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block-vvfat.c
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/*
* QEMU Block driver for virtual VFAT (shadows a local directory)
*
* Copyright (c) 2004 Johannes E. Schindelin
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <sys/stat.h>
#include <dirent.h>
#include <assert.h>
#include "vl.h"
#include "block_int.h"
// TODO: new file
// TODO: delete file
// TODO: make root directory larger
// TODO: make directory clusters connected, so they are reserved anyway... add a member which tells how many clusters are reserved after a directory
// TODO: introduce another member in mapping_t which says where the directory resides in s->directory (for mkdir and rmdir)
// in _read and _write, before treating direntries or file contents, get_mapping to know what it is.
// TODO: mkdir
// TODO: rmdir
// TODO: when commit_data'ing a direntry and is_consistent, commit_remove
// TODO: reset MODE_MODIFIED when commit_remove'ing
#define DEBUG
/* dynamic array functions */
typedef struct array_t {
char* pointer;
unsigned int size,next,item_size;
} array_t;
static inline void array_init(array_t* array,unsigned int item_size)
{
array->pointer=0;
array->size=0;
array->next=0;
array->item_size=item_size;
}
static inline void array_free(array_t* array)
{
if(array->pointer)
free(array->pointer);
array->size=array->next=0;
}
/* make sure that memory is reserved at pointer[index*item_size] */
static inline void* array_get(array_t* array,unsigned int index) {
if((index+1)*array->item_size>array->size) {
int new_size=(index+32)*array->item_size;
array->pointer=realloc(array->pointer,new_size);
if(!array->pointer)
return 0;
array->size=new_size;
array->next=index+1;
}
return array->pointer+index*array->item_size;
}
static inline void* array_get_next(array_t* array) {
unsigned int next=array->next;
void* result=array_get(array,next);
array->next=next+1;
return result;
}
static inline void* array_insert(array_t* array,unsigned int index,unsigned int count) {
if((array->next+count)*array->item_size>array->size) {
int increment=count*array->item_size;
array->pointer=realloc(array->pointer,array->size+increment);
if(!array->pointer)
return 0;
array->size+=increment;
}
memmove(array->pointer+(index+count)*array->item_size,
array->pointer+index*array->item_size,
(array->next-index)*array->item_size);
array->next+=count;
return array->pointer+index*array->item_size;
}
/* this performs a "roll", so that the element which was at index_from becomes
* index_to, but the order of all other elements is preserved. */
static inline int array_roll(array_t* array,int index_to,int index_from,int count)
{
char* buf;
char* from;
char* to;
int is;
if(!array ||
index_to<0 || index_to>=array->next ||
index_from<0 || index_from>=array->next)
return -1;
if(index_to==index_from)
return 0;
is=array->item_size;
from=array->pointer+index_from*is;
to=array->pointer+index_to*is;
buf=malloc(is*count);
memcpy(buf,from,is*count);
if(index_to<index_from)
memmove(to+is*count,to,from-to);
else
memmove(from,from+is*count,to-from);
memcpy(to,buf,is*count);
free(buf);
return 0;
}
int array_remove(array_t* array,int index)
{
if(array_roll(array,array->next-1,index,1))
return -1;
array->next--;
return 0;
}
/* These structures are used to fake a disk and the VFAT filesystem.
