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                         break;
  37                 if (j+1 >= len)
  38                         break;
  39                 if (c < 0x80) {
  40                         /* 0xxxxxxx */
  41                 } else {
  42                         uint8_t topbits = 0xc0;
  43                         if (j+2 >= len)
  44                                 break;
  45                         if (c < 0x800) {
  46                                 /* 110yyyxx 10xxxxxx */
  47                         } else {
  48                                 if (j+3 >= len)
  49                                         break;
  50                                 /* 1110yyyy 10yyyyxx 10xxxxxx */
  51                                 str[j++] = (uint8_t) (0xe0 | (c >> 12));
  52                                 topbits = 0x80;
  53                         }
  54                         str[j++] = (uint8_t) (topbits | ((c >> 6) & 0x3f));
  55                         c = 0x80 | (c & 0x3f);
  56                 }
  57                 str[j++] = (uint8_t) c;
  58         }
  59         str[j] = '\0';
  60 }
  61 #endif
  62
  63 #ifndef UTIL2
  64 #ifdef UNUSED
  65 static const char *usage_to_string(enum volume_id_usage usage_id)
  66 {
  67         switch (usage_id) {
  68         case VOLUME_ID_FILESYSTEM:
  69                 return "filesystem";
  70         case VOLUME_ID_PARTITIONTABLE:
  71                 return "partitiontable";
  72         case VOLUME_ID_OTHER:
  73                 return "other";
  74         case VOLUME_ID_RAID:
  75                 return "raid";
  76         case VOLUME_ID_DISKLABEL:
  77                 return "disklabel";
  78         case VOLUME_ID_CRYPTO:
  79                 return "crypto";
  80         case VOLUME_ID_UNPROBED:
  81                 return "unprobed";
  82         case VOLUME_ID_UNUSED:
  83                 return "unused";
  84         }
  85         return NULL;
  86 }
  87
  88 void volume_id_set_usage_part(struct volume_id_partition *part, enum volume_id_usage usage_id)
  89 {
  90         part->usage_id = usage_id;
  91         part->usage = usage_to_string(usage_id);
  92 }
  93
  94 void volume_id_set_usage(struct volume_id *id, enum volume_id_usage usage_id)
  95 {
  96         id->usage_id = usage_id;
  97         id->usage = usage_to_string(usage_id);
  98 }
  99
 100 void volume_id_set_label_raw(struct volume_id *id, const uint8_t *buf, size_t count)
 101 {
 102         memcpy(id->label_raw, buf, count);
 103         id->label_raw_len = count;
 104 }
 105 #endif
 106
 107 #ifdef NOT_NEEDED
 108 static size_t strnlen(const char *s, size_t maxlen)
 109 {
 110         size_t i;
 111         if (!maxlen) return 0;
 112         if (!s) return 0;
 113         for (i = 0; *s && i < maxlen; ++s) ++i;
 114         return i;
 115 }
 116 #endif
 117
 118 #endif
 119 #ifdef UTIL2
 120
 121 void volume_id_set_label_string(struct volume_id *id, const uint8_t *buf, size_t count)
 122 {
 123         unsigned i;
 124
 125         memcpy(id->label, buf, count);
 126
 127         /* remove trailing whitespace */
 128         i = strnlen(id->label, count);
 129         while (i--) {
 130                 if (!isspace(id->label[i]))
 131                         break;
 132         }
 133         id->label[i+1] = '\0';
 134 }
 135
 136 void volume_id_set_label_unicode16(struct volume_id *id, const uint8_t *buf, enum endian endianess, size_t count)
 137 {
 138         volume_id_set_unicode16(id->label, sizeof(id->label), buf, endianess, count);
 139 }
 140
 141 void volume_id_set_uuid(struct volume_id *id, const uint8_t *buf, enum uuid_format format)
 142 {
 143         unsigned i;
 144         unsigned count = (format == UUID_DCE_STRING ? VOLUME_ID_UUID_SIZE : 4 << format);
 145
 146 //      memcpy(id->uuid_raw, buf, count);
 147 //      id->uuid_raw_len = count;
 148
 149         /* if set, create string in the same format, the native platform uses */
 150         for (i = 0; i < count; i++)
 151                 if (buf[i] != 0)
 152                         goto set;
 153         return; /* all bytes are zero, leave it empty ("") */
 154
 155 set:
 156         switch (format) {
 157         case UUID_DOS:
 158                 sprintf(id->uuid, "%02X%02X-%02X%02X",
 159                         buf[3], buf[2], buf[1], buf[0]);
 160                 break;
 161         case UUID_NTFS:
 162                 sprintf(id->uuid, "%02X%02X%02X%02X%02X%02X%02X%02X",
 163                         buf[7], buf[6], buf[5], buf[4],
 164                         buf[3], buf[2], buf[1], buf[0]);
 165                 break;
 166         case UUID_DCE:
 167                 sprintf(id->uuid,
 168                         "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
 169                         buf[0], buf[1], buf[2], buf[3],
 170                         buf[4], buf[5],
 171                         buf[6], buf[7],
 172                         buf[8], buf[9],
 173                         buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]);
 174                 break;
 175         case UUID_DCE_STRING:
 176                 memcpy(id->uuid, buf, count);
 177                 id->uuid[count] = '\0';
 178                 break;
 179         }
 180 }
 181
 182 /* Do not use xlseek here. With it, single corrupted filesystem
 183  * may result in attempt to seek past device -> exit.
