1#!/bin/sh 2 3# 4# SPDX-License-Identifier: BSD-2-Clause 5# 6# Copyright (c) 2022 Peter Holm <pho@FreeBSD.org> 7# 8# Redistribution and use in source and binary forms, with or without 9# modification, are permitted provided that the following conditions 10# are met: 11# 1. Redistributions of source code must retain the above copyright 12# notice, this list of conditions and the following disclaimer. 13# 2. Redistributions in binary form must reproduce the above copyright 14# notice, this list of conditions and the following disclaimer in the 15# documentation and/or other materials provided with the distribution. 16# 17# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27# SUCH DAMAGE. 28# 29 30# Demonstrate that a mapped SHARED file can be updated past LIMIT_FSIZE 31 32# Kostik wrote: 33# This one should be reproducible when you 34# - have file larger than e.g. RLIMIT_FSIZE 35# - mmaped it without closing the file descriptor 36# - dirty its pages beyond the limit 37# - then unmap 38# - then close the file descriptor. 39 40[ `id -u ` -ne 0 ] && echo "Must be root!" && exit 1 41 42. ../default.cfg 43 44cat > /tmp/setrlimit2.c <<EOF 45#include <sys/param.h> 46#include <sys/mman.h> 47#include <sys/resource.h> 48#include <sys/stat.h> 49 50#include <err.h> 51#include <errno.h> 52#include <fcntl.h> 53#include <signal.h> 54#include <stdio.h> 55#include <stdlib.h> 56#include <unistd.h> 57 58static int signals; 59 60static void 61handler(int sig __unused) 62{ 63 signals++; 64} 65 66int 67main(int argc, char *argv[]) 68{ 69 struct rlimit rlim; 70 struct sigaction act; 71 struct stat st; 72 size_t len; 73 int error, fd, ps; 74 char *file, *p; 75 76 if (argc != 2) { 77 fprintf(stderr, "Usage: %s <data file>\n", argv[0]); 78 exit(1); 79 } 80 act.sa_handler = handler; 81 act.sa_flags = 0; 82 sigemptyset(&act.sa_mask); 83 if (sigaction(SIGXFSZ, &act, NULL) != 0) 84 err(1, "sigaction"); 85 86 file = argv[1]; 87 ps = getpagesize(); 88 if ((fd = open(file, O_RDWR)) == -1) 89 err(1, "open(%s)", file); 90 if ((error = fstat(fd, &st)) == -1) 91 err(1, "stat(%s)", file); 92 len = round_page(st.st_size); 93 if ((p = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)) == MAP_FAILED) 94 err(1, "mmap"); 95 rlim.rlim_cur = rlim.rlim_max = len / 2;; 96 if (setrlimit(RLIMIT_FSIZE, &rlim) == -1) 97 err(1, "setrlimit(%ld)", len / 2); 98 99 p[len / 2 + ps] = 'a'; 100 101 if (munmap(p, len) == -1) 102 err(1, "unmap()"); 103 close(fd); 104 105} 106EOF 107here=`pwd` 108cd /tmp 109mycc -o setrlimit2 -Wall -Wextra -O0 -g setrlimit2.c || exit 1 110data=/tmp/setrlimit2.data 111dd if=/dev/zero of=$data bs=1m count=1 status=none 112h1=`md5 < $data` 113 114./setrlimit2 $data 115 116h2=`md5 < $data` 117rm -f /tmp/setrlimit2 /tmp/setrlimit2.c 118[ $h1 = $h2 ] && exit 1 || exit 0 119