util-linux/volume_id/util.c

   1 /*
   2  * volume_id - reads filesystem label and uuid
   3  *
   4  * Copyright (C) 2005 Kay Sievers <kay.sievers@vrfy.org>
   5  *
   6  *      This library is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU Lesser General Public
   8  *      License as published by the Free Software Foundation; either
   9  *      version 2.1 of the License, or (at your option) any later version.
  10  *
  11  *      This library is distributed in the hope that it will be useful,
  12  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14  *      Lesser General Public License for more details.
  15  *
  16  *      You should have received a copy of the GNU Lesser General Public
  17  *      License along with this library; if not, write to the Free Software
  18  *      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  19  */
  20
  21 #include "volume_id_internal.h"
  22
  23 void volume_id_set_unicode16(char *str, size_t len, const uint8_t *buf, enum endian endianess, size_t count)
  24 {
  25         unsigned i, j;
  26         unsigned c;
  27
  28         j = 0;
  29         for (i = 0; i + 2 <= count; i += 2) {
  30                 if (endianess == LE)
  31                         c = (buf[i+1] << 8) | buf[i];
  32                 else
  33                         c = (buf[i] << 8) | buf[i+1];
  34                 if (c == 0) {
  35                         str[j] = '\0';
  36                         break;
  37                 } else if (c < 0x80) {
  38                         if (j+1 >= len)
  39                                 break;
  40                         str[j++] = (uint8_t) c;
  41                 } else if (c < 0x800) {
  42                         if (j+2 >= len)
  43                                 break;
  44                         str[j++] = (uint8_t) (0xc0 | (c >> 6));
  45                         str[j++] = (uint8_t) (0x80 | (c & 0x3f));
  46                 } else {
  47                         if (j+3 >= len)
  48                                 break;
  49                         str[j++] = (uint8_t) (0xe0 | (c >> 12));
  50                         str[j++] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
  51                         str[j++] = (uint8_t) (0x80 | (c & 0x3f));
  52                 }
  53         }
  54         str[j] = '\0';
  55 }
  56
  57 #ifdef UNUSED
  58 static const char *usage_to_string(enum volume_id_usage usage_id)
  59 {
  60         switch (usage_id) {
  61         case VOLUME_ID_FILESYSTEM:
  62                 return "filesystem";
  63         case VOLUME_ID_PARTITIONTABLE:
  64                 return "partitiontable";
  65         case VOLUME_ID_OTHER:
  66                 return "other";
  67         case VOLUME_ID_RAID:
  68                 return "raid";
  69         case VOLUME_ID_DISKLABEL:
  70                 return "disklabel";
  71         case VOLUME_ID_CRYPTO:
  72                 return "crypto";
  73         case VOLUME_ID_UNPROBED:
  74                 return "unprobed";
  75         case VOLUME_ID_UNUSED:
  76                 return "unused";
  77         }
  78         return NULL;
  79 }
  80
  81 void volume_id_set_usage_part(struct volume_id_partition *part, enum volume_id_usage usage_id)
  82 {
  83         part->usage_id = usage_id;
  84         part->usage = usage_to_string(usage_id);
  85 }
  86
  87 void volume_id_set_usage(struct volume_id *id, enum volume_id_usage usage_id)
  88 {
  89         id->usage_id = usage_id;
  90         id->usage = usage_to_string(usage_id);
  91 }
  92
  93 void volume_id_set_label_raw(struct volume_id *id, const uint8_t *buf, size_t count)
  94 {
  95         memcpy(id->label_raw, buf, count);
  96         id->label_raw_len = count;
  97 }
  98 #endif
  99
 100 #ifdef NOT_NEEDED
 101 static size_t strnlen(const char *s, size_t maxlen)
 102 {
 103         size_t i;
 104         if (!maxlen) return 0;
 105         if (!s) return 0;
 106         for (i = 0; *s && i < maxlen; ++s) ++i;
 107         return i;
 108 }
 109 #endif
 110
 111 void volume_id_set_label_string(struct volume_id *id, const uint8_t *buf, size_t count)
 112 {
 113         unsigned i;
 114
 115         memcpy(id->label, buf, count);
 116
 117         /* remove trailing whitespace */
 118         i = strnlen(id->label, count);
 119         while (i--) {
 120                 if (!isspace(id->label[i]))
 121                         break;
 122         }
 123         id->label[i+1] = '\0';
 124 }
 125
 126 void volume_id_set_label_unicode16(struct volume_id *id, const uint8_t *buf, enum endian endianess, size_t count)
 127 {
 128          volume_id_set_unicode16(id->label, sizeof(id->label), buf, endianess, count);
 129 }
 130
 131 void volume_id_set_uuid(struct volume_id *id, const uint8_t *buf, enum uuid_format format)
 132 {
 133         unsigned i;
 134         unsigned count = 0;
 135
 136         switch (format) {
 137         case UUID_DOS:
 138                 count = 4;
 139                 break;
 140         case UUID_NTFS:
 141         case UUID_HFS:
 142                 count = 8;
 143                 break;
 144         case UUID_DCE:
 145                 count = 16;
 146                 break;
 147         case UUID_DCE_STRING:
 148                 /* 36 is ok, id->uuid has one extra byte for NUL */
 149                 count = VOLUME_ID_UUID_SIZE;
