rulimine/stage23/lib/part.s2.c
2021-03-04 09:15:10 +01:00

338 lines
8.8 KiB
C

#include <stddef.h>
#include <stdint.h>
#include <lib/part.h>
#include <drivers/disk.h>
#if defined (bios)
# include <lib/real.h>
#endif
#include <lib/libc.h>
#include <lib/blib.h>
#include <lib/print.h>
#include <mm/pmm.h>
#include <fs/file.h>
#define BLOCK_SIZE_IN_SECTORS 8
enum {
CACHE_NOT_READY = 0,
CACHE_READY
};
static bool cache_block(struct volume *volume, uint64_t block) {
if (volume->cache_status == CACHE_READY && block == volume->cached_block)
return true;
volume->cache_status = CACHE_NOT_READY;
if (volume->cache == NULL)
volume->cache =
ext_mem_alloc_aligned(BLOCK_SIZE_IN_SECTORS * volume->sector_size,
4096);
if (!disk_read_sectors(volume, volume->cache,
volume->first_sect + block * BLOCK_SIZE_IN_SECTORS,
BLOCK_SIZE_IN_SECTORS))
return false;
volume->cache_status = CACHE_READY;
volume->cached_block = block;
return true;
}
bool volume_read(struct volume *volume, void *buffer, uint64_t loc, uint64_t count) {
uint64_t block_size = BLOCK_SIZE_IN_SECTORS * volume->sector_size;
uint64_t progress = 0;
while (progress < count) {
uint64_t block = (loc + progress) / block_size;
if (!cache_block(volume, block))
return false;
uint64_t chunk = count - progress;
uint64_t offset = (loc + progress) % block_size;
if (chunk > block_size - offset)
chunk = block_size - offset;
memcpy(buffer + progress, &volume->cache[offset], chunk);
progress += chunk;
}
return true;
}
struct gpt_table_header {
// the head
char signature[8];
uint32_t revision;
uint32_t header_size;
uint32_t crc32;
uint32_t _reserved0;
// the partitioning info
uint64_t my_lba;
uint64_t alternate_lba;
uint64_t first_usable_lba;
uint64_t last_usable_lba;
// the guid
struct guid disk_guid;
// entries related
uint64_t partition_entry_lba;
uint32_t number_of_partition_entries;
uint32_t size_of_partition_entry;
uint32_t partition_entry_array_crc32;
} __attribute__((packed));
struct gpt_entry {
struct guid partition_type_guid;
struct guid unique_partition_guid;
uint64_t starting_lba;
uint64_t ending_lba;
uint64_t attributes;
uint16_t partition_name[36];
} __attribute__((packed));
bool gpt_get_guid(struct guid *guid, struct volume *volume) {
struct gpt_table_header header = {0};
int sector_size = volume->sector_size;
// read header, located after the first block
volume_read(volume, &header, sector_size * 1, sizeof(header));
// check the header
// 'EFI PART'
if (strncmp(header.signature, "EFI PART", 8))
return false;
if (header.revision != 0x00010000)
return false;
*guid = header.disk_guid;
return true;
}
static int gpt_get_part(struct volume *ret, struct volume *volume, int partition) {
struct gpt_table_header header = {0};
int sector_size = volume->sector_size;
// read header, located after the first block
volume_read(volume, &header, sector_size * 1, sizeof(header));
// check the header
// 'EFI PART'
if (strncmp(header.signature, "EFI PART", 8))
return INVALID_TABLE;
if (header.revision != 0x00010000)
return INVALID_TABLE;
// parse the entries if reached here
if ((uint32_t)partition >= header.number_of_partition_entries)
return END_OF_TABLE;
struct gpt_entry entry = {0};
volume_read(volume, &entry,
(header.partition_entry_lba * sector_size) + (partition * sizeof(entry)),
sizeof(entry));
struct guid empty_guid = {0};
if (!memcmp(&entry.unique_partition_guid, &empty_guid, sizeof(struct guid)))
return NO_PARTITION;
#if defined (uefi)
ret->efi_handle = volume->efi_handle;
#endif
ret->drive = volume->drive;
ret->partition = partition;
ret->sector_size = sector_size;
ret->first_sect = entry.starting_lba;
ret->sect_count = (entry.ending_lba - entry.starting_lba) + 1;
ret->backing_dev = volume;
struct guid guid;
if (!fs_get_guid(&guid, ret)) {
ret->guid_valid = false;
} else {
ret->guid_valid = true;
ret->guid = guid;
}
