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gerrit-public.fairphone.software / fp2-dev / platform / external / fsck_msdos / refs/tags/FP2-open-16.07.1 / . / fat.c
blob: 9253dce9a8fce369fbd6f959a58f8af48fe73e3b [file] [log] [blame]
/*
* Copyright (C) 1995, 1996, 1997 Wolfgang Solfrank
* Copyright (c) 1995 Martin Husemann
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Martin Husemann
* and Wolfgang Solfrank.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/cdefs.h>
#include <assert.h>
#ifndef lint
__RCSID("$NetBSD: fat.c,v 1.12 2000/10/10 20:24:52 is Exp $");
static const char rcsid[] =
"$FreeBSD: src/sbin/fsck_msdosfs/fat.c,v 1.9 2008/01/31 13:22:13 yar Exp $";
#endif /* not lint */
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdio.h>
#include <unistd.h>
#include "ext.h"
#include "fsutil.h"
#include "fatcache.h"
#include "fragment.h"
static int checkclnum(struct bootblock *, cl_t, cl_t *);
static int clustdiffer(cl_t, cl_t *, cl_t *, int,int *);
static int tryclear(struct bootblock* ,struct cluster_chain_descriptor *, cl_t, cl_t *);
int _readfat(int, struct bootblock *, int, u_char **);
static cl_t firstfreecl = 0xFFFFFFFF;
/*-
* The first 2 FAT entries contain pseudo-cluster numbers with the following
* layout:
*
* 31...... ........ ........ .......0
* rrrr1111 11111111 11111111 mmmmmmmm FAT32 entry 0
* rrrrsh11 11111111 11111111 11111xxx FAT32 entry 1
*
* 11111111 mmmmmmmm FAT16 entry 0
* sh111111 11111xxx FAT16 entry 1
*
* r = reserved
* m = BPB media ID byte
* s = clean flag (1 = dismounted; 0 = still mounted)
* h = hard error flag (1 = ok; 0 = I/O error)
* x = any value ok
*/
int
checkdirty(int fs, struct bootblock *boot)
{
off_t off;
u_char *buffer;
int ret = 0;
if (boot->ClustMask != CLUST16_MASK && boot->ClustMask != CLUST32_MASK)
return 0;
off = boot->ResSectors;
off *= boot->BytesPerSec;
buffer = malloc(boot->BytesPerSec);
if (buffer == NULL) {
perror("No space for FAT");
return 1;
}
if (lseek(fs, off, SEEK_SET) != off) {
perror("Unable to read FAT");
goto err;
}
if (read(fs, buffer, boot->BytesPerSec) != boot->BytesPerSec) {
perror("Unable to read FAT");
goto err;
}
/*
* If we don't understand the FAT, then the file system must be
* assumed to be unclean.
*/
if (buffer[0] != boot->Media || buffer[1] != 0xff)
goto err;
if (boot->ClustMask == CLUST16_MASK) {
if ((buffer[2] & 0xf8) != 0xf8 || (buffer[3] & 0x3f) != 0x3f)
goto err;
} else {
if (buffer[2] != 0xff || (buffer[3] & 0x0f) != 0x0f
|| (buffer[4] & 0xf8) != 0xf8 || buffer[5] != 0xff
|| buffer[6] != 0xff || (buffer[7] & 0x03) != 0x03)
goto err;
}
/*
* Now check the actual clean flag (and the no-error flag).
