blob: 825ba60292ad16ce0a99536b2aef3e9e297f354a [file] [log] [blame]
/* libs/diskconfig/diskconfig.c
*
* Copyright 2008, The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "config_mbr"
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <cutils/log.h>
#include <diskconfig/diskconfig.h>
/* start and len are in LBA units */
static void
cfg_pentry(struct pc_partition *pentry, uint8_t status, uint8_t type,
uint32_t start, uint32_t len)
{
if (len > 0) {
/* seems that somes BIOSens can get wedged on boot while verifying
* the mbr if these are 0 */
memset(&pentry->start, 0xff, sizeof(struct chs));
memset(&pentry->end, 0xff, sizeof(struct chs));
} else {
/* zero out the c/h/s entries.. they are not used */
memset(&pentry->start, 0, sizeof(struct chs));
memset(&pentry->end, 0, sizeof(struct chs));
}
pentry->status = status;
pentry->type = type;
pentry->start_lba = start;
pentry->len_lba = len;
LOGI("Configuring pentry. status=0x%x type=0x%x start_lba=%u len_lba=%u",
pentry->status, pentry->type, pentry->start_lba, pentry->len_lba);
}
static inline uint32_t
kb_to_lba(uint32_t len_kb, uint32_t sect_size)
{
uint64_t lba;
lba = (uint64_t)len_kb * 1024;
/* bump it up to the next LBA boundary just in case */
lba = (lba + (uint64_t)sect_size - 1) & ~((uint64_t)sect_size - 1);
lba /= (uint64_t)sect_size;
if (lba >= 0xffffffffULL)
LOGE("Error converting kb -> lba. 32bit overflow, expect weirdness");
return (uint32_t)(lba & 0xffffffffULL);
}
static struct write_list *
mk_pri_pentry(struct disk_info *dinfo, struct part_info *pinfo, int pnum,
uint32_t *lba)
{
struct write_list *item;
struct pc_partition *pentry;
if (pnum >= PC_NUM_BOOT_RECORD_PARTS) {
LOGE("Maximum number of primary partition exceeded.");
return NULL;
}
if (!(item = alloc_wl(sizeof(struct pc_partition)))) {
LOGE("Unable to allocate memory for partition entry.");
return NULL;
}
{
/* DO NOT DEREFERENCE */
struct pc_boot_record *mbr = (void *)PC_MBR_DISK_OFFSET;
/* grab the offset in mbr where to write this partition entry. */
item->offset = (loff_t)((uint32_t)((uint8_t *)(&mbr->ptable[pnum])));
}
pentry = (struct pc_partition *) &item->data;
/* need a standard primary partition entry */
if (pinfo) {
/* need this to be 64 bit in case len_kb is large */
uint64_t len_lba;
if (pinfo->len_kb != (uint32_t)-1) {
/* bump it up to the next LBA boundary just in case */
len_lba = ((uint64_t)pinfo->len_kb * 1024);
len_lba += ((uint64_t)dinfo->sect_size - 1);
len_lba &= ~((uint64_t)dinfo->sect_size - 1);
len_lba /= (uint64_t)dinfo->sect_size;
} else {
/* make it fill the rest of disk */
len_lba = dinfo->num_lba - *lba;
}
cfg_pentry(pentry, ((pinfo->flags & PART_ACTIVE_FLAG) ?
PC_PART_ACTIVE : PC_PART_NORMAL),
pinfo->type, *lba, (uint32_t)len_lba);
pinfo->start_lba = *lba;
*lba += (uint32_t)len_lba;
} else {
/* this should be made an extended partition, and should take
* up the rest of the disk as a primary partition */
cfg_pentry(pentry, PC_PART_NORMAL, PC_PART_TYPE_EXTENDED,
*lba, dinfo->num_lba - *lba);
/* note that we do not update the *lba because we now have to
* create a chain of extended partition tables, and first one is at
* *lba */
}
return item;
}
/* This function configures an extended boot record at the beginning of an
* extended partition. This creates a logical partition and a pointer to
* the next EBR.
*
* ext_lba == The start of the toplevel extended partition (pointed to by the
* entry in the MBR).
*/
static struct write_list *
mk_ext_pentry(struct disk_info *dinfo, struct part_info *pinfo, uint32_t *lba,
uint32_t ext_lba, struct part_info *pnext)
{
struct write_list *item;
struct pc_boot_record *ebr;
uint32_t len; /* in lba units */
if (!(item = alloc_wl(sizeof(struct pc_boot_record)))) {
LOGE("Unable to allocate memory for EBR.");
return NULL;
}
/* we are going to write the ebr at the current LBA, and then bump the
* lba counter since that is where the logical data partition will start */
item->offset = (*lba) * dinfo->sect_size;
(*lba)++;
ebr = (struct pc_boot_record *) &item->data;
memset(ebr, 0, sizeof(struct pc_boot_record));
ebr->mbr_sig = PC_BIOS_BOOT_SIG;
if (pinfo->len_kb != (uint32_t)-1)
len = kb_to_lba(pinfo->len_kb, dinfo->sect_size);
else {
if (pnext) {
LOGE("Only the last partition can be specified to fill the disk "
"(name = '%s')", pinfo->name);
goto fail;
}
len = dinfo->num_lba - *lba;
/* update the pinfo structure to reflect the new size, for
* bookkeeping */
pinfo->len_kb =
(uint32_t)(((uint64_t)len * (uint64_t)dinfo->sect_size) /
((uint64_t)1024));
}
cfg_pentry(&ebr->ptable[PC_EBR_LOGICAL_PART], PC_PART_NORMAL,
pinfo->type, 1, len);
pinfo->start_lba = *lba;
*lba += len;
/* If this is not the last partition, we have to create a link to the
* next extended partition.
