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On 22 Nov 2003, H. Peter Anvin wrote: > > > > Hmm.. Looking at the signal sending code, we actually do special-case > > "init" there already - but only for the "kill -1" case. If the test for > > "pid > 1" was moved into "group_send_sig_info()" instead, that would > > pretty much do it, I think. > > > > Okay... I'm going to ask the obvious dumb question: > > Why do we bother special-casing init at all? Because the kernel depends on it existing. "init" literally _is_ special from a kernel standpoint, because its' the "reaper of zombies" (and, may I add, that would be a great name for a rock band). So without init, the kernel wouldn't have anybody to fall back on when a parent process dies, and would become very very unhappy. Historically it actually oopsed the kernel. UNIX semantics literally _require_ that "getppid()" should return 1 if your parent dies, and that's "current->p_parent->tgid". So we have to have a parent with pid 1, and thus init really _is_ special. Yeah, we could have _other_ special cases (we could create another process that is invisible and has pid 1), but the fact is, _some_ special case is required. It might as well be "you can't kill init". Linus - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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