*/
if (boot->ClustMask == CLUST16_MASK) {
if ((buffer[3] & 0xc0) == 0xc0)
ret = 1;
} else {
if ((buffer[7] & 0x0c) == 0x0c)
ret = 1;
}
err:
free(buffer);
return ret;
}
/*
* Check a cluster number for valid value
*/
static struct fragment *lastfree= NULL;
static struct fragment *lastbad= NULL;
int checkclnum(struct bootblock *boot, cl_t cl, cl_t *next)
{
struct fragment *frag;
struct fragment *insert;
if((*next >= (CLUST_EOFS & boot->ClustMask)) && (*next <= (CLUST_EOF & boot->ClustMask)))
return FSOK;
if(*next >= (CLUST_RSRVD & boot->ClustMask)){
*next |= ~boot->ClustMask;
}
/*if it is a free cluster,add to rb_free_root tree*/
if (*next == CLUST_FREE) {
boot->NumFree++;
/*find the first free cluster ,this value will be used to update fsinfo*/
if(firstfreecl > cl)
firstfreecl = cl;
if(lastfree){
if( cl == (lastfree->head + lastfree->length)){
lastfree->length += 1;
return FSOK;
}
}
frag = New_fragment();
if(!frag){
fsck_info("No space \n");
return FSERROR;
}
frag->head = cl;
frag->length = 1;
insert = RB_INSERT(FSCK_MSDOS_FRAGMENT,&rb_free_root,frag);
if(insert){
fsck_info("%s:fragment(head:0x%x) exist\n",__func__,frag->head);
return FSERROR;
}
lastfree = frag;
return FSOK;
}
/*if it is a bad cluster ,add to rb_bad_root tree*/
if (*next == CLUST_BAD) {
boot->NumBad++;
if(lastbad){
if(cl == (lastbad->head + lastbad->length)){
lastbad->length += 1;
return FSOK;
}
}
frag = New_fragment();
if(!frag){
fsck_info("No Space\n");
return FSERROR;
}
frag->head = cl;
frag->length = 1;
insert = RB_INSERT(FSCK_MSDOS_FRAGMENT,&rb_bad_root,frag);
if(insert){
fsck_info("%s:fragment(head:0x%x) exist\n",__func__,frag->head);
return FSERROR;
}
lastbad = frag;
return FSOK;
}
if (*next < CLUST_FIRST || (*next >= boot->NumClusters && *next < (CLUST_EOFS & boot->ClustMask))) {
pwarn("Cluster %u in FAT continues with %s cluster number %u\n",
cl,
*next < CLUST_RSRVD ? "out of range" : "reserved",
*next&boot->ClustMask);
if (ask(1, "Truncate")) {
/*do nothing about truncate*/
return FSFATMOD;
}
return FSERROR;
}
return FSOK;
}
/*
* Read a FAT from disk. Returns 1 if successful, 0 otherwise.
*/
int
_readfat(int fs, struct bootblock *boot, int no, u_char **buffer)
{
off_t off;
printf("Attempting to allocate %u KB for FAT\n",
(boot->FATsecs * boot->BytesPerSec) / 1024);
*buffer = malloc(boot->FATsecs * boot->BytesPerSec);
if (*buffer == NULL) {
perror("No space for FAT");
return 0;
}
off = boot->ResSectors + no * boot->FATsecs;
off *= boot->BytesPerSec;
if (lseek(fs, off, SEEK_SET) != off) {
perror("Unable to read FAT");
goto err;
}
if (read(fs, *buffer, boot->FATsecs * boot->BytesPerSec)
!= boot->FATsecs * boot->BytesPerSec) {
perror("Unable to read FAT");
goto err;
}
return 1;
err:
free(*buffer);
return 0;
}
/*
* Read a FAT and decode it into internal format
*/
unsigned int *fat_bitmap;
int checkfat(int fs, struct bootblock *boot, int no,u_char *buffer)
{
struct cluster_chain_descriptor *fat = NULL,*nextcl_fat,*insert,*remove,tofind;
struct fatcache *cache = NULL;
u_char *p;
cl_t cl,prevcl = 0, nextclus;
int len = 0;
int ret = FSOK,err = 0;
boot->NumFree = boot->NumBad = 0;
fat_bitmap = calloc(boot->NumClusters/32+1,sizeof(unsigned int));
if(!fat_bitmap){
fsck_err("NO space left\n");
return FSFATAL;
}
if (buffer[0] != boot->Media
|| buffer[1] != 0xff || buffer[2] != 0xff
|| (boot->ClustMask == CLUST16_MASK && buffer[3] != 0xff)
|| (boot->ClustMask == CLUST32_MASK
&& ((buffer[3]&0x0f) != 0x0f
|| buffer[4] != 0xff || buffer[5] != 0xff
|| buffer[6] != 0xff || (buffer[7]&0x0f) != 0x0f))) {
/* Windows 95 OSR2 (and possibly any later) changes
* the FAT signature to 0xXXffff7f for FAT16 and to
* 0xXXffff0fffffff07 for FAT32 upon boot, to know that the
* file system is dirty if it doesn't reboot cleanly.
