assert_tar_extract() {

	# When extracting a tar file like this:

	#

	#     bzip2 -dc foo.tar.bz2 | tar xof -

	#

	# For some tar files (see bug #309001), tar will

	# close its stdin pipe when the decompressor still has

	# remaining data to be written to its stdout pipe. This

	# causes the decompressor to be killed by SIGPIPE. In

	# this case, we want to ignore pipe writers killed by

	# SIGPIPE, and trust the exit status of tar. We borrow

	# WIFSIGNALED and WTERMSIG bitwise operations from

	# glibc's bits/waitstatus.h.

	local x pipestatus=${PIPESTATUS[*]}

	for x in $pipestatus ; do

		if [[ $x -ne 0 ]] ; then

			# WIFSIGNALED(status)

			(( ( ( ( x & 0x7f ) + 1 ) >> 1 ) > 0 )) || die "$@"

			# WTERMSIG(status) == SIGPIPE

			(( ( x & 0x7f ) == 13 )) || die "$@"

		fi

	done

	# Require normal success for the last process (tar).

	[[ $x -eq 0 ]] || die "$@"

}