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 * $FreeBSD$
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 <mntopts.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <sysexits.h>
52 #include <unistd.h>
53
54 static void
usage(void)55 usage(void)
56 {
57
58 errx(EX_USAGE, "usage: mksnap_ffs snapshot_name");
59 }
60
61 int
main(int argc,char ** argv)62 main(int argc, char **argv)
63 {
64 char errmsg[255], path[PATH_MAX];
65 char *cp, *snapname;
66 struct statfs stfsbuf;
67 struct group *grp;
68 struct stat stbuf;
69 struct iovec *iov;
70 int fd, iovlen;
71
72 if (argc == 2)
73 snapname = argv[1];
74 else if (argc == 3)
75 snapname = argv[2]; /* Old usage. */
76 else
77 usage();
78
79 /*
80 * Check that the user running this program has permission
81 * to create and remove a snapshot file from the directory
82 * in which they have requested to have it made. If the
83 * directory is sticky and not owned by the user, then they
84 * will not be able to remove the snapshot when they are
85 * done with it.
86 */
87 if (strlen(snapname) >= PATH_MAX)
88 errx(1, "pathname too long %s", snapname);
89 cp = strrchr(snapname, '/');
90 if (cp == NULL) {
91 strlcpy(path, ".", PATH_MAX);
92 } else if (cp == snapname) {
93 strlcpy(path, "/", PATH_MAX);
94 } else {
95 strlcpy(path, snapname, cp - snapname + 1);
96 }
97 if (statfs(path, &stfsbuf) < 0)
98 err(1, "%s", path);
99 if (stat(path, &stbuf) < 0)
100 err(1, "%s", path);
101 if (!S_ISDIR(stbuf.st_mode))
102 errx(1, "%s: Not a directory", path);
103 if (access(path, W_OK) < 0)
104 err(1, "Lack write permission in %s", path);
105 if ((stbuf.st_mode & S_ISTXT) && stbuf.st_uid != getuid())
106 errx(1, "Lack write permission in %s: Sticky bit set", path);
107
108 /*
109 * Having verified access to the directory in which the
110 * snapshot is to be built, proceed with creating it.
111 */
112 if ((grp = getgrnam("operator")) == NULL)
113 errx(1, "Cannot retrieve operator gid");
114
115 iov = NULL;
116 iovlen = 0;
117 build_iovec(&iov, &iovlen, "fstype", "ffs", 4);
118 build_iovec(&iov, &iovlen, "from", snapname, (size_t)-1);
119 build_iovec(&iov, &iovlen, "fspath", stfsbuf.f_mntonname, (size_t)-1);
120 build_iovec(&iov, &iovlen, "errmsg", errmsg, sizeof(errmsg));
121 build_iovec(&iov, &iovlen, "update", NULL, 0);
122 build_iovec(&iov, &iovlen, "snapshot", NULL, 0);
123
124 *errmsg = '\0';
125 if (nmount(iov, iovlen, stfsbuf.f_flags) < 0) {
126 errmsg[sizeof(errmsg) - 1] = '\0';
127 err(1, "Cannot create snapshot %s%s%s", snapname,
128 *errmsg != '\0' ? ": " : "", errmsg);
129 }
130 if ((fd = open(snapname, O_RDONLY)) < 0)
131 err(1, "Cannot open %s", snapname);
132 if (fstat(fd, &stbuf) != 0)
133 err(1, "Cannot stat %s", snapname);
134 if ((stbuf.st_flags & SF_SNAPSHOT) == 0)
135 errx(1, "File %s is not a snapshot", snapname);
136 if (fchown(fd, -1, grp->gr_gid) != 0)
137 err(1, "Cannot chown %s", snapname);
138 if (fchmod(fd, S_IRUSR | S_IRGRP) != 0)
139 err(1, "Cannot chmod %s", snapname);
140
141 exit(EXIT_SUCCESS);
142 }
143