tests/epipe - master - niceSOFT/grep

#!/bin/sh
# Check that a write failure with errno == EPIPE
# doesn't cause grep to issue multiple "write error" diagnostics.

. "${srcdir=.}/init.sh"; path_prepend_ ../src

if
   # Use awk to output a bounded amount of data to the grep in question,
   # so that the test doesn't loop forever if grep is buggy.
   # Use an explicit /dev/null for the benefit of older (pre-POSIX) awks.
   #
   # Carefully close fd 3 when not needed, as a sanity check.
   #
   # Do not use "trap - PIPE" or "trap 'something' PIPE" here, since we may
   # be running in an environment where SIGPIPE is ignored, and in such an
   # environment POSIX says that "trap '' PIPE" is all we can do portably.
   (
     ${AWK-awk} 'BEGIN { for (i=0; i<1000000; i++) print i; }' /dev/null 3>&- |
     (trap '' PIPE; exec grep . 2>&3 3>&-) |
     :
   ) 3>&1 | (
     read line1 && echo >&2 "$line1" &&
     read line2 && echo >&2 "$line2"
   )
then fail=1
else fail=0
fi

Exit $fail