fix: dup() fd before from_raw_fd to prevent double-close - #20
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UnixStream::from_raw_fd() takes ownership of the file descriptor. When Host is dropped, Rust closes the fd — but the caller that constructed the "fd://" address still holds the original fd, expecting it to remain open. This causes a double-close: the fd is closed out from under the original holder, and if both sides later use it, one operates on a recycled fd assigned to an unrelated resource (use-after-close). Call libc::dup(fd) first to create an independent copy that this Host owns and can safely close, leaving the original fd untouched. Also add an error check for dup() failure instead of panicking on EBADF.
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Problem
UnixStream::from_raw_fd()takes ownership of the file descriptor per Rust's FFI contract. When the resultingHoststruct is eventually dropped, Rust callsclose()on the fd.However, the caller that constructed the
fd://address string still holds the original fd — that is the entire purpose of passing fds viafd://(to share an already-open descriptor between processes/components). This causes a double-close: the fd is closed out from under the original holder. If both sides subsequently use it, one operates on a recycled fd assigned to an unrelated resource (use-after-close / fd reuse).Fix
libc::dup(fd)beforefrom_raw_fd()to create an independent copyfrom_raw_fd(), which Host now legitimately ownsdup()failure (EBADF) instead of silently creating a broken streamFiles changed
executor/src/host/mod.rs: 8-line change inHost::connect()