block-vvfat.c 77.6 KB
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/* vim:set shiftwidth=4 ts=8: */
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/*
 * QEMU Block driver for virtual VFAT (shadows a local directory)
 * 
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 * Copyright (c) 2004,2005 Johannes E. Schindelin
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 * 
 * 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"

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#ifndef S_IWGRP
#define S_IWGRP 0
#endif
#ifndef S_IWOTH
#define S_IWOTH 0
#endif

/* TODO: add ":bootsector=blabla.img:" */
/* LATER TODO: add automatic boot sector generation from
    BOOTEASY.ASM and Ranish Partition Manager
    Note that DOS assumes the system files to be the first files in the 
    file system (test if the boot sector still relies on that fact)! */
/* MAYBE TODO: write block-visofs.c */
/* TODO: call try_commit() only after a timeout */

/* #define DEBUG */

#ifdef DEBUG

#define DLOG(a) a

#undef stderr
#define stderr STDERR
FILE* stderr = NULL;
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static void checkpoint();
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#ifdef __MINGW32__
void nonono(const char* file, int line, const char* msg) {
    fprintf(stderr, "Nonono! %s:%d %s\n", file, line, msg);
    exit(-5);
}
#undef assert
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#define assert(a) do {if (!(a)) nonono(__FILE__, __LINE__, #a);}while(0)
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#endif

#else

#define DLOG(a)

#endif
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/* 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;
}

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/* does not automatically grow */
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static inline void* array_get(array_t* array,unsigned int index) {
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    assert(index >= 0);
    assert(index < array->next);
    return array->pointer + index * array->item_size;
}

static inline int array_ensure_allocated(array_t* array, 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 -1;
	array->size = new_size;
	array->next = index + 1;
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    }
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    return 0;
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}

static inline void* array_get_next(array_t* array) {
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    unsigned int next = array->next;
    void* result;

    if (array_ensure_allocated(array, next) < 0)
	return NULL;

    array->next = next + 1;
    result = array_get(array, next);

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    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;
}

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inline int array_remove_slice(array_t* array,int index, int count)
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{
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    assert(index >=0);
    assert(count > 0);
    assert(index + count <= array->next);
    if(array_roll(array,array->next-1,index,count))
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	return -1;
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    array->next -= count;
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    return 0;
}

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int array_remove(array_t* array,int index)
{
    return array_remove_slice(array, index, 1);
}

/* return the index for a given member */
int array_index(array_t* array, void* pointer)
{
    size_t offset = (char*)pointer - array->pointer;
    assert(offset >= 0);
    assert((offset % array->item_size) == 0);
    assert(offset/array->item_size < array->next);
    return offset/array->item_size;
}

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/* 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;
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    uint16_t total_sectors16;
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    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;
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    uint8_t fs_type; /* 0x1 = FAT12, 0x6 = FAT16, 0xb = FAT32 */
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    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 {
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    /* begin is the first cluster, end is the last+1 */
    uint32_t begin,end;
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    /* as s->directory is growable, no pointer may be used here */
    unsigned int dir_index;
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    /* the clusters of a file may be in any order; this points to the first */
    int first_mapping_index;
    union {
	/* offset is
	 * - the offset in the file (in clusters) for a file, or
	 * - the next cluster of the directory for a directory, and
	 * - the address of the buffer for a faked entry
	 */
	struct {
	    uint32_t offset;
	} file;
	struct {
	    int parent_mapping_index;
	    int first_dir_index;
	} dir;
    } info;
    /* path contains the full path, i.e. it always starts with s->path */
    char* path;

    enum { MODE_UNDEFINED = 0, MODE_NORMAL = 1, MODE_MODIFIED = 2,
	MODE_DIRECTORY = 4, MODE_FAKED = 8,
	MODE_DELETED = 16, MODE_RENAMED = 32 } mode;
    int read_only;
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} mapping_t;

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#ifdef DEBUG
static void print_direntry(const struct direntry_t*);
static void print_mapping(const struct mapping_t* mapping);
#endif
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/* here begins the real VVFAT driver */

typedef struct BDRVVVFATState {
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    BlockDriverState* bs; /* pointer to parent */
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    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;
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    uint32_t last_cluster_of_root_directory;
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    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;
   
    int current_fd;
    mapping_t* current_mapping;
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    unsigned char* cluster; /* points to current cluster */
    unsigned char* cluster_buffer; /* points to a buffer to hold temp data */
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    unsigned int current_cluster;

    /* write support */
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    BlockDriverState* write_target;
    char* qcow_filename;
    BlockDriverState* qcow;
    void* fat2;
    char* used_clusters;
    array_t commits;
    const char* path;
    int downcase_short_names;
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} BDRVVVFATState;


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;
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    /* FAT12/FAT16/FAT32 */
    partition->fs_type=(s->fat_type==12?0x1:s->fat_type==16?0x6:0xb);
    partition->end_head=s->bs->heads-1;
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    partition->end_sector=0xff; /* end sector & upper 2 bits of cylinder */;
    partition->end_cylinder=0xff; /* lower 8 bits of end cylinder */;
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    partition->start_sector_long=cpu_to_le32(s->bs->secs);
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    partition->end_sector_long=cpu_to_le32(s->sector_count);

    real_mbr->magic[0]=0x55; real_mbr->magic[1]=0xaa;
}

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/* direntry functions */

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/* 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);
}

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static char is_free(const direntry_t* direntry)
{
    /* return direntry->name[0]==0 ; */
    return direntry->attributes == 0 || direntry->name[0]==0xe5;
}

static char is_volume_label(const direntry_t* direntry)
{
    return direntry->attributes == 0x28;
}

static char is_long_name(const direntry_t* direntry)
{
    return direntry->attributes == 0xf;
}

static char is_short_name(const direntry_t* direntry)
{
    return !is_volume_label(direntry) && !is_long_name(direntry)
	&& !is_free(direntry);
}

static char is_directory(const direntry_t* direntry)
{
    return direntry->attributes & 0x10 && direntry->name[0] != 0xe5;
}

static inline char is_dot(const direntry_t* direntry)
{
    return is_short_name(direntry) && direntry->name[0] == '.';
}

static char is_file(const direntry_t* direntry)
{
    return is_short_name(direntry) && !is_directory(direntry);
}

static inline uint32_t begin_of_direntry(const direntry_t* direntry)
{
    return le16_to_cpu(direntry->begin)|(le16_to_cpu(direntry->begin_hi)<<16);
}

static inline uint32_t filesize_of_direntry(const direntry_t* direntry)
{
    return le32_to_cpu(direntry->size);
}

static void set_begin_of_direntry(direntry_t* direntry, uint32_t begin)
{
    direntry->begin = cpu_to_le16(begin & 0xffff);
    direntry->begin_hi = cpu_to_le16((begin >> 16) & 0xffff);
}

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/* fat functions */

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static inline uint8_t fat_chksum(const direntry_t* entry)
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{
    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)
{
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    if(s->fat_type==32) {
	uint32_t* entry=array_get(&(s->fat),cluster);
	*entry=cpu_to_le32(value);
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    } else if(s->fat_type==16) {
	uint16_t* entry=array_get(&(s->fat),cluster);
	*entry=cpu_to_le16(value&0xffff);
    } else {
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	int offset = (cluster*3/2);
	unsigned char* p = array_get(&(s->fat), offset);
        switch (cluster&1) {
	case 0:
		p[0] = value&0xff;
		p[1] = (p[1]&0xf0) | ((value>>8)&0xf);
		break;
	case 1:
		p[0] = (p[0]&0xf) | ((value&0xf)<<4);
		p[1] = (value>>4);
		break;
	}
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    }
}

static inline uint32_t fat_get(BDRVVVFATState* s,unsigned int cluster)
{
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    if(s->fat_type==32) {
	uint32_t* entry=array_get(&(s->fat),cluster);
	return le32_to_cpu(*entry);
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    } else if(s->fat_type==16) {
	uint16_t* entry=array_get(&(s->fat),cluster);
	return le16_to_cpu(*entry);
    } else {
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	const uint8_t* x=s->fat.pointer+cluster*3/2;
	return ((x[0]|(x[1]<<8))>>(cluster&1?4:0))&0x0fff;
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    }
}

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)
{
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    if (s->fat_type == 12) {
	array_init(&(s->fat),1);
	array_ensure_allocated(&(s->fat),
		s->sectors_per_fat * 0x200 * 3 / 2 - 1);
    } else {
	array_init(&(s->fat),(s->fat_type==32?4:2));
	array_ensure_allocated(&(s->fat),
		s->sectors_per_fat * 0x200 / s->fat.item_size - 1);
    }
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    memset(s->fat.pointer,0,s->fat.size);
    
    switch(s->fat_type) {
	case 12: s->max_fat_value=0xfff; break;
	case 16: s->max_fat_value=0xffff; break;
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	case 32: s->max_fat_value=0x0fffffff; break;
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	default: s->max_fat_value=0; /* error... */
    }

}

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/* TODO: in create_short_filename, 0xe5->0x05 is not yet handled! */
/* TODO: in parse_short_filename, 0x05->0xe5 is not yet handled! */
static inline direntry_t* create_short_and_long_name(BDRVVVFATState* s,
	unsigned int directory_start, const char* filename, int is_dot)
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{
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    int i,j,long_index=s->directory.next;
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    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;
    }
    
    entry_long=create_long_filename(s,filename);
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    i = strlen(filename); 
    for(j = i - 1; j>0  && filename[j]!='.';j--);
    if (j > 0)
	i = (j > 8 ? 8 : j);
    else if (i > 8)
	i = 8;

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    entry=array_get_next(&(s->directory));
    memset(entry->name,0x20,11);
    strncpy(entry->name,filename,i);
    
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    if(j > 0)
	for (i = 0; i < 3 && filename[j+1+i]; i++)
	    entry->extension[i] = filename[j+1+i];
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    /* upcase & remove unwanted characters */
    for(i=10;i>=0;i--) {
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	if(i==10 || i==7) for(;i>0 && entry->name[i]==' ';i--);
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	if(entry->name[i]<=' ' || entry->name[i]>0x7f
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		|| strchr(".*?<>|\":/\\[];,+='",entry->name[i]))
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	    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++)
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	    if(!is_long_name(entry1) && !memcmp(entry1->name,entry->name,11))
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		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);
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	while(entry_long<entry && is_long_name(entry_long)) {
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	    entry_long->reserved[1]=chksum;
	    entry_long++;
	}
    }

    return entry;
}

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/*
 * Read a directory. (the index of the corresponding mapping must be passed).
 */
static int read_directory(BDRVVVFATState* s, int mapping_index)
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{
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    mapping_t* mapping = array_get(&(s->mapping), mapping_index);
    direntry_t* direntry;
    const char* dirname = mapping->path;
    int first_cluster = mapping->begin;
    int parent_index = mapping->info.dir.parent_mapping_index;
    mapping_t* parent_mapping = (mapping_t*)
	(parent_index >= 0 ? array_get(&(s->mapping), parent_index) : 0);
    int first_cluster_of_parent = parent_mapping ? parent_mapping->begin : -1;
667 668 669 670 671

