1 /* vi: set sw=4 ts=4: */
3 * mountpoint implementation for busybox
5 * Copyright (C) 2005 Bernhard Reutner-Fischer
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
9 * Based on sysvinit's mountpoint
11 //config:config MOUNTPOINT
12 //config: bool "mountpoint (4.9 kb)"
15 //config: mountpoint checks if the directory is a mountpoint.
17 //applet:IF_MOUNTPOINT(APPLET_NOEXEC(mountpoint, mountpoint, BB_DIR_BIN, BB_SUID_DROP, mountpoint))
19 //kbuild:lib-$(CONFIG_MOUNTPOINT) += mountpoint.o
21 //usage:#define mountpoint_trivial_usage
22 //usage: "[-q] <[-dn] DIR | -x DEVICE>"
23 //usage:#define mountpoint_full_usage "\n\n"
24 //usage: "Check if the directory is a mountpoint\n"
25 //usage: "\n -q Quiet"
26 //usage: "\n -d Print major/minor device number of the filesystem"
27 //usage: "\n -n Print device name of the filesystem"
28 //usage: "\n -x Print major/minor device number of the blockdevice"
30 //usage:#define mountpoint_example_usage
31 //usage: "$ mountpoint /proc\n"
32 //usage: "/proc is not a mountpoint\n"
33 //usage: "$ mountpoint /sys\n"
34 //usage: "/sys is a mountpoint\n"
38 int mountpoint_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
39 int mountpoint_main(int argc UNUSED_PARAM, char **argv)
46 opt = getopt32(argv, "^" "qdxn" "\0" "=1");
54 rc = (opt & OPT_x) ? stat(arg, &st) : lstat(arg, &st);
59 if (S_ISBLK(st.st_mode)) {
60 printf("%u:%u\n", major(st.st_rdev),
64 errno = 0; /* make perror_msg work as error_msg */
65 msg = "%s: not a block device";
70 if (S_ISDIR(st.st_mode)) {
71 dev_t st_dev = st.st_dev;
72 ino_t st_ino = st.st_ino;
73 char *p = xasprintf("%s/..", arg);
75 if (stat(p, &st) == 0) {
76 //int is_mnt = (st_dev != st.st_dev) || (st_dev == st.st_dev && st_ino == st.st_ino);
77 int is_not_mnt = (st_dev == st.st_dev) && (st_ino != st.st_ino);
80 printf("%u:%u\n", major(st_dev), minor(st_dev));
82 const char *d = find_block_device(arg);
83 /* name is undefined, but device is mounted -> anonymous superblock! */
84 /* happens with btrfs */
87 /* TODO: iterate /proc/mounts, or /proc/self/mountinfo
88 * to find out the device name */
90 printf("%s %s\n", d, arg);
92 if (!(opt & (OPT_q | OPT_d | OPT_n)))
93 printf("%s is %sa mountpoint\n", arg, is_not_mnt ? "not " : "");
97 /* else: stat had set errno, just fall through */
102 bb_perror_msg(msg, arg);