Hi,
the attched scripts show that it happens randomly that the ksh
Version JM 93t+ 2010-06-21 (included all patches I know) has
a race condition. That is that the FIFO is open for writing
before it was opened for reading. Soemtime this cause errors
like
./heretest[34]: /tmp/rjp.sYkvyXVX: cannot create [Interrupted system call]
+ rm -f /tmp/rj.RxDohfHm /tmp/rjp.sYkvyXVX
sometimes it simply hand in e.g.
strace -p 32613
Process 32613 attached - interrupt to quit
open("/tmp/rjp.Ei3x9ZHp", O_WRONLY|O_CREAT|O_TRUNC, 0666
I've tried to replace O_CREAT with O_NONBLOCK in case of
opening an existing FIFO in sh_open() of src/cmd/ksh93/sh/io.c
but this leads to an other error like
open("/tmp/rjp.VUuQZEjc", O_WRONLY|O_APPEND|O_NONBLOCK|O_LARGEFILE) = -1
ENXIO (No such device or address)
in and endless loop. As the used stat(2) system call returns
for the repalcement of the creation flag it seems that the
FIFO will never be open on the other side for writing.
Using the bash or pdksh works flawless.
Werner
--
"Having a smoking section in a restaurant is like having
a peeing section in a swimming pool." -- Edward Burr
#!/bin/ksh
typeset -i i
typeset -i j=0
echo KSH ${.sh.version} -- $(rpm -q ksh)
while true
do
let i=0
while (( i < 1000 ))
do
./heretest
let i++
done
let j++
echo Test Iteration $j
date
done
#!/bin/ksh
trap 'rm -f $DETAIL_LOG $CHANNEL_LIMITING_PIPE' EXIT
DETAIL_LOG=$(mktemp /tmp/rj.XXXXXXXX) || exit 1
CHANNEL_LIMITING_PIPE=$(mktemp -u /tmp/rjp.XXXXXXXX) || exit 1
mknod $CHANNEL_LIMITING_PIPE p || exit 1
(/bin/ksh << END_OF_MLOAD1
echo '000000000000000000000000000000000000000000 ' > /dev/null
echo '111111111111111111111111111111111111111111 ' > /dev/null
echo '222222222222222222222222222222222222222222 ' > /dev/null
echo '333333333333333333333333333333333333333333 ' > /dev/null
echo '444444444444444444444444444444444444444444 ' > /dev/null
echo '555555555555555555555555555555555555555555 ' > /dev/null
echo '666666666666666666666666666666666666666666 ' > /dev/null
echo '777777777777777777777777777777777777777777 ' > /dev/null
echo '888888888888888888888888888888888888888888 ' > /dev/null
echo '999999999999999999999999999999999999999999 ' > /dev/null
echo '000000000000000000000000000000000000000000 ' > /dev/null
echo '111111111111111111111111111111111111111111 ' > /dev/null
echo '222222222222222222222222222222222222222222 ' > /dev/null
echo '333333333333333333333333333333333333333333 ' > /dev/null
echo '444444444444444444444444444444444444444444 ' > /dev/null
echo '555555555555555555555555555555555555555555 ' > /dev/null
echo '666666666666666666666666666666666666666666 ' > /dev/null
echo '777777777777777777777777777777777777777777 ' > /dev/null
echo '888888888888888888888888888888888888888888 ' > /dev/null
echo '999999999999999999999999999999999999999999 ' > /dev/null
cat < $CHANNEL_LIMITING_PIPE > $DETAIL_LOG
END_OF_MLOAD1
) &
/bin/cat << END_OF_FEXP > $CHANNEL_LIMITING_PIPE
echo 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
echo 'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb'
echo 'cccccccccccccccccccccccccccccccccccccccccc'
echo 'dddddddddddddddddddddddddddddddddddddddddd'
echo 'eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee'
echo 'ffffffffffffffffffffffffffffffffffffffffff'
echo 'gggggggggggggggggggggggggggggggggggggggggg'
echo 'hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh'
END_OF_FEXP
wait
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