mksnap_ffs.c revision 122035
1/* 2 * Copyright (c) 2003 Networks Associates Technology, Inc. 3 * All rights reserved. 4 * 5 * This software was developed for the FreeBSD Project by Marshall 6 * Kirk McKusick and Network Associates Laboratories, the Security 7 * Research Division of Network Associates, Inc. under DARPA/SPAWAR 8 * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS 9 * research program. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. The names of the authors may not be used to endorse or promote 20 * products derived from this software without specific prior written 21 * permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * $FreeBSD: head/sbin/mksnap_ffs/mksnap_ffs.c 122035 2003-11-04 07:04:01Z mckusick $ 36 */ 37 38#include <sys/param.h> 39#include <sys/mount.h> 40#include <sys/stat.h> 41#include <ufs/ufs/ufsmount.h> 42#include <err.h> 43#include <errno.h> 44#include <fcntl.h> 45#include <grp.h> 46#include <limits.h> 47#include <stdio.h> 48#include <stdlib.h> 49#include <string.h> 50#include <sysexits.h> 51#include <unistd.h> 52 53void usage(void); 54 55int 56main(int argc, char **argv) 57{ 58 char *dir, *cp, path[PATH_MAX]; 59 struct ufs_args args; 60 struct group *grp; 61 struct stat stbuf; 62 int fd; 63 64 if (argc != 3) 65 usage(); 66 67 dir = argv[1]; 68 args.fspec = argv[2]; 69 70 /* 71 * Check that the user running this program has permission 72 * to create and remove a snapshot file from the directory 73 * in which they have requested to have it made. If the 74 * directory is sticky and not owned by the user, then they 75 * will not be able to remove the snapshot when they are 76 * done with it. 77 */ 78 if (strlen(args.fspec) >= PATH_MAX) 79 errx(1, "pathname too long %s", args.fspec); 80 cp = strrchr(args.fspec, '/'); 81 if (cp == NULL) { 82 strlcpy(path, ".", PATH_MAX); 83 } else if (cp == args.fspec) { 84 strlcpy(path, "/", PATH_MAX); 85 } else { 86 strlcpy(path, args.fspec, cp - args.fspec + 1); 87 } 88 if (stat(path, &stbuf) < 0) 89 err(1, "%s", path); 90 if (!S_ISDIR(stbuf.st_mode)) 91 errx(1, "%s: Not a directory", path); 92 if (access(path, W_OK) < 0) 93 err(1, "Lack write permission in %s", path); 94 if ((stbuf.st_mode & S_ISTXT) && stbuf.st_uid != getuid()) 95 errx(1, "Lack write permission in %s: Sticky bit set", path); 96 97 /* 98 * Having verified access to the directory in which the 99 * snapshot is to be built, proceed with creating it. 100 */ 101 if ((grp = getgrnam("operator")) == NULL) 102 errx(1, "Cannot retrieve operator gid"); 103 if (mount("ffs", dir, MNT_UPDATE | MNT_SNAPSHOT, &args) < 0) 104 err(1, "Cannot create %s", args.fspec); 105 if ((fd = open(args.fspec, O_RDONLY)) < 0) 106 err(1, "Cannot open %s", args.fspec); 107 if (fstat(fd, &stbuf) != 0) 108 err(1, "Cannot stat %s", args.fspec); 109 if ((stbuf.st_flags & SF_SNAPSHOT) == 0) 110 errx(1, "File %s is not a snapshot", args.fspec); 111 if (fchown(fd, -1, grp->gr_gid) != 0) 112 err(1, "Cannot chown %s", args.fspec); 113 if (fchmod(fd, S_IRUSR | S_IRGRP) != 0) 114 err(1, "Cannot chmod %s", args.fspec); 115 116 exit(EXIT_SUCCESS); 117} 118 119void 120usage() 121{ 122 123 fprintf(stderr, "usage: mksnap_ffs mountpoint snapshot_name\n"); 124 exit(EX_USAGE); 125} 126