* Check this special condition before errorring out.
*/
if (buffer[0] == boot->Media && buffer[1] == 0xff
&& buffer[2] == 0xff
&& ((boot->ClustMask == CLUST16_MASK && buffer[3] == 0x7f)
|| (boot->ClustMask == CLUST32_MASK
&& buffer[3] == 0x0f && buffer[4] == 0xff
&& buffer[5] == 0xff && buffer[6] == 0xff
&& buffer[7] == 0x07)))
ret |= FSDIRTY;
else {
/* just some odd byte sequence in FAT */
switch (boot->ClustMask) {
case CLUST32_MASK:
pwarn("%s (%02x%02x%02x%02x%02x%02x%02x%02x)\n",
"FAT starts with odd byte sequence",
buffer[0], buffer[1], buffer[2], buffer[3],
buffer[4], buffer[5], buffer[6], buffer[7]);
break;
case CLUST16_MASK:
pwarn("%s (%02x%02x%02x%02x)\n",
"FAT starts with odd byte sequence",
buffer[0], buffer[1], buffer[2], buffer[3]);
break;
default:
pwarn("%s (%02x%02x%02x)\n",
"FAT starts with odd byte sequence",
buffer[0], buffer[1], buffer[2]);
break;
}
if (ask(1, "Correct"))
ret |= FSFIXFAT;
}
}
fsck_info("Begin to handle the cluster chain\n");
for (cl = CLUST_FIRST; cl < boot->NumClusters;cl++) {
/*have handled it by cluster chain*/
if(BIT(fat_bitmap[cl/32],cl%32))
continue;
prevcl = nextclus = cl;
len = 0;
switch (boot->ClustMask) {
case CLUST32_MASK:
p = buffer + 4*cl;
break;
case CLUST16_MASK:
p = buffer + 2*cl;
break;
default:
p = buffer + 3*(cl/2);
break;
}
while(nextclus >= CLUST_FIRST && nextclus < boot->NumClusters){
switch (boot->ClustMask) {
case CLUST32_MASK:
nextclus = p[0] + (p[1] << 8)
+ (p[2] << 16) + (p[3] << 24);
nextclus &= boot->ClustMask;
p = buffer + 4*nextclus;
break;
case CLUST16_MASK:
nextclus = p[0] + (p[1] << 8);
p = buffer + 2*nextclus;
break;
/*FAT12 is special*/
default:
/* odd */
if(!(nextclus & 0x1))
nextclus = (p[0] + (p[1] << 8)) & 0x0fff;
else
nextclus = ((p[1] >> 4) + (p[2] << 4)) & 0x0fff;
p = buffer + 3*(nextclus/2);
break;
}
err = checkclnum(boot,prevcl,&nextclus);
ret |= err;
if(err & FSERROR)
return -1;
//truncate the rest clusters
if(err & FSFATMOD)
break;
len++;
/*
*TODO:because this cluster chain is special,such as
*fatentry->fatcache->fatcache->fatcache->NULL
*so you should treat the first fatcache specially
*/
if(len == 1){
if(nextclus == CLUST_FREE || nextclus == CLUST_BAD ){
SET_BIT(fat_bitmap[prevcl/32],prevcl%32);
break;
}
}
/*last cluster*/
if((nextclus >= (CLUST_EOFS & boot->ClustMask)) && (nextclus <= (CLUST_EOF & boot->ClustMask)) && (len != 1)){
SET_BIT(fat_bitmap[prevcl/32],prevcl%32);
break;
}
/*rsrvd*/
if(nextclus == CLUST_FREE || ((nextclus >= (CLUST_RSRVD & boot->ClustMask)) && (nextclus < (CLUST_EOFS & boot->ClustMask)))){
fsck_warn("Cluster chain starting at %u ends with cluster marked %s,cl = %d ,nextclus = %d\n",cl,rsrvdcltype(nextclus),cl,nextclus);
SET_BIT(fat_bitmap[prevcl/32],prevcl%32);
/*if the next cluster is free or reversed ,just clear the existing cluster chain ,let this free or reversed cluster alone*/
ret |= tryclear(boot,fat,cl,&prevcl);
break;
}
/*out of range*/
if(nextclus < CLUST_FIRST ||(( nextclus >= boot->NumClusters) && (nextclus < (CLUST_EOFS & boot->ClustMask)))){
fsck_warn("Clusters chain starting at %u ends with cluster out of range (%u) \n",cl,nextclus);
SET_BIT(fat_bitmap[prevcl/32],prevcl%32);
ret |= tryclear(boot,fat,cl,&prevcl);
break;
}
if((nextclus >= CLUST_FIRST && nextclus < boot->NumClusters)&& BIT(fat_bitmap[nextclus/32],nextclus%32)){
/*
*it is interesting,because 0x3->0x34->0x35->EOF,then you find 0x100->0x3.
