bug in split - improper handling of a short read

[Boehn, Gunnar von]

Hello,

I think I have found a bug in split.
My split version is (coreutils) 4.5.4

My system: GNU/Debian (unstable)


Description:
 Split quits if its not able to read the expected number of bytes.
 This is might ok for files but gives problems when working with pipes.


Example:

#tar -czf - /data  | strace split -b 650m  - /backup/backuptar- 

read(0, "address@hidden;%\217\302\275\301"..., 4096)
= 4096 
write(3, "address@hidden;%\217\302\275\301"...,
4096) = 4096 
read(0, "_#\306W1s\2654\247\16\350\357*\nF\4\324S^j\2448\317D \342"...,
4096) = 2048 
write(3, "_#\306W1s\2654\247\16\350\357*\nF\4\324S^j\2448\317D \342"...,
2048) = 2048 
close(0)                                = 0 
close(3)                                = 0 
exit_group(0)                           = ? 


At a random points of the process,
tar is to slow and split can not read the full expected pipe size of 4k.
Then split quits.

I think this is a bug, because according to man read -
its legal to not get the expected byte size when reading from pipes.



I hope that thie report help.
Keep up the good work

Kind regards
Gunnar