* For this reason we need to use __attribute__((packed)). */
typedef struct bootsector_t {
uint8_t jump[3];
uint8_t name[8];
uint16_t sector_size;
uint8_t sectors_per_cluster;
uint16_t reserved_sectors;
uint8_t number_of_fats;
uint16_t root_entries;
uint16_t zero;
uint8_t media_type;
uint16_t sectors_per_fat;
uint16_t sectors_per_track;
uint16_t number_of_heads;
uint32_t hidden_sectors;
uint32_t total_sectors;
union {
struct {
uint8_t drive_number;
uint8_t current_head;
uint8_t signature;
uint32_t id;
uint8_t volume_label[11];
} __attribute__((packed)) fat16;
struct {
uint32_t sectors_per_fat;
uint16_t flags;
uint8_t major,minor;
uint32_t first_cluster_of_root_directory;
uint16_t info_sector;
uint16_t backup_boot_sector;
uint16_t ignored;
} __attribute__((packed)) fat32;
} u;
uint8_t fat_type[8];
uint8_t ignored[0x1c0];
uint8_t magic[2];
} __attribute__((packed)) bootsector_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; /* 0x6 = FAT16, 0xb = FAT32 */
uint8_t end_head;
uint8_t end_sector;
uint8_t end_cylinder;
uint32_t start_sector_long;
uint32_t end_sector_long;
} __attribute__((packed)) partition_t;
typedef struct mbr_t {
uint8_t ignored[0x1be];
partition_t partition[4];
uint8_t magic[2];
} __attribute__((packed)) mbr_t;
typedef struct direntry_t {
uint8_t name[8];
uint8_t extension[3];
uint8_t attributes;
uint8_t reserved[2];
uint16_t ctime;
uint16_t cdate;
uint16_t adate;
uint16_t begin_hi;
uint16_t mtime;
uint16_t mdate;
uint16_t begin;
uint32_t size;
} __attribute__((packed)) direntry_t;
/* this structure are used to transparently access the files */
typedef struct mapping_t {
/* begin is the first cluster, end is the last+1,
* offset is the offset in the file in clusters of this slice */
off_t begin,end,offset;
char* filename;
/* as s->directory is growable, no pointer may be used here */
unsigned int dir_index;
enum { MODE_NORMAL,MODE_UNDEFINED,MODE_MODIFIED,MODE_DELETED,MODE_DIRECTORY } mode;
} mapping_t;
/* this structure is used to hold sectors which need to be written, but it's
* not known yet where to write them. */
typedef struct commit_t {
uint32_t cluster_num;
uint8_t* buf;
} commit_t;
/* write support exists for fat, direntry and file contents */
typedef enum {
WRITE_UNDEFINED,WRITE_FAT,WRITE_DIRENTRY,WRITE_DATA
} write_action_t;
/* here begins the real VVFAT driver */
typedef struct BDRVVVFATState {
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;
unsigned int cluster_size;
unsigned int sectors_per_cluster;
unsigned int sectors_per_fat;
unsigned int sectors_of_root_directory;
unsigned int sectors_for_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 */
unsigned int first_file_mapping; /* index of the first mapping which is not a directory, but a file */
uint32_t max_fat_value;
int current_fd;
char current_fd_is_writable; /* =0 if read only, !=0 if read/writable */
mapping_t* current_mapping;
unsigned char* cluster;
unsigned int current_cluster;
/* write support */
array_t commit;
/* for each file, the file contents, the direntry, and the fat entries are
* written, but not necessarily in that order */
write_action_t action[3];
} BDRVVVFATState;
static int vvfat_probe(const uint8_t *buf, int buf_size, const char *filename)