*it is right here,must merge them
*/
tofind.head = nextclus;
nextcl_fat = RB_FIND(FSCK_MSDOS_CACHE,&rb_root,&tofind);
/*if nextcl_fat == fat ,unfortunately ,it is a cluster loop,such as 0x2->0x3->0x4->0x2*/
if(nextcl_fat && (nextcl_fat != fat)){
if(len == 1){
/*the first one ,you should malloc both fatEntry and fatcache*/
fat = New_fatentry();
if(!fat)
return FSFATAL;
fat->head = prevcl;
fat->length = 1;
/*
*i was puzzled whether check the pointer insert here
*if some error,there is a exsting fatentry in rb tree.NOT check maybe a good choice
*/
insert = RB_INSERT(FSCK_MSDOS_CACHE,&rb_root,fat);
if(insert){
fsck_err("%s:fatentry(head:0x%x) exist\n",__func__,fat->head);
return FSFATAL;
}
cache = New_fatcache();
if(!cache)
return FSFATAL;
cache->head = prevcl;
cache->length = 1;
err = add_fatcache_To_ClusterChain(fat,cache);
if(err){
fsck_err("add_fatcache_To_ClusterChain ,err = %d \n",err);
return FSFATAL;
}
/*merge nextcl_fat chain to new one*/
cache->next = nextcl_fat->child;
fat->length += nextcl_fat->length;
}else{
/*
*we use fat directly here,after handling a cluster chain ,must set fat = NULL,
*otherwise ,the fat is prev cluster chain
*/
add_fatcache_Totail(fat,nextcl_fat->child);
fat->length += nextcl_fat->length;
}
nextcl_fat->child = NULL;
/*now delete nextcl_fat entry ,because have merge its child to fat*/
remove = RB_REMOVE(FSCK_MSDOS_CACHE,&rb_root,nextcl_fat);
free(nextcl_fat);
SET_BIT(fat_bitmap[prevcl/32],prevcl%32);
break;
}
/*
*it is very complex here,if a cluster has been handled ,but it is not a head of a cluster chain,there are some cases:
*case 1:Due to some error ,this cluster has been removed from rb tree by tryclear()
*case 2:clsuter chains linked
*case 3:cluster loop
*whatever ,i think tryclear() is a simplest solution
*/
fsck_err("Cluster chian is wrong\n");
Dump_fatentry(fat);
Dump_fatentry(nextcl_fat);
/*sometimes ,fat == NULL here,it means this cluster chain haven't be insert to rb tree,ok,do nothing here*/
if(!fat)
break;
if(ask(1,"Clear chain starting at %u",nextclus)){
/*
*compare with orginal code,i delete some codes here
*because i handle fat chain by chain here,
*it never appear situation that three or more cluster chains linked
*/
ret |= tryclear(boot,fat,cl,&prevcl);
break;
}
}
/*it is a legal cluster ,add it*/
SET_BIT(fat_bitmap[prevcl/32],prevcl%32);
if(len == 1){
/*TODO:
*that is the first cluster of this legal chain
*it is special ,normally, we just add nextcluster to chain
*but if it is first one ,we must add both two.
