/*
* This is a special case code to check for an MDRAID device. We do
* this special since it requires checking for a superblock at the end
* of the device.
*/
static int check_mdraid(int fd, unsigned char *ret_uuid)
{
struct mdp_superblock_s *md;
blkid_loff_t offset;
char buf[4096];
if (fd < 0)
return -BLKID_ERR_PARAM;
offset = (blkid_get_dev_size(fd) & ~((blkid_loff_t)65535)) - 65536;
if (blkid_llseek(fd, offset, 0) < 0 ||
read(fd, buf, 4096) != 4096)
return -BLKID_ERR_IO;
/* Check for magic number */
if (memcmp("\251+N\374", buf, 4) && memcmp("\374N+\251", buf, 4))
return -BLKID_ERR_PARAM;
if (!ret_uuid)
return 0;
*ret_uuid = 0;
/* The MD UUID is not contiguous in the superblock, make it so */
md = (struct mdp_superblock_s *)buf;
if (md->set_uuid0 || md->set_uuid1 || md->set_uuid2 || md->set_uuid3) {
memcpy(ret_uuid, &md->set_uuid0, 4);
memcpy(ret_uuid + 4, &md->set_uuid1, 12);
}
return 0;
}
static int valid_offset(int fd, blkid_loff_t offset)
{
char ch;
if (blkid_llseek(fd, offset, 0) < 0)
return 0;
if (read(fd, &ch, 1) < 1)
return 0;
return 1;
}
static unsigned char *get_buffer(struct blkid_probe *pr,
blkid_loff_t off, size_t len)
{
ssize_t ret_read;
unsigned char *newbuf;
if (off + len <= SB_BUFFER_SIZE) {
if (!pr->sbbuf) {
pr->sbbuf = malloc(SB_BUFFER_SIZE);
if (!pr->sbbuf)
return NULL;
if (lseek(pr->fd, 0, SEEK_SET) < 0)
return NULL;
ret_read = read(pr->fd, pr->sbbuf, SB_BUFFER_SIZE);
if (ret_read < 0)
ret_read = 0;
pr->sb_valid = ret_read;
}
if (off+len > pr->sb_valid)
return NULL;
return pr->sbbuf + off;
} else {
if (len > pr->buf_max) {
newbuf = realloc(pr->buf, len);
if (newbuf == NULL)
return NULL;
pr->buf = newbuf;
pr->buf_max = len;
}
if (blkid_llseek(pr->fd, off, SEEK_SET) < 0)
return NULL;
ret_read = read(pr->fd, pr->buf, len);
if (ret_read != (ssize_t) len)
return NULL;
return pr->buf;
}
}
