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, see the file LICENSE in this tarball.
   8  *
   9  * Based on sysvinit's mountpoint
  10  */
  11
  12 #include <sys/stat.h>
  13 #include <errno.h> /* errno */
  14 #include <string.h> /* strerror */
  15 #include <getopt.h> /* optind */
  16 #include "busybox.h"
  17
  18 int mountpoint_main(int argc, char **argv)
  19 {
  20         int opt = bb_getopt_ulflags(argc, argv, "qdx");
  21 #define OPT_q (1)
  22 #define OPT_d (2)
  23 #define OPT_x (4)
  24
  25         if (optind != argc - 1)
  26                 bb_show_usage();
  27         {
  28                 char *arg = argv[optind];
  29                 struct stat st;
  30
  31                 if ( (opt & OPT_x && stat(arg, &st) == 0) || (lstat(arg, &st) == 0) ) {
  32                         if (opt & OPT_x) {
  33                                 if (S_ISBLK(st.st_mode))
  34                                 {
  35                                         bb_printf("%u:%u\n", major(st.st_rdev),
  36                                                                 minor(st.st_rdev));
  37                                         return EXIT_SUCCESS;
  38                                 } else {
  39                                         if (opt & OPT_q)
  40                                                 putchar('\n');
  41                                         else
  42                                                 bb_error_msg("%s: not a block device", arg);
  43                                 }
  44                                 return EXIT_FAILURE;
  45                         } else
  46                         if (S_ISDIR(st.st_mode)) {
  47                                 dev_t st_dev = st.st_dev;
  48                                 ino_t st_ino = st.st_ino;
  49                                 char *p = bb_xasprintf("%s/..", arg);
  50
  51                                 if (stat(p, &st) == 0) {
  52                                         short ret = (st_dev != st.st_dev) ||
  53                                                 (st_dev == st.st_dev && st_ino == st.st_ino);
  54                                         if (opt & OPT_d)
  55                                                 bb_printf("%u:%u\n", major(st_dev), minor(st_dev));
  56                                         else if (!(opt & OPT_q))
  57                                                 bb_printf("%s is %sa mountpoint\n", arg, ret?"":"not ");
  58                                         return !ret;
  59                                 }
  60                         } else {
  61                                 if (!(opt & OPT_q))
  62                                         bb_error_msg("%s: not a directory", arg);
  63                                 return EXIT_FAILURE;
  64                         }
  65                 }
  66                 if (!(opt & OPT_q))
  67                         bb_perror_msg(arg);
  68                 return EXIT_FAILURE;
  69         }
  70 }