*/
fat = New_fatentry();
if(!fat){
fsck_err("No space \n");
return FSFATAL;
}
fat->head = cl;
insert = RB_INSERT(FSCK_MSDOS_CACHE,&rb_root,fat);
if(insert){
fsck_err("%s:fatentry(head:0x%x) exist\n",__func__,fat->head);
return FSFATAL;
}
cache = New_fatcache();
if(!cache){
fsck_err("No space \n");
return FSFATAL;
}
cache->head = prevcl;
cache->length = 1;
err = add_fatcache_To_ClusterChain(fat,cache);
if(err){
fsck_err("add_fatcache_To_ClusterChain ,err = %d \n",err);
}
if(nextclus >= (CLUST_EOFS & boot->ClustMask) && nextclus <= (CLUST_EOF & boot->ClustMask)){
break;
}
if(prevcl + 1 == nextclus){
cache->length += 1;
fat->length += 1;
prevcl = nextclus;
continue;
}else{
cache = New_fatcache();
if(!cache){
fsck_err("No space\n");
return FSFATAL;
}
cache->head = nextclus;
cache->length = 1;
err = add_fatcache_To_ClusterChain(fat,cache);
if(err){
fsck_err("add_fatcache_To_ClusterChain ,err = %d \n",err);
}
}
}else{
if(nextclus >= (CLUST_EOFS & boot->ClustMask) && nextclus <= (CLUST_EOF & boot->ClustMask)){
break;
}
if( prevcl + 1 == nextclus){
/*if it is continuous ,just modify the length*/
cache->length += 1;
fat->length += 1;
}else{
cache = New_fatcache();
if(!cache){
fsck_err("No Space\n");
return FSFATAL;
}
cache->head = nextclus;
cache->length = 1;
err = add_fatcache_To_ClusterChain(fat,cache);
if(err){
fsck_err("add_fatcache_To_ClusterChain ,err = %d \n",err);
}
}
}
prevcl = nextclus;
}
/*set fat = NULL,otherwise this fat pointer will impact the next process*/
fat = NULL;
}
#if 0
fsck_info("Dump cluster chains\n");
RB_FOREACH(fat, FSCK_MSDOS_CACHE,&rb_root){
fsck_info("head:0x%x:length:0x%x\n",fat->head,fat->length);
}
#endif
free(fat_bitmap);
return ret;
}
/*
* Get type of reserved cluster
*/
char *
rsrvdcltype(cl_t cl)
{
if (cl == CLUST_FREE)
return "free";
if (cl < CLUST_BAD)
return "reserved";
if (cl > CLUST_BAD)
return "as EOF";
return "bad";
}
/*
*if *res = 1,that means *cp1 = *cp2
*if *res = 0 ,means *cp2 = *cp1;
*/
static int
clustdiffer(cl_t cl, cl_t *cp1, cl_t *cp2, int fatnum, int *res)
{
fsck_debug("clustdiff:%u : %u \n",*cp1,*cp2);
if (*cp1 == CLUST_FREE || *cp1 >= CLUST_RSRVD) {
if (*cp2 == CLUST_FREE || *cp2 >= CLUST_RSRVD) {
if ((*cp1 != CLUST_FREE && *cp1 < CLUST_BAD
&& *cp2 != CLUST_FREE && *cp2 < CLUST_BAD)
|| (*cp1 > CLUST_BAD && *cp2 > CLUST_BAD)) {
pwarn("Cluster %u is marked %s with different indicators\n",
cl, rsrvdcltype(*cp1));
if (ask(1, "Fix")) {
*res = 0;
return FSFATMOD;
}
return FSFATAL;
}
pwarn("Cluster %u is marked %s in FAT 0, %s in FAT %d\n",
cl, rsrvdcltype(*cp1), rsrvdcltype(*cp2), fatnum);
if (ask(1, "Use FAT 0's entry")) {
*res = 0;
return FSFATMOD;
}
if (ask(1, "Use FAT %d's entry", fatnum)) {
*res = 1;
return FSFATMOD;
}
return FSFATAL;
}
