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diff --git a/pipermail/pycrypto/2012q1/000553.html b/pipermail/pycrypto/2012q1/000553.html new file mode 100644 index 0000000..aa41eba --- /dev/null +++ b/pipermail/pycrypto/2012q1/000553.html @@ -0,0 +1,116 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<HTML> + <HEAD> + <TITLE> [pycrypto] Run test suite with /dev/random + </TITLE> + <LINK REL="Index" HREF="index.html" > + <LINK REL="made" HREF="mailto:pycrypto%40lists.dlitz.net?Subject=Re%3A%20%5Bpycrypto%5D%20Run%20test%20suite%20with%20/dev/random&In-Reply-To=%3C20120131044540.GA5208%40rivest.dlitz.net%3E"> + <META NAME="robots" CONTENT="index,nofollow"> + <style type="text/css"> + pre { + white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ + } + </style> + <META http-equiv="Content-Type" content="text/html; charset=us-ascii"> + <LINK REL="Previous" HREF="000551.html"> + <LINK REL="Next" HREF="000554.html"> + </HEAD> + <BODY BGCOLOR="#ffffff"> + <H1>[pycrypto] Run test suite with /dev/random</H1> + <B>Dwayne C. Litzenberger</B> + <A HREF="mailto:pycrypto%40lists.dlitz.net?Subject=Re%3A%20%5Bpycrypto%5D%20Run%20test%20suite%20with%20/dev/random&In-Reply-To=%3C20120131044540.GA5208%40rivest.dlitz.net%3E" + TITLE="[pycrypto] Run test suite with /dev/random">dlitz at dlitz.net + </A><BR> + <I>Mon Jan 30 23:45:40 EST 2012</I> + <P><UL> + <LI>Previous message: <A HREF="000551.html">[pycrypto] Run test suite with /dev/random +</A></li> + <LI>Next message: <A HREF="000554.html">[pycrypto] Run test suite with /dev/random +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#553">[ date ]</a> + <a href="thread.html#553">[ thread ]</a> + <a href="subject.html#553">[ subject ]</a> + <a href="author.html#553">[ author ]</a> + </LI> + </UL> + <HR> +<!--beginarticle--> +<PRE>On Sat, Jan 28, 2012 at 02:14:10AM +0100, Sebastian Ramacher wrote: +><i>There is no file object anymore. The I/O stack got rewritten in Python 3. +</I>><i>If open would be called without buffering=0, all the assumptions would be +</I>><i>correct again (and one would have fread like behavior). But since +</I>><i>buffering equals 0, open returns a FileIO instance. And FileIO.read just +</I>><i>behaves as the underlying syscall which is read(2). [1, 2] +</I>><i> +</I>><i>[1] <A HREF="http://docs.python.org/py3k/library/io.html#raw-i-o">http://docs.python.org/py3k/library/io.html#raw-i-o</A> +</I>><i>[2] <A HREF="http://docs.python.org/py3k/library/io.html#io.RawIOBase">http://docs.python.org/py3k/library/io.html#io.RawIOBase</A> +</I> +What the hell? So, open() returns an object that *isn't* a file-like +object (according to the definition of a file-like object) just because I +asked for a zero-length buffer? What happened to "explicit is better than +implicit"? "Special cases aren't special enough to break the rules"? + +*Sigh* I still consider this to be a bug in Python, but I guess it's +unlikely to ever be fixed... :-/ + +Ok, I'm willing to accept a patch that implements your workaround, if you +can address a few remaining issues: + +1. BlockingIOError needs to be handled. If the signal occurs immediately + after the read(2) syscall is invoked, it will set errno=EAGAIN and + Python will raise BlockingIOError. (At least, that's what the + documentation says.) + +2. If EOF is encountered for some reason, your loop would never terminate. + This shouldn't happen normally, but the RNG is a critical piece of + essentially untestable code, so it's okay to code it a little more + defensively than usual. (Who knows? We might encounter a broken + /dev/urandom implementation, or somebody might build a broken chroot + environment). + + If DevURandomRNG._read gets an EOF, it should behave like a normal + file-like object. That is, it should return the truncated string, and + subsequently always return b"". Basically, if self.__file.read(...) == + b"", then return data. + + There's no BlockingIOError defined in Python 2.x, so that will need to + be taken into account. + +3. Please also include a comment in the code that explains why this needs + to be done. + +Cheers, +- Dwayne + +P.S. Thank you for tracking this down. As a packager, I guess you receive +more than your fair share of flak for problems created by other people! +Even though I enthusiastically reject some of your patches, I (and probably +many users of PyCrypto) appreciate the work that you are doing. :) + +-- +Dwayne C. Litzenberger <<A HREF="http://lists.dlitz.net/cgi-bin/mailman/listinfo/pycrypto">dlitz at dlitz.net</A>> + OpenPGP: 19E1 1FE8 B3CF F273 ED17 4A24 928C EC13 39C2 5CF7 +</PRE> + + +<!--endarticle--> + <HR> + <P><UL> + <!--threads--> + <LI>Previous message: <A HREF="000551.html">[pycrypto] Run test suite with /dev/random +</A></li> + <LI>Next message: <A HREF="000554.html">[pycrypto] Run test suite with /dev/random +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#553">[ date ]</a> + <a href="thread.html#553">[ thread ]</a> + <a href="subject.html#553">[ subject ]</a> + <a href="author.html#553">[ author ]</a> + </LI> + </UL> + +<hr> +<a href="http://lists.dlitz.net/cgi-bin/mailman/listinfo/pycrypto">More information about the pycrypto +mailing list</a><br> +</body></html> |