illumos gate

We observed that, on Illumos/OpenIndiana, some output lines disappear when
shell redirections are combined with "tee".

This problem does not occur on Solaris 10 nor on Linux.

The following shell script allows to reproduce the issue. It writes 100 lines
on the standard output, but after redirections and "tee", some lines may be
randomly lost, i.e., one sees only 98, 96, 95, 94 (etc.) lines rather than 100.

#! /bin/sh

# the bug does not occur if #! /bin/sh is replaced by #! /bin/bash
# the bug does not occur if #! /bin/sh is replaced by #! /bin/ksh
# the bug does not occur if #! /bin/sh is replaced by #! /bin/ksh93

RUN() {
# this function echoes all numbers from 1 to 100 on standard output
# the bug also occurs if function RUN is replaced by a separate shell script
N=1
while [ $N -le 100 ]
do
    echo "$N" | tee 
    # the "tee" command must be present for the bug to be observed
    # the bug also occurs if "tee" is replaced by "tee filename" 
    # the bug also occurs if "tee" is replaced by "tee -a filename" 
    N=`expr $N + 1`
done
}

P=1
while [ $P -le 20 ]
do
    ( RUN 2>&1 ) > aux ; wc -l aux
    rm aux
    P=`expr $P + 1`
done

The normal output (as observed on Linux or Solaris 10) consists of 20 lines
containing "100 aux". On Illumos, the output can be the following:

      98 aux
      96 aux
      94 aux
      93 aux
      94 aux
      96 aux
      93 aux
      95 aux
      96 aux
      93 aux
      95 aux
      97 aux
      99 aux
      96 aux
      97 aux
      98 aux
     100 aux
      96 aux
      97 aux
     100 aux

Frédéric Lang and Hubert Garavel