{
if (strstart(filename, "fat:", NULL) ||
strstart(filename, "fatrw:", NULL))
return 100;
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]);
memset(s->first_sectors,0,512);
partition->attributes=0x80; /* bootable */
partition->start_head=1;
partition->start_sector=1;
partition->start_cylinder=0;
partition->fs_type=(s->fat_type==16?0x6:0xb); /* FAT16/FAT32 */
partition->end_head=0xf;
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(0x3f);
partition->end_sector_long=cpu_to_le32(s->sector_count);
real_mbr->magic[0]=0x55; real_mbr->magic[1]=0xaa;
}
/* dest is assumed to hold 258 bytes, and pads with 0xffff up to next multiple of 26 */
static inline int short2long_name(unsigned char* dest,const char* src)
{
int i;
for(i=0;i<129 && src[i];i++) {
dest[2*i]=src[i];
dest[2*i+1]=0;
}
dest[2*i]=dest[2*i+1]=0;
for(i=2*i+2;(i%26);i++)
dest[i]=0xff;
return i;
}
static inline direntry_t* create_long_filename(BDRVVVFATState* s,const char* filename)
{
char buffer[258];
int length=short2long_name(buffer,filename),
number_of_entries=(length+25)/26,i;
direntry_t* entry;
for(i=0;i<number_of_entries;i++) {
entry=array_get_next(&(s->directory));
entry->attributes=0xf;
entry->reserved[0]=0;
entry->begin=0;
entry->name[0]=(number_of_entries-i)|(i==0?0x40:0);
}
for(i=0;i<length;i++) {
int offset=(i%26);
if(offset<10) offset=1+offset;
else if(offset<22) offset=14+offset-10;
else offset=28+offset-22;
entry=array_get(&(s->directory),s->directory.next-1-(i/26));
entry->name[offset]=buffer[i];
}
return array_get(&(s->directory),s->directory.next-number_of_entries);
}
/* fat functions */
static inline uint8_t fat_chksum(direntry_t* entry)
{
uint8_t chksum=0;
int i;
for(i=0;i<11;i++)
chksum=(((chksum&0xfe)>>1)|((chksum&0x01)?0x80:0))
+(unsigned char)entry->name[i];
return chksum;
}
/* if return_time==0, this returns the fat_date, else the fat_time */
static uint16_t fat_datetime(time_t time,int return_time) {
struct tm* t;
#ifdef _WIN32
t=localtime(&time); /* this is not thread safe */
#else
struct tm t1;
t=&t1;
localtime_r(&time,t);
#endif
if(return_time)
return cpu_to_le16((t->tm_sec/2)|(t->tm_min<<5)|(t->tm_hour<<11));
return cpu_to_le16((t->tm_mday)|((t->tm_mon+1)<<5)|((t->tm_year-80)<<9));
}
static inline void fat_set(BDRVVVFATState* s,unsigned int cluster,uint32_t value)
{
if(s->fat_type==12) {
assert(0); /* TODO */
} else if(s->fat_type==16) {
uint16_t* entry=array_get(&(s->fat),cluster);
*entry=cpu_to_le16(value&0xffff);
} else {
uint32_t* entry=array_get(&(s->fat),cluster);
*entry=cpu_to_le32(value);
}
}
static inline uint32_t fat_get(BDRVVVFATState* s,unsigned int cluster)
{
//fprintf(stderr,"want to get fat for cluster %d\n",cluster);
if(s->fat_type==12) {
const uint8_t* x=s->fat.pointer+cluster*3/2;
return ((x[0]|(x[1]<<8))>>(cluster&1?4:0))&0x0fff;
} else if(s->fat_type==16) {
uint16_t* entry=array_get(&(s->fat),cluster);
return le16_to_cpu(*entry);
} else {
uint32_t* entry=array_get(&(s->fat),cluster);
return le32_to_cpu(*entry);
}
}
static inline int fat_eof(BDRVVVFATState* s,uint32_t fat_entry)
{
if(fat_entry>s->max_fat_value-8)
return -1;
return 0;
}
static inline void init_fat(BDRVVVFATState* s)
{
int i;
array_init(&(s->fat),(s->fat_type==32?4:2));
