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vvfat mbr fixes, by Ivan Kalvachev. 

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3234 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
ths 2007-09-25 14:47:03 +00:00
parent b427c72613
commit b570094d9b
1 changed files with 66 additions and 29 deletions
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95
block-vvfat.c
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@ -242,21 +242,25 @@ typedef struct bootsector_t {
uint8_t magic[2];
} __attribute__((packed)) bootsector_t;
typedef struct {
uint8_t head;
uint8_t sector;
uint8_t cylinder;
} mbr_chs_t;
typedef struct partition_t {
uint8_t attributes; /* 0x80 = bootable */
uint8_t start_head;
uint8_t start_sector;
uint8_t start_cylinder;
uint8_t fs_type; /* 0x1 = FAT12, 0x6 = FAT16, 0xb = FAT32 */
uint8_t end_head;
uint8_t end_sector;
uint8_t end_cylinder;
mbr_chs_t start_CHS;
uint8_t fs_type; /* 0x1 = FAT12, 0x6 = FAT16, 0xe = FAT16_LBA, 0xb = FAT32, 0xc = FAT32_LBA */
mbr_chs_t end_CHS;
uint32_t start_sector_long;
uint32_t end_sector_long;
uint32_t length_sector_long;
} __attribute__((packed)) partition_t;
typedef struct mbr_t {
uint8_t ignored[0x1be];
uint8_t ignored[0x1b8];
uint32_t nt_id;
uint8_t ignored2[2];
partition_t partition[4];
uint8_t magic[2];
} __attribute__((packed)) mbr_t;
@ -350,26 +354,57 @@ typedef struct BDRVVVFATState {
int downcase_short_names;
} BDRVVVFATState;
/* take the sector position spos and convert it to Cylinder/Head/Sector position
* if the position is outside the specified geometry, fill maximum value for CHS
* and return 1 to signal overflow.
*/
static int sector2CHS(BlockDriverState* bs, mbr_chs_t * chs, int spos){
int head,sector;
sector = spos % (bs->secs); spos/= bs->secs;
head = spos % (bs->heads); spos/= bs->heads;
if(spos >= bs->cyls){
/* Overflow,
it happens if 32bit sector positions are used, while CHS is only 24bit.
Windows/Dos is said to take 1023/255/63 as nonrepresentable CHS */
chs->head = 0xFF;
chs->sector = 0xFF;
chs->cylinder = 0xFF;
return 1;
}
chs->head = (uint8_t)head;
chs->sector = (uint8_t)( (sector+1) | ((spos>>8)<<6) );
chs->cylinder = (uint8_t)spos;
return 0;
}
static void init_mbr(BDRVVVFATState* s)
{
/* TODO: if the files mbr.img and bootsect.img exist, use them */
mbr_t* real_mbr=(mbr_t*)s->first_sectors;
partition_t* partition=&(real_mbr->partition[0]);
int lba;
memset(s->first_sectors,0,512);
/* Win NT Disk Signature */
real_mbr->nt_id= cpu_to_le32(0xbe1afdfa);
partition->attributes=0x80; /* bootable */
partition->start_head=1;
partition->start_sector=1;
partition->start_cylinder=0;
/* LBA is used when partition is outside the CHS geometry */
lba = sector2CHS(s->bs, &partition->start_CHS, s->first_sectors_number-1);
lba|= sector2CHS(s->bs, &partition->end_CHS, s->sector_count);
/*LBA partitions are identified only by start/length_sector_long not by CHS*/
partition->start_sector_long =cpu_to_le32(s->first_sectors_number-1);
partition->length_sector_long=cpu_to_le32(s->sector_count - s->first_sectors_number+1);
/* FAT12/FAT16/FAT32 */
partition->fs_type=(s->fat_type==12?0x1:s->fat_type==16?0x6:0xb);
partition->end_head=s->bs->heads-1;
partition->end_sector=0xff; /* end sector & upper 2 bits of cylinder */;
partition->end_cylinder=0xff; /* lower 8 bits of end cylinder */;
partition->start_sector_long=cpu_to_le32(s->bs->secs);
partition->end_sector_long=cpu_to_le32(s->sector_count);
/* DOS uses different types when partition is LBA,
probably to prevent older versions from using CHS on them */
partition->fs_type= s->fat_type==12 ? 0x1:
s->fat_type==16 ? (lba?0xe:0x06):
/*fat_tyoe==32*/ (lba?0xc:0x0b);
real_mbr->magic[0]=0x55; real_mbr->magic[1]=0xaa;
}
@ -973,10 +1008,9 @@ DLOG(if (stderr == NULL) {
s->fat_type=16;
/* LATER TODO: if FAT32, adjust */
s->sector_count=0xec04f;
s->sectors_per_cluster=0x10;
/* LATER TODO: this could be wrong for FAT32 */
bs->cyls=1023; bs->heads=15; bs->secs=63;
/* 504MB disk*/
bs->cyls=1024; bs->heads=16; bs->secs=63;
s->current_cluster=0xffffffff;
@ -991,12 +1025,6 @@ DLOG(if (stderr == NULL) {
if (!strstart(dirname, "fat:", NULL))
return -1;
if (strstr(dirname, ":rw:")) {
if (enable_write_target(s))
return -1;
bs->read_only = 0;
}
if (strstr(dirname, ":floppy:")) {
floppy = 1;
s->fat_type = 12;
@ -1005,6 +1033,8 @@ DLOG(if (stderr == NULL) {
bs->cyls = 80; bs->heads = 2; bs->secs = 36;
}
s->sector_count=bs->cyls*bs->heads*bs->secs;
if (strstr(dirname, ":32:")) {
fprintf(stderr, "Big fat greek warning: FAT32 has not been tested. You are welcome to do so!\n");
s->fat_type = 32;
@ -1015,6 +1045,12 @@ DLOG(if (stderr == NULL) {
s->sector_count=2880;
}
if (strstr(dirname, ":rw:")) {
if (enable_write_target(s))
return -1;
bs->read_only = 0;
}
i = strrchr(dirname, ':') - dirname;
assert(i >= 3);
if (dirname[i-2] == ':' && isalpha(dirname[i-1]))
@ -1024,11 +1060,12 @@ DLOG(if (stderr == NULL) {
dirname += i+1;
bs->total_sectors=bs->cyls*bs->heads*bs->secs;
if (s->sector_count > bs->total_sectors)
s->sector_count = bs->total_sectors;
if(init_directories(s, dirname))
return -1;
s->sector_count = s->faked_sectors + s->sectors_per_cluster*s->cluster_count;
if(s->first_sectors_number==0x40)
init_mbr(s);