mountpoint: add new command

This is libmount based re-implementation of the mountpoint(1) command.
The original implementation is maintained in sysvinit suite.

The mountpoint(1) in util-linux is not enabled by default (for now) --
use --enable-mountpoint to enable the util.

Signed-off-by: Karel Zak <kzak@redhat.com>

4 files changed, 225 insertions, 0 deletions

diff --git a/sys-utils/.gitignore b/sys-utils/.gitignore
index b8af98f1a..3ae7e4a7b 100644
--- a/sys-utils/.gitignore
+++ b/sys-utils/.gitignore
@@ -18,6 +18,7 @@ lscpu
 mips32.8
 mips64.8
 mips.8
+mountpoint
 parisc32.8
 parisc64.8
 parisc.8
diff --git a/sys-utils/Makefile.am b/sys-utils/Makefile.am
index d916d3d04..53cdc3718 100644
--- a/sys-utils/Makefile.am
+++ b/sys-utils/Makefile.am
@@ -31,6 +31,13 @@ fstrim_SOURCES = fstrim.c $(top_srcdir)/lib/strutils.c
 rtcwake_SOURCES = rtcwake.c $(top_srcdir)/lib/strutils.c
 dmesg_SOURCES = dmesg.c $(top_srcdir)/lib/strutils.c
 
