blob: a93bc698eea6d259caa661693d53a7c1fe5f21a0
| 1 | /* |
| 2 | * realpath.c - realpath() aware of device mapper |
| 3 | * Originated from the util-linux project. |
| 4 | */ |
| 5 | |
| 6 | #ifdef HAVE_CONFIG_H |
| 7 | #include "config.h" |
| 8 | #endif |
| 9 | |
| 10 | #include <stdlib.h> |
| 11 | #include <stdio.h> |
| 12 | #include <string.h> |
| 13 | |
| 14 | #ifdef HAVE_LIMITS_H |
| 15 | #include <limits.h> |
| 16 | #endif |
| 17 | #ifdef HAVE_CTYPE_H |
| 18 | #include <ctype.h> |
| 19 | #endif |
| 20 | |
| 21 | #include "param.h" |
| 22 | #include "realpath.h" |
| 23 | |
| 24 | /* If there is no realpath() on the system, provide a dummy one. */ |
| 25 | #ifndef HAVE_REALPATH |
| 26 | char *ntfs_realpath(const char *path, char *resolved_path) |
| 27 | { |
| 28 | strncpy(resolved_path, path, PATH_MAX); |
| 29 | resolved_path[PATH_MAX] = '\0'; |
| 30 | return resolved_path; |
| 31 | } |
| 32 | #endif |
| 33 | |
| 34 | |
| 35 | #ifdef linux |
| 36 | |
| 37 | /* |
| 38 | * Converts private "dm-N" names to "/dev/mapper/<name>" |
| 39 | * |
| 40 | * Since 2.6.29 (patch 784aae735d9b0bba3f8b9faef4c8b30df3bf0128) kernel sysfs |
| 41 | * provides the real DM device names in /sys/block/<ptname>/dm/name |
| 42 | */ |
| 43 | static char * |
| 44 | canonicalize_dm_name(const char *ptname, char *canonical) |
| 45 | { |
| 46 | FILE *f; |
| 47 | size_t sz; |
| 48 | char path[MAPPERNAMELTH + 24]; |
| 49 | char name[MAPPERNAMELTH + 16]; |
| 50 | char *res = NULL; |
| 51 | |
| 52 | snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptname); |
| 53 | if (!(f = fopen(path, "r"))) |
| 54 | return NULL; |
| 55 | |
| 56 | /* read "<name>\n" from sysfs */ |
| 57 | if (fgets(name, sizeof(name), f) && (sz = strlen(name)) > 1) { |
| 58 | name[sz - 1] = '\0'; |
| 59 | snprintf(path, sizeof(path), "/dev/mapper/%s", name); |
| 60 | res = strcpy(canonical, path); |
| 61 | } |
| 62 | fclose(f); |
| 63 | return res; |
| 64 | } |
| 65 | |
| 66 | /* |
| 67 | * Canonicalize a device path |
| 68 | * |
| 69 | * Workaround from "basinilya" for fixing device mapper paths. |
| 70 | * |
| 71 | * Background (Phillip Susi, 2011-04-09) |
| 72 | * - ntfs-3g canonicalizes the device name so that if you mount with |
| 73 | * /dev/mapper/foo, the device name listed in mtab is /dev/dm-n, |
| 74 | * so you can not umount /dev/mapper/foo |
| 75 | * - umount won't even recognize and translate /dev/dm-n to the mount |
| 76 | * point, apparently because of the '-' involved. Editing mtab and |
| 77 | * removing the '-' allows you to umount /dev/dmn successfully. |
| 78 | * |
| 79 | * This code restores the devmapper name after canonicalization, |
| 80 | * until a proper fix is implemented. |
| 81 | */ |
| 82 | |
| 83 | char *ntfs_realpath_canonicalize(const char *path, char *canonical) |
| 84 | { |
| 85 | char *p; |
| 86 | |
| 87 | if (path == NULL) |
| 88 | return NULL; |
| 89 | |
| 90 | if (!ntfs_realpath(path, canonical)) |
| 91 | return NULL; |
| 92 | |
| 93 | p = strrchr(canonical, '/'); |
| 94 | if (p && strncmp(p, "/dm-", 4) == 0 && isdigit(*(p + 4))) { |
| 95 | p = canonicalize_dm_name(p+1, canonical); |
| 96 | if (p) |
| 97 | return p; |
| 98 | } |
| 99 | |
| 100 | return canonical; |
| 101 | } |
| 102 | |
| 103 | #endif |
| 104 |