    DIR* dir=opendir(dirname);
    struct dirent* entry;
    int i;

672 673 674 675
    assert(mapping->mode & MODE_DIRECTORY);

    if(!dir) {
	mapping->end = mapping->begin;
676
	return -1;
677 678 679 680 681 682
    }
   
    i = mapping->info.dir.first_dir_index =
	    first_cluster == 0 ? 0 : s->directory.next;

    /* actually read the directory, and allocate the mappings */ 
683 684 685 686
    while((entry=readdir(dir))) {
	unsigned int length=strlen(dirname)+2+strlen(entry->d_name);
        char* buffer;
	direntry_t* direntry;
687
        struct stat st;
688 689 690
	int is_dot=!strcmp(entry->d_name,".");
	int is_dotdot=!strcmp(entry->d_name,"..");

691
	if(first_cluster == 0 && (is_dotdot || is_dot))
692 693 694
	    continue;
	
	buffer=(char*)malloc(length);
695
	assert(buffer);
696 697 698 699 700 701 702 703
	snprintf(buffer,length,"%s/%s",dirname,entry->d_name);

	if(stat(buffer,&st)<0) {
	    free(buffer);
            continue;
	}

	/* create directory entry for this file */
704 705
	direntry=create_short_and_long_name(s, i, entry->d_name,
		is_dot || is_dotdot);
706 707 708 709 710 711 712 713 714
	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)
715
	    set_begin_of_direntry(direntry, first_cluster_of_parent);
716
	else if(is_dot)
717
	    set_begin_of_direntry(direntry, first_cluster);
718
	else
719 720 721 722 723 724 725
	    direntry->begin=0; /* do that later */
        if (st.st_size > 0x7fffffff) {
	    fprintf(stderr, "File %s is larger than 2GB\n", buffer);
	    free(buffer);
	    return -2;
        }
	direntry->size=cpu_to_le32(S_ISDIR(st.st_mode)?0:st.st_size);
726 727

	/* create mapping for this file */
728 729
	if(!is_dot && !is_dotdot && (S_ISDIR(st.st_mode) || st.st_size)) {
	    s->current_mapping=(mapping_t*)array_get_next(&(s->mapping));
730 731
	    s->current_mapping->begin=0;
	    s->current_mapping->end=st.st_size;
732 733 734 735
	    /*
	     * we get the direntry of the most recent direntry, which
	     * contains the short name and all the relevant information.
	     */
736
	    s->current_mapping->dir_index=s->directory.next-1;
737 738 739 740 741 742 743 744 745 746 747 748
	    s->current_mapping->first_mapping_index = -1;
	    if (S_ISDIR(st.st_mode)) {
		s->current_mapping->mode = MODE_DIRECTORY;
		s->current_mapping->info.dir.parent_mapping_index =
		    mapping_index;
	    } else {
		s->current_mapping->mode = MODE_UNDEFINED;
		s->current_mapping->info.file.offset = 0;
	    }
	    s->current_mapping->path=buffer;
	    s->current_mapping->read_only =
		(st.st_mode & (S_IWUSR | S_IWGRP | S_IWOTH)) == 0;
749 750 751 752 753 754 755 756 757 758
	}
    }
    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));
    }

759 760 761 762 763 764 765 766
/* TODO: if there are more entries, bootsector has to be adjusted! */
#define ROOT_ENTRIES (0x02 * 0x10 * s->sectors_per_cluster)
    if (mapping_index == 0 && s->directory.next < ROOT_ENTRIES) {
	/* root directory */
	int cur = s->directory.next;
	array_ensure_allocated(&(s->directory), ROOT_ENTRIES - 1);
	memset(array_get(&(s->directory), cur), 0,
		(ROOT_ENTRIES - cur) * sizeof(direntry_t));
767
    }
768 769 770 771 772 773 774 775 776 777 778 779
	
     /* reget the mapping, since s->mapping was possibly realloc()ed */
    mapping = (mapping_t*)array_get(&(s->mapping), mapping_index);
    first_cluster += (s->directory.next - mapping->info.dir.first_dir_index)
	* 0x20 / s->cluster_size;
    mapping->end = first_cluster;

    direntry = (direntry_t*)array_get(&(s->directory), mapping->dir_index);
    set_begin_of_direntry(direntry, mapping->begin);
   
    return 0;
}
780

781 782 783 784
static inline uint32_t sector2cluster(BDRVVVFATState* s,off_t sector_num)
{
    return (sector_num-s->faked_sectors)/s->sectors_per_cluster;
}
785

786 787 788 789
static inline off_t cluster2sector(BDRVVVFATState* s, uint32_t cluster_num)
{
    return s->faked_sectors + s->sectors_per_cluster * cluster_num;
}
790

791 792 793 794
static inline uint32_t sector_offset_in_cluster(BDRVVVFATState* s,off_t sector_num)
{
    return (sector_num-s->first_sectors_number-2*s->sectors_per_fat)%s->sectors_per_cluster;
}
795

796 797 798 799 800 801
#ifdef DBG
static direntry_t* get_direntry_for_mapping(BDRVVVFATState* s,mapping_t* mapping)
{
    if(mapping->mode==MODE_UNDEFINED)
	return 0;
    return (direntry_t*)(s->directory.pointer+sizeof(direntry_t)*mapping->dir_index);
802
}
803
#endif
804

805 806
static int init_directories(BDRVVVFATState* s,
	const char* dirname)
807
{
808 809
    bootsector_t* bootsector;
    mapping_t* mapping;
810 811 812 813 814 815
    unsigned int i;
    unsigned int cluster;

    memset(&(s->first_sectors[0]),0,0x40*0x200);

    s->cluster_size=s->sectors_per_cluster*0x200;
816 817 818 819 820 821 822 823 824 825 826 827
    s->cluster_buffer=malloc(s->cluster_size);
    assert(s->cluster_buffer);

    /*
     * The formula: sc = spf+1+spf*spc*(512*8/fat_type),
     * where sc is sector_count,
     * spf is sectors_per_fat,
     * spc is sectors_per_clusters, and
     * fat_type = 12, 16 or 32.
     */
    i = 1+s->sectors_per_cluster*0x200*8/s->fat_type;
    s->sectors_per_fat=(s->sector_count+i)/i; /* round up */
828 829 830 831 832 833 834 835 836 837 838 839 840 841
    
    array_init(&(s->mapping),sizeof(mapping_t));
    array_init(&(s->directory),sizeof(direntry_t));

    /* add volume label */
    {
	direntry_t* entry=array_get_next(&(s->directory));
	entry->attributes=0x28; /* archive | volume label */
	snprintf(entry->name,11,"QEMU VVFAT");
    }

    /* Now build FAT, and write back information into directory */
    init_fat(s);

842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870
    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));
    mapping->begin = 0;
    mapping->dir_index = 0;
    mapping->info.dir.parent_mapping_index = -1;
    mapping->first_mapping_index = -1;
    mapping->path = strdup(dirname);
    i = strlen(mapping->path);
    if (i > 0 && mapping->path[i - 1] == '/')
	mapping->path[i - 1] = '\0';
    mapping->mode = MODE_DIRECTORY;
    mapping->read_only = 0;
    s->path = mapping->path;

    for (i = 0, cluster = 0; i < s->mapping.next; i++) {
	int j;
	/* MS-DOS expects the FAT to be 0 for the root directory 
	 * (except for the media byte). */
	/* LATER TODO: still true for FAT32? */
	int fix_fat = (i != 0);
	mapping = array_get(&(s->mapping), i);

        if (mapping->mode & MODE_DIRECTORY) {
	    mapping->begin = cluster;
	    if(read_directory(s, i)) {
		fprintf(stderr, "Could not read directory %s\n",
			mapping->path);
871 872
		return -1;
	    }
873 874 875
	    mapping = array_get(&(s->mapping), i);
	} else {
	    assert(mapping->mode == MODE_UNDEFINED);
876
	    mapping->mode=MODE_NORMAL;
877 878 879 880 881 882 883 884 885 886
	    mapping->begin = cluster;
	    if (mapping->end > 0) {
		direntry_t* direntry = array_get(&(s->directory),
			mapping->dir_index);

		mapping->end = cluster + 1 + (mapping->end-1)/s->cluster_size;
		set_begin_of_direntry(direntry, mapping->begin);
	    } else {
		mapping->end = cluster + 1;
		fix_fat = 0;
887
	    }
888 889 890 891 892 893 894 895 896 897 898 899 900
	}

	assert(mapping->begin < mapping->end);

	/* fix fat for entry */
	if (fix_fat) {
	    for(j = mapping->begin; j < mapping->end - 1; j++)
		fat_set(s, j, j+1);
	    fat_set(s, mapping->end - 1, s->max_fat_value);
	}

	/* next free cluster */
	cluster = mapping->end;
901

902 903 904
	if(cluster > s->cluster_count) {
	    fprintf(stderr,"Directory does not fit in FAT%d\n",s->fat_type);
	    return -1;
905 906 907
	}
    }

908 909 910 911 912 913 914
    mapping = array_get(&(s->mapping), 0);
    s->sectors_of_root_directory = mapping->end * s->sectors_per_cluster;
    s->last_cluster_of_root_directory = mapping->end;

    /* the FAT signature */
    fat_set(s,0,s->max_fat_value);
    fat_set(s,1,s->max_fat_value);
915

916 917 918
    s->current_mapping = NULL;

    bootsector=(bootsector_t*)(s->first_sectors+(s->first_sectors_number-1)*0x200);
919 920 921 922 923 924 925 926 927
    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);
928 929 930
    bootsector->total_sectors16=s->sector_count>0xffff?0:cpu_to_le16(s->sector_count);
    bootsector->media_type=(s->fat_type!=12?0xf8:s->sector_count==5760?0xf9:0xf8); /* media descriptor */
    s->fat.pointer[0] = bootsector->media_type;
931
    bootsector->sectors_per_fat=cpu_to_le16(s->sectors_per_fat);
932 933
    bootsector->sectors_per_track=cpu_to_le16(s->bs->secs);
    bootsector->number_of_heads=cpu_to_le16(s->bs->heads);
934
    bootsector->hidden_sectors=cpu_to_le32(s->first_sectors_number==1?0:0x3f);
935
    bootsector->total_sectors=cpu_to_le32(s->sector_count>0xffff?s->sector_count:0);
936

