release/src/router/busybox/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 #ifdef UTIL2
  24 void volume_id_set_unicode16(char *str, size_t len, const uint8_t *buf, enum endian endianess, size_t count)
  25 {
  26         unsigned i, j;
  27         unsigned c;
  28
  29         j = 0;
  30         for (i = 0; i + 2 <= count; i += 2) {
  31                 if (endianess == LE)
  32                         c = (buf[i+1] << 8) | buf[i];
  33                 else
  34                         c = (buf[i] << 8) | buf[i+1];
  35                 if (c == 0) {
  36                         str[j] = '\0';
  37                         break;
  38                 } else if (c < 0x80) {
  39                         if (j+1 >= len)
  40                                 break;
  41                         str[j++] = (uint8_t) c;
  42                 } else if (c < 0x800) {
  43                         if (j+2 >= len)
  44                                 break;
  45                         str[j++] = (uint8_t) (0xc0 | (c >> 6));
  46                         str[j++] = (uint8_t) (0x80 | (c & 0x3f));
  47                 } else {
  48                         if (j+3 >= len)
  49                                 break;
  50                         str[j++] = (uint8_t) (0xe0 | (c >> 12));
  51                         str[j++] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
  52                         str[j++] = (uint8_t) (0x80 | (c & 0x3f));
  53                 }
  54         }
  55         str[j] = '\0';
  56 }
  57 #endif
  58
  59 #ifndef UTIL2
  60 #ifdef UNUSED
  61 static const char *usage_to_string(enum volume_id_usage usage_id)
  62 {
  63         switch (usage_id) {
  64         case VOLUME_ID_FILESYSTEM:
  65                 return "filesystem";
  66         case VOLUME_ID_PARTITIONTABLE:
  67                 return "partitiontable";
  68         case VOLUME_ID_OTHER:
  69                 return "other";
  70         case VOLUME_ID_RAID:
  71                 return "raid";
  72         case VOLUME_ID_DISKLABEL:
  73                 return "disklabel";
  74         case VOLUME_ID_CRYPTO:
  75                 return "crypto";
  76         case VOLUME_ID_UNPROBED:
  77                 return "unprobed";
  78         case VOLUME_ID_UNUSED:
  79                 return "unused";
  80         }
  81         return NULL;
  82 }
  83
  84 void volume_id_set_usage_part(struct volume_id_partition *part, enum volume_id_usage usage_id)
  85 {
  86         part->usage_id = usage_id;
  87         part->usage = usage_to_string(usage_id);
  88 }
  89
  90 void volume_id_set_usage(struct volume_id *id, enum volume_id_usage usage_id)
  91 {
  92         id->usage_id = usage_id;
  93         id->usage = usage_to_string(usage_id);
  94 }
  95
  96 void volume_id_set_label_raw(struct volume_id *id, const uint8_t *buf, size_t count)
  97 {
  98         memcpy(id->label_raw, buf, count);
  99         id->label_raw_len = count;
 100 }
 101 #endif
 102
 103 #ifdef NOT_NEEDED
 104 static size_t strnlen(const char *s, size_t maxlen)
 105 {
 106         size_t i;
 107         if (!maxlen) return 0;
 108         if (!s) return 0;
 109         for (i = 0; *s && i < maxlen; ++s) ++i;
 110         return i;
 111 }
 112 #endif
 113
 114 #endif
 115 #ifdef UTIL2
 116
 117 void volume_id_set_label_string(struct volume_id *id, const uint8_t *buf, size_t count)
 118 {
 119         unsigned i;
 120
 121         memcpy(id->label, buf, count);
 122
 123         /* remove trailing whitespace */
 124         i = strnlen(id->label, count);
 125         while (i--) {
 126                 if (!isspace(id->label[i]))
 127                         break;
 128         }
 129         id->label[i+1] = '\0';
 130 }
 131
 132 void volume_id_set_label_unicode16(struct volume_id *id, const uint8_t *buf, enum endian endianess, size_t count)
 133 {
 134          volume_id_set_unicode16(id->label, sizeof(id->label), buf, endianess, count);
 135 }
 136
 137 void volume_id_set_uuid(struct volume_id *id, const uint8_t *buf, enum uuid_format format)
 138 {
 139         unsigned i;
 140         unsigned count = 0;
 141
 142         switch (format) {
 143         case UUID_DOS:
 144                 count = 4;
 145                 break;
 146         case UUID_NTFS:
 147         case UUID_HFS:
 148                 count = 8;
 149                 break;
 150         case UUID_DCE:
 151                 count = 16;
 152                 break;
 153         case UUID_DCE_STRING:
 154                 /* 36 is ok, id->uuid has one extra byte for NUL */
 155                 count = VOLUME_ID_UUID_SIZE;
 156                 break;
 157         }
 158 //      memcpy(id->uuid_raw, buf, count);
 159 //      id->uuid_raw_len = count;
 160
 161         /* if set, create string in the same format, the native platform uses */
 162         for (i = 0; i < count; i++)
 163                 if (buf[i] != 0)
 164                         goto set;
 165         return; /* all bytes are zero, leave it empty ("") */
