Messages in this thread |  | | From | "H. Peter Anvin" <> | Subject | Re: /dev/random probs in 2.4test(12-pre3) | Date | 1 Dec 2000 10:18:56 -0800 |
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Followup to: <Pine.LNX.4.10.10012011720050.23462-100000@sphinx.mythic-beasts.com> By author: Matthew Kirkwood <matthew@hairy.beasts.org> In newsgroup: linux.dev.kernel > > Hi, > > It looks like the random driver in 2.4test will return a > short read, rather than blocking. This is breaking vpnd > (http://sunsite.dk/vpnd/) which breaks with "failed to > gather random data" or similar. > > Here's a sample strace: > > open("/dev/random", O_RDONLY) = 3 > read(3, "q\321Nu\204\251^\234i\254\350\370\363\"\305\366R\2708V"..., 72) = 29 > close(3) = 0 > > Have the semantics of the device changed, or is vpnd doing > something wrong? >
vpnd is doing something wrong: it's assuming short reads won't happen. /dev/random will block if there is NOTHING to be read; however, if there are bytes to be read, it will return them even if it is less than the user asked for.
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