937 938
    /* LATER TODO: if FAT32, this is wrong */
    bootsector->u.fat16.drive_number=s->fat_type==12?0:0x80; /* assume this is hda (TODO) */
939 940 941 942 943 944 945 946 947 948 949
    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;
}

B
bellard 已提交
950
#ifdef DEBUG
951
static BDRVVVFATState *vvv = NULL;
B
bellard 已提交
952
#endif
953 954 955 956

static int enable_write_target(BDRVVVFATState *s);
static int is_consistent(BDRVVVFATState *s);

B
bellard 已提交
957
static int vvfat_open(BlockDriverState *bs, const char* dirname, int flags)
958 959
{
    BDRVVVFATState *s = bs->opaque;
960
    int floppy = 0;
961 962
    int i;

B
bellard 已提交
963
#ifdef DEBUG
964
    vvv = s;
B
bellard 已提交
965
#endif
966 967 968 969 970 971 972 973

DLOG(if (stderr == NULL) {
    stderr = fopen("vvfat.log", "a");
    setbuf(stderr, NULL);
})

    s->bs = bs;

974
    s->fat_type=16;
975
    /* LATER TODO: if FAT32, adjust */
976
    s->sector_count=0xec04f;
977 978 979
    s->sectors_per_cluster=0x10;
    /* LATER TODO: this could be wrong for FAT32 */
    bs->cyls=1023; bs->heads=15; bs->secs=63;
980 981 982 983

    s->current_cluster=0xffffffff;

    s->first_sectors_number=0x40;
984 985 986 987 988 989
    /* read only is the default for safety */
    bs->read_only = 1;
    s->qcow = s->write_target = NULL;
    s->qcow_filename = NULL;
    s->fat2 = NULL;
    s->downcase_short_names = 1;
990
    
991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015
    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;
	s->first_sectors_number = 1;
	s->sectors_per_cluster=2;
	bs->cyls = 80; bs->heads = 2; bs->secs = 36;
    }

    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;
    } else if (strstr(dirname, ":16:")) {
	s->fat_type = 16;
    } else if (strstr(dirname, ":12:")) {
	s->fat_type = 12;
	s->sector_count=2880;
1016
    }
1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029

    i = strrchr(dirname, ':') - dirname;
    assert(i >= 3);
    if (dirname[i-2] == ':' && isalpha(dirname[i-1]))
	/* workaround for DOS drive names */
	dirname += i-1;
    else
	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))
1030 1031 1032 1033 1034
	return -1;

    if(s->first_sectors_number==0x40)
	init_mbr(s);

1035 1036 1037 1038 1039
    /* for some reason or other, MS-DOS does not like to know about CHS... */
    if (floppy)
	bs->heads = bs->cyls = bs->secs = 0;

    //    assert(is_consistent(s));
1040 1041 1042 1043 1044 1045
    return 0;
}

static inline void vvfat_close_current_file(BDRVVVFATState *s)
{
    if(s->current_mapping) {
1046 1047 1048 1049 1050
	s->current_mapping = NULL;
	if (s->current_fd) {
		close(s->current_fd);
		s->current_fd = 0;
	}
1051
    }
1052
    s->current_cluster = -1;
1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064
}

/* 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;
    while(1) {
	mapping_t* mapping;
	index3=(index1+index2)/2;
	mapping=array_get(&(s->mapping),index3);
1065 1066
	assert(mapping->begin < mapping->end);
	if(mapping->begin>=cluster_num) {
1067 1068
	    assert(index2!=index3 || index2==0);
	    if(index2==index3)
1069
		return index1;
1070 1071 1072
	    index2=index3;
	} else {
	    if(index1==index3)
1073
		return mapping->end<=cluster_num ? index2 : index1;
1074 1075 1076
	    index1=index3;
	}
	assert(index1<=index2);
1077 1078 1079 1080 1081
	DLOG(mapping=array_get(&(s->mapping),index1);
	assert(mapping->begin<=cluster_num);
	assert(index2 >= s->mapping.next || 
		((mapping = array_get(&(s->mapping),index2)) &&
		mapping->end>cluster_num)));
1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093
    }
}

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;
1094
    assert(mapping->begin<=cluster_num && mapping->end>cluster_num);
1095 1096 1097
    return mapping;
}

1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117
/*
 * This function simply compares path == mapping->path. Since the mappings
 * are sorted by cluster, this is expensive: O(n).
 */
static inline mapping_t* find_mapping_for_path(BDRVVVFATState* s,
	const char* path)
{
    int i;

    for (i = 0; i < s->mapping.next; i++) {
	mapping_t* mapping = array_get(&(s->mapping), i);
	if (mapping->first_mapping_index < 0 &&
		!strcmp(path, mapping->path))
	    return mapping;
    }

    return NULL;
}

static int open_file(BDRVVVFATState* s,mapping_t* mapping)
1118 1119 1120 1121
{
    if(!mapping)
	return -1;
    if(!s->current_mapping ||
1122
	    strcmp(s->current_mapping->path,mapping->path)) {
1123
	/* open file */
1124
	int fd = open(mapping->path, O_RDONLY | O_BINARY | O_LARGEFILE);
1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138
	if(fd<0)
	    return -1;
	vvfat_close_current_file(s);
	s->current_fd = fd;
	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;
1139
	assert(!s->current_mapping || s->current_fd || (s->current_mapping->mode & MODE_DIRECTORY));
1140 1141 1142 1143 1144
	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);
1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161

	    assert(!mapping || (cluster_num>=mapping->begin && cluster_num<mapping->end));

	    if (mapping && mapping->mode & MODE_DIRECTORY) {
		vvfat_close_current_file(s);
		s->current_mapping = mapping;
read_cluster_directory:
		offset = s->cluster_size*(cluster_num-s->current_mapping->begin);
		s->cluster = s->directory.pointer+offset
			+ 0x20*s->current_mapping->info.dir.first_dir_index;
		assert(((s->cluster-(unsigned char*)s->directory.pointer)%s->cluster_size)==0);
		assert((char*)s->cluster+s->cluster_size <= s->directory.pointer+s->directory.next*s->directory.item_size);
		s->current_cluster = cluster_num;
		return 0;
	    }

	    if(open_file(s,mapping))
1162
		return -2;
1163 1164
	} else if (s->current_mapping->mode & MODE_DIRECTORY)
	    goto read_cluster_directory;
1165

1166 1167 1168
	assert(s->current_fd);

	offset=s->cluster_size*(cluster_num-s->current_mapping->begin)+s->current_mapping->info.file.offset;
1169 1170
	if(lseek(s->current_fd, offset, SEEK_SET)!=offset)
	    return -3;
1171
	s->cluster=s->cluster_buffer;
1172 1173 1174 1175 1176 1177 1178 1179 1180 1181
	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;
}

1182 1183
#ifdef DEBUG
static void hexdump(const void* address, uint32_t len)
1184
{
1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196
    const unsigned char* p = address;
    int i, j;

    for (i = 0; i < len; i += 16) {
	for (j = 0; j < 16 && i + j < len; j++)
	    fprintf(stderr, "%02x ", p[i + j]);
	for (; j < 16; j++)
	    fprintf(stderr, "   ");
	fprintf(stderr, " ");
	for (j = 0; j < 16 && i + j < len; j++)
	    fprintf(stderr, "%c", (p[i + j] < ' ' || p[i + j] > 0x7f) ? '.' : p[i + j]);
	fprintf(stderr, "\n");
1197 1198 1199
    }
}

1200
static void print_direntry(const direntry_t* direntry)
1201
{
1202 1203 1204 1205
    int j = 0;
    char buffer[1024];

    fprintf(stderr, "direntry 0x%x: ", (int)direntry);
1206 1207
    if(!direntry)
	return;
1208
    if(is_long_name(direntry)) {
1209 1210 1211
	unsigned char* c=(unsigned char*)direntry;
	int i;
	for(i=1;i<11 && c[i] && c[i]!=0xff;i+=2)
1212 1213
#define ADD_CHAR(c) {buffer[j] = (c); if (buffer[j] < ' ') buffer[j] = '°'; j++;}
	    ADD_CHAR(c[i]);
1214
	for(i=14;i<26 && c[i] && c[i]!=0xff;i+=2)
1215
	    ADD_CHAR(c[i]);
1216
	for(i=28;i<32 && c[i] && c[i]!=0xff;i+=2)
1217 1218 1219
	    ADD_CHAR(c[i]);
	buffer[j] = 0;
	fprintf(stderr, "%s\n", buffer);
1220 1221 1222
    } else {
	int i;
	for(i=0;i<11;i++)
1223 1224 1225 1226
	    ADD_CHAR(direntry->name[i]);
	buffer[j] = 0;
	fprintf(stderr,"%s attributes=0x%02x begin=%d size=%d\n",
		buffer,
1227
		direntry->attributes,
1228
		begin_of_direntry(direntry),le32_to_cpu(direntry->size));
1229 1230 1231
    }
}

1232
static void print_mapping(const mapping_t* mapping)
1233
{
1234 1235 1236 1237 1238
    fprintf(stderr, "mapping (0x%x): begin, end = %d, %d, dir_index = %d, first_mapping_index = %d, name = %s, mode = 0x%x, " , (int)mapping, mapping->begin, mapping->end, mapping->dir_index, mapping->first_mapping_index, mapping->path, mapping->mode);
    if (mapping->mode & MODE_DIRECTORY)
	fprintf(stderr, "parent_mapping_index = %d, first_dir_index = %d\n", mapping->info.dir.parent_mapping_index, mapping->info.dir.first_dir_index);
    else
	fprintf(stderr, "offset = %d\n", mapping->info.file.offset);
1239
}
1240
#endif
1241

1242 1243
static int vvfat_read(BlockDriverState *bs, int64_t sector_num, 
                    uint8_t *buf, int nb_sectors)
1244
{
1245
    BDRVVVFATState *s = bs->opaque;
1246 1247
    int i;

