Date: Mon, 13 Dec 2004 14:39:51 -0800 From: Joe Kelsey <joe@zircon.seattle.wa.us> To: Julian Elischer <julian@elischer.org> Cc: arch@freebsd.org Subject: Re: Fixing Posix semaphores Message-ID: <1102977591.30309.203.camel@zircon.zircon.seattle.wa.us> In-Reply-To: <41BE15EE.5060704@elischer.org> References: <1102975803.30309.196.camel@zircon.zircon.seattle.wa.us> <41BE15EE.5060704@elischer.org>
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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. /Joe
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