Messages in this thread |  | | Date | Sat, 2 Dec 2000 12:03:56 -0600 (CST) | From | Jeff Garzik <> | Subject | Re: /dev/random probs in 2.4test(12-pre3) |
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On Sat, 2 Dec 2000, Igmar Palsenberg wrote: > > 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.
"totally block"?
For a blocking fd, read(2) has always blocked until some data is available. There has never been a guarantee, for any driver, that a read(2) will return the full amount of bytes requested.
There is no need to document this... man read(2) ;-)
Jeff
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