Fixing Posix semaphores

Julian Elischer julian at
Mon Dec 13 14:21:35 PST 2004

Joe Kelsey wrote:

>I have a desire to fix posix semaphores in at least 5.3.  The current
>implementation doesn't actually follow the "spirit" of the standard,
>even though it technically qualifies in a somewhat degraded sense.  I
>refer to the fact that the current implementation treats posix
>semaphores as completely contained inside the kernel and essentially
>divorced from the filesystem.  The true "spirit" of the standard places
>the semaphores directly in the file system, similar to named pipes.
>However the current implementation treats the supplied "name" as a
>14-character identifier, required to begin with a slash and contain no
>other slashes.  Pretty weak.
>Well, in order to fix this, we need to add file system code and come up
>with a new type.  I currently have some time to spend on something like
>this and am willing to put in whatever effort it takes.  Does anyone
>want to add their own ideas or requirements?
>I currently run 5.3, but I suppose I could think about running current
>at some point in the future.

I don't think that the spirit is to do what you suggest.
I have always interpretted it to be a separate namespace.
does the posix "mknod" definition mention how to make a semaphore?

An interesting problem but I'm not sure if it's needed..

P.S. CC's trimmed to arch (correct place) and current (not so correct 
but ok)
next round should probably stay on just "arch".

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