pwarn("Cluster %u is marked %s in FAT 0, but continues with cluster %u in FAT %d\n",
cl, rsrvdcltype(*cp1), *cp2, fatnum);
if (ask(1, "Use continuation from FAT %d", fatnum)) {
*res = 1;
return FSFATMOD;
}
if (ask(1, "Use mark from FAT 0")) {
*res = 0;
return FSFATMOD;
}
return FSFATAL;
}
if (*cp2 == CLUST_FREE || *cp2 >= CLUST_RSRVD) {
pwarn("Cluster %u continues with cluster %u in FAT 0, but is marked %s in FAT %d\n",
cl, *cp1, rsrvdcltype(*cp2), fatnum);
if (ask(1, "Use continuation from FAT 0")) {
*res = 0;
return FSFATMOD;
}
if (ask(1, "Use mark from FAT %d", fatnum)) {
*res = 1;
return FSFATMOD;
}
return FSERROR;
}
pwarn("Cluster %u continues with cluster %u in FAT 0, but with cluster %u in FAT %d\n",
cl, *cp1, *cp2, fatnum);
if (ask(1, "Use continuation from FAT 0")) {
*res = 0;
return FSFATMOD;
}
if (ask(1, "Use continuation from FAT %d", fatnum)) {
*res = 1;
return FSFATMOD;
}
return FSERROR;
}
/*
* Compare two FAT copies in memory. Resolve any conflicts and merge them
* into the first one.
*/
int
comparefat(struct bootblock *boot, u_char*first, u_char *second, int fatnum)
{
cl_t cl;
u_char *sp,*fp,*wp;
int ret = FSOK,res = 0;
cl_t first_cl,second_cl,w_cl;
fsck_info("Begin to compare FAT\n");
for (cl = CLUST_FIRST; cl < boot->NumClusters; cl++){
switch(boot->ClustMask){
case CLUST32_MASK:
fp = first + 4*cl;
sp = second + 4*cl;
first_cl = (fp[0] + (fp[1]<<8) + (fp[2]<<16) + (fp[3]<<24)) & boot->ClustMask;
second_cl = (sp[0] + (sp[1]<<8) + (sp[2]<<16) + (sp[3]<<24)) & boot->ClustMask;
break;
case CLUST16_MASK:
fp = first + 2*cl;
sp = second + 2*cl;
first_cl = (fp[0] + (fp[1] << 8)) & boot->ClustMask;
second_cl = (sp[0] + (sp[1] << 8)) & boot->ClustMask;
break;
default:
fp = first + 3*(cl/2);
sp = second + 3*(cl/2);
if(cl & 0x1){
first_cl = ((fp[1]>>4) + (fp[2]<<4)) & 0x0fff;
second_cl = ((sp[1]>>4) + (sp[2]<<4)) & 0x0fff;
}else{
first_cl = (fp[0] + (fp[1] << 8)) & 0x0fff;
second_cl = (sp[0] + (sp[1] << 8)) & 0x0fff;
}
break;
}
if(first_cl == second_cl)
continue;
fsck_warn("%u is not same(%u ; %u)\n",cl,first_cl,second_cl);
ret |= clustdiffer(cl, &first_cl,&second_cl, fatnum,&res);
if(res){
wp = fp;
w_cl = second_cl;
}else{
wp = sp;
w_cl = first_cl;
}
/* fisrt_cl = second_cl */
switch(boot->ClustMask){
case CLUST32_MASK:
*wp++ = (u_char)w_cl;
*wp++ = (u_char)(w_cl >>8);
*wp++ = (u_char)(w_cl >> 16);
*wp &= 0xf0;
*wp |= (w_cl >>24) &0x0f;
break;
case CLUST16_MASK:
*wp++ = (u_char)w_cl;
*wp = (u_char)(w_cl >> 8);
break;
default:
if(cl & 0x1){
/* wp[1] ,wp[2]*/
wp++;
*wp++ |= (u_char)((w_cl << 4) & 0xf0);
*wp = (u_char)(w_cl >> 4);
}else{
/* wp[0] ,wp[1]*/
*wp++ = (u_char)w_cl;
*wp |= (u_char)((w_cl >> 8) & 0x0f);
}
break;
}
}
return ret;
}
void
clearchain(struct bootblock *boot,struct cluster_chain_descriptor *fat, cl_t head)
