Date: Thu, 18 Jul 1996 19:10:19 -0700 (PDT) From: Mark Diekhans <markd@Grizzly.COM> To: joerg_wunsch@uriah.heep.sax.de, Bill Paul <wpaul@skynet.ctr.columbia.edu> Cc: FreeBSD-gnats-submit@freebsd.org, bugs@freefall.freebsd.org Subject: Re: kern/1397: can't send to a pipe Message-ID: <199607190210.TAA00823@Grizzly.COM> In-Reply-To: <199607181648.SAA06346@uriah.heep.sax.de> (message from J Wunsch on Thu, 18 Jul 1996 18:48:35 %2B0200 (MET DST))
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Hi J"org and Bill, >From: J Wunsch <j@uriah.heep.sax.de> >Pipes are no longer implemented as sockets. Using socket operations >on them was illegal all the time, even if the kernel has not been >reporting the error. Cool, I always though sockets were a little overkill for pipes... >From: Bill Paul <wpaul@skynet.ctr.columbia.edu> >He didn't mean fstat(1), he meant fstat(2). Look at the sample source >he supplied: he's calling fstat(2) on one of the pipe descriptors >returned by pipe(2) and he says he's getting S_IFSOCK as a result. >However since John's new pipe code does not in fact (ab)use sockets, >attempts to use socket system calls on the descriptors fail. This >is a contradiction: if socket operations won't work, fstat(2) should >not identify the descriptors as S_IFSOCK. Exactly! >In this case, he could replace pipe(2) with socketpair(2) in the The code (a Tcl extension) I am dealing with has an open file descriptor and tries to figure out what to do with it, so this isn't a solution. It uses send on sockets since its more reliable. >application, but that doesn't change the fact that fstat(2) is reporting >a bogus result. I suppose a new type has to be added (S_IPIPE?), but >a question (in my mind at least) of compatibility with other *BSD systems. Reporting FIFO would probably be better than SOCK, at least that wouldn't lead people to do the wrong thing because they think its a socket. Given all of this, the definition of S_ISFIFO probably is wrong as well: #define S_ISFIFO(m) (((m) & 0170000) == 0010000 || \ ((m) & 0170000) == 0140000) /* fifo or socket */ Mark
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