ret->part_guid_valid = true;
ret->part_guid = entry.unique_partition_guid;
return 0;
}
struct mbr_entry {
uint8_t status;
uint8_t chs_first_sect[3];
uint8_t type;
uint8_t chs_last_sect[3];
uint32_t first_sect;
uint32_t sect_count;
} __attribute__((packed));
static int mbr_get_logical_part(struct volume *ret, struct volume *extended_part,
int partition) {
struct mbr_entry entry;
size_t ebr_sector = 0;
for (int i = 0; i < partition; i++) {
size_t entry_offset = ebr_sector * extended_part->sector_size + 0x1ce;
volume_read(extended_part, &entry, entry_offset, sizeof(struct mbr_entry));
if (entry.type != 0x0f && entry.type != 0x05)
return END_OF_TABLE;
ebr_sector = entry.first_sect;
}
size_t entry_offset = ebr_sector * extended_part->sector_size + 0x1be;
volume_read(extended_part, &entry, entry_offset, sizeof(struct mbr_entry));
if (entry.type == 0)
return NO_PARTITION;
#if defined (uefi)
ret->efi_handle = extended_part->efi_handle;
#endif
ret->drive = extended_part->drive;
ret->partition = partition + 4;
ret->sector_size = extended_part->sector_size;
ret->first_sect = extended_part->first_sect + ebr_sector + entry.first_sect;
ret->sect_count = entry.sect_count;
ret->backing_dev = extended_part->backing_dev;
struct guid guid;
if (!fs_get_guid(&guid, ret)) {
ret->guid_valid = false;
} else {
ret->guid_valid = true;
ret->guid = guid;
}
ret->part_guid_valid = false;
return 0;
}
static int mbr_get_part(struct volume *ret, struct volume *volume, int partition) {
// Check if actually valid mbr
uint16_t hint = 0;
volume_read(volume, &hint, 444, sizeof(uint16_t));
if (hint && hint != 0x5a5a)
return INVALID_TABLE;
struct mbr_entry entry;
if (partition > 3) {
for (int i = 0; i < 4; i++) {
size_t entry_offset = 0x1be + sizeof(struct mbr_entry) * i;
volume_read(volume, &entry, entry_offset, sizeof(struct mbr_entry));
if (entry.type != 0x0f)
continue;
struct volume extended_part = {0};
#if defined (uefi)
extended_part.efi_handle = volume->efi_handle;
#endif
extended_part.drive = volume->drive;
extended_part.partition = i;
extended_part.sector_size = volume->sector_size;
extended_part.first_sect = entry.first_sect;
extended_part.sect_count = entry.sect_count;
extended_part.backing_dev = volume;
return mbr_get_logical_part(ret, &extended_part, partition - 4);
}
return END_OF_TABLE;
}
size_t entry_offset = 0x1be + sizeof(struct mbr_entry) * partition;
volume_read(volume, &entry, entry_offset, sizeof(struct mbr_entry));
if (entry.type == 0)
return NO_PARTITION;
#if defined (uefi)
ret->efi_handle = volume->efi_handle;
#endif
ret->drive = volume->drive;
ret->partition = partition;
ret->sector_size = volume->sector_size;
ret->first_sect = entry.first_sect;
ret->sect_count = entry.sect_count;
ret->backing_dev = volume;
struct guid guid;
if (!fs_get_guid(&guid, ret)) {
ret->guid_valid = false;
} else {
ret->guid_valid = true;
ret->guid = guid;
}
ret->part_guid_valid = false;
return 0;
}
int part_get(struct volume *part, struct volume *volume, int partition) {
int ret;
ret = gpt_get_part(part, volume, partition);
if (ret != INVALID_TABLE)
return ret;
ret = mbr_get_part(part, volume, partition);
if (ret != INVALID_TABLE)
return ret;
return INVALID_TABLE;
}
struct volume **volume_index = NULL;
size_t volume_index_i = 0;
struct volume *volume_get_by_guid(struct guid *guid) {
for (size_t i = 0; i < volume_index_i; i++) {
if (volume_index[i]->guid_valid
&& memcmp(&volume_index[i]->guid, guid, 16) == 0) {
return volume_index[i];
}
if (volume_index[i]->part_guid_valid
&& memcmp(&volume_index[i]->part_guid, guid, 16) == 0) {
return volume_index[i];
}
}
return NULL;
}
struct volume *volume_get_by_coord(int drive, int partition) {
for (size_t i = 0; i < volume_index_i; i++) {
if (volume_index[i]->drive == drive
&& volume_index[i]->partition == partition) {
return volume_index[i];
}
}
return NULL;
}