216 lines
5.2 KiB
C
216 lines
5.2 KiB
C
/*
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* mountpoint(1) - see if a directory is a mountpoint
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*
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* This is libmount based reimplementation of the mountpoint(1)
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* from sysvinit project.
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*
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*
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* Copyright (C) 2011 Red Hat, Inc. All rights reserved.
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* Written by Karel Zak <kzak@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#include <getopt.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <libmount.h>
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#include "nls.h"
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#include "xalloc.h"
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#include "c.h"
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#include "closestream.h"
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#include "pathnames.h"
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struct mountpoint_control {
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char *path;
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dev_t dev;
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struct stat st;
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unsigned int
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dev_devno:1,
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fs_devno:1,
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nofollow:1,
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quiet:1;
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};
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static int dir_to_device(struct mountpoint_control *ctl)
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{
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struct libmnt_table *tb = mnt_new_table_from_file(_PATH_PROC_MOUNTINFO);
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struct libmnt_fs *fs;
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struct libmnt_cache *cache;
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int rc = -1;
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if (!tb) {
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/*
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* Fallback. Traditional way to detect mountpoints. This way
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* is independent on /proc, but not able to detect bind mounts.
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*/
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struct stat pst;
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char buf[PATH_MAX], *cn;
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int len;
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cn = mnt_resolve_path(ctl->path, NULL); /* canonicalize */
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len = snprintf(buf, sizeof(buf), "%s/..", cn ? cn : ctl->path);
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free(cn);
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if (len < 0 || (size_t) len >= sizeof(buf))
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return -1;
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if (stat(buf, &pst) !=0)
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return -1;
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if (ctl->st.st_dev != pst.st_dev || ctl->st.st_ino == pst.st_ino) {
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ctl->dev = ctl->st.st_dev;
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return 0;
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}
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return -1;
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}
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/* to canonicalize all necessary paths */
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cache = mnt_new_cache();
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mnt_table_set_cache(tb, cache);
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mnt_unref_cache(cache);
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fs = mnt_table_find_target(tb, ctl->path, MNT_ITER_BACKWARD);
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if (fs && mnt_fs_get_target(fs)) {
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ctl->dev = mnt_fs_get_devno(fs);
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rc = 0;
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}
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mnt_unref_table(tb);
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return rc;
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}
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static int print_devno(const struct mountpoint_control *ctl)
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{
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if (!S_ISBLK(ctl->st.st_mode)) {
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if (!ctl->quiet)
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warnx(_("%s: not a block device"), ctl->path);
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return -1;
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}
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printf("%u:%u\n", major(ctl->st.st_rdev), minor(ctl->st.st_rdev));
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return 0;
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}
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static void __attribute__((__noreturn__)) usage(void)
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{
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FILE *out = stdout;
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fputs(USAGE_HEADER, out);
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fprintf(out,
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_(" %1$s [-qd] /path/to/directory\n"
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" %1$s -x /dev/device\n"), program_invocation_short_name);
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fputs(USAGE_SEPARATOR, out);
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fputs(_("Check whether a directory or file is a mountpoint.\n"), out);
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fputs(USAGE_OPTIONS, out);
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fputs(_(" -q, --quiet quiet mode - don't print anything\n"
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" --nofollow do not follow symlink\n"
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" -d, --fs-devno print maj:min device number of the filesystem\n"
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" -x, --devno print maj:min device number of the block device\n"), out);
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fputs(USAGE_SEPARATOR, out);
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printf(USAGE_HELP_OPTIONS(20));
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printf(USAGE_MAN_TAIL("mountpoint(1)"));
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exit(EXIT_SUCCESS);
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}
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int main(int argc, char **argv)
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{
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int c;
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struct mountpoint_control ctl = { NULL };
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enum {
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OPT_NOFOLLOW = CHAR_MAX + 1
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};
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static const struct option longopts[] = {
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{ "quiet", no_argument, NULL, 'q' },
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{ "nofollow", no_argument, NULL, OPT_NOFOLLOW },
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{ "fs-devno", no_argument, NULL, 'd' },
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{ "devno", no_argument, NULL, 'x' },
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{ "help", no_argument, NULL, 'h' },
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{ "version", no_argument, NULL, 'V' },
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{ NULL, 0, NULL, 0 }
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};
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setlocale(LC_ALL, "");
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bindtextdomain(PACKAGE, LOCALEDIR);
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textdomain(PACKAGE);
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close_stdout_atexit();
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mnt_init_debug(0);
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while ((c = getopt_long(argc, argv, "qdxhV", longopts, NULL)) != -1) {
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switch(c) {
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case 'q':
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ctl.quiet = 1;
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break;
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case OPT_NOFOLLOW:
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ctl.nofollow = 1;
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break;
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case 'd':
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ctl.fs_devno = 1;
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break;
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case 'x':
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ctl.dev_devno = 1;
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break;
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case 'h':
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usage();
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case 'V':
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print_version(EXIT_SUCCESS);
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default:
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errtryhelp(EXIT_FAILURE);
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}
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}
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if (optind + 1 != argc) {
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warnx(_("bad usage"));
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errtryhelp(EXIT_FAILURE);
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}
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if (ctl.nofollow && ctl.dev_devno)
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errx(EXIT_FAILURE, _("%s and %s are mutually exclusive"),
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"--devno", "--nofollow");
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ctl.path = argv[optind];
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c = ctl.nofollow ? lstat(ctl.path, &ctl.st) : stat(ctl.path, &ctl.st);
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if (c) {
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if (!ctl.quiet)
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err(EXIT_FAILURE, "%s", ctl.path);
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return EXIT_FAILURE;
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}
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if (ctl.dev_devno)
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return print_devno(&ctl) ? EXIT_FAILURE : EXIT_SUCCESS;
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if ((ctl.nofollow && S_ISLNK(ctl.st.st_mode)) || dir_to_device(&ctl)) {
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if (!ctl.quiet)
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printf(_("%s is not a mountpoint\n"), ctl.path);
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return EXIT_FAILURE;
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}
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if (ctl.fs_devno)
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printf("%u:%u\n", major(ctl.dev), minor(ctl.dev));
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else if (!ctl.quiet)
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printf(_("%s is a mountpoint\n"), ctl.path);
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return EXIT_SUCCESS;
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}
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