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Author neologix
Recipients georg.brandl, loewis, neologix, nijel, pitrou, r.david.murray
Date 2011-01-04.21:58:17
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> Martin v. Löwis <> added the comment:
> I wonder why reading from /dev/urandom has a loop in the first place, though - isn't it guaranteed that you can read as many bytes as you want in one go? This goes back to #934711, and apparently, even the original patch had the loop - for reasons that got never questioned.

I found surprising that a read from /dev/urandom would be
uninterruptible, so I digged a little, and found this mail from 1998:

[patch] fix for urandom read(2) not interruptible

"It's a bug in random.c that doesn' t check for signal pending inside the
read(2) code, so you have no chance to kill the process via signals until
the read(2) syscall is finished, and it could take a lot of time before
return, if the buffer given to the read syscall is very big..."

I've had a quick look at the source code, and indeed, read(2) from
/dev/urandom can now be interrupted by a signal, so looping seems to
be justified.

> ----------
> nosy: +loewis
> status: pending -> open
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Date User Action Args
2011-01-04 21:58:19neologixsetrecipients: + neologix, loewis, georg.brandl, nijel, pitrou, r.david.murray
2011-01-04 21:58:17neologixlinkissue10824 messages
2011-01-04 21:58:17neologixcreate