{
struct fatcache * curr,*next;
struct fragment *frag, *insert;
fsck_debug("%s:fat:%p , head(%d) ,length(%d)\n",__func__,fat,fat->head,fat->length);
assert(fat);
if(fat->head != head)
return;
/*re-calc free blocks*/
boot->NumFree += fat->length;
/*move to free tree for writefat()*/
curr = fat->child;
while(curr){
next = curr->next;
frag = New_fragment();
if(!frag){
fsck_warn("%s: No space left\n",__func__);
goto free;
}
frag->head = curr->head;
frag->length = curr->length;
insert = RB_INSERT(FSCK_MSDOS_FRAGMENT,&rb_free_root,frag);
if(insert)
fsck_warn("%s:fragment(head:0x%x) exist\n",__func__,frag->head);
free:
free(curr);
curr = next;
}
/*must remove from rb tree before free*/
RB_REMOVE(FSCK_MSDOS_CACHE,&rb_root,fat);
free(fat);
}
int
tryclear(struct bootblock* boot, struct cluster_chain_descriptor *fat, cl_t head, cl_t *trunc)
{
fsck_debug("fat:%p ,head :%d ,trunc :%d \n",fat,head,*trunc);
if(!fat || !trunc){
pwarn("%s :null pointer\n",__func__);
return FSERROR;
}
if (ask(1, "Clear chain starting at %u", head)) {
clearchain(boot,fat, head);
return FSFATMOD;
} else if (ask(1, "Truncate")) {
Trunc(boot,fat,*trunc);
return FSFATMOD;
} else
return FSERROR;
}
/*
* Write out FATs encoding them from the internal format
*/
int
writefat(int fs, struct bootblock *boot, int correct_fat)
{
u_char *buffer, *p;
cl_t cl;
unsigned int i;
u_int32_t fatsz;
off_t off;
int ret = FSOK;
struct cluster_chain_descriptor *fat;
struct fatcache* cache,*next_cache;
struct fragment *frag;
fsck_debug("begin to writefat \n");
buffer = malloc(fatsz = boot->FATsecs * boot->BytesPerSec);
if (buffer == NULL) {
perror("No space for FAT");
return FSFATAL;
}
memset(buffer, 0, fatsz);
p = buffer;
if (correct_fat) {
*p++ = (u_char)boot->Media;
*p++ = 0xff;
*p++ = 0xff;
switch (boot->ClustMask) {
case CLUST16_MASK:
*p++ = 0xff;
break;
case CLUST32_MASK:
*p++ = 0x0f;
*p++ = 0xff;
*p++ = 0xff;
*p++ = 0xff;
*p++ = 0x0f;
break;
}
} else {
/* use same FAT signature as the old FAT has */
int count;
u_char *old_fat;
switch (boot->ClustMask) {
case CLUST32_MASK:
count = 8;
break;
case CLUST16_MASK:
count = 4;
break;
default:
count = 3;
break;
}
if (!_readfat(fs, boot, boot->ValidFat >= 0 ? boot->ValidFat :0,
&old_fat)) {
free(buffer);
return FSFATAL;
}
memcpy(p, old_fat, count);
free(old_fat);
p += count;
}
fsck_info("begin to write FAT\n");
fat = RB_MIN(FSCK_MSDOS_CACHE,&rb_root);
if(!fat){
fsck_info("%s:rb tree is empty\n",__func__);
return FSFATAL;
}
fsck_info("write valid cluster chain\n");
while(fat){
cache = fat->child;
while(cache){
cl = cache->head;
for( i = 0 ; i < (cache->length - 1);i++)
SetNextClusToFAT(boot,buffer,cl+i ,cl+i+1);
next_cache = cache->next;
if(next_cache)
SetNextClusToFAT(boot,buffer,cl+cache->length -1,next_cache->head);
