blob: 8b9e1d779d6fdd6cf79bc961b9609c0b3c9d9382
| 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 GPLv2 or later, see file LICENSE in this source tree. |
| 8 | * |
| 9 | * Based on sysvinit's mountpoint |
| 10 | */ |
| 11 | //config:config MOUNTPOINT |
| 12 | //config: bool "mountpoint" |
| 13 | //config: default y |
| 14 | //config: help |
| 15 | //config: mountpoint checks if the directory is a mountpoint. |
| 16 | |
| 17 | //applet:IF_MOUNTPOINT(APPLET(mountpoint, BB_DIR_BIN, BB_SUID_DROP)) |
| 18 | |
| 19 | //kbuild:lib-$(CONFIG_MOUNTPOINT) += mountpoint.o |
| 20 | |
| 21 | //usage:#define mountpoint_trivial_usage |
| 22 | //usage: "[-q] <[-dn] DIR | -x DEVICE>" |
| 23 | //usage:#define mountpoint_full_usage "\n\n" |
| 24 | //usage: "Check if the directory is a mountpoint\n" |
| 25 | //usage: "\n -q Quiet" |
| 26 | //usage: "\n -d Print major/minor device number of the filesystem" |
| 27 | //usage: "\n -n Print device name of the filesystem" |
| 28 | //usage: "\n -x Print major/minor device number of the blockdevice" |
| 29 | //usage: |
| 30 | //usage:#define mountpoint_example_usage |
| 31 | //usage: "$ mountpoint /proc\n" |
| 32 | //usage: "/proc is not a mountpoint\n" |
| 33 | //usage: "$ mountpoint /sys\n" |
| 34 | //usage: "/sys is a mountpoint\n" |
| 35 | |
| 36 | #include "libbb.h" |
| 37 | |
| 38 | int mountpoint_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| 39 | int mountpoint_main(int argc UNUSED_PARAM, char **argv) |
| 40 | { |
| 41 | struct stat st; |
| 42 | const char *msg; |
| 43 | char *arg; |
| 44 | int rc, opt; |
| 45 | |
| 46 | opt_complementary = "=1"; /* must have one argument */ |
| 47 | opt = getopt32(argv, "qdxn"); |
| 48 | #define OPT_q (1) |
| 49 | #define OPT_d (2) |
| 50 | #define OPT_x (4) |
| 51 | #define OPT_n (8) |
| 52 | arg = argv[optind]; |
| 53 | msg = "%s"; |
| 54 | |
| 55 | rc = (opt & OPT_x) ? stat(arg, &st) : lstat(arg, &st); |
| 56 | if (rc != 0) |
| 57 | goto err; |
| 58 | |
| 59 | if (opt & OPT_x) { |
| 60 | if (S_ISBLK(st.st_mode)) { |
| 61 | printf("%u:%u\n", major(st.st_rdev), |
| 62 | minor(st.st_rdev)); |
| 63 | return EXIT_SUCCESS; |
| 64 | } |
| 65 | errno = 0; /* make perror_msg work as error_msg */ |
| 66 | msg = "%s: not a block device"; |
| 67 | goto err; |
| 68 | } |
| 69 | |
| 70 | errno = ENOTDIR; |
| 71 | if (S_ISDIR(st.st_mode)) { |
| 72 | dev_t st_dev = st.st_dev; |
| 73 | ino_t st_ino = st.st_ino; |
| 74 | char *p = xasprintf("%s/..", arg); |
| 75 | |
| 76 | if (stat(p, &st) == 0) { |
| 77 | //int is_mnt = (st_dev != st.st_dev) || (st_dev == st.st_dev && st_ino == st.st_ino); |
| 78 | int is_not_mnt = (st_dev == st.st_dev) && (st_ino != st.st_ino); |
| 79 | |
| 80 | if (opt & OPT_d) |
| 81 | printf("%u:%u\n", major(st_dev), minor(st_dev)); |
| 82 | if (opt & OPT_n) { |
| 83 | const char *d = find_block_device(arg); |
| 84 | /* name is undefined, but device is mounted -> anonymous superblock! */ |
| 85 | /* happens with btrfs */ |
| 86 | if (!d) { |
| 87 | d = "UNKNOWN"; |
| 88 | /* TODO: iterate /proc/mounts, or /proc/self/mountinfo |
| 89 | * to find out the device name */ |
| 90 | } |
| 91 | printf("%s %s\n", d, arg); |
| 92 | } |
| 93 | if (!(opt & (OPT_q | OPT_d | OPT_n))) |
| 94 | printf("%s is %sa mountpoint\n", arg, is_not_mnt ? "not " : ""); |
| 95 | return is_not_mnt; |
| 96 | } |
| 97 | arg = p; |
| 98 | /* else: stat had set errno, just fall through */ |
| 99 | } |
| 100 | |
| 101 | err: |
| 102 | if (!(opt & OPT_q)) |
| 103 | bb_perror_msg(msg, arg); |
| 104 | return EXIT_FAILURE; |
| 105 | } |
| 106 |