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/* 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 (4.5 kb)"
//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;
}
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