else
SetNextClusToFAT(boot,buffer,cl+cache->length -1,CLUST_EOF);
cache = next_cache;
}
fat = RB_NEXT(FSCK_MSDOS_CACHE,0,fat);
}
/*the FreeNumber may be not correct*/
fsck_info("write free cluster\n");
RB_FOREACH(frag, FSCK_MSDOS_FRAGMENT,&rb_free_root){
cl = frag->head;
for(i = 0 ; i < frag->length ;i++)
SetNextClusToFAT(boot,buffer,cl+i ,CLUST_FREE);
}
fsck_info("write bad cluster\n");
RB_FOREACH(frag, FSCK_MSDOS_FRAGMENT,&rb_bad_root){
cl = frag->head;
for(i = 0 ; i < frag->length ;i++)
SetNextClusToFAT(boot,buffer,cl+i ,CLUST_BAD);
}
fsck_debug("write FATs\n");
for (i = 0; i < boot->FATs; i++) {
fsck_debug("write FAT copy %d \n",i);
off = boot->ResSectors + i * boot->FATsecs;
off *= boot->BytesPerSec;
if (lseek(fs, off, SEEK_SET) != off
|| write(fs, buffer, fatsz) != fatsz) {
perror("Unable to write FAT");
ret = FSFATAL; /* Return immediately? XXX */
}
}
free(buffer);
return ret;
}
/*
* Check a complete in-memory FAT for lost cluster chains
*/
int
checklost(int dosfs, struct bootblock *boot)
{
int mod = FSOK;
int ret;
struct cluster_chain_descriptor *fat, *next;
fat = RB_MIN(FSCK_MSDOS_CACHE,&rb_root);
if(!fat){
fsck_info("%s:rb_root tree is empty\n",__func__);
//After format FAT16,nothing left
if(boot->ClustMask & CLUST16_MASK)
return FSOK;
else
return FSFATAL;
}
while(fat){
if(fat->flag & FAT_USED){
fat = RB_NEXT(FSCK_MSDOS_CACHE,0,fat);
continue;
}
fsck_info("Lost cluster chain at head %u ,%d Cluster(s) lost\n",fat->head, fat->length);
mod |= ret = reconnect(dosfs, boot,fat, fat->head);
if (mod & FSFATAL) {
/* If the reconnect failed, then just clear the chain */
pwarn("Error reconnecting chain - clearing\n");
mod &= ~FSFATAL;
next = RB_NEXT(FSCK_MSDOS_CACHE,0,fat);
clearchain(boot,fat,fat->head);
mod |= FSFATMOD;
fat = next;
continue;
}
if (ret == FSERROR && ask(1, "Clear")) {
next = RB_NEXT(FSCK_MSDOS_CACHE,0,fat);
clearchain(boot, fat, fat->head);
mod |= FSFATMOD;
fat = next;
continue;
}
fat = RB_NEXT(FSCK_MSDOS_CACHE,0,fat);
}
finishlf();
fsck_debug("Verify Filesystem information\n");
//verify the fs infomation
if (boot->FSInfo){
ret = 0;
if (boot->FSFree != boot->NumFree) {
pwarn("Free space in FSInfo block (%d) not correct (%d)\n",
boot->FSFree, boot->NumFree);
if (ask(1, "Fix")) {
boot->FSFree = boot->NumFree;
ret = 1;
}
}
if (boot->NumFree) {
if ((boot->FSNext >= boot->NumClusters)) {
pwarn("Next free cluster in FSInfo block out of range\n");
if (ask(1, "Fix")){
boot->FSNext = firstfreecl;
ret = 1;
}
}
}
if (boot->FSNext > boot->NumClusters || boot->FSNext < CLUST_FIRST) {
pwarn("FSNext block (%d) not correct NumClusters (%d)\n",
boot->FSNext, boot->NumClusters);
boot->FSNext=CLUST_FIRST; // boot->FSNext can have -1 value.
}
if (ret)
mod |= writefsinfo(dosfs, boot);
}
return mod;
}