1 /*
2 * Copyright (c) 1992, 1993, 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software donated to Berkeley by
6 * Jan-Simon Pendry.
7 *
8 * %sccs.include.redist.c%
9 */
10
11 #ifndef lint
12 char copyright[] =
13 "@(#) Copyright (c) 1992, 1993, 1994\n\
14 The Regents of the University of California. All rights reserved.\n";
15 #endif /* not lint */
16
17 #ifndef lint
18 static char sccsid[] = "@(#)mount_null.c 8.6 (Berkeley) 04/26/95";
19 #endif /* not lint */
20
21 #include <sys/param.h>
22 #include <sys/mount.h>
23 #include <miscfs/nullfs/null.h>
24
25 #include <err.h>
26 #include <stdio.h>
27 #include <unistd.h>
28 #include <stdlib.h>
29 #include <string.h>
30
31 #include "mntopts.h"
32
33 struct mntopt mopts[] = {
34 MOPT_STDOPTS,
35 { NULL }
36 };
37
38 int subdir __P((const char *, const char *));
39 void usage __P((void));
40
41 int
main(argc,argv)42 main(argc, argv)
43 int argc;
44 char *argv[];
45 {
46 struct null_args args;
47 int ch, mntflags;
48 char target[MAXPATHLEN];
49
50 mntflags = 0;
51 while ((ch = getopt(argc, argv, "o:")) != EOF)
52 switch(ch) {
53 case 'o':
54 getmntopts(optarg, mopts, &mntflags, 0);
55 break;
56 case '?':
57 default:
58 usage();
59 }
60 argc -= optind;
61 argv += optind;
62
63 if (argc != 2)
64 usage();
65
66 if (realpath(argv[0], target) == 0)
67 err(1, "%s", target);
68
69 if (subdir(target, argv[1]) || subdir(argv[1], target))
70 errx(1, "%s (%s) and %s are not distinct paths",
71 argv[0], target, argv[1]);
72
73 args.target = target;
74
75 if (mount("loopback", argv[1], mntflags, &args))
76 err(1, NULL);
77 exit(0);
78 }
79
80 int
subdir(p,dir)81 subdir(p, dir)
82 const char *p;
83 const char *dir;
84 {
85 int l;
86
87 l = strlen(dir);
88 if (l <= 1)
89 return (1);
90
91 if ((strncmp(p, dir, l) == 0) && (p[l] == '/' || p[l] == '\0'))
92 return (1);
93
94 return (0);
95 }
96
97 void
usage()98 usage()
99 {
100 (void)fprintf(stderr,
101 "usage: mount_null [-o options] target_fs mount_point\n");
102 exit(1);
103 }
104