 184  * It's better to ignore such fs and continue.  */
 185 void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
 186 {
 187         uint8_t *dst;
 188         unsigned small_off;
 189         ssize_t read_len;
 190
 191         dbg("get buffer off 0x%llx(%llu), len 0x%zx",
 192                 (unsigned long long) off, (unsigned long long) off, len);
 193
 194         /* check if requested area fits in superblock buffer */
 195         if (off + len <= SB_BUFFER_SIZE
 196          /* && off <= SB_BUFFER_SIZE - want this paranoid overflow check? */
 197         ) {
 198                 if (id->sbbuf == NULL) {
 199                         id->sbbuf = xmalloc(SB_BUFFER_SIZE);
 200                 }
 201                 small_off = off;
 202                 dst = id->sbbuf;
 203
 204                 /* check if we need to read */
 205                 len += off;
 206                 if (len <= id->sbbuf_len)
 207                         goto ret; /* we already have it */
 208
 209                 dbg("read sbbuf len:0x%x", (unsigned) len);
 210                 id->sbbuf_len = len;
 211                 off = 0;
 212                 goto do_read;
 213         }
 214
 215         if (len > SEEK_BUFFER_SIZE) {
 216                 dbg("seek buffer too small %d", SEEK_BUFFER_SIZE);
 217                 return NULL;
 218         }
 219         dst = id->seekbuf;
 220
 221         /* check if we need to read */
 222         if ((off >= id->seekbuf_off)
 223          && ((off + len) <= (id->seekbuf_off + id->seekbuf_len))
 224         ) {
 225                 small_off = off - id->seekbuf_off; /* can't overflow */
 226                 goto ret; /* we already have it */
 227         }
 228
 229         id->seekbuf_off = off;
 230         id->seekbuf_len = len;
 231         id->seekbuf = xrealloc(id->seekbuf, len);
 232         small_off = 0;
 233         dst = id->seekbuf;
 234         dbg("read seekbuf off:0x%llx len:0x%zx",
 235                                 (unsigned long long) off, len);
 236  do_read:
 237         if (lseek(id->fd, off, SEEK_SET) != off) {
 238                 dbg("seek(0x%llx) failed", (unsigned long long) off);
 239                 goto err;
 240         }
 241         read_len = full_read(id->fd, dst, len);
 242         if (read_len != len) {
 243                 dbg("requested 0x%x bytes, got 0x%x bytes",
 244                                 (unsigned) len, (unsigned) read_len);
 245  err:
 246                 /* No filesystem can be this tiny. It's most likely
 247                  * non-associated loop device, empty drive and so on.
 248                  * Flag it, making it possible to short circuit future
 249                  * accesses. Rationale:
 250                  * users complained of slow blkid due to empty floppy drives.
 251                  */
 252                 if (off < 64*1024)
 253                         id->error = 1;
 254                 /* id->seekbuf_len or id->sbbuf_len is wrong now! Fixing. */
 255                 volume_id_free_buffer(id);
 256                 return NULL;
 257         }
 258  ret:
 259         return dst + small_off;
 260 }
 261
 262 void volume_id_free_buffer(struct volume_id *id)
 263 {
 264         free(id->sbbuf);
 265         id->sbbuf = NULL;
 266         id->sbbuf_len = 0;
 267         free(id->seekbuf);
 268         id->seekbuf = NULL;
 269         id->seekbuf_len = 0;
 270         id->seekbuf_off = 0; /* paranoia */
 271 }
 272 #endif