Clean NWNX binaries from LD_PRELOAD. #1711
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Mingun
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Dec 5, 2023
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| void NWNXCore::CleanupPreload() | ||
| { | ||
| const auto* preload = std::getenv("LD_PRELOAD"); | ||
| const std::regex regex("(([^: ]+)?NWNX_[^: ]+)"); | ||
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| std::string newPreload = preload; | ||
| while (std::regex_search(newPreload, regex)) | ||
| { | ||
| newPreload = std::regex_replace(newPreload, regex, ""); | ||
| } | ||
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| setenv("LD_PRELOAD", newPreload.c_str(), true); | ||
| } | ||
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I think, that such global changes in user-supplied environment requires some comment about reasons, because this is a very non-standard actions
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Hi, you're right, sorry, it's easy to forget about context when you've been freshly discussing it elsewhere. For the record, the issue is that sub-processes launched by any nwnx plugin will inherit LD_PRELOAD and attempt to preload NWNX_Core.so. This only works when preloaded onto nwn (nwmain or nwserver), and other process startups will fail.
@jhett12321 can you please add a comment here as well? Maybe something in the readme too if you find a good place for it.
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NWNX is loaded/injected on linux by specifying the "LD_PRELOAD" environment variable before starting the server.
This has the unintended side effect of causing all child processes spawned by NWNX plugins to inherit LD_PRELOAD and attempt to preload NWNX_Core.so again, causing these processes to immediately crash
If NWNX attempts to load outside of the nwn process, it will immediately throw a linker error:
This PR adds a workaround that will remove all entries with a
NWNX_prefix from the process level environment variables.User and system environment variables should remain untouched.