Bug 24486 – dd if=/dev/urandom of=x bs=1M count=10 creates a random size file

• Status: RESOLVED FIXED
• Product: Gentoo Linux

[Description Keith Hudson 2003-07-14 15:51:55 UTC]

dd if/dev/urandom of=x bs=1M count=10 should create file x which is 10M in size.
It creates files of all diffrent sizes.  /dev/zero works fine though

Reproducible: Always
Steps to Reproduce:
1.dd if=/dev/urandom of=x bs=1M count=10
2.x will be anything but 10M in size
3.

Actual Results:  
dd if=/dev/urandom of=x bs=1M count=10
1+9 records in
1+9 records out
keith@localhost beer $ ls -l
total 2988
-rw-r--r--    1 keith    parent    3052986 Jul 14 17:47 x


Expected Results:  
dd if=/dev/urandom of=x bs=1M count=10
10+0 records in
10+0 records out
ls -l
total 10256
-rw-r--r--    1 keith    parent   10485760 Jul 14 17:49 x

[Comment 1 Lisa Seelye (RETIRED) 2003-07-14 20:37:19 UTC]

Do you have enough entropy built up for /dev/urandom?

This works for me:
lisa@lisa distcc $ dd if=/dev/urandom of=x bs=1M count=10
10+0 records in
10+0 records out
lisa@lisa distcc $ ls -lh
-rw-r--r--    1 lisa     wheel         10M Jul 14 23:35 x
..
-rw-r--r--    1 lisa     wheel    10485760 Jul 14 23:35 x

[Comment 2 Keith Hudson 2003-07-14 20:56:21 UTC]

System build date was june 6th.  Workstation is used daily. So yes I should.

[Comment 3 Jay Pfeifer (RETIRED) 2003-07-14 23:16:20 UTC]

this is fixed in pfeifer-sources-2.4.21_pre4. it is a lowlatency bug in random.c 
 
Jay 

[Comment 4 Jay Pfeifer (RETIRED) 2003-09-06 23:05:22 UTC]

*** Bug 28034 has been marked as a duplicate of this bug. ***