2 * mountpoint(1) - see if a directory is a mountpoint
4 * This is libmount based reimplementation of the mountpoint(1)
5 * from sysvinit project.
8 * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
9 * Written by Karel Zak <kzak@redhat.com>
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
16 * This program is distributed in the hope that it would be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
21 * You should have received a copy of the GNU General Public License along
22 * with this program; if not, write to the Free Software Foundation, Inc.,
23 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
32 #include <sys/types.h>
40 #include "closestream.h"
41 #include "pathnames.h"
43 #define MOUNTPOINT_EXIT_NOMNT 32
45 struct mountpoint_control
{
56 static int dir_to_device(struct mountpoint_control
*ctl
)
58 struct libmnt_table
*tb
= mnt_new_table_from_file(_PATH_PROC_MOUNTINFO
);
60 struct libmnt_cache
*cache
;
65 * Fallback. Traditional way to detect mountpoints. This way
66 * is independent on /proc, but not able to detect bind mounts.
69 char buf
[PATH_MAX
], *cn
;
72 cn
= mnt_resolve_path(ctl
->path
, NULL
); /* canonicalize */
74 len
= snprintf(buf
, sizeof(buf
), "%s/..", cn
? cn
: ctl
->path
);
77 if (len
< 0 || (size_t) len
>= sizeof(buf
))
79 if (stat(buf
, &pst
) !=0)
82 if (ctl
->st
.st_dev
!= pst
.st_dev
|| ctl
->st
.st_ino
== pst
.st_ino
) {
83 ctl
->dev
= ctl
->st
.st_dev
;
90 /* to canonicalize all necessary paths */
91 cache
= mnt_new_cache();
92 mnt_table_set_cache(tb
, cache
);
93 mnt_unref_cache(cache
);
95 fs
= mnt_table_find_target(tb
, ctl
->path
, MNT_ITER_BACKWARD
);
96 if (fs
&& mnt_fs_get_target(fs
)) {
97 ctl
->dev
= mnt_fs_get_devno(fs
);
105 static int print_devno(const struct mountpoint_control
*ctl
)
107 if (!S_ISBLK(ctl
->st
.st_mode
)) {
109 warnx(_("%s: not a block device"), ctl
->path
);
112 printf("%u:%u\n", major(ctl
->st
.st_rdev
), minor(ctl
->st
.st_rdev
));
116 static void __attribute__((__noreturn__
)) usage(void)
119 fputs(USAGE_HEADER
, out
);
121 _(" %1$s [-qd] /path/to/directory\n"
122 " %1$s -x /dev/device\n"), program_invocation_short_name
);
124 fputs(USAGE_SEPARATOR
, out
);
125 fputs(_("Check whether a directory or file is a mountpoint.\n"), out
);
127 fputs(USAGE_OPTIONS
, out
);
128 fputs(_(" -q, --quiet quiet mode - don't print anything\n"
129 " --nofollow do not follow symlink\n"
130 " -d, --fs-devno print maj:min device number of the filesystem\n"
131 " -x, --devno print maj:min device number of the block device\n"), out
);
132 fputs(USAGE_SEPARATOR
, out
);
133 printf(USAGE_HELP_OPTIONS(20));
134 printf(USAGE_MAN_TAIL("mountpoint(1)"));
139 int main(int argc
, char **argv
)
142 struct mountpoint_control ctl
= { NULL
};
145 OPT_NOFOLLOW
= CHAR_MAX
+ 1
148 static const struct option longopts
[] = {
149 { "quiet", no_argument
, NULL
, 'q' },
150 { "nofollow", no_argument
, NULL
, OPT_NOFOLLOW
},
151 { "fs-devno", no_argument
, NULL
, 'd' },
152 { "devno", no_argument
, NULL
, 'x' },
153 { "help", no_argument
, NULL
, 'h' },
154 { "version", no_argument
, NULL
, 'V' },
158 setlocale(LC_ALL
, "");
159 bindtextdomain(PACKAGE
, LOCALEDIR
);
161 close_stdout_atexit();
165 while ((c
= getopt_long(argc
, argv
, "qdxhV", longopts
, NULL
)) != -1) {
184 print_version(EXIT_SUCCESS
);
186 errtryhelp(EXIT_FAILURE
);
190 if (optind
+ 1 != argc
) {
191 warnx(_("bad usage"));
192 errtryhelp(EXIT_FAILURE
);
194 if (ctl
.nofollow
&& ctl
.dev_devno
)
195 errx(EXIT_FAILURE
, _("%s and %s are mutually exclusive"),
196 "--devno", "--nofollow");
198 ctl
.path
= argv
[optind
];
199 c
= ctl
.nofollow
? lstat(ctl
.path
, &ctl
.st
) : stat(ctl
.path
, &ctl
.st
);
202 err(EXIT_FAILURE
, "%s", ctl
.path
);
206 return print_devno(&ctl
) ? MOUNTPOINT_EXIT_NOMNT
: EXIT_SUCCESS
;
208 if ((ctl
.nofollow
&& S_ISLNK(ctl
.st
.st_mode
)) || dir_to_device(&ctl
)) {
210 printf(_("%s is not a mountpoint\n"), ctl
.path
);
211 return MOUNTPOINT_EXIT_NOMNT
;
214 printf("%u:%u\n", major(ctl
.dev
), minor(ctl
.dev
));
216 printf(_("%s is a mountpoint\n"), ctl
.path
);