*
* Otherwise, there's nothing to do since the "pointer entry" is
* already zero-filled.
*/
if (pnext) {
/* The start lba for next partition is an offset from the beginning
* of the top-level extended partition */
uint32_t next_start_lba = *lba - ext_lba;
uint32_t next_len_lba;
if (pnext->len_kb != (uint32_t)-1)
next_len_lba = 1 + kb_to_lba(pnext->len_kb, dinfo->sect_size);
else
next_len_lba = dinfo->num_lba - *lba;
cfg_pentry(&ebr->ptable[PC_EBR_NEXT_PTR_PART], PC_PART_NORMAL,
PC_PART_TYPE_EXTENDED, next_start_lba, next_len_lba);
}
return item;
fail:
free_wl(item);
return NULL;
}
struct write_list *
config_mbr(struct disk_info *dinfo)
{
struct part_info *pinfo;
uint32_t cur_lba = dinfo->skip_lba;
uint32_t ext_lba = 0;
struct write_list *wr_list = NULL;
struct write_list *temp_wr = NULL;
int cnt = 0;
int extended = 0;
if (!dinfo->part_lst)
return NULL;
for (cnt = 0; cnt < dinfo->num_parts; ++cnt) {
pinfo = &dinfo->part_lst[cnt];
/* Should we create an extedned partition? */
if (cnt == (PC_NUM_BOOT_RECORD_PARTS - 1)) {
if (cnt + 1 < dinfo->num_parts) {
extended = 1;
ext_lba = cur_lba;
if ((temp_wr = mk_pri_pentry(dinfo, NULL, cnt, &cur_lba)))
wlist_add(&wr_list, temp_wr);
else {
LOGE("Cannot create primary extended partition.");
goto fail;
}
}
}
/* if extended, need 1 lba for ebr */
if ((cur_lba + extended) >= dinfo->num_lba)
goto nospace;
else if (pinfo->len_kb != (uint32_t)-1) {
uint32_t sz_lba = (pinfo->len_kb / dinfo->sect_size) * 1024;
if ((cur_lba + sz_lba + extended) > dinfo->num_lba)
goto nospace;
}
if (!extended)
temp_wr = mk_pri_pentry(dinfo, pinfo, cnt, &cur_lba);
else {
struct part_info *pnext;
pnext = cnt + 1 < dinfo->num_parts ? &dinfo->part_lst[cnt+1] : NULL;
temp_wr = mk_ext_pentry(dinfo, pinfo, &cur_lba, ext_lba, pnext);
}
if (temp_wr)
wlist_add(&wr_list, temp_wr);
else {
LOGE("Cannot create partition %d (%s).", cnt, pinfo->name);
goto fail;
}
}
/* fill in the rest of the MBR with empty parts (if needed). */
for (; cnt < PC_NUM_BOOT_RECORD_PARTS; ++cnt) {
struct part_info blank;
cur_lba = 0;
memset(&blank, 0, sizeof(struct part_info));
if (!(temp_wr = mk_pri_pentry(dinfo, &blank, cnt, &cur_lba))) {
LOGE("Cannot create blank partition %d.", cnt);
goto fail;
}
wlist_add(&wr_list, temp_wr);
}
return wr_list;
nospace:
LOGE("Not enough space to add parttion '%s'.", pinfo->name);
fail:
wlist_free(wr_list);
return NULL;
}
/* Returns the device path of the partition referred to by 'name'
* Must be freed by the caller.
*/
char *
find_mbr_part(struct disk_info *dinfo, const char *name)
{
struct part_info *plist = dinfo->part_lst;
int num = 0;
char *dev_name = NULL;
int has_extended = (dinfo->num_parts > PC_NUM_BOOT_RECORD_PARTS);
for(num = 1; num <= dinfo->num_parts; ++num) {
if (!strcmp(plist[num-1].name, name))
break;
}
if (num > dinfo->num_parts)
return NULL;
if (has_extended && (num >= PC_NUM_BOOT_RECORD_PARTS))
num++;
if (!(dev_name = malloc(MAX_NAME_LEN))) {
LOGE("Cannot allocate memory.");
return NULL;
}
num = snprintf(dev_name, MAX_NAME_LEN, "%s%d", dinfo->device, num);
if (num >= MAX_NAME_LEN) {
LOGE("Device name is too long?!");
free(dev_name);
return NULL;
}
return dev_name;
}