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Bug 593232 - g_rand_new: read no more than requested from /dev/urandom
g_rand_new: read no more than requested from /dev/urandom
Status: RESOLVED FIXED
Product: glib
Classification: Platform
Component: general
unspecified
Other Linux
: Normal normal
: ---
Assigned To: gtkdev
gtkdev
: 419150 (view as bug list)
Depends on:
Blocks:
 
 
Reported: 2009-08-26 21:42 UTC by Jonas Holmberg
Modified: 2009-09-08 19:44 UTC
See Also:
GNOME target: ---
GNOME version: ---

Attachments
Turn off buffering on dev_urandom before freading it (247 bytes, patch)
2009-08-26 21:42 UTC, Jonas Holmberg 		none Details | Review
Turn off buffering on dev_urandom before freading it (242 bytes, patch)
2009-08-27 08:39 UTC, Jonas Holmberg 		none Details | Review

Description Jonas Holmberg 2009-08-26 21:42:32 UTC 
Created attachment 141801 [details] [review]
Turn off buffering on dev_urandom before freading it

The call to fread() in g_rand_new() will result in 4096 bytes being read from
/dev/urandom, although only 16 of those bytes will be used. Turning off
buffering with setvbuf(3) before the call to fread() makes it read no more than
requested. This improves performance a lot and saves entropy.
Comment 1 Jonas Holmberg 2009-08-27 08:39:47 UTC 
Created attachment 141832 [details] [review]
Turn off buffering on dev_urandom before freading it

No need for a size when turning buffering off.
Comment 2 Tim-Philipp Müller 2009-08-27 09:25:13 UTC 
Performance issue, so adding 'perf' keyword. Duplicate of bug #419150 really, albeit with slightly different emphasis.
Comment 3 Tim-Philipp Müller 2009-09-08 19:44:21 UTC 
*** Bug 419150 has been marked as a duplicate of this bug. ***