1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262
    for(i=0;i<nb_sectors;i++,sector_num++) {
	if (sector_num >= s->sector_count)
	   return -1;
	if (s->qcow) {
	    int n;
	    if (s->qcow->drv->bdrv_is_allocated(s->qcow,
			sector_num, nb_sectors-i, &n)) {
DLOG(fprintf(stderr, "sectors %d+%d allocated\n", (int)sector_num, n));
		if (s->qcow->drv->bdrv_read(s->qcow, sector_num, buf+i*0x200, n))
		    return -1;
		i += n - 1;
		sector_num += n - 1;
		continue;
	    }
DLOG(fprintf(stderr, "sector %d not allocated\n", (int)sector_num));
1263
	}
1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278
	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 {
	    uint32_t sector=sector_num-s->faked_sectors,
	    sector_offset_in_cluster=(sector%s->sectors_per_cluster),
	    cluster_num=sector/s->sectors_per_cluster;
	    if(read_cluster(s, cluster_num) != 0) {
		/* LATER TODO: strict: return -1; */
		memset(buf+i*0x200,0,0x200);
		continue;
1279
	    }
1280
	    memcpy(buf+i*0x200,s->cluster+sector_offset_in_cluster*0x200,0x200);
1281 1282 1283 1284 1285
	}
    }
    return 0;
}

1286
/* LATER TODO: statify all functions */
1287

1288 1289
/*
 * Idea of the write support (use snapshot):
1290
 *
1291 1292
 * 1. check if all data is consistent, recording renames, modifications,
 *    new files and directories (in s->commits).
1293
 *
1294
 * 2. if the data is not consistent, stop committing
1295
 *
1296 1297
 * 3. handle renames, and create new files and directories (do not yet
 *    write their contents)
1298
 *
1299 1300
 * 4. walk the directories, fixing the mapping and direntries, and marking
 *    the handled mappings as not deleted
1301
 *
1302
 * 5. commit the contents of the files
1303
 *
1304
 * 6. handle deleted files and directories
1305 1306 1307
 *
 */

1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320
typedef struct commit_t {
    char* path;
    union {
	struct { uint32_t cluster; } rename;
	struct { int dir_index; uint32_t modified_offset; } writeout;
	struct { uint32_t first_cluster; } new_file;
	struct { uint32_t cluster; } mkdir;
    } param;
    /* DELETEs and RMDIRs are handled differently: see handle_deletes() */
    enum {
	ACTION_RENAME, ACTION_WRITEOUT, ACTION_NEW_FILE, ACTION_MKDIR
    } action;
} commit_t;
1321

1322
static void clear_commits(BDRVVVFATState* s)
1323 1324
{
    int i;
1325 1326 1327 1328 1329 1330 1331 1332 1333
DLOG(fprintf(stderr, "clear_commits (%d commits)\n", s->commits.next));
    for (i = 0; i < s->commits.next; i++) {
	commit_t* commit = array_get(&(s->commits), i);
	assert(commit->path || commit->action == ACTION_WRITEOUT);
	if (commit->action != ACTION_WRITEOUT) {
	    assert(commit->path);
	    free(commit->path);
	} else
	    assert(commit->path == NULL);
1334
    }
1335
    s->commits.next = 0;
1336 1337
}

1338 1339
static void schedule_rename(BDRVVVFATState* s,
	uint32_t cluster, char* new_path)
1340
{
1341 1342 1343 1344
    commit_t* commit = array_get_next(&(s->commits));
    commit->path = new_path;
    commit->param.rename.cluster = cluster;
    commit->action = ACTION_RENAME;
1345 1346
}

1347 1348
static void schedule_writeout(BDRVVVFATState* s,
	int dir_index, uint32_t modified_offset)
1349
{
1350 1351 1352 1353 1354
    commit_t* commit = array_get_next(&(s->commits));
    commit->path = NULL;
    commit->param.writeout.dir_index = dir_index;
    commit->param.writeout.modified_offset = modified_offset;
    commit->action = ACTION_WRITEOUT;
1355 1356
}

1357 1358
static void schedule_new_file(BDRVVVFATState* s,
	char* path, uint32_t first_cluster)
1359
{
1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419
    commit_t* commit = array_get_next(&(s->commits));
    commit->path = path;
    commit->param.new_file.first_cluster = first_cluster;
    commit->action = ACTION_NEW_FILE;
}

static void schedule_mkdir(BDRVVVFATState* s, uint32_t cluster, char* path)
{
    commit_t* commit = array_get_next(&(s->commits));
    commit->path = path;
    commit->param.mkdir.cluster = cluster;
    commit->action = ACTION_MKDIR;
}

typedef struct {
    unsigned char name[1024];
    int checksum, len;
    int sequence_number;
} long_file_name;

static void lfn_init(long_file_name* lfn)
{
   lfn->sequence_number = lfn->len = 0;
   lfn->checksum = 0x100;
}

/* return 0 if parsed successfully, > 0 if no long name, < 0 if error */
static int parse_long_name(long_file_name* lfn,
	const direntry_t* direntry)
{
    int i, j, offset;
    const unsigned char* pointer = (const unsigned char*)direntry;

    if (!is_long_name(direntry))
	return 1;

    if (pointer[0] & 0x40) {
	lfn->sequence_number = pointer[0] & 0x3f;
	lfn->checksum = pointer[13];
	lfn->name[0] = 0;
    } else if ((pointer[0] & 0x3f) != --lfn->sequence_number)
	return -1;
    else if (pointer[13] != lfn->checksum)
	return -2;
    else if (pointer[12] || pointer[26] || pointer[27])
	return -3;

    offset = 13 * (lfn->sequence_number - 1);
    for (i = 0, j = 1; i < 13; i++, j+=2) {
	if (j == 11)
	    j = 14;
	else if (j == 26)
	    j = 28;

	if (pointer[j+1] == 0)
	    lfn->name[offset + i] = pointer[j];
	else if (pointer[j+1] != 0xff || (pointer[0] & 0x40) == 0)
	    return -4;
	else
	    lfn->name[offset + i] = 0;
1420
    }
1421 1422 1423 1424

    if (pointer[0] & 0x40)
	lfn->len = offset + strlen(lfn->name + offset);

1425 1426 1427
    return 0;
}

1428 1429 1430
/* returns 0 if successful, >0 if no short_name, and <0 on error */
static int parse_short_name(BDRVVVFATState* s,
	long_file_name* lfn, direntry_t* direntry)
1431
{
1432
    int i, j;
1433

1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444
    if (!is_short_name(direntry))
	return 1;

    for (j = 7; j >= 0 && direntry->name[j] == ' '; j--);
    for (i = 0; i <= j; i++) {
	if (direntry->name[i] <= ' ' || direntry->name[i] > 0x7f)
	    return -1;
	else if (s->downcase_short_names)
	    lfn->name[i] = tolower(direntry->name[i]);
	else
	    lfn->name[i] = direntry->name[i];
1445 1446
    }

1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464
    for (j = 2; j >= 0 && direntry->extension[j] == ' '; j--);
    if (j >= 0) {
	lfn->name[i++] = '.';
	lfn->name[i + j + 1] = '\0';
	for (;j >= 0; j--) {
	    if (direntry->extension[j] <= ' ' || direntry->extension[j] > 0x7f)
		return -2;
	    else if (s->downcase_short_names)
		lfn->name[i + j] = tolower(direntry->extension[j]);
	    else
		lfn->name[i + j] = direntry->extension[j];
	}
    } else
	lfn->name[i + j + 1] = '\0';

    lfn->len = strlen(lfn->name);

    return 0;
1465 1466
}

1467 1468
static inline uint32_t modified_fat_get(BDRVVVFATState* s,
	unsigned int cluster)
1469
{
1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494
    if (cluster < s->last_cluster_of_root_directory) {
	if (cluster + 1 == s->last_cluster_of_root_directory)
	    return s->max_fat_value;
	else
	    return cluster + 1;
    }

    if (s->fat_type==32) {
        uint32_t* entry=((uint32_t*)s->fat2)+cluster;
        return le32_to_cpu(*entry);
    } else if (s->fat_type==16) {
        uint16_t* entry=((uint16_t*)s->fat2)+cluster;
        return le16_to_cpu(*entry);
    } else {
        const uint8_t* x=s->fat2+cluster*3/2;
        return ((x[0]|(x[1]<<8))>>(cluster&1?4:0))&0x0fff;
    }
}

static inline int cluster_was_modified(BDRVVVFATState* s, uint32_t cluster_num)
{
    int was_modified = 0;
    int i, dummy;

    if (s->qcow == NULL)
1495
	return 0;
1496 1497 1498 1499 1500 1501

    for (i = 0; !was_modified && i < s->sectors_per_cluster; i++)
	was_modified = s->qcow->drv->bdrv_is_allocated(s->qcow,
		cluster2sector(s, cluster_num) + i, 1, &dummy);

    return was_modified;
1502 1503
}

1504
static const char* get_basename(const char* path)
1505
{
1506 1507 1508 1509 1510
    char* basename = strrchr(path, '/');
    if (basename == NULL)
	return path;
    else
	return basename + 1; /* strip '/' */
1511 1512
}

1513 1514 1515 1516 1517 1518 1519 1520 1521 1522
/*
 * The array s->used_clusters holds the states of the clusters. If it is
 * part of a file, it has bit 2 set, in case of a directory, bit 1. If it
 * was modified, bit 3 is set.
 * If any cluster is allocated, but not part of a file or directory, this
 * driver refuses to commit.
 */
typedef enum {
     USED_DIRECTORY = 1, USED_FILE = 2, USED_ANY = 3, USED_ALLOCATED = 4
} used_t;
1523

1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535
/*
 * get_cluster_count_for_direntry() not only determines how many clusters
 * are occupied by direntry, but also if it was renamed or modified.
 *
 * A file is thought to be renamed *only* if there already was a file with
 * exactly the same first cluster, but a different name.
 *
 * Further, the files/directories handled by this function are
 * assumed to be *not* deleted (and *only* those).
 */
static uint32_t get_cluster_count_for_direntry(BDRVVVFATState* s,
	direntry_t* direntry, const char* path)
1536
{
1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562
    /*
     * This is a little bit tricky:
     * IF the guest OS just inserts a cluster into the file chain,
     * and leaves the rest alone, (i.e. the original file had clusters
     * 15 -> 16, but now has 15 -> 32 -> 16), then the following happens:
     *
     * - do_commit will write the cluster into the file at the given
     *   offset, but
     *
     * - the cluster which is overwritten should be moved to a later
     *   position in the file.
     *
     * I am not aware that any OS does something as braindead, but this
     * situation could happen anyway when not committing for a long time.
     * Just to be sure that this does not bite us, detect it, and copy the
     * contents of the clusters to-be-overwritten into the qcow.
     */
    int copy_it = 0;
    int was_modified = 0;
    int32_t ret = 0;

    uint32_t cluster_num = begin_of_direntry(direntry);
    uint32_t offset = 0;
    int first_mapping_index = -1;
    mapping_t* mapping = NULL;
    const char* basename2 = NULL;
1563

