TETeMPOraL·Apr 3, 2024
Conan is a package manager for C/C++, written in Python. See: https://conan.io/.
The way it works is that you can provide "recipes", which are Python scripts, that automate the process of collecting source code (usually from a remote Git repository, or a remote source tarball), patching it, making its dependencies and transitive dependencies available, building for specific platform and architecture (via any number of build systems), then packaging up and serving binaries. There's a lot of complexity involved.
Here are the two recipes I mentioned:
libcurl: https://github.com/conan-io/conan-center-index/blob/master/r...
OpenSSL v3: https://github.com/conan-io/conan-center-index/blob/master/r...
Now, for the sake of this thread I want to highlight three things here:
- Conan recipes are usually made by people unaffiliated with the libraries
Read the rest
they're packaging;
- The recipes are fully Turing-complete, do a lot of work, have their own bugs - therefore they should really be treated as software comonents themselves, for the purpose of OSS clearing/supply chain verification, except as far as I know, nobody does it;
- The recipes can, and do, patch source code and build scripts. There's supporting infrastruture for this built into Conan, and of course one can also do it by brute-force search and replace. See e.g. ZLib recipe that does it both at the same time:
https://github.com/conan-io/conan-center-index/blob/7b0ac710... -- `_patch_sources` does both direct search-and-replace in source files, and applies the patches from https://github.com/conan-io/conan-center-index/tree/master/r....
Good luck keeping track of what exact code goes into your program, when using Turing-complete "recipe" programs fetched from the Internet, which fetch your libraries from somewhere else on the Internet.