"interrupted system call" when using "tee" builtin in ksh
The following ksh testcase...
-- snip --
f 'pipe' snip --
mknod 'pipe' p
(sleep 4; cat pipe) &
(sleep 2; print 'aa') | tee -a 'pipe'
... generates an "interrupted system call" when using the "tee"
builtin within ksh. If "tee" is an external utility this does not happen (both use identical code, the issue in this case is that the builtin may get hit by the SIGCHLD and doesn't protect the |open()|-call against EINTR) ...