1564
    vvfat_close_current_file(s);
1565

1566 1567
    /* the root directory */
    if (cluster_num == 0)
1568 1569
	return 0;

1570 1571 1572
    /* write support */
    if (s->qcow) {
	basename2 = get_basename(path);
1573

1574 1575 1576
	mapping = find_mapping_for_cluster(s, cluster_num);

	if (mapping) {
B
bellard 已提交
1577 1578
	    const char* basename;

1579 1580 1581
	    assert(mapping->mode & MODE_DELETED);
	    mapping->mode &= ~MODE_DELETED;

B
bellard 已提交
1582
	    basename = get_basename(mapping->path);
1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595

	    assert(mapping->mode & MODE_NORMAL);

	    /* rename */
	    if (strcmp(basename, basename2))
		schedule_rename(s, cluster_num, strdup(path));
	} else if (is_file(direntry))
	    /* new file */
	    schedule_new_file(s, strdup(path), cluster_num);
	else {
	    assert(0);
	    return 0;
	}
1596 1597
    }

1598 1599 1600 1601 1602 1603 1604
    while(1) {
	if (s->qcow) {
	    if (!copy_it && cluster_was_modified(s, cluster_num)) {
		if (mapping == NULL ||
			mapping->begin > cluster_num ||
			mapping->end <= cluster_num)
		mapping = find_mapping_for_cluster(s, cluster_num);
1605

1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673

		if (mapping &&
			(mapping->mode & MODE_DIRECTORY) == 0) {

		    /* was modified in qcow */
		    if (offset != mapping->info.file.offset + s->cluster_size
			    * (cluster_num - mapping->begin)) {
			/* offset of this cluster in file chain has changed */
			assert(0);
			copy_it = 1;
		    } else if (offset == 0) {
			const char* basename = get_basename(mapping->path);

			if (strcmp(basename, basename2))
			    copy_it = 1;
			first_mapping_index = array_index(&(s->mapping), mapping);
		    }

		    if (mapping->first_mapping_index != first_mapping_index
			    && mapping->info.file.offset > 0) {
			assert(0);
			copy_it = 1;
		    }

		    /* need to write out? */
		    if (!was_modified && is_file(direntry)) {
			was_modified = 1;
			schedule_writeout(s, mapping->dir_index, offset);
		    }
		}
	    }

	    if (copy_it) {
		int i, dummy;
		/*
		 * This is horribly inefficient, but that is okay, since
		 * it is rarely executed, if at all.
		 */
		int64_t offset = cluster2sector(s, cluster_num);

		vvfat_close_current_file(s);
		for (i = 0; i < s->sectors_per_cluster; i++)
		    if (!s->qcow->drv->bdrv_is_allocated(s->qcow,
				offset + i, 1, &dummy)) {
			if (vvfat_read(s->bs,
				    offset, s->cluster_buffer, 1))
			    return -1;
			if (s->qcow->drv->bdrv_write(s->qcow,
				    offset, s->cluster_buffer, 1))
			    return -2;
		    }
	    }
	}

	ret++;
	if (s->used_clusters[cluster_num] & USED_ANY)
	    return 0;
	s->used_clusters[cluster_num] = USED_FILE;

	cluster_num = modified_fat_get(s, cluster_num);

	if (fat_eof(s, cluster_num))
	    return ret;
	else if (cluster_num < 2 || cluster_num > s->max_fat_value - 16)
	    return -1;

	offset += s->cluster_size;
    }
1674 1675
}

1676 1677 1678 1679 1680 1681 1682
/*
 * This function looks at the modified data (qcow). 
 * It returns 0 upon inconsistency or error, and the number of clusters
 * used by the directory, its subdirectories and their files.
 */
static int check_directory_consistency(BDRVVVFATState *s,
	int cluster_num, const char* path)
1683
{
1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714
    int ret = 0;
    unsigned char* cluster = malloc(s->cluster_size);
    direntry_t* direntries = (direntry_t*)cluster;
    mapping_t* mapping = find_mapping_for_cluster(s, cluster_num);

    long_file_name lfn;
    int path_len = strlen(path);
    char path2[PATH_MAX];

    assert(path_len < PATH_MAX); /* len was tested before! */
    strcpy(path2, path);
    path2[path_len] = '/';
    path2[path_len + 1] = '\0';

    if (mapping) {
	const char* basename = get_basename(mapping->path);
	const char* basename2 = get_basename(path);

	assert(mapping->mode & MODE_DIRECTORY);

	assert(mapping->mode & MODE_DELETED);
	mapping->mode &= ~MODE_DELETED;

	if (strcmp(basename, basename2))
	    schedule_rename(s, cluster_num, strdup(path));
    } else
	/* new directory */
	schedule_mkdir(s, cluster_num, strdup(path));
		
    lfn_init(&lfn);
    do {
1715
	int i;
1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747
	int subret = 0;

	ret++;

	if (s->used_clusters[cluster_num] & USED_ANY) {
	    fprintf(stderr, "cluster %d used more than once\n", (int)cluster_num);
	    return 0;
	}
	s->used_clusters[cluster_num] = USED_DIRECTORY;

DLOG(fprintf(stderr, "read cluster %d (sector %d)\n", (int)cluster_num, (int)cluster2sector(s, cluster_num)));
	subret = vvfat_read(s->bs, cluster2sector(s, cluster_num), cluster,
		s->sectors_per_cluster);
	if (subret) {
	    fprintf(stderr, "Error fetching direntries\n");
	fail:
	    free(cluster);
	    return 0;
	}

	for (i = 0; i < 0x10 * s->sectors_per_cluster; i++) {
	    int cluster_count;

DLOG(fprintf(stderr, "check direntry %d: \n", i); print_direntry(direntries + i));
	    if (is_volume_label(direntries + i) || is_dot(direntries + i) ||
		    is_free(direntries + i))
		continue;

	    subret = parse_long_name(&lfn, direntries + i);
	    if (subret < 0) {
		fprintf(stderr, "Error in long name\n");
		goto fail;
1748
	    }
1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793
	    if (subret == 0 || is_free(direntries + i))
		continue;

	    if (fat_chksum(direntries+i) != lfn.checksum) {
		subret = parse_short_name(s, &lfn, direntries + i);
		if (subret < 0) {
		    fprintf(stderr, "Error in short name (%d)\n", subret);
		    goto fail;
		}
		if (subret > 0 || !strcmp(lfn.name, ".")
			|| !strcmp(lfn.name, ".."))
		    continue;
	    }
	    lfn.checksum = 0x100; /* cannot use long name twice */

	    if (path_len + 1 + lfn.len >= PATH_MAX) {
		fprintf(stderr, "Name too long: %s/%s\n", path, lfn.name);
		goto fail;
	    }
	    strcpy(path2 + path_len + 1, lfn.name);

	    if (is_directory(direntries + i)) {
		if (begin_of_direntry(direntries + i) == 0) {
		    DLOG(fprintf(stderr, "invalid begin for directory: %s\n", path2); print_direntry(direntries + i));
		    goto fail;
		}
		cluster_count = check_directory_consistency(s,
			begin_of_direntry(direntries + i), path2);
		if (cluster_count == 0) {
		    DLOG(fprintf(stderr, "problem in directory %s:\n", path2); print_direntry(direntries + i));
		    goto fail;
		}
	    } else if (is_file(direntries + i)) {
		/* check file size with FAT */
		cluster_count = get_cluster_count_for_direntry(s, direntries + i, path2);
		if (cluster_count !=
			(le32_to_cpu(direntries[i].size) + s->cluster_size
			 - 1) / s->cluster_size) {
		    DLOG(fprintf(stderr, "Cluster count mismatch\n"));
		    goto fail;
		}
	    } else
		assert(0); /* cluster_count = 0; */

	    ret += cluster_count;
1794 1795
	}

1796 1797
	cluster_num = modified_fat_get(s, cluster_num);
    } while(!fat_eof(s, cluster_num));
1798

1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846
    free(cluster);
    return ret;
}

/* returns 1 on success */
static int is_consistent(BDRVVVFATState* s)
{
    int i, check;
    int used_clusters_count = 0;

DLOG(checkpoint());
    /*
     * - get modified FAT
     * - compare the two FATs (TODO)
     * - get buffer for marking used clusters
     * - recurse direntries from root (using bs->bdrv_read to make
     *    sure to get the new data)
     *   - check that the FAT agrees with the size
     *   - count the number of clusters occupied by this directory and
     *     its files
     * - check that the cumulative used cluster count agrees with the
     *   FAT
     * - if all is fine, return number of used clusters
     */
    if (s->fat2 == NULL) {
	int size = 0x200 * s->sectors_per_fat;
	s->fat2 = malloc(size);
	memcpy(s->fat2, s->fat.pointer, size);
    }
    check = vvfat_read(s->bs,
	    s->first_sectors_number, s->fat2, s->sectors_per_fat);
    if (check) {
	fprintf(stderr, "Could not copy fat\n");
	return 0;
    }
    assert (s->used_clusters);
    for (i = 0; i < sector2cluster(s, s->sector_count); i++)
	s->used_clusters[i] &= ~USED_ANY;

    clear_commits(s);

    /* mark every mapped file/directory as deleted.
     * (check_directory_consistency() will unmark those still present). */
    if (s->qcow)
	for (i = 0; i < s->mapping.next; i++) {
	    mapping_t* mapping = array_get(&(s->mapping), i);
	    if (mapping->first_mapping_index < 0)
		mapping->mode |= MODE_DELETED;
1847
	}
1848 1849 1850 1851 1852

    used_clusters_count = check_directory_consistency(s, 0, s->path);
    if (used_clusters_count <= 0) {
	DLOG(fprintf(stderr, "problem in directory\n"));
	return 0;
1853 1854
    }

1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892
    check = s->last_cluster_of_root_directory;
    for (i = check; i < sector2cluster(s, s->sector_count); i++) {
	if (modified_fat_get(s, i)) {
	    if(!s->used_clusters[i]) {
		DLOG(fprintf(stderr, "FAT was modified (%d), but cluster is not used?\n", i));
		return 0;
	    }
	    check++;
	}

	if (s->used_clusters[i] == USED_ALLOCATED) {
	    /* allocated, but not used... */
	    DLOG(fprintf(stderr, "unused, modified cluster: %d\n", i));
	    return 0;
	}
    }

    if (check != used_clusters_count)
	return 0;

    return used_clusters_count;
}

static inline void adjust_mapping_indices(BDRVVVFATState* s,
	int offset, int adjust)
{
    int i;

    for (i = 0; i < s->mapping.next; i++) {
	mapping_t* mapping = array_get(&(s->mapping), i);

