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vvfat: introduce offset_to_bootsector, offset_to_fat and offset_to_root_dir 

- offset_to_bootsector is the number of sectors up to FAT bootsector
- offset_to_fat is the number of sectors up to first File Allocation Table
- offset_to_root_dir is the number of sectors up to root directory sector

Replace first_sectors_number - 1 by offset_to_bootsector.
Replace first_sectors_number by offset_to_fat.
Replace faked_sectors by offset_to_rootdir.

Signed-off-by: Hervé Poussineau <hpoussin@reactos.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Hervé Poussineau 2017-05-22 23:11:57 +02:00 committed by Kevin Wolf
parent ad05b31857
commit 4dc705dc7e
1 changed files with 43 additions and 27 deletions
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70
block/vvfat.c
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@ -319,22 +319,24 @@ static void print_mapping(const struct mapping_t* mapping);
typedef struct BDRVVVFATState {
CoMutex lock;
BlockDriverState* bs; /* pointer to parent */
unsigned int first_sectors_number; /* 1 for a single partition, 0x40 for a disk with partition table */
unsigned char first_sectors[0x40*0x200];
int fat_type; /* 16 or 32 */
array_t fat,directory,mapping;
char volume_label[11];
uint32_t offset_to_bootsector; /* 0 for floppy, 0x3f for disk */
unsigned int cluster_size;
unsigned int sectors_per_cluster;
unsigned int sectors_per_fat;
unsigned int sectors_of_root_directory;
uint32_t last_cluster_of_root_directory;
unsigned int faked_sectors; /* how many sectors are faked before file data */
uint32_t sector_count; /* total number of sectors of the partition */
uint32_t cluster_count; /* total number of clusters of this partition */
uint32_t max_fat_value;
uint32_t offset_to_fat;
uint32_t offset_to_root_dir;
int current_fd;
mapping_t* current_mapping;
@ -393,15 +395,15 @@ static void init_mbr(BDRVVVFATState *s, int cyls, int heads, int secs)
partition->attributes=0x80; /* bootable */
/* LBA is used when partition is outside the CHS geometry */
lba = sector2CHS(&partition->start_CHS, s->first_sectors_number - 1,
lba = sector2CHS(&partition->start_CHS, s->offset_to_bootsector,
cyls, heads, secs);
lba |= sector2CHS(&partition->end_CHS, s->bs->total_sectors - 1,
cyls, heads, secs);
/*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->start_sector_long = cpu_to_le32(s->offset_to_bootsector);
partition->length_sector_long = cpu_to_le32(s->bs->total_sectors
- s->first_sectors_number + 1);
- s->offset_to_bootsector);
/* FAT12/FAT16/FAT32 */
/* DOS uses different types when partition is LBA,
@ -822,12 +824,12 @@ static int read_directory(BDRVVVFATState* s, int mapping_index)
static inline uint32_t sector2cluster(BDRVVVFATState* s,off_t sector_num)
{
return (sector_num-s->faked_sectors)/s->sectors_per_cluster;
return (sector_num - s->offset_to_root_dir) / s->sectors_per_cluster;
}
static inline off_t cluster2sector(BDRVVVFATState* s, uint32_t cluster_num)
{
return s->faked_sectors + s->sectors_per_cluster * cluster_num;
return s->offset_to_root_dir + s->sectors_per_cluster * cluster_num;
}
static int init_directories(BDRVVVFATState* s,
@ -854,6 +856,9 @@ static int init_directories(BDRVVVFATState* s,
i = 1+s->sectors_per_cluster*0x200*8/s->fat_type;
s->sectors_per_fat=(s->sector_count+i)/i; /* round up */
s->offset_to_fat = s->offset_to_bootsector + 1;
s->offset_to_root_dir = s->offset_to_fat + s->sectors_per_fat * 2;
array_init(&(s->mapping),sizeof(mapping_t));
array_init(&(s->directory),sizeof(direntry_t));
@ -867,7 +872,6 @@ static int init_directories(BDRVVVFATState* s,
/* Now build FAT, and write back information into directory */
init_fat(s);
s->faked_sectors=s->first_sectors_number+s->sectors_per_fat*2;
s->cluster_count=sector2cluster(s, s->sector_count);
mapping = array_get_next(&(s->mapping));
@ -945,7 +949,8 @@ static int init_directories(BDRVVVFATState* s,
s->current_mapping = NULL;
bootsector=(bootsector_t*)(s->first_sectors+(s->first_sectors_number-1)*0x200);
bootsector = (bootsector_t *)(s->first_sectors
+ s->offset_to_bootsector * 0x200);
bootsector->jump[0]=0xeb;
bootsector->jump[1]=0x3e;
bootsector->jump[2]=0x90;
@ -956,16 +961,18 @@ static int init_directories(BDRVVVFATState* s,
bootsector->number_of_fats=0x2; /* number of FATs */