array_get(&(s->fat),s->sectors_per_fat*0x200/s->fat.item_size-1);
memset(s->fat.pointer,0,s->fat.size);
fat_set(s,0,0x7ffffff8);
for(i=1;i<s->sectors_for_directory/s->sectors_per_cluster-1;i++)
fat_set(s,i,i+1);
fat_set(s,i,0x7fffffff);
switch(s->fat_type) {
case 12: s->max_fat_value=0xfff; break;
case 16: s->max_fat_value=0xffff; break;
case 32: s->max_fat_value=0xfffffff; break;
default: s->max_fat_value=0; /* error... */
}
}
static inline int long2unix_name(unsigned char* dest,int dest_size,direntry_t* direntry_short) {
int i=-1,j;
int chksum=fat_chksum(direntry_short);
while(1) {
char* buf=(char*)(direntry_short+i);
if((buf[0]&0x3f)!=-i || direntry_short[i].reserved[1]!=chksum ||
direntry_short[i].attributes!=0xf) {
if(i<-1)
return -3;
/* take short name */
for(j=7;j>0 && direntry_short->name[j]==' ';j--);
if(j+1>dest_size)
return -1;
strncpy(dest,direntry_short->name,j+1);
dest+=j+1; dest_size-=j+1;
for(j=2;j>=0 && direntry_short->extension[j]==' ';j--);
if(j>=0) {
if(j+2>dest_size)
return -1;
dest[0]='.';
strncpy(dest+1,direntry_short->extension,j+1);
}
return 0;
}
for(j=0;j<13;j++) {
dest_size--;
if(dest_size<0)
return -2;
dest[0]=buf[2*j+((j<5)?1:(j<11)?4:6)];
if(dest[0]==0 && (buf[0]&0x40)!=0)
return 0;
dest++;
}
/* last entry, but no trailing \0? */
if(buf[0]&0x40)
return -3;
i--;
}
}
static inline direntry_t* create_short_filename(BDRVVVFATState* s,unsigned int directory_start,const char* filename,int is_dot)
{
int i,long_index=s->directory.next;
direntry_t* entry=0;
direntry_t* entry_long=0;
if(is_dot) {
entry=array_get_next(&(s->directory));
memset(entry->name,0x20,11);
memcpy(entry->name,filename,strlen(filename));
return entry;
}
for(i=1;i<8 && filename[i] && filename[i]!='.';i++);
entry_long=create_long_filename(s,filename);
entry=array_get_next(&(s->directory));
memset(entry->name,0x20,11);
strncpy(entry->name,filename,i);
if(filename[i]) {
int len=strlen(filename);
for(i=len;i>0 && filename[i-1]!='.';i--);
if(i>0)
memcpy(entry->extension,filename+i,(len-i>3?3:len-i));
}
/* upcase & remove unwanted characters */
for(i=10;i>=0;i--) {
if(i==10 || i==7) for(;i>1 && entry->name[i]==' ';i--);
if(entry->name[i]<=' ' || entry->name[i]>0x7f
|| strchr("*?<>|\":/\\[];,+='",entry->name[i]))
entry->name[i]='_';
else if(entry->name[i]>='a' && entry->name[i]<='z')
entry->name[i]+='A'-'a';
}
/* mangle duplicates */
while(1) {
direntry_t* entry1=array_get(&(s->directory),directory_start);
int j;
for(;entry1<entry;entry1++)
if(!(entry1->attributes&0xf) && !memcmp(entry1->name,entry->name,11))
break; /* found dupe */
if(entry1==entry) /* no dupe found */
break;
/* use all 8 characters of name */
if(entry->name[7]==' ') {
int j;
for(j=6;j>0 && entry->name[j]==' ';j--)
entry->name[j]='~';
}
/* increment number */
for(j=7;j>0 && entry->name[j]=='9';j--)
entry->name[j]='0';
if(j>0) {
if(entry->name[j]<'0' || entry->name[j]>'9')
entry->name[j]='0';
else
entry->name[j]++;
}
}
/* calculate checksum; propagate to long name */
if(entry_long) {
uint8_t chksum=fat_chksum(entry);
/* calculate anew, because realloc could have taken place */
entry_long=array_get(&(s->directory),long_index);
while(entry_long<entry
&& entry_long->attributes==0xf) {