#define ADJUST_MAPPING_INDEX(name) \
	if (mapping->name >= offset) \
	    mapping->name += adjust

	ADJUST_MAPPING_INDEX(first_mapping_index);
	if (mapping->mode & MODE_DIRECTORY)
	    ADJUST_MAPPING_INDEX(info.dir.parent_mapping_index);
1893
    }
1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924
}

/* insert or update mapping */
static mapping_t* insert_mapping(BDRVVVFATState* s,
	uint32_t begin, uint32_t end)
{
    /*
     * - find mapping where mapping->begin >= begin,
     * - if mapping->begin > begin: insert
     *   - adjust all references to mappings!
     * - else: adjust
     * - replace name
     */
    int index = find_mapping_for_cluster_aux(s, begin, 0, s->mapping.next);
    mapping_t* mapping = NULL;
    mapping_t* first_mapping = array_get(&(s->mapping), 0);

    if (index < s->mapping.next && (mapping = array_get(&(s->mapping), index))
	    && mapping->begin < begin) {
	mapping->end = begin;
	index++;
	mapping = array_get(&(s->mapping), index);
    }
    if (index >= s->mapping.next || mapping->begin > begin) {
	mapping = array_insert(&(s->mapping), index, 1);
	mapping->path = NULL;
	adjust_mapping_indices(s, index, +1);
    }

    mapping->begin = begin;
    mapping->end = end;
1925

1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955
DLOG(mapping_t* next_mapping;
assert(index + 1 >= s->mapping.next ||
((next_mapping = array_get(&(s->mapping), index + 1)) &&
 next_mapping->begin >= end)));

    if (s->current_mapping && first_mapping != (mapping_t*)s->mapping.pointer)
	s->current_mapping = array_get(&(s->mapping),
		s->current_mapping - first_mapping);

    return mapping;
}

static int remove_mapping(BDRVVVFATState* s, int mapping_index)
{
    mapping_t* mapping = array_get(&(s->mapping), mapping_index);
    mapping_t* first_mapping = array_get(&(s->mapping), 0);

    /* free mapping */
    if (mapping->first_mapping_index < 0)
	free(mapping->path);

    /* remove from s->mapping */
    array_remove(&(s->mapping), mapping_index);

    /* adjust all references to mappings */
    adjust_mapping_indices(s, mapping_index, -1);

    if (s->current_mapping && first_mapping != (mapping_t*)s->mapping.pointer)
	s->current_mapping = array_get(&(s->mapping),
		s->current_mapping - first_mapping);
1956 1957 1958 1959

    return 0;
}

1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971
static void adjust_dirindices(BDRVVVFATState* s, int offset, int adjust)
{
    int i;
    for (i = 0; i < s->mapping.next; i++) {
	mapping_t* mapping = array_get(&(s->mapping), i);
	if (mapping->dir_index >= offset)
	    mapping->dir_index += adjust;
	if ((mapping->mode & MODE_DIRECTORY) &&
		mapping->info.dir.first_dir_index >= offset)
	    mapping->info.dir.first_dir_index += adjust;
    }
}
1972

1973 1974
static direntry_t* insert_direntries(BDRVVVFATState* s,
	int dir_index, int count)
1975
{
1976 1977 1978 1979 1980 1981 1982 1983
    /*
     * make room in s->directory,
     * adjust_dirindices
     */
    direntry_t* result = array_insert(&(s->directory), dir_index, count);
    if (result == NULL)
	return NULL;
    adjust_dirindices(s, dir_index, count);
1984 1985 1986
    return result;
}

1987 1988 1989 1990 1991 1992 1993 1994
static int remove_direntries(BDRVVVFATState* s, int dir_index, int count)
{
    int ret = array_remove_slice(&(s->directory), dir_index, count);
    if (ret)
	return ret;
    adjust_dirindices(s, dir_index, -count);
    return 0;
}
1995

1996 1997 1998 1999 2000 2001 2002 2003
/*
 * Adapt the mappings of the cluster chain starting at first cluster
 * (i.e. if a file starts at first_cluster, the chain is followed according
 * to the modified fat, and the corresponding entries in s->mapping are
 * adjusted)
 */
static int commit_mappings(BDRVVVFATState* s,
	uint32_t first_cluster, int dir_index)
2004
{
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074
    mapping_t* mapping = find_mapping_for_cluster(s, first_cluster);
    direntry_t* direntry = array_get(&(s->directory), dir_index);
    uint32_t cluster = first_cluster;

    vvfat_close_current_file(s);

    assert(mapping);
    assert(mapping->begin == first_cluster);
    mapping->first_mapping_index = -1;
    mapping->dir_index = dir_index;
    mapping->mode = (dir_index <= 0 || is_directory(direntry)) ?
	MODE_DIRECTORY : MODE_NORMAL;

    while (!fat_eof(s, cluster)) {
	uint32_t c, c1;

	for (c = cluster, c1 = modified_fat_get(s, c); c + 1 == c1;
		c = c1, c1 = modified_fat_get(s, c1));

	c++;
	if (c > mapping->end) {
	    int index = array_index(&(s->mapping), mapping);
	    int i, max_i = s->mapping.next - index;
	    for (i = 1; i < max_i && mapping[i].begin < c; i++);
	    while (--i > 0)
		remove_mapping(s, index + 1);
	}
	assert(mapping == array_get(&(s->mapping), s->mapping.next - 1)
		|| mapping[1].begin >= c);
	mapping->end = c;

	if (!fat_eof(s, c1)) {
	    int i = find_mapping_for_cluster_aux(s, c1, 0, s->mapping.next);
	    mapping_t* next_mapping = i >= s->mapping.next ? NULL :
		array_get(&(s->mapping), i);

	    if (next_mapping == NULL || next_mapping->begin > c1) {
		int i1 = array_index(&(s->mapping), mapping);

		next_mapping = insert_mapping(s, c1, c1+1);

		if (c1 < c)
		    i1++;
		mapping = array_get(&(s->mapping), i1);
	    }

	    next_mapping->dir_index = mapping->dir_index;
	    next_mapping->first_mapping_index = 
		mapping->first_mapping_index < 0 ?
		array_index(&(s->mapping), mapping) :
		mapping->first_mapping_index;
	    next_mapping->path = mapping->path;
	    next_mapping->mode = mapping->mode;
	    next_mapping->read_only = mapping->read_only;
	    if (mapping->mode & MODE_DIRECTORY) {
		next_mapping->info.dir.parent_mapping_index =
			mapping->info.dir.parent_mapping_index;
		next_mapping->info.dir.first_dir_index =
			mapping->info.dir.first_dir_index +
			0x10 * s->sectors_per_cluster *
			(mapping->end - mapping->begin);
	    } else
		next_mapping->info.file.offset = mapping->info.file.offset +
			mapping->end - mapping->begin;

	    mapping = next_mapping;
	}
		
	cluster = c1;
    }
2075 2076 2077 2078

    return 0;
}

2079 2080
static int commit_direntries(BDRVVVFATState* s,
	int dir_index, int parent_mapping_index)
2081
{
2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110
    direntry_t* direntry = array_get(&(s->directory), dir_index);
    uint32_t first_cluster = dir_index == 0 ? 0 : begin_of_direntry(direntry);
    mapping_t* mapping = find_mapping_for_cluster(s, first_cluster);

    int factor = 0x10 * s->sectors_per_cluster;
    int old_cluster_count, new_cluster_count;
    int current_dir_index = mapping->info.dir.first_dir_index;
    int first_dir_index = current_dir_index;
    int ret, i;
    uint32_t c;

DLOG(fprintf(stderr, "commit_direntries for %s, parent_mapping_index %d\n", mapping->path, parent_mapping_index));

    assert(direntry);
    assert(mapping);
    assert(mapping->begin == first_cluster);
    assert(mapping->info.dir.first_dir_index < s->directory.next);
    assert(mapping->mode & MODE_DIRECTORY);
    assert(dir_index == 0 || is_directory(direntry));

    mapping->info.dir.parent_mapping_index = parent_mapping_index;

    if (first_cluster == 0) {
	old_cluster_count = new_cluster_count =
	    s->last_cluster_of_root_directory;
    } else {
	for (old_cluster_count = 0, c = first_cluster; !fat_eof(s, c);
		c = fat_get(s, c))
	    old_cluster_count++;
2111

2112 2113 2114 2115
	for (new_cluster_count = 0, c = first_cluster; !fat_eof(s, c);
		c = modified_fat_get(s, c))
	    new_cluster_count++;
    }
2116

2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135
    if (new_cluster_count > old_cluster_count) {
	if (insert_direntries(s,
		current_dir_index + factor * old_cluster_count,
		factor * (new_cluster_count - old_cluster_count)) == NULL)
	    return -1;
    } else if (new_cluster_count < old_cluster_count)
	remove_direntries(s,
		current_dir_index + factor * new_cluster_count,
		factor * (old_cluster_count - new_cluster_count));

    for (c = first_cluster; !fat_eof(s, c); c = modified_fat_get(s, c)) {
	void* direntry = array_get(&(s->directory), current_dir_index);
	int ret = vvfat_read(s->bs, cluster2sector(s, c), direntry,
		s->sectors_per_cluster);
	if (ret)
	    return ret;
	assert(!strncmp(s->directory.pointer, "QEMU", 4));
	current_dir_index += factor;
    }
2136

2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152
    ret = commit_mappings(s, first_cluster, dir_index);
    if (ret)
	return ret;

    /* recurse */
    for (i = 0; i < factor * new_cluster_count; i++) {
	direntry = array_get(&(s->directory), first_dir_index + i);
	if (is_directory(direntry) && !is_dot(direntry)) {
	    mapping = find_mapping_for_cluster(s, first_cluster);
	    assert(mapping->mode & MODE_DIRECTORY);
	    ret = commit_direntries(s, first_dir_index + i,
		array_index(&(s->mapping), mapping));
	    if (ret)
		return ret;
	}
    }
2153

