Исправление undefined behavior в обработчике сигналов#5
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drewrukin wants to merge 1 commit intofreemind001:mainfrom
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Исправление undefined behavior в обработчике сигналов#5drewrukin wants to merge 1 commit intofreemind001:mainfrom
drewrukin wants to merge 1 commit intofreemind001:mainfrom
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Remove std::cout call from signal_handler(). iostream functions are not async-signal-safe (POSIX.1-2017 §2.4.3). If a signal arrives while another thread or the main flow is already inside std::cout, this causes undefined behavior: potential deadlock on the internal stdio mutex, data corruption, or crash. loop.stop() writes to an eventfd, which is async-signal-safe, so it is sufficient on its own. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Описание
std::coutизsignal_handler()вmain.cppstd::coutне является async-signal-safe (POSIX.1-2017 §2.4.3). Если сигналприходит в момент, когда основной поток уже находится внутри
std::cout(например, при отладочном выводе в
input_handler), это приводит к undefinedbehavior: deadlock на мьютексе stdio, порча данных или краш.
loop.stop()пишет в eventfd, что является async-signal-safe, поэтомудостаточно одного этого вызова. Пользовательское сообщение не теряется —
процесс и так завершается.
Тестирование
mkdir build && cd build && cmake .. && make)--debug, отправить SIGINT (Ctrl+C) — убедиться в чистом завершении--debug, отправить SIGTERM (kill <pid>) — убедиться в чистом завершении