busybox/util-linux/volume_id/util.c
Denis Vlasenko 28ea4298e3 volume_id: abort early on read failures.
should help with probing missing fdd's
2009-02-15 05:51:19 +00:00

283 lines
7.0 KiB
C

/*
* volume_id - reads filesystem label and uuid
*
* Copyright (C) 2005 Kay Sievers <kay.sievers@vrfy.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "volume_id_internal.h"
void volume_id_set_unicode16(char *str, size_t len, const uint8_t *buf, enum endian endianess, size_t count)
{
unsigned i, j;
unsigned c;
j = 0;
for (i = 0; i + 2 <= count; i += 2) {
if (endianess == LE)
c = (buf[i+1] << 8) | buf[i];
else
c = (buf[i] << 8) | buf[i+1];
if (c == 0) {
str[j] = '\0';
break;
} else if (c < 0x80) {
if (j+1 >= len)
break;
str[j++] = (uint8_t) c;
} else if (c < 0x800) {
if (j+2 >= len)
break;
str[j++] = (uint8_t) (0xc0 | (c >> 6));
str[j++] = (uint8_t) (0x80 | (c & 0x3f));
} else {
if (j+3 >= len)
break;
str[j++] = (uint8_t) (0xe0 | (c >> 12));
str[j++] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
str[j++] = (uint8_t) (0x80 | (c & 0x3f));
}
}
str[j] = '\0';
}
#ifdef UNUSED
static const char *usage_to_string(enum volume_id_usage usage_id)
{
switch (usage_id) {
case VOLUME_ID_FILESYSTEM:
return "filesystem";
case VOLUME_ID_PARTITIONTABLE:
return "partitiontable";
case VOLUME_ID_OTHER:
return "other";
case VOLUME_ID_RAID:
return "raid";
case VOLUME_ID_DISKLABEL:
return "disklabel";
case VOLUME_ID_CRYPTO:
return "crypto";
case VOLUME_ID_UNPROBED:
return "unprobed";
case VOLUME_ID_UNUSED:
return "unused";
}
return NULL;
}
void volume_id_set_usage_part(struct volume_id_partition *part, enum volume_id_usage usage_id)
{
part->usage_id = usage_id;
part->usage = usage_to_string(usage_id);
}
void volume_id_set_usage(struct volume_id *id, enum volume_id_usage usage_id)
{
id->usage_id = usage_id;
id->usage = usage_to_string(usage_id);
}
void volume_id_set_label_raw(struct volume_id *id, const uint8_t *buf, size_t count)
{
memcpy(id->label_raw, buf, count);
id->label_raw_len = count;
}
#endif
#ifdef NOT_NEEDED
static size_t strnlen(const char *s, size_t maxlen)
{
size_t i;
if (!maxlen) return 0;
if (!s) return 0;
for (i = 0; *s && i < maxlen; ++s) ++i;
return i;
}
#endif
void volume_id_set_label_string(struct volume_id *id, const uint8_t *buf, size_t count)
{
unsigned i;
memcpy(id->label, buf, count);
/* remove trailing whitespace */
i = strnlen(id->label, count);
while (i--) {
if (!isspace(id->label[i]))
break;
}
id->label[i+1] = '\0';
}
void volume_id_set_label_unicode16(struct volume_id *id, const uint8_t *buf, enum endian endianess, size_t count)
{
volume_id_set_unicode16(id->label, sizeof(id->label), buf, endianess, count);
}
void volume_id_set_uuid(struct volume_id *id, const uint8_t *buf, enum uuid_format format)
{
unsigned i;
unsigned count = 0;
switch (format) {
case UUID_DOS:
count = 4;
break;
case UUID_NTFS:
case UUID_HFS:
count = 8;
break;
case UUID_DCE:
count = 16;
break;
case UUID_DCE_STRING:
/* 36 is ok, id->uuid has one extra byte for NUL */
count = VOLUME_ID_UUID_SIZE;
break;
}
// memcpy(id->uuid_raw, buf, count);
// id->uuid_raw_len = count;