entry_long->reserved[1]=chksum;
entry_long++;
}
}
return entry;
}
static int read_directory(BDRVVVFATState* s,const char* dirname,
int first_cluster_of_parent)
{
DIR* dir=opendir(dirname);
struct dirent* entry;
struct stat st;
unsigned int start_of_directory=s->directory.next;
/* mappings before first_file_mapping are directories */
unsigned int first_directory_mapping=s->first_file_mapping;
unsigned int first_cluster=(start_of_directory/0x10/s->sectors_per_cluster);
int i;
if(!dir)
return -1;
while((entry=readdir(dir))) {
unsigned int length=strlen(dirname)+2+strlen(entry->d_name);
char* buffer;
direntry_t* direntry;
int is_dot=!strcmp(entry->d_name,".");
int is_dotdot=!strcmp(entry->d_name,"..");
if(start_of_directory==1 && (is_dotdot || is_dot))
continue;
buffer=(char*)malloc(length);
snprintf(buffer,length,"%s/%s",dirname,entry->d_name);
if(stat(buffer,&st)<0) {
free(buffer);
continue;
}
/* create directory entry for this file */
//fprintf(stderr,"create direntry at %d (cluster %d) for %s\n",s->directory.next,s->directory.next/0x10/s->sectors_per_cluster,entry->d_name);
direntry=create_short_filename(s,start_of_directory,entry->d_name,is_dot||is_dotdot);
direntry->attributes=(S_ISDIR(st.st_mode)?0x10:0x20);
direntry->reserved[0]=direntry->reserved[1]=0;
direntry->ctime=fat_datetime(st.st_ctime,1);
direntry->cdate=fat_datetime(st.st_ctime,0);
direntry->adate=fat_datetime(st.st_atime,0);
direntry->begin_hi=0;
direntry->mtime=fat_datetime(st.st_mtime,1);
direntry->mdate=fat_datetime(st.st_mtime,0);
if(is_dotdot)
direntry->begin=cpu_to_le16(first_cluster_of_parent);
else if(is_dot)
direntry->begin=cpu_to_le16(first_cluster);
else
direntry->begin=cpu_to_le16(0); /* do that later */
direntry->size=cpu_to_le32(st.st_size);
/* create mapping for this file */
if(!is_dot && !is_dotdot) {
if(S_ISDIR(st.st_mode))
s->current_mapping=(mapping_t*)array_insert(&(s->mapping),s->first_file_mapping++,1);
else
s->current_mapping=(mapping_t*)array_get_next(&(s->mapping));
s->current_mapping->begin=0;
s->current_mapping->end=st.st_size;
s->current_mapping->offset=0;
s->current_mapping->filename=buffer;
s->current_mapping->dir_index=s->directory.next-1;
s->current_mapping->mode=(S_ISDIR(st.st_mode)?MODE_DIRECTORY:MODE_UNDEFINED);
}
}
closedir(dir);
/* fill with zeroes up to the end of the cluster */
while(s->directory.next%(0x10*s->sectors_per_cluster)) {
direntry_t* direntry=array_get_next(&(s->directory));
memset(direntry,0,sizeof(direntry_t));
}
/* reserve next cluster also (for new files) */
for(i=0;i<0x10*s->sectors_per_cluster;i++) {
direntry_t* direntry=array_get_next(&(s->directory));
memset(direntry,0,sizeof(direntry_t));
}
/* was it the first directory? */
if(start_of_directory==1) {
mapping_t* mapping=array_insert(&(s->mapping),0,1);
mapping->filename=strdup(dirname);
mapping->mode=MODE_DIRECTORY;
mapping->begin=0;
mapping->end=1;
mapping->offset=0;
mapping->dir_index=0xffffffff;
s->sectors_of_root_directory=s->directory.next/0x10;
}
/* recurse directories */
{
int i;
//fprintf(stderr,"iterating subdirectories of %s (first cluster %d): %d to %d\n",dirname,first_cluster,first_directory_mapping,last_directory_mapping);
for(i=first_directory_mapping;i<s->first_file_mapping;i++) {
