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https://github.com/mpv-player/mpv
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This code runs posix_spawnp() within a fork() in some cases, in order to "disown" processes which are meant as being started detached. But posix_spawnp() is not marked as async-signal-safe, so what we do is not allowed. It could for example cause deadlocks, depending on implementation and luck at runtime. Turns out posix_spawnp() is useless crap. Replace it with "classic" fork() to ensure correctness. We could probably use another mechanism to start a process "disowned" than doing a double-fork(). The only problem with "disowning" a process is calling setsid() (which posix_spawnp() didn't support, but maybe will in newer revisions), and removing as as parent from the child process (the double-fork() will make PID 1 the parent). But there is no good way to either remove us as parent, or to "reap" the PID in a way that is safe and less of a mess than the current code. This is because POSIX/UNIX is a miserable heap of shit. (Less shit than "alternatives" like win32, no doubt.) Because POSIX/UNIX is a miserable heap of shit, execvp() is also not specified as async-signal-safe. It's funny how you can run a full fledged HTTP server in an async-signal-safe context, but not start a shitty damn process. Unix is really, really, really extremely bad at this process management stuff. So we reimplement execvp() in an async-signal-safe way. The new code assumes that CLOEXEC is a thing. Since POSIX/UNIX is such a heap of shit, O_CLOEXEC and FD_CLOEXEC were (probably) added at different times, but both must be present. io.h defines them to 0 if they don't exist, and in this case the code will error out at runtime. Surely we could do without CLOEXEC via fallback, but I'll do that only if at least 1 bug is reported wrt. this issue. The idea how to report exec() failure or success is from musl. The way as_execvpe() is also inspired by musl (for example, the list of error codes that should make it fail is the same as in musl's code). |
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| .. | ||
| android | ||
| macos | ||
| win32 | ||
| atomic.h | ||
| compiler.h | ||
| endian.h | ||
| getpid.h | ||
| glob-win.c | ||
| io.c | ||
| io.h | ||
| macOS_swift_bridge.h | ||
| macosx_application_objc.h | ||
| macosx_application.h | ||
| macosx_application.m | ||
| macosx_compat.h | ||
| macosx_events_objc.h | ||
| macosx_events.h | ||
| macosx_events.m | ||
| macosx_menubar_objc.h | ||
| macosx_menubar.h | ||
| macosx_menubar.m | ||
| macosx_touchbar.h | ||
| macosx_touchbar.m | ||
| macosx_versions.h | ||
| main-fn-cocoa.c | ||
| main-fn-unix.c | ||
| main-fn-win.c | ||
| main-fn.h | ||
| mpv.exe.manifest | ||
| mpv.rc | ||
| path-macosx.m | ||
| path-unix.c | ||
| path-uwp.c | ||
| path-win.c | ||
| path.h | ||
| polldev.c | ||
| polldev.h | ||
| posix-spawn.h | ||
| semaphore_osx.c | ||
| semaphore.h | ||
| strnlen.h | ||
| subprocess-dummy.c | ||
| subprocess-posix.c | ||
| subprocess-win.c | ||
| subprocess.c | ||
| subprocess.h | ||
| terminal-dummy.c | ||
| terminal-unix.c | ||
| terminal-win.c | ||
| terminal.h | ||
| threads.c | ||
| threads.h | ||
| timer-darwin.c | ||
| timer-linux.c | ||
| timer-win2.c | ||
| timer.c | ||
| timer.h | ||
| w32_keyboard.c | ||
| w32_keyboard.h | ||
| win32-console-wrapper.c | ||
| windows_utils.c | ||
| windows_utils.h | ||