LXR busybox/miscutils/mountpoint.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * mountpoint implementation for busybox
   4 *
   5 * Copyright (C) 2005 Bernhard Reutner-Fischer
   6 *
   7 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
   8 *
   9 * Based on sysvinit's mountpoint
  10 */
  11
  12#include "libbb.h"
  13
  14int mountpoint_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  15int mountpoint_main(int argc UNUSED_PARAM, char **argv)
  16{
  17        struct stat st;
  18        const char *msg;
  19        char *arg;
  20        int rc, opt;
  21
  22        opt_complementary = "=1"; /* must have one argument */
  23        opt = getopt32(argv, "qdxn");
  24#define OPT_q (1)
  25#define OPT_d (2)
  26#define OPT_x (4)
  27#define OPT_n (8)
  28        arg = argv[optind];
  29        msg = "%s";
  30
  31        rc = (opt & OPT_x) ? stat(arg, &st) : lstat(arg, &st);
  32        if (rc != 0)
  33                goto err;
  34
  35        if (opt & OPT_x) {
  36                if (S_ISBLK(st.st_mode)) {
  37                        printf("%u:%u\n", major(st.st_rdev),
  38                                                minor(st.st_rdev));
  39                        return EXIT_SUCCESS;
  40                }
  41                errno = 0; /* make perror_msg work as error_msg */
  42                msg = "%s: not a block device";
  43                goto err;
  44        }
  45
  46        errno = ENOTDIR;
  47        if (S_ISDIR(st.st_mode)) {
  48                dev_t st_dev = st.st_dev;
  49                ino_t st_ino = st.st_ino;
  50                char *p = xasprintf("%s/..", arg);
  51
  52                if (stat(p, &st) == 0) {
  53                        //int is_mnt = (st_dev != st.st_dev) || (st_dev == st.st_dev && st_ino == st.st_ino);
  54                        int is_not_mnt = (st_dev == st.st_dev) && (st_ino != st.st_ino);
  55
  56                        if (opt & OPT_d)
  57                                printf("%u:%u\n", major(st_dev), minor(st_dev));
  58                        if (opt & OPT_n) {
  59                                const char *d = find_block_device(arg);
  60                                /* name is undefined, but device is mounted -> anonymous superblock! */
  61                                /* happens with btrfs */
  62                                if (!d) {
  63                                        d = "UNKNOWN";
  64                                        /* TODO: iterate /proc/mounts, or /proc/self/mountinfo
  65                                         * to find out the device name */
  66                                }
  67                                printf("%s %s\n", d, arg);
  68                        }
  69                        if (!(opt & (OPT_q | OPT_d | OPT_n)))
  70                                printf("%s is %sa mountpoint\n", arg, is_not_mnt ? "not " : "");
  71                        return is_not_mnt;
  72                }
  73                arg = p;
  74                /* else: stat had set errno, just fall through */
  75        }
  76
  77 err:
  78        if (!(opt & OPT_q))
  79                bb_perror_msg(msg, arg);
  80        return EXIT_FAILURE;
  81}
  82