mapping_t* mapping=array_get(&(s->mapping),i);
direntry_t* direntry=array_get(&(s->directory),mapping->dir_index);
/* the directory to be read can add more subdirectories */
int last_dir_mapping=s->first_file_mapping;
assert(mapping->mode==MODE_DIRECTORY);
/* first, tell the mapping where the directory will start */
mapping->begin=s->directory.next/0x10/s->sectors_per_cluster;
if(i>0) {
mapping[-1].end=mapping->begin;
assert(mapping[-1].begin<mapping->begin);
}
/* then tell the direntry */
direntry->begin=cpu_to_le16(mapping->begin);
//fprintf(stderr,"read directory %s (begin %d)\n",mapping->filename,(int)mapping->begin);
/* then read it */
if(read_directory(s,mapping->filename,first_cluster))
return -1;
if(last_dir_mapping!=s->first_file_mapping) {
int diff=s->first_file_mapping-last_dir_mapping;
assert(diff>0);
if(last_dir_mapping!=i+1) {
int count=last_dir_mapping-i-1;
int to=s->first_file_mapping-count;
assert(count>0);
assert(to>i+1);
array_roll(&(s->mapping),to,i+1,count);
/* could have changed due to realloc */
mapping=array_get(&(s->mapping),i);
mapping->end=mapping[1].begin;
}
i+=diff;
}
}
}
return 0;
}
static int init_directory(BDRVVVFATState* s,const char* dirname)
{
bootsector_t* bootsector=(bootsector_t*)&(s->first_sectors[(s->first_sectors_number-1)*0x200]);
unsigned int i;
unsigned int cluster;
memset(&(s->first_sectors[0]),0,0x40*0x200);
/* TODO: if FAT32, this is probably wrong */
s->sectors_per_fat=0xfc;
s->sectors_per_cluster=0x10;
s->cluster_size=s->sectors_per_cluster*0x200;
s->cluster=malloc(s->cluster_size);
array_init(&(s->mapping),sizeof(mapping_t));
array_init(&(s->directory),sizeof(direntry_t));
array_init(&(s->commit),sizeof(commit_t));
/* add volume label */
{
direntry_t* entry=array_get_next(&(s->directory));
entry->attributes=0x28; /* archive | volume label */
snprintf(entry->name,11,"QEMU VVFAT");
}
if(read_directory(s,dirname,0))
return -1;
/* make sure that the number of directory entries is multiple of 0x200/0x20 (to fit the last sector exactly) */
s->sectors_for_directory=s->directory.next/0x10;
s->faked_sectors=s->first_sectors_number+s->sectors_per_fat*2+s->sectors_for_directory;
s->cluster_count=(s->sector_count-s->faked_sectors)/s->sectors_per_cluster;
/* Now build FAT, and write back information into directory */
init_fat(s);
cluster=s->sectors_for_directory/s->sectors_per_cluster;
assert(s->sectors_for_directory%s->sectors_per_cluster==0);
/* set the end of the last read directory */
if(s->first_file_mapping>0) {
mapping_t* mapping=array_get(&(s->mapping),s->first_file_mapping-1);
mapping->end=cluster;
}
for(i=1;i<s->mapping.next;i++) {
mapping_t* mapping=array_get(&(s->mapping),i);
direntry_t* direntry=array_get(&(s->directory),mapping->dir_index);
if(mapping->mode==MODE_DIRECTORY) {
/* directory */
int i;
#ifdef DEBUG
fprintf(stderr,"assert: %s %d < %d\n",mapping->filename,(int)mapping->begin,(int)mapping->end);
#endif
assert(mapping->begin<mapping->end);
for(i=mapping->begin;i<mapping->end-1;i++)
fat_set(s,i,i+1);
fat_set(s,i,0x7fffffff);
} else {
/* as the space is virtual, we can be sloppy about it */
unsigned int end_cluster=cluster+mapping->end/s->cluster_size;
if(end_cluster>=s->cluster_count) {