bootsector->root_entries=cpu_to_le16(s->sectors_of_root_directory*0x10);
bootsector->total_sectors16=s->sector_count>0xffff?0:cpu_to_le16(s->sector_count);
bootsector->media_type=(s->first_sectors_number>1?0xf8:0xf0); /* media descriptor (f8=hd, f0=3.5 fd)*/
/* media descriptor: hard disk=0xf8, floppy=0xf0 */
bootsector->media_type = (s->offset_to_bootsector > 0 ? 0xf8 : 0xf0);
s->fat.pointer[0] = bootsector->media_type;
bootsector->sectors_per_fat=cpu_to_le16(s->sectors_per_fat);
bootsector->sectors_per_track = cpu_to_le16(secs);
bootsector->number_of_heads = cpu_to_le16(heads);
bootsector->hidden_sectors=cpu_to_le32(s->first_sectors_number==1?0:0x3f);
bootsector->hidden_sectors = cpu_to_le32(s->offset_to_bootsector);
bootsector->total_sectors=cpu_to_le32(s->sector_count>0xffff?s->sector_count:0);
/* LATER TODO: if FAT32, this is wrong */
bootsector->u.fat16.drive_number=s->first_sectors_number==1?0:0x80; /* fda=0, hda=0x80 */
/* drive_number: fda=0, hda=0x80 */
bootsector->u.fat16.drive_number = s->offset_to_bootsector == 0 ? 0 : 0x80;
bootsector->u.fat16.current_head=0;
bootsector->u.fat16.signature=0x29;
bootsector->u.fat16.id=cpu_to_le32(0xfabe1afd);
@ -1122,7 +1129,6 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
secs = s->fat_type == 12 ? 18 : 36;
s->sectors_per_cluster = 1;
}
s->first_sectors_number = 1;
cyls = 80;
heads = 2;
} else {
@ -1130,7 +1136,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
if (!s->fat_type) {
s->fat_type = 16;
}
s->first_sectors_number = 0x40;
s->offset_to_bootsector = 0x3f;
cyls = s->fat_type == 12 ? 64 : 1024;
heads = 16;
secs = 63;
@ -1166,7 +1172,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
fprintf(stderr, "vvfat %s chs %d,%d,%d\n",
dirname, cyls, heads, secs);
s->sector_count = cyls * heads * secs - (s->first_sectors_number - 1);
s->sector_count = cyls * heads * secs - s->offset_to_bootsector;
if (qemu_opt_get_bool(opts, "rw", false)) {
if (!bdrv_is_read_only(bs)) {
@ -1196,7 +1202,8 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
goto fail;
}
s->sector_count = s->faked_sectors + s->sectors_per_cluster*s->cluster_count;
s->sector_count = s->offset_to_root_dir
+ s->sectors_per_cluster * s->cluster_count;
/* Disable migration when vvfat is used rw */
if (s->qcow) {
@ -1212,7 +1219,7 @@ static int vvfat_open(BlockDriverState *bs, QDict *options, int flags,
}
}
if (s->first_sectors_number == 0x40) {
if (s->offset_to_bootsector > 0) {
init_mbr(s, cyls, heads, secs);
}
@ -1425,15 +1432,24 @@ static int vvfat_read(BlockDriverState *bs, int64_t sector_num,
}
DLOG(fprintf(stderr, "sector %d not allocated\n", (int)sector_num));
}
if(sector_num<s->faked_sectors) {
if(sector_num<s->first_sectors_number)
memcpy(buf+i*0x200,&(s->first_sectors[sector_num*0x200]),0x200);
else if(sector_num-s->first_sectors_number<s->sectors_per_fat)
memcpy(buf+i*0x200,&(s->fat.pointer[(sector_num-s->first_sectors_number)*0x200]),0x200);
else if(sector_num-s->first_sectors_number-s->sectors_per_fat<s->sectors_per_fat)
memcpy(buf+i*0x200,&(s->fat.pointer[(sector_num-s->first_sectors_number-s->sectors_per_fat)*0x200]),0x200);
if (sector_num < s->offset_to_root_dir) {
if (sector_num < s->offset_to_fat) {
memcpy(buf + i * 0x200,
&(s->first_sectors[sector_num * 0x200]),
0x200);
} else if (sector_num < s->offset_to_fat + s->sectors_per_fat) {
memcpy(buf + i * 0x200,
&(s->fat.pointer[(sector_num
- s->offset_to_fat) * 0x200]),
0x200);
} else if (sector_num < s->offset_to_root_dir) {
memcpy(buf + i * 0x200,
&(s->fat.pointer[(sector_num - s->offset_to_fat
- s->sectors_per_fat) * 0x200]),
0x200);
}
} else {
uint32_t sector=sector_num-s->faked_sectors,
uint32_t sector = sector_num - s->offset_to_root_dir,
sector_offset_in_cluster=(sector%s->sectors_per_cluster),
cluster_num=sector/s->sectors_per_cluster;
if(cluster_num > s->cluster_count || read_cluster(s, cluster_num) != 0) {
@ -2045,7 +2061,7 @@ DLOG(checkpoint());
memcpy(s->fat2, s->fat.pointer, size);
}
check = vvfat_read(s->bs,
s->first_sectors_number, s->fat2, s->sectors_per_fat);
s->offset_to_fat, s->fat2, s->sectors_per_fat);
if (check) {
fprintf(stderr, "Could not copy fat\n");
return 0;
@ -2864,7 +2880,7 @@ DLOG(checkpoint());
* - do not allow to write non-ASCII filenames
*/
if (sector_num < s->first_sectors_number)
if (sector_num < s->offset_to_fat)
return -1;
for (i = sector2cluster(s, sector_num);