Hi Nate, > One manifestation of this is a race conditions in system(), which > (depending on the implementation) is non-atomic in that it first calls > a fork() and then an exec(). The need for O_CLOFORK might be made more clear by looking at a long-standing Go issue, i.e. unrelated to system(3), which was started in 2017 by Russ Cox when he summed up the current race-condition behaviour of trying to execve(2) a newly created file: https://github.com/golang/go/issues/22315. I raised it on linux-kernel in 2017, https://marc.info/?l=linux-kernel&m=150834137201488, and linked to a proposed patch from 2011, ‘[PATCH] fs: add FD_CLOFORK and O_CLOFORK’ by Changli Gao. As I said, long-standing. The Go issue is worth a read. Russ wondered ‘What would Java do’ only to find that Java already had an issue open for the same problem since 2014. I think the kernel is the place to fix the problem, just as with FD_CLOEXEC/O_CLOEXEC. Ian Lance Taylor says on the Go issue that it looks like ‘Solaris and macOS and OpenBSD have O_CLOFORK already. Hopefully it will catch on further’. -- Cheers, Ralph.
