175 lines
4.2 KiB
Bash
Executable File
175 lines
4.2 KiB
Bash
Executable File
#!/bin/sh
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#
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# Copyright (c) 2012 Peter Holm
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without
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# modification, are permitted provided that the following conditions
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# are met:
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# 1. Redistributions of source code must retain the above copyright
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# notice, this list of conditions and the following disclaimer.
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# 2. Redistributions in binary form must reproduce the above copyright
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# notice, this list of conditions and the following disclaimer in the
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# documentation and/or other materials provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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# SUCH DAMAGE.
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#
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# Demonstrate that close() of an flock'd file is not atomic.
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# Fails with "flock_open_close: execv(/mnt/test): Text file busy"
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# Test scenario by: jhb
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[ `id -u ` -ne 0 ] && echo "Must be root!" && exit 1
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. ../default.cfg
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odir=`pwd`
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cd /tmp
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sed '1,/^EOF/d' < $odir/$0 > flock_open_close.c
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rm -f /tmp/flock_open_close
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mycc -o flock_open_close -Wall -Wextra -O2 -g flock_open_close.c -lpthread || exit 1
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rm -f flock_open_close.c
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mount | grep $mntpoint | grep -q /dev/md && umount -f $mntpoint
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mdconfig -l | grep -q md$mdstart && mdconfig -d -u $mdstart
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mdconfig -a -t swap -s 1g -u $mdstart || exit 1
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bsdlabel -w md$mdstart auto
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newfs $newfs_flags md${mdstart}$part > /dev/null
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mount /dev/md${mdstart}$part $mntpoint
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chmod 777 $mntpoint
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cp /bin/test $mntpoint
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chown $testuser $mntpoint/test
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chmod +w $mntpoint/test
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su $testuser -c "/tmp/flock_open_close $mntpoint/test" &
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pid=$!
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while kill -0 $! 2>/dev/null; do
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mksnap_ffs $mntpoint $mntpoint/.snap/snap
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sleep 2
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rm -f $mntpoint/.snap/snap
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sleep 1
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done
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wait $pid
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s=$?
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for i in `jot 10`; do
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mount | grep -q md${mdstart}$part && \
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umount $mntpoint && mdconfig -d -u $mdstart && break
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sleep 2
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done
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if mount | grep -q md${mdstart}$part; then
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fstat $mntpoint
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echo "umount $mntpoint failed"
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exit 1
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fi
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rm -f /tmp/flock_open_close
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exit $s
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EOF
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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static void
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usage(void)
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{
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fprintf(stderr, "Usage: flock_close_race <binary> [args]\n");
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exit(1);
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}
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static void
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child(const char *binary)
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{
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int fd;
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/* Exit as soon as our parent exits. */
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while (getppid() != 1) {
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fd = open(binary, O_RDWR | O_EXLOCK);
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if (fd < 0) {
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/*
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* This may get ETXTBSY since exit() will
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* close its open fd's (thus releasing the
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* lock), before it releases the vmspace (and
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* mapping of the binary).
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*/
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if (errno == ETXTBSY)
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continue;
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err(2, "can't open %s", binary);
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}
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close(fd);
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}
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exit(0);
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}
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static void
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exec_child(char **av)
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{
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int fd;
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fd = open(av[0], O_RDONLY | O_SHLOCK);
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execv(av[0], av);
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/* "flock_open_close: execv(/mnt/test): Text file busy" seen */
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err(127, "execv(%s)", av[0]);
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}
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int
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main(int ac, char **av)
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{
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struct stat sb;
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pid_t pid;
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int e, i, status;
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if (ac < 2)
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usage();
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if (stat(av[1], &sb) != 0)
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err(1, "stat(%s)", av[1]);
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if (!S_ISREG(sb.st_mode))
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errx(1, "%s not an executable", av[1]);
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pid = fork();
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if (pid < 0)
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err(1, "fork");
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if (pid == 0)
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child(av[1]);
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e = 0;
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for (i = 0; i < 200000; i++) {
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pid = fork();
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if (pid < 0)
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err(1, "vfork");
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if (pid == 0)
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exec_child(av + 1);
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wait(&status);
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if (WIFEXITED(status) && WEXITSTATUS(status) == 127) {
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fprintf(stderr, "FAIL\n");
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e = 1;
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break;
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}
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if (WIFEXITED(status) && WEXITSTATUS(status) != 1) {
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/* /bin/test returns 1 */
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e = 1;
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break;
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}
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}
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return (e);
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}
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