+if BUILD_MOUNTPOINT
+bin_PROGRAMS += mountpoint
+mountpoint_LDADD = $(ul_libmount_la)
+mountpoint_CFLAGS = $(AM_CFLAGS) -I$(ul_libmount_incdir)
+dist_man_MANS += mountpoint.1
+endif
+
 if BUILD_FALLOCATE
 usrbin_exec_PROGRAMS += fallocate
 fallocate_SOURCES = fallocate.c $(top_srcdir)/lib/strutils.c
diff --git a/sys-utils/mountpoint.1 b/sys-utils/mountpoint.1
new file mode 100644
index 000000000..be17c42dd
--- /dev/null
+++ b/sys-utils/mountpoint.1
@@ -0,0 +1,43 @@
+.\" -*- nroff -*-
+.TH MOUNTPOINT 1 "June 2011"
+.SH NAME
+mountpoint \- see if a directory is a mountpoint
+.SH SYNOPSIS
+.B mountpoint
+.RB [ \-q ]
+.RB [ \-d ]
+.I directory
+
+.B mountpoint
+.RB \-x
+.I device
+
+.SH DESCRIPTION
+.B mountpoint
+checks if the directory is mentioned in the /proc/self/mountinfo file.
+.SH OPTIONS
+.IP "\fB\-h, \-\-help\fP"
+Print help and exit.
+.IP "\fB\-q, \-\-quiet\fP"
+Be quiet - don't print anything.
+.IP "\fB\-d, \-\-fs\-devno\fP"
+Print major/minor device number of the filesystem on stdout.
+.IP "\fB\-x, \-\-devno\fP"
+Print major/minor device number of the blockdevice on stdout.
+.SH EXIT STATUS
+Zero if the directory is a mountpoint, non-zero if not.
+.SH AUTHOR
+.PP
+Karel Zak <kzak@redhat.com>
+.SH NOTES
+.PP
+The util-linux
+.B mountpoint
+implementation was written from scratch for libmount. The original version
+for sysvinit suite was written by Miquel van Smoorenburg.
+.SH SEE ALSO
+.BR mount (8)
+.SH AVAILABILITY
+The mountpoint command is part of the util-linux package and is available from
+ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
+
diff --git a/sys-utils/mountpoint.c b/sys-utils/mountpoint.c
new file mode 100644
index 000000000..92d283054
--- /dev/null
+++ b/sys-utils/mountpoint.c
@@ -0,0 +1,174 @@
+/*
+ * mountpoint(1) - see if a directory is a mountpoint
+ *
+ * This is libmount based reimplementation of the mountpoit(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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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 <unistd.h>
+
+
+#include <libmount.h>
+
+#include "nls.h"
+#include "xalloc.h"
+#include "c.h"
+
+static int quiet;
+
+static char *dir_to_device(const char *spec)
+{
+	struct libmnt_table *tb = mnt_new_table_from_file("/proc/self/mountinfo");
+	struct libmnt_fs *fs;
+	char *res = NULL;
+
+	if (!tb)
+		return NULL;
+
+	fs = mnt_table_find_target(tb, spec, MNT_ITER_BACKWARD);
+	if (fs && mnt_fs_get_target(fs))
+		res = xstrdup(mnt_fs_get_source(fs));
+
+	mnt_free_table(tb);
+	return res;
+}
+
+static int print_devno(const char *devname, struct stat *st)
+{
+	struct stat stbuf;
+
+	if (!st && stat(devname, &stbuf) == 0)
+		st = &stbuf;
+	if (!st)
+		return -1;
+	if (!S_ISBLK(st->st_mode)) {
+		if (!quiet)
+			warnx(_("%s: not a block device"), devname);
+		return -1;
+	}
+	printf("%u:%u\n", major(st->st_rdev), minor(st->st_rdev));
+	return 0;
+}
+
+static void __attribute__((__noreturn__)) usage(FILE *out)
+{
+	fprintf(out, _("Usage:\n"
+		" %1$s [-qd] /path/to/directory\n"
+		" %1$s -x /dev/device\n"),
+		program_invocation_short_name);
+
+	fprintf(out, _(
+	"\nOptions:\n"
+	" -q, --quiet        quiet mode - don't print anything\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"
+	" -h, --help         this help\n"
+	));
+
+	fprintf(out, _("\nFor more information see mountpoint(1).\n"));
+
+	exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
+}
+
+int main(int argc, char **argv)
+{
+	int c, fs_devno = 0, dev_devno = 0, rc = 0;
+	char *spec;
+	struct stat st;
+
+	static const struct option longopts[] = {
+		{ "quiet", 0, 0, 'q' },
+		{ "fs-devno", 0, 0, 'd' },
+		{ "devno", 0, 0, 'x' },
+		{ "help", 0, 0, 'h' },
+		{ NULL, 0, 0, 0 }
+	};
+
+	setlocale(LC_ALL, "");
+	bindtextdomain(PACKAGE, LOCALEDIR);
+	textdomain(PACKAGE);
+
+	mnt_init_debug(0);
+
+	while ((c = getopt_long(argc, argv, "qdxh", longopts, NULL)) != -1) {
+
+		switch(c) {
+		case 'q':
+			quiet = 1;
+			break;
+		case 'd':
+			fs_devno = 1;
+			break;
+		case 'x':
+			dev_devno = 1;
+			break;
+		case 'h':
+			usage(stdout);
+			break;
+		default:
+			usage(stderr);
+			break;
+		}
+	}
+
+	if (optind + 1 != argc)
+		usage(stderr);
+
+	spec = argv[optind++];
+
+	if (stat(spec, &st)) {
+		if (!quiet)
+			err(EXIT_FAILURE, "%s", spec);
+		return EXIT_FAILURE;
+	}
+	if (dev_devno)
+		rc = print_devno(spec, &st);
+	else {
+		char *src;
+
+		if (!S_ISDIR(st.st_mode)) {
+			if (!quiet)
+				errx(EXIT_FAILURE, _("%s: not a directory"), spec);
+			return EXIT_FAILURE;
+		}
+		src = dir_to_device(spec);
+		if (!src) {
+			if (!quiet)
+				printf(_("%s is not a mountpoint\n"), spec);
+			return EXIT_FAILURE;
+		}
+		if (fs_devno)
+			rc = print_devno(src, NULL);
+		else if (!quiet)
+			printf(_("%s is a mountpoint\n"), spec);
+		free(src);
+	}
+
+	return rc ? EXIT_FAILURE : EXIT_SUCCESS;
+}