1 /* $NetBSD: cmd_mapper.c,v 1.1 2019/01/17 20:47:42 kamil Exp $ */ 2 3 /*- 4 * Copyright (c) 2019 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __RCSID("$NetBSD: cmd_mapper.c,v 1.1 2019/01/17 20:47:42 kamil Exp $"); 31 32 #include <sys/mman.h> 33 34 #include <err.h> 35 #include <fcntl.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <unistd.h> 39 40 #define _PATH_DEV_MAPPER "/dev/mapper" 41 42 int main(int argc, char **argv) 43 { 44 int devfd; 45 char *map = NULL; 46 47 if ((devfd = open(_PATH_DEV_MAPPER, O_RDONLY)) == -1) 48 err(EXIT_FAILURE, "Cannot open %s", _PATH_DEV_MAPPER); 49 50 map = (char *)(mmap(0, sysconf(_SC_PAGESIZE), PROT_READ, MAP_SHARED, 51 devfd, 0)); 52 if (map == MAP_FAILED) 53 err(EXIT_FAILURE, "Mapping failed"); 54 55 printf("Message from device: %s\n",map); 56 57 if (munmap(map, sysconf(_SC_PAGESIZE)) == -1) 58 err(EXIT_FAILURE, "Unmap failed"); 59 60 if (close(devfd) == -1) 61 err(EXIT_FAILURE, "Cannot close %s", _PATH_DEV_MAPPER); 62 63 return EXIT_SUCCESS; 64 } 65