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#include "project.h"
#define TABLE_SIZE (((sizeof(GPT_entry)*GPT_PARITION_ENTRIES)/SECTOR_SIZE)+2)
void
header_calc_crc (GPT_header * h)
{
h->header_crc = 0;
h->header_crc = crc32 (0, h, sizeof (GPT_header));
}
GPT_header
header_new (GUID disk_guid, uint64_t lbas, int alt)
{
GPT_header ret = { 0 };
memcpy (ret.signature, GPT_HEADER_SIGNATURE, sizeof (ret.signature));
ret.revision = GPT_HEADER_REVISION_EFI10;
ret.header_size = sizeof (GPT_header);
ret.first_usable_lba = TABLE_SIZE;
ret.last_usable_lba = lbas - TABLE_SIZE;
ret.n_partition_entries = GPT_PARITION_ENTRIES;
ret.partition_entry_size = sizeof (GPT_entry);
ret.disk_guid = disk_guid;
if (!alt)
{
ret.my_lba = 1;
ret.alternate_lba = lbas - 1;
ret.partition_entry_lba = 2;
}
else
{
ret.my_lba = lbas - 1;
ret.alternate_lba = 1;
ret.partition_entry_lba = lbas - TABLE_SIZE;
}
header_calc_crc (&ret);
return ret;
}
uint32_t
header_calc_ent_crc (DISK * d, GPT_header * h)
{
int i;
GPT_entry e;
uint32_t crc = 0;
for (i = 0; i < h->n_partition_entries; ++i)
{
e = entry_read (d, h, i);
crc = crc32 (crc, &e, h->partition_entry_size);
}
return crc;
}
void
header_show (DISK * d, GPT_header * h)
{
GPT_header c = *h;
uint32_t crc;
int i;
if (h->my_lba < h->alternate_lba)
{
printf (" GPT:\n");
}
else
{
printf (" ALTERNATE GPT:\n");
}
c.header_crc = 0;
crc = crc32 (0, &c, sizeof (c));
printf (" Signature %s, CRC %s\n",
(memcmp (h->signature, GPT_HEADER_SIGNATURE, sizeof (h->signature)))
? "INVALID" : "valid",
(crc == h->header_crc) ? "matches" : "DOES NOT MATCH");
printf (" rev=0x%08x lba=%lld alternate=%lld\n",
h->revision, (long long) h->my_lba, (long long) h->alternate_lba);
printf (" usable lbas %lld-%lld\n",
(long long) h->first_usable_lba, (long long) h->last_usable_lba);
printf (" DISK GUID: %s\n", guid_to_a (h->disk_guid));
crc = header_calc_ent_crc (d, h);
printf (" patitions (at lba %lld) CRC %s:\n",
(long long) h->partition_entry_lba,
(crc == h->partition_entry_crc) ? "matches" : "DOES NOT MATCH");
for (i = 0; i < h->n_partition_entries; ++i)
{
GPT_entry e = entry_read (d, h, i);
if (!entry_empty (&e))
{
printf (" %d:\n", i);
entry_show (&e);
}
}
}
int
header_validate (DISK * d, GPT_header * h)
{
GPT_header c = *h;
uint32_t crc;
c.header_crc = 0;
if (memcmp (h->signature, GPT_HEADER_SIGNATURE, sizeof (h->signature)))
return 0;
crc = crc32 (0, &c, sizeof (c));
if (crc != h->header_crc)
return 0;
crc = header_calc_ent_crc (d, h);
if (crc == h->partition_entry_crc)
return 0;
return 1;
}
void
header_redo_ent_crc (DISK * d, GPT_header * h)
{
h->partition_entry_crc = header_calc_ent_crc (d, h);
h->header_crc = 0;
h->header_crc = crc32 (0, h, sizeof (*h));
}
void
header_write (DISK * d, GPT_header * h)
{
uint8_t buf[512];
memcpy (buf, h, sizeof (*h));
printf ("Writing header to lba %lld\n", (long long) h->my_lba);
disk_write (d, buf, h->my_lba, 1);
}
int
headers_validate (DISK * d, GPT_headers * h)
{
if (!header_validate (d, &h->header))
return 0;
return header_validate (d, &h->alt_header);
}
GPT_headers
headers_get (DISK * d)
{
GPT_headers ret;
uint8_t buf[512];
uint64_t lbas;
lbas = disk_lbas (d);
disk_read (d, buf, 1, 1);
memcpy (&ret.header, buf, sizeof (ret.header));
lbas--;
if (lbas != ret.header.alternate_lba)
{
fprintf (stderr, "WARNING: alternate lba is not at end of disk\n");
}
disk_read (d, buf, ret.header.alternate_lba, 1);
memcpy (&ret.alt_header, buf, sizeof (ret.alt_header));
return ret;
}
GPT_headers
headers_get_one (DISK * d)
{
GPT_headers ret;
uint8_t buf[512];
uint64_t lbas;
int table_size;
lbas = disk_lbas (d);
disk_read (d, buf, 1, 1);
memcpy (&ret.header, buf, sizeof (ret.header));
table_size=ret.header.first_usable_lba;
ret.header.last_usable_lba=lbas-table_size;
ret.alt_header=ret.header;
ret.header.alternate_lba=lbas-1;
ret.alt_header.alternate_lba=1;
ret.alt_header.my_lba=lbas-1;
ret.alt_header.partition_entry_lba = (lbas - table_size)+1;
return ret;
}
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