Date: Mon, 13 Dec 2004 14:55:11 -0800 From: Julian Elischer <julian@elischer.org> To: Joe Kelsey <joe@zircon.seattle.wa.us> Cc: arch@freebsd.org Subject: Re: Fixing Posix semaphores Message-ID: <41BE1DCF.4070209@elischer.org> In-Reply-To: <1102977591.30309.203.camel@zircon.zircon.seattle.wa.us> References: <1102975803.30309.196.camel@zircon.zircon.seattle.wa.us> <41BE15EE.5060704@elischer.org> <1102977591.30309.203.camel@zircon.zircon.seattle.wa.us>
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Joe Kelsey wrote: >On Mon, 2004-12-13 at 14:21 -0800, Julian Elischer wrote: > > >>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? >> >> > >POSIX does not define or allow use of mknod to create a named semaphore. >Only sem_open() can create a named semaphore. The "spirit", as >implemented in other OS', clearly indicates the use of file system >names, not the restricted 14-character name used by FreeBSD. For >instance, Solaris uses file system names. > What does it gain you? (other than more letters to the name). > >/Joe > > >
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