diff options
Diffstat (limited to 'utils.c')
| -rw-r--r-- | utils.c | 58 |
1 files changed, 58 insertions, 0 deletions
@@ -1027,6 +1027,64 @@ static int blk_file_in_dev_list(struct btrfs_fs_devices* fs_devices, } /* + * Resolve a pathname to a device mapper node to /dev/mapper/<name> + * Returns NULL on invalid input or malloc failure; Other failures + * will be handled by the caller using the input pathame. + */ +char *canonicalize_dm_name(const char *ptname) +{ + FILE *f; + size_t sz; + char path[PATH_MAX], name[PATH_MAX], *res = NULL; + + if (!ptname || !*ptname) + return NULL; + + snprintf(path, sizeof(path), "/sys/block/%s/dm/name", ptname); + if (!(f = fopen(path, "r"))) + return NULL; + + /* read <name>\n from sysfs */ + if (fgets(name, sizeof(name), f) && (sz = strlen(name)) > 1) { + name[sz - 1] = '\0'; + snprintf(path, sizeof(path), "/dev/mapper/%s", name); + + if (access(path, F_OK) == 0) + res = strdup(path); + } + fclose(f); + return res; +} + +/* + * Resolve a pathname to a canonical device node, e.g. /dev/sda1 or + * to a device mapper pathname. + * Returns NULL on invalid input or malloc failure; Other failures + * will be handled by the caller using the input pathame. + */ +char *canonicalize_path(const char *path) +{ + char *canonical, *p; + + if (!path || !*path) + return NULL; + + canonical = realpath(path, NULL); + if (!canonical) + return strdup(path); + p = strrchr(canonical, '/'); + if (p && strncmp(p, "/dm-", 4) == 0 && isdigit(*(p + 4))) { + char *dm = canonicalize_dm_name(p + 1); + + if (dm) { + free(canonical); + return dm; + } + } + return canonical; +} + +/* * returns 1 if the device was mounted, < 0 on error or 0 if everything * is safe to continue. */ |