libutil: Use poll() in FdSource::hasData() to avoid fd_set overflow#15757
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Mic92
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Apr 27, 2026
FD_SET writes past the stack fd_set when fd >= FD_SETSIZE. hasData() runs before every frame in withFramedSink(), so clients with many open fds would corrupt the stack (or abort under glibc _FORTIFY_SOURCE) during addToStore(). poll() has no such limit; Windows keeps select() since its fd_set is a bounded handle array.
xokdvium
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Apr 27, 2026
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friedenberg
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May 16, 2026
- clean-nix-fetcher-cache: interactive wipe of tarball-cache-v2/, tarball-cache/, gitv3/, and fetcher-cache-v4.sqlite*. Refuses to run if any nix processes are alive. Excluded from the aggregate `clean` recipe. - build-nix: split into [linux] (wrapped with prlimit --nofile=1023:1023) and [macos] (unchanged) variants to dodge the upstream nix FD_SETSIZE crash exposed by 2.34.6's RLIMIT_NOFILE bump (NixOS/nix#15205). The select->poll fix (NixOS/nix#15757) is on master only as of 2026-05. - build-home (linux): wrap the `nix run home-manager` invocation with the same prlimit guard. - debug-nix-env-isolation: probe whether env is the differentiator for a `nix build` "missing object" failure that reproduces in one shell but not another. Runs the build under current / minimal / from-file envs and writes each log to .tmp/debug-nix-env-isolation/<ts>/. Tracking issue: #79. :clown: Generated with [Clown](https://github.com/amarbel-llc/clown)
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FD_SET writes past the stack fd_set when fd >= FD_SETSIZE. hasData() runs before every frame in withFramedSink(), so clients with many open fds would corrupt the stack (or abort under glibc _FORTIFY_SOURCE) during addToStore(). poll() has no such limit; Windows keeps select() since its fd_set is a bounded handle array.
This was only ever called on the client for remote building, so not security relevant.
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