/* if set, create string in the same format, the native platform uses */
for (i = 0; i < count; i++)
if (buf[i] != 0)
goto set;
return; /* all bytes are zero, leave it empty ("") */
set:
switch (format) {
case UUID_DOS:
sprintf(id->uuid, "%02X%02X-%02X%02X",
buf[3], buf[2], buf[1], buf[0]);
break;
case UUID_NTFS:
sprintf(id->uuid, "%02X%02X%02X%02X%02X%02X%02X%02X",
buf[7], buf[6], buf[5], buf[4],
buf[3], buf[2], buf[1], buf[0]);
break;
case UUID_HFS:
sprintf(id->uuid, "%02X%02X%02X%02X%02X%02X%02X%02X",
buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5], buf[6], buf[7]);
break;
case UUID_DCE:
sprintf(id->uuid,
"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
buf[0], buf[1], buf[2], buf[3],
buf[4], buf[5],
buf[6], buf[7],
buf[8], buf[9],
buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]);
break;
case UUID_DCE_STRING:
memcpy(id->uuid, buf, count);
id->uuid[count] = '\0';
break;
}
}
/* Do not use xlseek here. With it, single corrupted filesystem
* may result in attempt to seek past device -> exit.
* It's better to ignore such fs and continue. */
void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
{
uint8_t *dst;
unsigned small_off;
ssize_t read_len;
dbg("get buffer off 0x%llx(%llu), len 0x%zx",
(unsigned long long) off, (unsigned long long) off, len);
/* check if requested area fits in superblock buffer */
if (off + len <= SB_BUFFER_SIZE
/* && off <= SB_BUFFER_SIZE - want this paranoid overflow check? */
) {
if (id->sbbuf == NULL) {
id->sbbuf = xmalloc(SB_BUFFER_SIZE);
}
small_off = off;
dst = id->sbbuf;
/* check if we need to read */
len += off;
if (len <= id->sbbuf_len)
goto ret; /* we already have it */
dbg("read sbbuf len:0x%x", (unsigned) len);
id->sbbuf_len = len;
off = 0;
goto do_read;
}
if (len > SEEK_BUFFER_SIZE) {
dbg("seek buffer too small %d", SEEK_BUFFER_SIZE);
return NULL;
}
dst = id->seekbuf;
/* check if we need to read */
if ((off >= id->seekbuf_off)
&& ((off + len) <= (id->seekbuf_off + id->seekbuf_len))
) {
small_off = off - id->seekbuf_off; /* can't overflow */
goto ret; /* we already have it */
}
id->seekbuf_off = off;
id->seekbuf_len = len;
id->seekbuf = xrealloc(id->seekbuf, len);
small_off = 0;
dst = id->seekbuf;
dbg("read seekbuf off:0x%llx len:0x%zx",
(unsigned long long) off, len);
do_read:
if (lseek(id->fd, off, SEEK_SET) != off) {
dbg("seek(0x%llx) failed", (unsigned long long) off);
goto err;
}
read_len = full_read(id->fd, dst, len);
if (read_len != len) {
dbg("requested 0x%x bytes, got 0x%x bytes",
(unsigned) len, (unsigned) read_len);
err:
/* No filesystem can be this tiny. It's most likely
* non-associated loop device, empty drive and so on.
* Flag it, making it possible to short circuit future
* accesses. Rationale:
* users complained of slow blkid due to empty floppy drives.
*/
if (off < 64*1024)
id->error = 1;
/* id->seekbuf_len or id->sbbuf_len is wrong now! Fixing. */
volume_id_free_buffer(id);
return NULL;
}
ret:
return dst + small_off;
}
void volume_id_free_buffer(struct volume_id *id)
{
free(id->sbbuf);
id->sbbuf = NULL;
id->sbbuf_len = 0;
free(id->seekbuf);
id->seekbuf = NULL;
id->seekbuf_len = 0;
id->seekbuf_off = 0; /* paranoia */
}