1#!/bin/sh 2# 3# $OpenBSD: xargs-copy.sh,v 1.1 2017/10/16 13:52:50 anton Exp $ 4# 5# Copyright (c) 2017 Anton Lindqvist <anton@openbsd.org> 6# 7# Permission to use, copy, modify, and distribute this software for any 8# purpose with or without fee is hereby granted, provided that the above 9# copyright notice and this permission notice appear in all copies. 10# 11# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 19# Regression caused by usage of memcpy() instead of memmove(). 20# Including the second argument causes the arguments to exceed the size 21# constraints. 22# It's therefore copied and later used as the first argument in the second 23# invocation of the default utility. 24 25arg_max() { 26 printf '#include <limits.h>\nARG_MAX\n' | cc -E - | tail -1 | bc 27} 28 29XARGS=${1:-/usr/bin/xargs} 30 31# ARG_MAX - 4K - strlen("/bin/echo") - strlen("x\n") 32n=$(($(arg_max) - 4*1024 - 9 - 2)) 33(echo x; jot -b x -s '' $n) | env -i $XARGS >/dev/null 34