fprintf(stderr,"Directory does not fit in FAT%d\n",s->fat_type);
return -1;
}
mapping->begin=cluster;
mapping->mode=MODE_NORMAL;
mapping->offset=0;
direntry->size=cpu_to_le32(mapping->end);
if(direntry->size==0) {
direntry->begin=0;
mapping->end=cluster;
continue;
}
direntry->begin=cpu_to_le16(cluster);
mapping->end=end_cluster+1;
for(;cluster<end_cluster;cluster++)
fat_set(s,cluster,cluster+1);
fat_set(s,cluster,0x7fffffff);
cluster++;
}
}
s->current_mapping=0;
bootsector->jump[0]=0xeb;
bootsector->jump[1]=0x3e;
bootsector->jump[2]=0x90;
memcpy(bootsector->name,"QEMU ",8);
bootsector->sector_size=cpu_to_le16(0x200);
bootsector->sectors_per_cluster=s->sectors_per_cluster;
bootsector->reserved_sectors=cpu_to_le16(1);
bootsector->number_of_fats=0x2; /* number of FATs */
bootsector->root_entries=cpu_to_le16(s->sectors_of_root_directory*0x10);
bootsector->zero=0;
bootsector->media_type=(s->first_sectors_number==1?0xf0:0xf8); /* media descriptor */
bootsector->sectors_per_fat=cpu_to_le16(s->sectors_per_fat);
bootsector->sectors_per_track=cpu_to_le16(0x3f);
bootsector->number_of_heads=cpu_to_le16(0x10);
bootsector->hidden_sectors=cpu_to_le32(s->first_sectors_number==1?0:0x3f);
/* TODO: if FAT32, adjust */
bootsector->total_sectors=cpu_to_le32(s->sector_count);
/* TODO: if FAT32, this is wrong */
bootsector->u.fat16.drive_number=0x80; /* assume this is hda (TODO) */
bootsector->u.fat16.current_head=0;
bootsector->u.fat16.signature=0x29;
bootsector->u.fat16.id=cpu_to_le32(0xfabe1afd);
memcpy(bootsector->u.fat16.volume_label,"QEMU VVFAT ",11);
memcpy(bootsector->fat_type,(s->fat_type==12?"FAT12 ":s->fat_type==16?"FAT16 ":"FAT32 "),8);
bootsector->magic[0]=0x55; bootsector->magic[1]=0xaa;
return 0;
}
static int vvfat_open(BlockDriverState *bs, const char* dirname)
{
BDRVVVFATState *s = bs->opaque;
int i;
/* TODO: automatically determine which FAT type */
s->fat_type=16;
s->sector_count=0xec04f;
s->current_cluster=0xffffffff;
s->first_file_mapping=0;
/* TODO: if simulating a floppy, this is 1, because there is no partition table */
s->first_sectors_number=0x40;
if (strstart(dirname, "fat:", &dirname)) {
/* read only is the default for safety */
bs->read_only = 1;
} else if (strstart(dirname, "fatrw:", &dirname)) {
/* development only for now */
bs->read_only = 0;
} else {
return -1;
}
if(init_directory(s,dirname))
return -1;
if(s->first_sectors_number==0x40)
init_mbr(s);
/* TODO: this could be wrong for FAT32 */
bs->cyls=1023; bs->heads=15; bs->secs=63;
bs->total_sectors=bs->cyls*bs->heads*bs->secs;
/* write support */
for(i=0;i<3;i++)
s->action[i]=WRITE_UNDEFINED;
return 0;
}
static inline void vvfat_close_current_file(BDRVVVFATState *s)
{
if(s->current_mapping) {
s->current_mapping = 0;
close(s->current_fd);
}
}
/* mappings between index1 and index2-1 are supposed to be ordered
* return value is the index of the last mapping for which end>cluster_num
*/
static inline int find_mapping_for_cluster_aux(BDRVVVFATState* s,int cluster_num,int index1,int index2)
{
int index3=index1+1;
//fprintf(stderr,"find_aux: cluster_num=%d, index1=%d,index2=%d\n",cluster_num,index1,index2);
while(1) {
mapping_t* mapping;
index3=(index1+index2)/2;