2154 2155
    return 0;
}
2156

2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176
/* commit one file (adjust contents, adjust mapping),
   return first_mapping_index */
static int commit_one_file(BDRVVVFATState* s,
	int dir_index, uint32_t offset)
{
    direntry_t* direntry = array_get(&(s->directory), dir_index);
    uint32_t c = begin_of_direntry(direntry);
    uint32_t first_cluster = c;
    mapping_t* mapping = find_mapping_for_cluster(s, c);
    uint32_t size = filesize_of_direntry(direntry);
    char* cluster = malloc(s->cluster_size);
    uint32_t i;
    int fd = 0;

    assert(offset < size);
    assert((offset % s->cluster_size) == 0);

    for (i = s->cluster_size; i < offset; i += s->cluster_size)
	c = modified_fat_get(s, c);

B
bellard 已提交
2177
    fd = open(mapping->path, O_RDWR | O_CREAT | O_BINARY, 0666);
2178 2179 2180 2181
    if (fd < 0) {
	fprintf(stderr, "Could not open %s... (%s, %d)\n", mapping->path,
		strerror(errno), errno);
	return fd;
2182
    }
2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235
    if (offset > 0)
	if (lseek(fd, offset, SEEK_SET) != offset)
	    return -3;

    while (offset < size) {
	uint32_t c1;
	int rest_size = (size - offset > s->cluster_size ?
		s->cluster_size : size - offset);
	int ret;

	c1 = modified_fat_get(s, c);

	assert((size - offset == 0 && fat_eof(s, c)) ||
		(size > offset && c >=2 && !fat_eof(s, c)));
	assert(size >= 0);

	ret = vvfat_read(s->bs, cluster2sector(s, c),
	    cluster, (rest_size + 0x1ff) / 0x200);

	if (ret < 0)
	    return ret;

	if (write(fd, cluster, rest_size) < 0)
	    return -2;

	offset += rest_size;
	c = c1;
    }

    ftruncate(fd, size);
    close(fd);

    return commit_mappings(s, first_cluster, dir_index);
}

#ifdef DEBUG
/* test, if all mappings point to valid direntries */
static void check1(BDRVVVFATState* s)
{
    int i;
    for (i = 0; i < s->mapping.next; i++) {
	mapping_t* mapping = array_get(&(s->mapping), i);
	if (mapping->mode & MODE_DELETED) {
	    fprintf(stderr, "deleted\n");
	    continue;
	}
	assert(mapping->dir_index >= 0);
	assert(mapping->dir_index < s->directory.next);
	direntry_t* direntry = array_get(&(s->directory), mapping->dir_index);
	assert(mapping->begin == begin_of_direntry(direntry) || mapping->first_mapping_index >= 0);
	if (mapping->mode & MODE_DIRECTORY) {
	    assert(mapping->info.dir.first_dir_index + 0x10 * s->sectors_per_cluster * (mapping->end - mapping->begin) <= s->directory.next);
	    assert((mapping->info.dir.first_dir_index % (0x10 * s->sectors_per_cluster)) == 0);
2236 2237 2238 2239
	}
    }
}

2240 2241
/* test, if all direntries have mappings */
static void check2(BDRVVVFATState* s)
2242 2243
{
    int i;
2244
    int first_mapping = -1;
2245

2246 2247
    for (i = 0; i < s->directory.next; i++) {
	direntry_t* direntry = array_get(&(s->directory), i);
2248

2249 2250 2251 2252 2253 2254
	if (is_short_name(direntry) && begin_of_direntry(direntry)) {
	    mapping_t* mapping = find_mapping_for_cluster(s, begin_of_direntry(direntry));
	    assert(mapping);
	    assert(mapping->dir_index == i || is_dot(direntry));
	    assert(mapping->begin == begin_of_direntry(direntry) || is_dot(direntry));
	}
2255

2256 2257 2258
	if ((i % (0x10 * s->sectors_per_cluster)) == 0) {
	    /* cluster start */
	    int j, count = 0;
2259

2260 2261 2262
	    for (j = 0; j < s->mapping.next; j++) {
		mapping_t* mapping = array_get(&(s->mapping), j);
		if (mapping->mode & MODE_DELETED)
2263
		    continue;
2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278
		if (mapping->mode & MODE_DIRECTORY) {
		    if (mapping->info.dir.first_dir_index <= i && mapping->info.dir.first_dir_index + 0x10 * s->sectors_per_cluster > i) {
			assert(++count == 1);
			if (mapping->first_mapping_index == -1)
			    first_mapping = array_index(&(s->mapping), mapping);
			else
			    assert(first_mapping == mapping->first_mapping_index);
			if (mapping->info.dir.parent_mapping_index < 0)
			    assert(j == 0);
			else {
			    mapping_t* parent = array_get(&(s->mapping), mapping->info.dir.parent_mapping_index);
			    assert(parent->mode & MODE_DIRECTORY);
			    assert(parent->info.dir.first_dir_index < mapping->info.dir.first_dir_index);
			}
		    }
2279
		}
2280 2281 2282 2283 2284 2285 2286
	    }
	    if (count == 0)
		first_mapping = -1;
	}
    }
}
#endif
2287

2288 2289 2290
static int handle_renames_and_mkdirs(BDRVVVFATState* s)
{
    int i;
2291

2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337
#ifdef DEBUG
    fprintf(stderr, "handle_renames\n");
    for (i = 0; i < s->commits.next; i++) {
	commit_t* commit = array_get(&(s->commits), i);
	fprintf(stderr, "%d, %s (%d, %d)\n", i, commit->path ? commit->path : "(null)", commit->param.rename.cluster, commit->action);
    }
#endif

    for (i = 0; i < s->commits.next;) {
	commit_t* commit = array_get(&(s->commits), i);
	if (commit->action == ACTION_RENAME) {
	    mapping_t* mapping = find_mapping_for_cluster(s,
		    commit->param.rename.cluster);
	    char* old_path = mapping->path;

	    assert(commit->path);
	    mapping->path = commit->path;
	    if (rename(old_path, mapping->path))
		return -2;

	    if (mapping->mode & MODE_DIRECTORY) {
		int l1 = strlen(mapping->path);
		int l2 = strlen(old_path);
		int diff = l1 - l2;
		direntry_t* direntry = array_get(&(s->directory),
			mapping->info.dir.first_dir_index);
		uint32_t c = mapping->begin;
		int i = 0;

		/* recurse */
		while (!fat_eof(s, c)) {
		    do {
			direntry_t* d = direntry + i;

			if (is_file(d) || (is_directory(d) && !is_dot(d))) {
			    mapping_t* m = find_mapping_for_cluster(s,
				    begin_of_direntry(d));
			    int l = strlen(m->path);
			    char* new_path = malloc(l + diff + 1);

			    assert(!strncmp(m->path, mapping->path, l2));

			    strcpy(new_path, mapping->path);
			    strcpy(new_path + l1, m->path + l2);

			    schedule_rename(s, m->begin, new_path);
2338
			}
2339 2340 2341
			i++;
		    } while((i % (0x10 * s->sectors_per_cluster)) != 0);
		    c = fat_get(s, c);
2342 2343 2344
		}
	    }

2345 2346 2347 2348 2349 2350 2351
	    free(old_path);
	    array_remove(&(s->commits), i);
	    continue;
	} else if (commit->action == ACTION_MKDIR) {
	    mapping_t* mapping;
	    int j, parent_path_len;

B
bellard 已提交
2352 2353 2354 2355 2356 2357 2358
#ifdef __MINGW32__
            if (mkdir(commit->path))
                return -5;
#else
            if (mkdir(commit->path, 0755))
                return -5;
#endif
2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431

	    mapping = insert_mapping(s, commit->param.mkdir.cluster,
		    commit->param.mkdir.cluster + 1);
	    if (mapping == NULL)
		return -6;

	    mapping->mode = MODE_DIRECTORY;
	    mapping->read_only = 0;
	    mapping->path = commit->path;
	    j = s->directory.next;
	    assert(j);
	    insert_direntries(s, s->directory.next,
		    0x10 * s->sectors_per_cluster);
	    mapping->info.dir.first_dir_index = j;

	    parent_path_len = strlen(commit->path)
		- strlen(get_basename(commit->path)) - 1;
	    for (j = 0; j < s->mapping.next; j++) {
		mapping_t* m = array_get(&(s->mapping), j);
		if (m->first_mapping_index < 0 && m != mapping &&
			!strncmp(m->path, mapping->path, parent_path_len) &&
			strlen(m->path) == parent_path_len)
		    break;
	    }
	    assert(j < s->mapping.next);
	    mapping->info.dir.parent_mapping_index = j;

	    array_remove(&(s->commits), i);
	    continue;
	}

	i++;
    }
    return 0;
}

/*
 * TODO: make sure that the short name is not matching *another* file
 */
static int handle_commits(BDRVVVFATState* s)
{
    int i, fail = 0;

    vvfat_close_current_file(s);

    for (i = 0; !fail && i < s->commits.next; i++) {
	commit_t* commit = array_get(&(s->commits), i);
	switch(commit->action) {
	case ACTION_RENAME: case ACTION_MKDIR:
	    assert(0);
	    fail = -2;
	    break;
	case ACTION_WRITEOUT: {
	    direntry_t* entry = array_get(&(s->directory),
		    commit->param.writeout.dir_index);
	    uint32_t begin = begin_of_direntry(entry);
	    mapping_t* mapping = find_mapping_for_cluster(s, begin);

	    assert(mapping);
	    assert(mapping->begin == begin);
	    assert(commit->path == NULL);

	    if (commit_one_file(s, commit->param.writeout.dir_index,
			commit->param.writeout.modified_offset))
		fail = -3;

	    break;
	}
	case ACTION_NEW_FILE: {
	    int begin = commit->param.new_file.first_cluster;
	    mapping_t* mapping = find_mapping_for_cluster(s, begin);
	    direntry_t* entry;
	    int i;
2432

2433 2434 2435 2436 2437
	    /* find direntry */
	    for (i = 0; i < s->directory.next; i++) {
		entry = array_get(&(s->directory), i);
		if (is_file(entry) && begin_of_direntry(entry) == begin)
		    break;
2438 2439
	    }

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	    if (i >= s->directory.next) {
		fail = -6;
		continue;
	    }
2444

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	    /* make sure there exists an initial mapping */
	    if (mapping && mapping->begin != begin) {
		mapping->end = begin;
		mapping = NULL;
	    }
	    if (mapping == NULL) {
		mapping = insert_mapping(s, begin, begin+1);
	    }
	    /* most members will be fixed in commit_mappings() */
	    assert(commit->path);
	    mapping->path = commit->path;
	    mapping->read_only = 0;
	    mapping->mode = MODE_NORMAL;
	    mapping->info.file.offset = 0;

	    if (commit_one_file(s, i, 0))
		fail = -7;

	    break;
	}
	default:
	    assert(0);
	}
    }
    if (i > 0 && array_remove_slice(&(s->commits), 0, i))
	return -1;
    return fail;
}

static int handle_deletes(BDRVVVFATState* s)
{
    int i, deferred = 1, deleted = 1;

