#pragma once #include <atomic> #include <cstdlib> #include <thread> #include <poll.h> #include <signal.h> #include <sys/types.h> #include <unistd.h> namespace nix { class MonitorFdHup { private: std::thread thread; public: MonitorFdHup(int fd) { thread = std::thread([fd]() { while (true) { /* Wait indefinitely until a POLLHUP occurs. */ struct pollfd fds[1]; fds[0].fd = fd; /* This shouldn't be necessary, but macOS doesn't seem to like a zeroed out events field. See rdar://37537852. */ fds[0].events = POLLHUP; auto count = poll(fds, 1, -1); if (count == -1) abort(); // can't happen /* This shouldn't happen, but can on macOS due to a bug. See rdar://37550628. This may eventually need a delay or further coordination with the main thread if spinning proves too harmful. */ if (count == 0) continue; assert(fds[0].revents & POLLHUP); triggerInterrupt(); break; } }); }; ~MonitorFdHup() { pthread_cancel(thread.native_handle()); thread.join(); } }; } // namespace nix