1 files changed, 105 insertions, 0 deletions
diff --git a/util-linux/mountpoint.c b/util-linux/mountpoint.c
new file mode 100644
index 000000000..8b9e1d779
--- /dev/null
+++ b/util-linux/mountpoint.c
@@ -0,0 +1,105 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * mountpoint implementation for busybox
+ *
+ * Copyright (C) 2005 Bernhard Reutner-Fischer
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ *
+ * Based on sysvinit's mountpoint
+ */
+//config:config MOUNTPOINT
+//config:	bool "mountpoint"
+//config:	default y
+//config:	help
+//config:	  mountpoint checks if the directory is a mountpoint.
+
+//applet:IF_MOUNTPOINT(APPLET(mountpoint, BB_DIR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_MOUNTPOINT) += mountpoint.o
+
+//usage:#define mountpoint_trivial_usage
+//usage:       "[-q] <[-dn] DIR | -x DEVICE>"
+//usage:#define mountpoint_full_usage "\n\n"
+//usage:       "Check if the directory is a mountpoint\n"
+//usage:     "\n	-q	Quiet"
+//usage:     "\n	-d	Print major/minor device number of the filesystem"
+//usage:     "\n	-n	Print device name of the filesystem"
+//usage:     "\n	-x	Print major/minor device number of the blockdevice"
+//usage:
+//usage:#define mountpoint_example_usage
+//usage:       "$ mountpoint /proc\n"
+//usage:       "/proc is not a mountpoint\n"
+//usage:       "$ mountpoint /sys\n"
+//usage:       "/sys is a mountpoint\n"
+
+#include "libbb.h"
+
+int mountpoint_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int mountpoint_main(int argc UNUSED_PARAM, char **argv)
+{
+	struct stat st;
+	const char *msg;
+	char *arg;
+	int rc, opt;
+
+	opt_complementary = "=1"; /* must have one argument */
+	opt = getopt32(argv, "qdxn");
+#define OPT_q (1)
+#define OPT_d (2)
+#define OPT_x (4)
+#define OPT_n (8)
+	arg = argv[optind];
+	msg = "%s";
+
+	rc = (opt & OPT_x) ? stat(arg, &st) : lstat(arg, &st);
+	if (rc != 0)
+		goto err;
+
+	if (opt & OPT_x) {
+		if (S_ISBLK(st.st_mode)) {
+			printf("%u:%u\n", major(st.st_rdev),
+						minor(st.st_rdev));
+			return EXIT_SUCCESS;
+		}
+		errno = 0; /* make perror_msg work as error_msg */
+		msg = "%s: not a block device";
+		goto err;
+	}
+
+	errno = ENOTDIR;
+	if (S_ISDIR(st.st_mode)) {
+		dev_t st_dev = st.st_dev;
+		ino_t st_ino = st.st_ino;
+		char *p = xasprintf("%s/..", arg);
+
+		if (stat(p, &st) == 0) {
+			//int is_mnt = (st_dev != st.st_dev) || (st_dev == st.st_dev && st_ino == st.st_ino);
+			int is_not_mnt = (st_dev == st.st_dev) && (st_ino != st.st_ino);
+
+			if (opt & OPT_d)
+				printf("%u:%u\n", major(st_dev), minor(st_dev));
+			if (opt & OPT_n) {
+				const char *d = find_block_device(arg);
+				/* name is undefined, but device is mounted -> anonymous superblock! */
+				/* happens with btrfs */
+				if (!d) {
+					d = "UNKNOWN";
+					/* TODO: iterate /proc/mounts, or /proc/self/mountinfo
+					 * to find out the device name */
+				}
+				printf("%s %s\n", d, arg);
+			}
+			if (!(opt & (OPT_q | OPT_d | OPT_n)))
+				printf("%s is %sa mountpoint\n", arg, is_not_mnt ? "not " : "");
+			return is_not_mnt;
+		}
+		arg = p;
+		/* else: stat had set errno, just fall through */
+	}
+
+ err:
+	if (!(opt & OPT_q))
+		bb_perror_msg(msg, arg);
+	return EXIT_FAILURE;
+}