mapping=array_get(&(s->mapping),index3);
//fprintf(stderr,"index3: %d = (%d+%d)/2, end: %d\n",index3,index1,index2,(int)mapping->end);
if(mapping->end>cluster_num) {
assert(index2!=index3 || index2==0);
if(index2==index3)
return index2;
index2=index3;
} else {
if(index1==index3)
return index2;
index1=index3;
}
assert(index1<=index2);
}
}
static inline mapping_t* find_mapping_for_cluster(BDRVVVFATState* s,int cluster_num)
{
int index=find_mapping_for_cluster_aux(s,cluster_num,0,s->mapping.next);
mapping_t* mapping;
if(index>=s->mapping.next)
return 0;
mapping=array_get(&(s->mapping),index);
if(mapping->begin>cluster_num)
return 0;
return mapping;
}
static int open_file(BDRVVVFATState* s,mapping_t* mapping,int flags)
{
if(!mapping)
return -1;
assert(flags==O_RDONLY || flags==O_RDWR);
if(!s->current_mapping ||
strcmp(s->current_mapping->filename,mapping->filename) ||
(flags==O_RDWR && !s->current_fd_is_writable)) {
/* open file */
int fd = open(mapping->filename, flags | O_BINARY | O_LARGEFILE);
if(fd<0)
return -1;
vvfat_close_current_file(s);
s->current_fd = fd;
s->current_fd_is_writable = (flags==O_RDWR?-1:0);
s->current_mapping = mapping;
}
return 0;
}
static inline int read_cluster(BDRVVVFATState *s,int cluster_num)
{
if(s->current_cluster != cluster_num) {
int result=0;
off_t offset;
if(!s->current_mapping
|| s->current_mapping->begin>cluster_num
|| s->current_mapping->end<=cluster_num) {
/* binary search of mappings for file */
mapping_t* mapping=find_mapping_for_cluster(s,cluster_num);
if(open_file(s,mapping,O_RDONLY))
return -2;
}
offset=s->cluster_size*(cluster_num-s->current_mapping->begin+s->current_mapping->offset);
if(lseek(s->current_fd, offset, SEEK_SET)!=offset)
return -3;
result=read(s->current_fd,s->cluster,s->cluster_size);
if(result<0) {
s->current_cluster = -1;
return -1;
}
s->current_cluster = cluster_num;
}
return 0;
}
static int vvfat_read(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{
BDRVVVFATState *s = bs->opaque;
int i;
// fprintf(stderr,"vvfat_read: sector %d+%d\n",(int)sector_num,nb_sectors);
for(i=0;i<nb_sectors;i++,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);
else if(sector_num-s->first_sectors_number-s->sectors_per_fat*2<s->sectors_for_directory)
memcpy(buf+i*0x200,&(s->directory.pointer[(sector_num-s->first_sectors_number-s->sectors_per_fat*2)*0x200]),0x200);
} else {
uint32_t sector=sector_num-s->first_sectors_number-s->sectors_per_fat*2,
sector_offset_in_cluster=(sector%s->sectors_per_cluster),
cluster_num=sector/s->sectors_per_cluster;
if(read_cluster(s, cluster_num) != 0) {
//fprintf(stderr,"failed to read cluster %d\n",(int)cluster_num);
// TODO: strict: return -1;
memset(buf+i*0x200,0,0x200);
continue;
}
memcpy(buf+i*0x200,s->cluster+sector_offset_in_cluster*0x200,0x200);
}
}
return 0;
}
static void print_direntry(direntry_t* direntry)
{
if(!direntry)
return;
if(direntry->attributes==0xf) {
unsigned char* c=(unsigned char*)direntry;
int i;
for(i=1;i<11 && c[i] && c[i]!=0xff;i+=2)
fputc(c[i],stderr);
for(i=14;i<26 && c[i] && c[i]!=0xff;i+=2)
fputc(c[i],stderr);
for(i=28;i<32 && c[i] && c[i]!=0xff;i+=2)
fputc(c[i],stderr);
fputc('\n',stderr);
} else {
int i;
for(i=0;i<11;i++)
fputc(direntry->name[i],stderr);