Messages in this thread | | | Date | Sat, 19 Jun 1999 08:59:07 -0500 (EST) | From | "Mark H. Wood" <> | Subject | Re: UUIDs (and devfs and major/minor numbers) |
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On Thu, 17 Jun 1999, Nathan Hand wrote: > On Wed, Jun 16, 1999 at 11:15:43PM -0500, Edward S. Marshall wrote: > > On Thu, 17 Jun 1999 tytso@mit.edu wrote: > > > the names in /dev *are* policy, and kernel should not be dictating > > > policy. Therefore, the kernel should not be deciding what names appear > > > in /dev. Q.E.D. > > > > Like it or not, the names in /proc *are* policy, and kernel should not be > > dictating policy. Therefore, the kernel should not be deciding what names > > appear in /proc. Q.E.D. > > Oh don't worry, a lot of people agree with this and think that the > move away from sysctl was a big mistake.
That just moves the supposed problem: now the kernel is dictating "names" passed to sysctl(). The argument doesn't seem to be over names so much as it is over the *structure* imposed on the names.
The real question is whether there is any alternative to the kernel dictating these so-called policies. The kernel and userspace have to agree on a minimum set of "names" or the kernel is not usable. You can't decide to use your own arrangement of syscall number bindings; you have to use the same ones that the kernel recognizes. For a given syscall, you can't give the arguments in any order you like; you have to give what the kernel expects to get if you want the results *you* expect.
In the case of sysctl() the user and the kernel must agree on which names are passed because there is no mapping interposed. But things are different with /dev, because there is a mapping (major, minor) <- /dev/{name} . We can't take the sysctl() name policy away from the kernel because there is no other way for the user and the kernel to understand each other. We *can* take away the /dev name policy if we agree on the (major, minor) name policy, because of the mapping. Therefor I conclude that it is reasonable for the kernel to dictate sysctl() names but it is reasonable to refuse to have it dictate /dev names.
-- Mark H. Wood, Lead System Programmer mwood@IUPUI.Edu Specializing in unusual perspectives for more than twenty years.
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