probe-libblkid.c

   1 /*
   2  * Copyright (C) 2016 Jo-Philipp Wich <jo@mein.io>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License version 2.1
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <dlfcn.h>
  15 #include <string.h>
  16 #include <stdbool.h>
  17 #include <blkid/blkid.h>
  18 #include <libubox/utils.h>
  19
  20 #include "probe.h"
  21
  22
  23 static struct {
  24         bool loaded;
  25         blkid_probe (*alloc)(const char *);
  26         int (*probe)(blkid_probe);
  27         int (*lookup)(blkid_probe, const char *, const char **, size_t *);
  28         void (*free)(blkid_probe);
  29 } libblkid = { };
  30
  31
  32 static bool
  33 load_libblkid(void)
  34 {
  35         void *lib;
  36
  37         if (!libblkid.loaded) {
  38                 lib = dlopen("libblkid.so", RTLD_GLOBAL);
  39
  40                 if (lib) {
  41                         libblkid.alloc  = dlsym(lib, "blkid_new_probe_from_filename");
  42                         libblkid.probe  = dlsym(lib, "blkid_do_probe");
  43                         libblkid.lookup = dlsym(lib, "blkid_probe_lookup_value");
  44                         libblkid.free   = dlsym(lib, "blkid_free_probe");
  45                 }
  46
  47                 libblkid.loaded = true;
  48         }
  49
  50         return (libblkid.alloc && libblkid.probe && libblkid.lookup && libblkid.free);
  51 }
  52
  53 struct probe_info *
  54 probe_path_libblkid(const char *path)
  55 {
  56         blkid_probe pr;
  57         struct probe_info *info = NULL;
  58         size_t type_len, uuid_len, label_len, version_len;
  59         char *dev_ptr, *type_ptr, *uuid_ptr, *label_ptr, *version_ptr;
  60         const char *type_val, *uuid_val, *label_val, *version_val;
  61
  62         if (!load_libblkid())
  63                 return NULL;
  64
  65         pr = libblkid.alloc(path);
  66
  67         if (!pr)
  68                 return NULL;
  69
  70         if (libblkid.probe(pr) == 0) {
  71                 if (libblkid.lookup(pr, "TYPE", &type_val, &type_len))
  72                         type_len = 0;
  73
  74                 if (libblkid.lookup(pr, "UUID", &uuid_val, &uuid_len))
  75                         uuid_len = 0;
  76
  77                 if (libblkid.lookup(pr, "LABEL", &label_val, &label_len))
  78                         label_len = 0;
  79
  80                 if (libblkid.lookup(pr, "VERSION", &version_val, &version_len))
  81                         version_len = 0;
  82
  83                 if (type_len) {
  84                         info = calloc_a(sizeof(*info),
  85                                         &dev_ptr,     strlen(path) + 1,
  86                                         &type_ptr,    type_len,
  87                                         &uuid_ptr,    uuid_len,
  88                                         &label_ptr,   label_len,
  89                                         &version_ptr, version_len);
  90
  91                         if (info) {
  92                                 info->dev = strcpy(dev_ptr, path);
  93                                 info->type = strcpy(type_ptr, type_val);
  94
  95                                 if (uuid_len)
  96                                         info->uuid = strcpy(uuid_ptr, uuid_val);
  97
  98                                 if (label_len)
  99                                         info->label = strcpy(label_ptr, label_val);
 100
 101                                 if (version_len)
 102                                         info->version = strcpy(version_ptr, version_val);
 103                         }
 104                 }
 105         }
 106
 107         libblkid.free(pr);
 108
 109         return info;
 110 }