Bug 615284

Description of problem:
In a ksh script, when SIGPIPE trap action is specified and SIGPIPE occurs by the output of the built-in echo command, the output appears in a redirect file of a external command.

Version-Release number of selected component (if applicable):
ksh-20100202-1.el5

How reproducible:
Always

Steps to Reproduce:

Assume there is a huge ascii file /tmp/huge-text which takes more than one second to cat to terminal.

Run the following scripts with

ssh localhost /path/to/the/script.ksh

Steps to reproduce:

Case 1:
-------

the script.ksh is:

#!/bin/ksh
killparent()
{
	sleep 1
	/bin/kill -9 $1
}
trap "/bin/echo trap > /dev/null" 13
killparent ${PPID} &
/bin/cat /tmp/huge-text
print "echo1"
/bin/echo "echo2" > /tmp/echo2
trap 13

After running the script with ssh print the contents of the resulting file:
# cat /tmp/echo2

Actual results:
echo1
echo2

Expected results:
echo2

Case 2:
-------

the script.ksh is

#!/bin/ksh
killparent()
{
	sleep 1
	/bin/kill -9 $1
}
trap "/bin/echo trap >> /tmp/trap" 13
killparent ${PPID} &
/bin/cat /tmp/huge-text
echo "echo1"
/bin/echo "echo2"
trap 13

After running the script with ssh print the contents of the resulting file:
# cat /tmp/trap

Actual results:
echo1
trap
trap

Expected results:
trap
trap

Additional information:
Seems that the output of the echo builtin command is buffered and the buffer is flushed upon forking a child process.  However when the flush fails the content of the buffer is not erased and then appears in where it should not.

Maybe the ksh should either delete the buffer after flush (even unsucessful), not to buffer the echo output or not to buffer the redirection output.