    /* delete files corresponding to mappings marked as deleted */
    /* handle DELETEs and unused mappings (modified_fat_get(s, mapping->begin) == 0) */
    while (deferred && deleted) {
	deferred = 0;
	deleted = 0;

	for (i = 1; i < s->mapping.next; i++) {
	    mapping_t* mapping = array_get(&(s->mapping), i);
	    if (mapping->mode & MODE_DELETED) {
		direntry_t* entry = array_get(&(s->directory),
			mapping->dir_index);

		if (is_free(entry)) {
		    /* remove file/directory */
		    if (mapping->mode & MODE_DIRECTORY) {
			int j, next_dir_index = s->directory.next,
			first_dir_index = mapping->info.dir.first_dir_index;

			if (rmdir(mapping->path) < 0) {
			    if (errno == ENOTEMPTY) {
				deferred++;
				continue;
			    } else
				return -5;
2502
			}
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			for (j = 1; j < s->mapping.next; j++) {
			    mapping_t* m = array_get(&(s->mapping), j);
			    if (m->mode & MODE_DIRECTORY &&
				    m->info.dir.first_dir_index >
				    first_dir_index &&
				    m->info.dir.first_dir_index <
				    next_dir_index)
				next_dir_index =
				    m->info.dir.first_dir_index;
2513
			}
2514 2515
			remove_direntries(s, first_dir_index,
				next_dir_index - first_dir_index);
2516

2517
			deleted++;
2518
		    }
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		} else {
		    if (unlink(mapping->path))
			return -4;
		    deleted++;
2523
		}
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		DLOG(fprintf(stderr, "DELETE (%d)\n", i); print_mapping(mapping); print_direntry(entry));
		remove_mapping(s, i);
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	    }
	}
    }
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    return 0;
}

/*
 * synchronize mapping with new state:
 *
 * - copy FAT (with bdrv_read)
 * - mark all filenames corresponding to mappings as deleted
 * - recurse direntries from root (using bs->bdrv_read)
 * - delete files corresponding to mappings marked as deleted
 */
static int do_commit(BDRVVVFATState* s)
{
    int ret = 0;

    /* the real meat are the commits. Nothing to do? Move along! */
    if (s->commits.next == 0)
	return 0;

    vvfat_close_current_file(s);

    ret = handle_renames_and_mkdirs(s);
    if (ret) {
	fprintf(stderr, "Error handling renames (%d)\n", ret);
	assert(0);
	return ret;
    }

    /* copy FAT (with bdrv_read) */ 
    memcpy(s->fat.pointer, s->fat2, 0x200 * s->sectors_per_fat);

    /* recurse direntries from root (using bs->bdrv_read) */
    ret = commit_direntries(s, 0, -1);
    if (ret) {
	fprintf(stderr, "Fatal: error while committing (%d)\n", ret);
	assert(0);
	return ret;
    }

    ret = handle_commits(s);
    if (ret) {
	fprintf(stderr, "Error handling commits (%d)\n", ret);
	assert(0);
	return ret;
    }

    ret = handle_deletes(s);
    if (ret) {
	fprintf(stderr, "Error deleting\n");
        assert(0);
	return ret;
    }

    s->qcow->drv->bdrv_make_empty(s->qcow);

    memset(s->used_clusters, 0, sector2cluster(s, s->sector_count));

DLOG(checkpoint());
    return 0;
}

static int try_commit(BDRVVVFATState* s)
{
    vvfat_close_current_file(s);
DLOG(checkpoint());
    if(!is_consistent(s))
	return -1;
    return do_commit(s);
}

static int vvfat_write(BlockDriverState *bs, int64_t sector_num, 
                    const uint8_t *buf, int nb_sectors)
{
    BDRVVVFATState *s = bs->opaque; 
    int i, ret;

DLOG(checkpoint());

    vvfat_close_current_file(s);

    /*
     * Some sanity checks:
     * - do not allow writing to the boot sector
     * - do not allow to write non-ASCII filenames
     */

    if (sector_num < s->first_sectors_number)
	return -1;

    for (i = sector2cluster(s, sector_num);
	    i <= sector2cluster(s, sector_num + nb_sectors - 1);) {
	mapping_t* mapping = find_mapping_for_cluster(s, i);
	if (mapping) {
	    if (mapping->read_only) {
		fprintf(stderr, "Tried to write to write-protected file %s\n",
			mapping->path);
		return -1;
	    }

	    if (mapping->mode & MODE_DIRECTORY) {
		int begin = cluster2sector(s, i);
		int end = begin + s->sectors_per_cluster, k;
		int dir_index;
		const direntry_t* direntries;
		long_file_name lfn;

		lfn_init(&lfn);

		if (begin < sector_num)
		    begin = sector_num;
		if (end > sector_num + nb_sectors)
		    end = sector_num + nb_sectors;
		dir_index  = mapping->dir_index + 
		    0x10 * (begin - mapping->begin * s->sectors_per_cluster);
		direntries = (direntry_t*)(buf + 0x200 * (begin - sector_num));

		for (k = 0; k < (end - begin) * 0x10; k++) {
		    /* do not allow non-ASCII filenames */
		    if (parse_long_name(&lfn, direntries + k) < 0) {
			fprintf(stderr, "Warning: non-ASCII filename\n");
			return -1;
		    }
		    /* no access to the direntry of a read-only file */
		    else if (is_short_name(direntries+k) &&
			    (direntries[k].attributes & 1)) {
			if (memcmp(direntries + k,
				    array_get(&(s->directory), dir_index + k),
				    sizeof(direntry_t))) {
			    fprintf(stderr, "Warning: tried to write to write-protected file\n");
			    return -1;
			}
		    }
		}
	    }
	    i = mapping->end;
	} else
	    i++;
    }

    /*
     * Use qcow backend. Commit later.
     */
DLOG(fprintf(stderr, "Write to qcow backend: %d + %d\n", (int)sector_num, nb_sectors));
    ret = s->qcow->drv->bdrv_write(s->qcow, sector_num, buf, nb_sectors);
    if (ret < 0) {
	fprintf(stderr, "Error writing to qcow backend\n");
	return ret;
    }

    for (i = sector2cluster(s, sector_num);
	    i <= sector2cluster(s, sector_num + nb_sectors - 1); i++)
	if (i >= 0)
	    s->used_clusters[i] |= USED_ALLOCATED;

DLOG(checkpoint());
    /* TODO: add timeout */
    try_commit(s);

DLOG(checkpoint());
    return 0;
}

static int vvfat_is_allocated(BlockDriverState *bs,
	int64_t sector_num, int nb_sectors, int* n)
{
    BDRVVVFATState* s = bs->opaque;
    *n = s->sector_count - sector_num;
    if (*n > nb_sectors)
	*n = nb_sectors;
    else if (*n < 0)
	return 0;
    return 1;	
}

static int write_target_commit(BlockDriverState *bs, int64_t sector_num,
	const uint8_t* buffer, int nb_sectors) {
    BDRVVVFATState* s = bs->opaque;
    return try_commit(s);
}

static void write_target_close(BlockDriverState *bs) {
    BDRVVVFATState* s = bs->opaque;
    bdrv_delete(s->qcow);
    free(s->qcow_filename);
}

static BlockDriver vvfat_write_target = {
    "vvfat_write_target", 0, NULL, NULL, NULL,
    write_target_commit,
    write_target_close,
    NULL, NULL, NULL
};

static int enable_write_target(BDRVVVFATState *s)
{
    int size = sector2cluster(s, s->sector_count);
    s->used_clusters = calloc(size, 1);

    array_init(&(s->commits), sizeof(commit_t));

    s->qcow_filename = malloc(1024);
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    get_tmp_filename(s->qcow_filename, 1024);
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    if (bdrv_create(&bdrv_qcow,
		s->qcow_filename, s->sector_count, "fat:", 0) < 0)
	return -1;
    s->qcow = bdrv_new("");
    if (s->qcow == NULL || bdrv_open(s->qcow, s->qcow_filename, 0) < 0)
	return -1;

#ifndef _WIN32
    unlink(s->qcow_filename);
#endif

    s->bs->backing_hd = calloc(sizeof(BlockDriverState), 1);
    s->bs->backing_hd->drv = &vvfat_write_target;
    s->bs->backing_hd->opaque = s;

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    return 0;
}

static void vvfat_close(BlockDriverState *bs)
{
    BDRVVVFATState *s = bs->opaque;

    vvfat_close_current_file(s);
    array_free(&(s->fat));
    array_free(&(s->directory));
    array_free(&(s->mapping));
2758 2759
    if(s->cluster_buffer)
        free(s->cluster_buffer);
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}

BlockDriver bdrv_vvfat = {
    "vvfat",
    sizeof(BDRVVVFATState),
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    NULL, /* no probe for protocols */
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    vvfat_open,
    vvfat_read,
    vvfat_write,
    vvfat_close,
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    NULL, /* ??? Not sure if we can do any meaningful flushing.  */
2771
    NULL,
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    vvfat_is_allocated,
    .protocol_name = "fat",
2774 2775
};

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#ifdef DEBUG
static void checkpoint() {
    assert(((mapping_t*)array_get(&(vvv->mapping), 0))->end == 2);
    check1(vvv);
    check2(vvv);
    assert(!vvv->current_mapping || vvv->current_fd || (vvv->current_mapping->mode & MODE_DIRECTORY));
#if 0
    if (((direntry_t*)vvv->directory.pointer)[1].attributes != 0xf)
	fprintf(stderr, "Nonono!\n");
    mapping_t* mapping;
    direntry_t* direntry;
    assert(vvv->mapping.size >= vvv->mapping.item_size * vvv->mapping.next);
    assert(vvv->directory.size >= vvv->directory.item_size * vvv->directory.next);
    if (vvv->mapping.next<47)
	return;
    assert((mapping = array_get(&(vvv->mapping), 47)));
    assert(mapping->dir_index < vvv->directory.next);
    direntry = array_get(&(vvv->directory), mapping->dir_index);
    assert(!memcmp(direntry->name, "USB     H  ", 11) || direntry->name[0]==0);
#endif
    return;
    /* avoid compiler warnings: */
    hexdump(NULL, 100);
    remove_mapping(vvv, NULL);
    print_mapping(NULL);
    print_direntry(NULL);
}
#endif
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