Messages in this thread |  | | From | "H. Peter Anvin" <> | Subject | Re: /dev/random probs in 2.4test(12-pre3) | Date | 2 Dec 2000 23:16:20 -0800 |
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Followup to: <Pine.LNX.4.21.0012021955570.11787-100000@server.serve.me.nl> By author: Igmar Palsenberg <maillist@chello.nl> In newsgroup: linux.dev.kernel > > > Indeed, you are correct. Is vpnd broken then, for assuming > > that it can gather the required randomness in one read? > > Yep. It assumes that if the required randommness numbers aren't met a read > to /dev/random will block. > > And it's not the only program that assumes this : I also did. > > /dev/random is called a blocking random device, which more or less implies > that it will totally block. I suggest we put this somewhere in the kernel > docs, since lots of people out there assume that it totally blocks. >
That's pretty much ALWAYS wrong -- for pipes, sockets, you name it. A blocking read() will only block if there is nothing to read at all.
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