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/*
* SPDX-License-Identifier: GPL-2.0-or-later
*
* Copyright (C) 2011 Red Hat, Inc. All rights reserved.
* Written by Karel Zak <kzak@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mountpoint(1) - see if a directory is a mountpoint
*
* This is libmount based reimplementation of the mountpoint(1)
* from sysvinit project.
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <getopt.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <libmount.h>
#include "nls.h"
#include "xalloc.h"
#include "c.h"
#include "closestream.h"
#include "pathnames.h"
#define MOUNTPOINT_EXIT_NOMNT 32
struct mountpoint_control {
char *path;
dev_t dev;
struct stat st;
unsigned int
dev_devno:1,
fs_devno:1,
nofollow:1,
quiet:1;
};
static int dir_to_device(struct mountpoint_control *ctl)
{
struct libmnt_table *tb = mnt_new_table_from_file(_PATH_PROC_MOUNTINFO);
struct libmnt_fs *fs;
struct libmnt_cache *cache;
int rc = -1;
if (!tb) {
/*
* Fallback. Traditional way to detect mountpoints. This way
* is independent on /proc, but not able to detect bind mounts.
*/
struct stat pst;
char buf[PATH_MAX], *cn;
int len;
cn = mnt_resolve_path(ctl->path, NULL); /* canonicalize */
len = snprintf(buf, sizeof(buf), "%s/..", cn ? cn : ctl->path);
free(cn);
if (len < 0 || (size_t) len >= sizeof(buf))
return -1;
if (stat(buf, &pst) !=0)
return -1;
if (ctl->st.st_dev != pst.st_dev || ctl->st.st_ino == pst.st_ino) {
ctl->dev = ctl->st.st_dev;
return 0;
}
return -1;
}
/* to canonicalize all necessary paths */
cache = mnt_new_cache();
mnt_table_set_cache(tb, cache);
mnt_unref_cache(cache);
fs = mnt_table_find_target(tb, ctl->path, MNT_ITER_BACKWARD);
if (fs && mnt_fs_get_target(fs)) {
ctl->dev = mnt_fs_get_devno(fs);
rc = 0;
}
mnt_unref_table(tb);
return rc;
}
static int print_devno(const struct mountpoint_control *ctl)
{
if (!S_ISBLK(ctl->st.st_mode)) {
if (!ctl->quiet)
warnx(_("%s: not a block device"), ctl->path);
return -1;
}
printf("%u:%u\n", major(ctl->st.st_rdev), minor(ctl->st.st_rdev));
return 0;
}
static void __attribute__((__noreturn__)) usage(void)
{
FILE *out = stdout;
fputs(USAGE_HEADER, out);
fprintf(out,
_(" %1$s [-qd] /path/to/directory\n"
" %1$s -x /dev/device\n"), program_invocation_short_name);
fputs(USAGE_SEPARATOR, out);
fputs(_("Check whether a directory or file is a mountpoint.\n"), out);
fputs(USAGE_OPTIONS, out);
fputs(_(" -q, --quiet quiet mode - don't print anything\n"
" --nofollow do not follow symlink\n"
" -d, --fs-devno print maj:min device number of the filesystem\n"
" -x, --devno print maj:min device number of the block device\n"), out);
fputs(USAGE_SEPARATOR, out);
fprintf(out, USAGE_HELP_OPTIONS(20));
fprintf(out, USAGE_MAN_TAIL("mountpoint(1)"));
exit(EXIT_SUCCESS);
}
int main(int argc, char **argv)
{
int c;
struct mountpoint_control ctl = { NULL };
enum {
OPT_NOFOLLOW = CHAR_MAX + 1
};
static const struct option longopts[] = {
{ "quiet", no_argument, NULL, 'q' },
{ "nofollow", no_argument, NULL, OPT_NOFOLLOW },
{ "fs-devno", no_argument, NULL, 'd' },
{ "devno", no_argument, NULL, 'x' },
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, 'V' },
{ NULL, 0, NULL, 0 }
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
close_stdout_atexit();
mnt_init_debug(0);
while ((c = getopt_long(argc, argv, "qdxhV", longopts, NULL)) != -1) {
switch(c) {
case 'q':
ctl.quiet = 1;
break;
case OPT_NOFOLLOW:
ctl.nofollow = 1;
break;
case 'd':
ctl.fs_devno = 1;
break;
case 'x':
ctl.dev_devno = 1;
break;
case 'h':
usage();
case 'V':
print_version(EXIT_SUCCESS);
default:
errtryhelp(EXIT_FAILURE);
}
}
if (optind + 1 != argc) {
warnx(_("bad usage"));
errtryhelp(EXIT_FAILURE);
}
if (ctl.nofollow && ctl.dev_devno)
errx(EXIT_FAILURE, _("%s and %s are mutually exclusive"),
"--devno", "--nofollow");
ctl.path = argv[optind];
c = ctl.nofollow ? lstat(ctl.path, &ctl.st) : stat(ctl.path, &ctl.st);
if (c) {
if (!ctl.quiet)
err(EXIT_FAILURE, "%s", ctl.path);
return EXIT_FAILURE;
}
if (ctl.dev_devno)
return print_devno(&ctl) ? MOUNTPOINT_EXIT_NOMNT : EXIT_SUCCESS;
if ((ctl.nofollow && S_ISLNK(ctl.st.st_mode)) || dir_to_device(&ctl)) {
if (!ctl.quiet)
printf(_("%s is not a mountpoint\n"), ctl.path);
return MOUNTPOINT_EXIT_NOMNT;
}
if (ctl.fs_devno)
printf("%u:%u\n", major(ctl.dev), minor(ctl.dev));
else if (!ctl.quiet)
printf(_("%s is a mountpoint\n"), ctl.path);
return EXIT_SUCCESS;
}
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