 166
 167 set:
 168         switch (format) {
 169         case UUID_DOS:
 170                 sprintf(id->uuid, "%02X%02X-%02X%02X",
 171                         buf[3], buf[2], buf[1], buf[0]);
 172                 break;
 173         case UUID_NTFS:
 174                 sprintf(id->uuid, "%02X%02X%02X%02X%02X%02X%02X%02X",
 175                         buf[7], buf[6], buf[5], buf[4],
 176                         buf[3], buf[2], buf[1], buf[0]);
 177                 break;
 178         case UUID_HFS:
 179                 sprintf(id->uuid, "%02X%02X%02X%02X%02X%02X%02X%02X",
 180                         buf[0], buf[1], buf[2], buf[3],
 181                         buf[4], buf[5], buf[6], buf[7]);
 182                 break;
 183         case UUID_DCE:
 184                 sprintf(id->uuid,
 185                         "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
 186                         buf[0], buf[1], buf[2], buf[3],
 187                         buf[4], buf[5],
 188                         buf[6], buf[7],
 189                         buf[8], buf[9],
 190                         buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]);
 191                 break;
 192         case UUID_DCE_STRING:
 193                 memcpy(id->uuid, buf, count);
 194                 id->uuid[count] = '\0';
 195                 break;
 196         }
 197 }
 198
 199 /* Do not use xlseek here. With it, single corrupted filesystem
 200  * may result in attempt to seek past device -> exit.
 201  * It's better to ignore such fs and continue.  */
 202 void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
 203 {
 204         uint8_t *dst;
 205         unsigned small_off;
 206         ssize_t read_len;
 207
 208         dbg("get buffer off 0x%llx(%llu), len 0x%zx",
 209                 (unsigned long long) off, (unsigned long long) off, len);
 210
 211         /* check if requested area fits in superblock buffer */
 212         if (off + len <= SB_BUFFER_SIZE
 213          /* && off <= SB_BUFFER_SIZE - want this paranoid overflow check? */
 214         ) {
 215                 if (id->sbbuf == NULL) {
 216                         id->sbbuf = xmalloc(SB_BUFFER_SIZE);
 217                 }
 218                 small_off = off;
 219                 dst = id->sbbuf;
 220
 221                 /* check if we need to read */
 222                 len += off;
 223                 if (len <= id->sbbuf_len)
 224                         goto ret; /* we already have it */
 225
 226                 dbg("read sbbuf len:0x%x", (unsigned) len);
 227                 id->sbbuf_len = len;
 228                 off = 0;
 229                 goto do_read;
 230         }
 231
 232         if (len > SEEK_BUFFER_SIZE) {
 233                 dbg("seek buffer too small %d", SEEK_BUFFER_SIZE);
 234                 return NULL;
 235         }
 236         dst = id->seekbuf;
 237
 238         /* check if we need to read */
 239         if ((off >= id->seekbuf_off)
 240          && ((off + len) <= (id->seekbuf_off + id->seekbuf_len))
 241         ) {
 242                 small_off = off - id->seekbuf_off; /* can't overflow */
 243                 goto ret; /* we already have it */
 244         }
 245
 246         id->seekbuf_off = off;
 247         id->seekbuf_len = len;
 248         id->seekbuf = xrealloc(id->seekbuf, len);
 249         small_off = 0;
 250         dst = id->seekbuf;
 251         dbg("read seekbuf off:0x%llx len:0x%zx",
 252                                 (unsigned long long) off, len);
 253  do_read:
 254         if (lseek(id->fd, off, SEEK_SET) != off) {
 255                 dbg("seek(0x%llx) failed", (unsigned long long) off);
 256                 goto err;
 257         }
 258         read_len = full_read(id->fd, dst, len);
 259         if (read_len != len) {
 260                 dbg("requested 0x%x bytes, got 0x%x bytes",
 261                                 (unsigned) len, (unsigned) read_len);
 262  err:
 263                 /* No filesystem can be this tiny. It's most likely
 264                  * non-associated loop device, empty drive and so on.
 265                  * Flag it, making it possible to short circuit future
 266                  * accesses. Rationale:
 267                  * users complained of slow blkid due to empty floppy drives.
 268                  */
 269                 if (off < 64*1024)
 270                         id->error = 1;
 271                 /* id->seekbuf_len or id->sbbuf_len is wrong now! Fixing. */
 272                 volume_id_free_buffer(id);
 273                 return NULL;
 274         }
 275  ret:
 276         return dst + small_off;
 277 }
 278
 279 void volume_id_free_buffer(struct volume_id *id)
 280 {
 281         free(id->sbbuf);
 282         id->sbbuf = NULL;
 283         id->sbbuf_len = 0;
 284         free(id->seekbuf);
 285         id->seekbuf = NULL;
 286         id->seekbuf_len = 0;
 287         id->seekbuf_off = 0; /* paranoia */
 288 }
 289 #endif