[Cyberduck-trac] [Cyberduck] #10604: Running program takes minutes to execute

[Cyberduck]

#10604: Running program takes minutes to execute
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 Reporter:  jkvbe   |         Owner:
     Type:  defect  |        Status:  new
 Priority:  normal  |     Milestone:
Component:  cli     |       Version:  6.9.2
 Severity:  normal  |    Resolution:
 Keywords:          |  Architecture:
 Platform:          |
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Comment (by frwessling):

 Hey, we ran into this today and it appears as though the issues is with
 the use of /dev/random in certain calls that are being made.
 If the system in  use is low on entropy then /dev/random will block until
 there are enough bits to satisfy whatever request is being made.

 *How to test*
 # On a system w/low entropy (Linux VMs that don't see a lot of CPU I/O are
 good candidates):
 In one terminal or screen session run " time duck -h"
 # In another run:
 "lsof |grep duck|grep random"
 You will see calls to both /dev/urandom and /dev/random

 Now on that same system (as root) do the following:
 (if necessary "ctrl-c" your previously running duck session)
 "mv /dev/random /dev/random.orig"
 "cp -a /dev/urandom /dev/random"

 Once you've replaced /dev/random with /dev/urandom run:
 "time duck -h"
 It should return a *whole* lot quicker.
 In our case it went from 11m to 8s.

 Don't forget to put your system back the way it was:
 "rm -f /dev/random"
 "mv /dev/random.orig /dev/random"

 You can tell how much entropy is available (in bits) for /dev/random by:
 "cat /proc/sys/kernel/random/entropy_avail"

 In our test case where "duck -h" took 11m to run, we had about 118 bits of
 available entropy.

 *Some Suggestions for the devs:*
 # Only be use /dev/random (or libraries that invoke it) if absolutely
 necessary; otherwise use /dev/urandom
 # Provide a run-time option that would allow the user to choose the use
 /dev/urandom exclusively

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Ticket URL: <https://trac.cyberduck.io/ticket/10604#comment:6>
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