miscutils/mountpoint.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * mountpoint implementation for busybox
   4  *
   5  * Copyright (C) 2005 Bernhard 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 "busybox.h"
  13
  14 int mountpoint_main(int argc, char **argv)
  15 {
  16         int opt = bb_getopt_ulflags(argc, argv, "qdx");
  17 #define OPT_q (1)
  18 #define OPT_d (2)
  19 #define OPT_x (4)
  20
  21         if (optind != argc - 1)
  22                 bb_show_usage();
  23         {
  24                 char *arg = argv[optind];
  25                 struct stat st;
  26
  27                 if ( (opt & OPT_x && stat(arg, &st) == 0) || (lstat(arg, &st) == 0) ) {
  28                         if (opt & OPT_x) {
  29                                 if (S_ISBLK(st.st_mode))
  30                                 {
  31                                         bb_printf("%u:%u\n", major(st.st_rdev),
  32                                                                 minor(st.st_rdev));
  33                                         return EXIT_SUCCESS;
  34                                 } else {
  35                                         if (opt & OPT_q)
  36                                                 putchar('\n');
  37                                         else
  38                                                 bb_error_msg("%s: not a block device", arg);
  39                                 }
  40                                 return EXIT_FAILURE;
  41                         } else
  42                         if (S_ISDIR(st.st_mode)) {
  43                                 dev_t st_dev = st.st_dev;
  44                                 ino_t st_ino = st.st_ino;
  45                                 char *p = xasprintf("%s/..", arg);
  46
  47                                 if (stat(p, &st) == 0) {
  48                                         short ret = (st_dev != st.st_dev) ||
  49                                                 (st_dev == st.st_dev && st_ino == st.st_ino);
  50                                         if (opt & OPT_d)
  51                                                 bb_printf("%u:%u\n", major(st_dev), minor(st_dev));
  52                                         else if (!(opt & OPT_q))
  53                                                 bb_printf("%s is %sa mountpoint\n", arg, ret?"":"not ");
  54                                         return !ret;
  55                                 }
  56                         } else {
  57                                 if (!(opt & OPT_q))
  58                                         bb_error_msg("%s: not a directory", arg);
  59                                 return EXIT_FAILURE;
  60                         }
  61                 }
  62                 if (!(opt & OPT_q))
  63                         bb_perror_msg("%s", arg);
  64                 return EXIT_FAILURE;
  65         }
  66 }