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 8.5 (Berkeley) 03/27/94"; 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 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); 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(MOUNT_NULL, argv[1], mntflags, &args)) 76 err(1, NULL); 77 exit(0); 78 } 79 80 int 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 98 usage() 99 { 100 (void)fprintf(stderr, 101 "usage: mount_null [-o options] target_fs mount_point\n"); 102 exit(1); 103 } 104