 150                 break;
 151         }
 152 //      memcpy(id->uuid_raw, buf, count);
 153 //      id->uuid_raw_len = count;
 154
 155         /* if set, create string in the same format, the native platform uses */
 156         for (i = 0; i < count; i++)
 157                 if (buf[i] != 0)
 158                         goto set;
 159         return; /* all bytes are zero, leave it empty ("") */
 160
 161 set:
 162         switch (format) {
 163         case UUID_DOS:
 164                 sprintf(id->uuid, "%02X%02X-%02X%02X",
 165                         buf[3], buf[2], buf[1], buf[0]);
 166                 break;
 167         case UUID_NTFS:
 168                 sprintf(id->uuid, "%02X%02X%02X%02X%02X%02X%02X%02X",
 169                         buf[7], buf[6], buf[5], buf[4],
 170                         buf[3], buf[2], buf[1], buf[0]);
 171                 break;
 172         case UUID_HFS:
 173                 sprintf(id->uuid, "%02X%02X%02X%02X%02X%02X%02X%02X",
 174                         buf[0], buf[1], buf[2], buf[3],
 175                         buf[4], buf[5], buf[6], buf[7]);
 176                 break;
 177         case UUID_DCE:
 178                 sprintf(id->uuid,
 179                         "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
 180                         buf[0], buf[1], buf[2], buf[3],
 181                         buf[4], buf[5],
 182                         buf[6], buf[7],
 183                         buf[8], buf[9],
 184                         buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]);
 185                 break;
 186         case UUID_DCE_STRING:
 187                 memcpy(id->uuid, buf, count);
 188                 id->uuid[count] = '\0';
 189                 break;
 190         }
 191 }
 192
 193 /* Do not use xlseek here. With it, single corrupted filesystem
 194  * may result in attempt to seek past device -> exit.
 195  * It's better to ignore such fs and continue.  */
 196 void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
 197 {
 198         uint8_t *dst;
 199         unsigned small_off;
 200         ssize_t read_len;
 201
 202         dbg("get buffer off 0x%llx(%llu), len 0x%zx",
 203                 (unsigned long long) off, (unsigned long long) off, len);
 204
 205         /* check if requested area fits in superblock buffer */
 206         if (off + len <= SB_BUFFER_SIZE
 207          /* && off <= SB_BUFFER_SIZE - want this paranoid overflow check? */
 208         ) {
 209                 if (id->sbbuf == NULL) {
 210                         id->sbbuf = xmalloc(SB_BUFFER_SIZE);
 211                 }
 212                 small_off = off;
 213                 dst = id->sbbuf;
 214
 215                 /* check if we need to read */
 216                 len += off;
 217                 if (len <= id->sbbuf_len)
 218                         goto ret; /* we already have it */
 219
 220                 dbg("read sbbuf len:0x%x", (unsigned) len);
 221                 id->sbbuf_len = len;
 222                 off = 0;
 223                 goto do_read;
 224         }
 225
 226         if (len > SEEK_BUFFER_SIZE) {
 227                 dbg("seek buffer too small %d", SEEK_BUFFER_SIZE);
 228                 return NULL;
 229         }
 230         dst = id->seekbuf;
 231
 232         /* check if we need to read */
 233         if ((off >= id->seekbuf_off)
 234          && ((off + len) <= (id->seekbuf_off + id->seekbuf_len))
 235         ) {
 236                 small_off = off - id->seekbuf_off; /* can't overflow */
 237                 goto ret; /* we already have it */
 238         }
 239
 240         id->seekbuf_off = off;
 241         id->seekbuf_len = len;
 242         id->seekbuf = xrealloc(id->seekbuf, len);
 243         small_off = 0;
 244         dst = id->seekbuf;
 245         dbg("read seekbuf off:0x%llx len:0x%zx",
 246                                 (unsigned long long) off, len);
 247  do_read:
 248         if (lseek(id->fd, off, SEEK_SET) != off) {
 249                 dbg("seek(0x%llx) failed", (unsigned long long) off);
 250                 goto err;
 251         }
 252         read_len = full_read(id->fd, dst, len);
 253         if (read_len != len) {
 254                 dbg("requested 0x%x bytes, got 0x%x bytes",
 255                                 (unsigned) len, (unsigned) read_len);
 256  err:
 257                 /* No filesystem can be this tiny. It's most likely
 258                  * non-associated loop device, empty drive and so on.
 259                  * Flag it, making it possible to short circuit future
 260                  * accesses. Rationale:
 261                  * users complained of slow blkid due to empty floppy drives.
 262                  */
 263                 if (off < 64*1024)
 264                         id->error = 1;
 265                 /* id->seekbuf_len or id->sbbuf_len is wrong now! Fixing. */
 266                 volume_id_free_buffer(id);
 267                 return NULL;
 268         }
 269  ret:
 270         return dst + small_off;
 271 }
 272
 273 void volume_id_free_buffer(struct volume_id *id)
 274 {
 275         free(id->sbbuf);
 276         id->sbbuf = NULL;
 277         id->sbbuf_len = 0;
 278         free(id->seekbuf);
 279         id->seekbuf = NULL;
 280         id->seekbuf_len = 0;
 281         id->seekbuf_off = 0; /* paranoia */
 282 }