEL32.dll => not found
│   ├── libgcc_s_sjlj-1.dll => /usr/lib/gcc/i686-w64-mingw32/9.3-posix/libgcc_s_sjlj-1.dll
│   │   ├── KERNEL32.dll => not found
│   │   ├── libwinpthread-1.dll => /usr/i686-w64-mingw32/lib/libwinpthread-1.dll
│   │   │   ├── KERNEL32.dll => not found
│   │   │   └── msvcrt.dll => not found
│   │   └── msvcrt.dll => not found
│   ├── libwinpthread-1.dll => /usr/i686-w64-mingw32/lib/libwinpthread-1.dll
│   │   ├── KERNEL32.dll => not found
│   │   └── msvcrt.dll => not found
│   └── msvcrt.dll => not found
├── libwinpthread-1.dll => /usr/i686-w64-mingw32/lib/libwinpthread-1.dll
│   ├── KERNEL32.dll => not found
│   └── msvcrt.dll => not found
├── msvcrt.dll => not found
└── WS2_32.dll => not found

Performance

The performance might be a bit slower than expected due to pefile sometimes taking up to few seconds to parse a dll. We try to mitigate this by multiprocessing pefile's parsing. Using the most up to date pefile should help too. Specifically, the current version of pefile on PyPi -- version 2019.4.18, is noticeably faster than the version 2018.8.8 packaged in Debian Buster.

If the performance is an issue, you could give these projects a try:

  • ntldd - a cross-platform ldd-like program written in C
  • Dependency Walker - a freeware Windows GUI application that displays PE dependencies

Known issues

API Set dlls

Dlls that start with api- and ext-, e.g. api-ms-win-core-heap-l2-1-0.dll or ext-ms-win-ntuser-window-l1-1-1.dll, might get incorrectly marked as "not found".

Such dlls are part of Windows's API Set feature. The way the API Set works, is that often times the requested dlls don't even exist on the system, instead the library loader notices api-*.dll and ext-*.dll patterns and queries a mapping data-structure found in ApiSetSchema.dll to see which actual dlls those names map to and links those instead. For example, linking to api-ms-win-core-heap-l2-1-0.dll, in which one would expect to find the LocalAlloc function, would instead result in linking to kernel32.dll, and ext-ms-win-ntuser-window-l1-1-1.dll, in which one would expect to find the FindWindowEx function, would instead link to user32.dll.

mingw-ldd scans directories for actual dll files, so since api- and ext- dlls might not exist, they could be just some table mappings to other dlls instead, mingw-ldd is unable to find them and thus reports "not found". There is no public interface for applications to access this API Set dll mapping, the format of the mapping is not documented, and there are several reverse engineering articles attempting to document it, noting that ApiSetSchema.dll offsets change from architecture to architecture.

Because it's rather non-trivial and non-portable to access this mapping, mingw-ldd doesn't implement any API Set dll resolution. It also doesn't affect my use-case of mingw-ldd, which is to see if a Windows binary I have built is missing any dll dependency before I zip it and package for users to download. Because these API Set dlls are system libraries, you might just assume that they all are present. It's non-system dlls missing that I'm more concerned about.

This doesn't mean that I don't want to see API Set dll resolution implemented. Feel free to make a Python module parsing ApiSetSchema.dll that hides the portability details and I will make mingw-ldd use it.

Disclaimer

This project is not affiliated with MinGW, the name "mingw-ldd" is used primarely to facilitate online search discoverability as MinGW suit is missing ldd.

License

MIT