diff options
Diffstat (limited to 'sys-utils/mountpoint.c')
| -rw-r--r-- | sys-utils/mountpoint.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/sys-utils/mountpoint.c b/sys-utils/mountpoint.c new file mode 100644 index 0000000..b9904f3 --- /dev/null +++ b/sys-utils/mountpoint.c @@ -0,0 +1,219 @@ +/* + * mountpoint(1) - see if a directory is a mountpoint + * + * This is libmount based reimplementation of the mountpoint(1) + * from sysvinit project. + * + * + * 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. + * + * This program is distributed in the hope that it would be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#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); + printf(USAGE_HELP_OPTIONS(20)); + printf(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; +} |