#include <sys/cdefs.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include "ext.h"
#include "fsutil.h"
int
readboot(dosfs, boot)
int dosfs;
struct bootblock *boot;
{
u_char block[MAX_SECTOR_SIZE];
u_char fsinfo[MAX_SECTOR_SIZE];
int ret = FSOK;
if (read(dosfs, block, MAX_SECTOR_SIZE) != MAX_SECTOR_SIZE) {
perr("could not read boot block");
return FSFATAL;
}
if (block[0] != 0xE9 && (block[0] != 0xEB || block[2] != 0x90))
{
pfatal("Invalid BS_jmpBoot in boot block: %02x%02x%02x\n", block[0], block[1], block[2]);
return FSFATAL;
}
memset(boot, 0, sizeof *boot);
boot->ValidFat = -1;
boot->BytesPerSec = block[11] + (block[12] << 8);
boot->SecPerClust = block[13];
boot->ResSectors = block[14] + (block[15] << 8);
boot->FATs = block[16];
boot->RootDirEnts = block[17] + (block[18] << 8);
boot->Sectors = block[19] + (block[20] << 8);
boot->Media = block[21];
boot->FATsmall = block[22] + (block[23] << 8);
boot->SecPerTrack = block[24] + (block[25] << 8);
boot->Heads = block[26] + (block[27] << 8);
boot->HiddenSecs = block[28] + (block[29] << 8) + (block[30] << 16) + (block[31] << 24);
boot->HugeSectors = block[32] + (block[33] << 8) + (block[34] << 16) + (block[35] << 24);
boot->FATsecs = boot->FATsmall;
if (!boot->RootDirEnts)
boot->flags |= FAT32;
if (boot->flags & FAT32) {
boot->FATsecs = block[36] + (block[37] << 8)
+ (block[38] << 16) + (block[39] << 24);
if (block[40] & 0x80)
boot->ValidFat = block[40] & 0x0f;
if (block[42] || block[43]) {
pfatal("Unknown filesystem version: %x.%x\n",
block[43], block[42]);
return FSFATAL;
}
boot->RootCl = block[44] + (block[45] << 8)
+ (block[46] << 16) + (block[47] << 24);
boot->FSInfo = block[48] + (block[49] << 8);
boot->Backup = block[50] + (block[51] << 8);
if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
!= boot->FSInfo * boot->BytesPerSec
|| read(dosfs, fsinfo, boot->BytesPerSec)
!= boot->BytesPerSec) {
perr("could not read fsinfo block");
return FSFATAL;
}
if (memcmp(fsinfo, "RRaA", 4)
|| memcmp(fsinfo + 0x1e4, "rrAa", 4)
|| fsinfo[0x1fc]
|| fsinfo[0x1fd]
|| fsinfo[0x1fe] != 0x55
|| fsinfo[0x1ff] != 0xaa) {
pwarn("Invalid signature in fsinfo block");
if (ask(0, "fix")) {
memcpy(fsinfo, "RRaA", 4);
memcpy(fsinfo + 0x1e4, "rrAa", 4);
fsinfo[0x1fc] = fsinfo[0x1fd] = 0;
fsinfo[0x1fe] = 0x55;
fsinfo[0x1ff] = 0xaa;
fsinfo[0x3fc] = fsinfo[0x3fd] = 0;
fsinfo[0x3fe] = 0x55;
fsinfo[0x3ff] = 0xaa;
if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
!= boot->FSInfo * boot->BytesPerSec
|| write(dosfs, fsinfo, boot->BytesPerSec)
!= boot->BytesPerSec) {
perr("Unable to write FSInfo");
return FSFATAL;
}
ret = FSBOOTMOD;
} else
boot->FSInfo = 0;
}
if (boot->FSInfo) {
boot->FSFree = fsinfo[0x1e8] + (fsinfo[0x1e9] << 8)
+ (fsinfo[0x1ea] << 16)
+ (fsinfo[0x1eb] << 24);
boot->FSNext = fsinfo[0x1ec] + (fsinfo[0x1ed] << 8)
+ (fsinfo[0x1ee] << 16)
+ (fsinfo[0x1ef] << 24);
}
}
boot->ClusterOffset = (boot->RootDirEnts * 32 + boot->BytesPerSec - 1)
/ boot->BytesPerSec
+ boot->ResSectors
+ boot->FATs * boot->FATsecs
- CLUST_FIRST * boot->SecPerClust;
if (boot->BytesPerSec % DOSBOOTBLOCKSIZE != 0) {
pfatal("Invalid sector size: %u\n", boot->BytesPerSec);
return FSFATAL;
}
if (boot->SecPerClust == 0) {
pfatal("Invalid cluster size: %u\n", boot->SecPerClust);
return FSFATAL;
}
if (boot->Sectors) {
boot->HugeSectors = 0;
boot->NumSectors = boot->Sectors;
} else
boot->NumSectors = boot->HugeSectors;
boot->NumClusters = (boot->NumSectors - boot->ClusterOffset) / boot->SecPerClust;
if (boot->flags&FAT32)
boot->ClustMask = CLUST32_MASK;
else if (boot->NumClusters < (4085+2))
boot->ClustMask = CLUST12_MASK;
else if (boot->NumClusters < (65526+2))
boot->ClustMask = CLUST16_MASK;
else {
pfatal("Filesystem too big (%u clusters) for non-FAT32 partition\n",
boot->NumClusters-2);
return FSFATAL;
}
switch (boot->ClustMask) {
case CLUST32_MASK:
boot->NumFatEntries = (boot->FATsecs * boot->BytesPerSec) / 4;
break;
case CLUST16_MASK:
boot->NumFatEntries = (boot->FATsecs * boot->BytesPerSec) / 2;
break;
default:
boot->NumFatEntries = (boot->FATsecs * boot->BytesPerSec * 2) / 3;
break;
}
if (boot->NumFatEntries < boot->NumClusters) {
pwarn("FAT size too small, %u entries won't fit into %u sectors\n",
boot->NumClusters, boot->FATsecs);
boot->NumClusters = boot->NumFatEntries;
if (ask(0, "Fix total sectors")) {
boot->NumSectors = (boot->NumClusters * boot->SecPerClust) + boot->ClusterOffset;
if (boot->Sectors) {
boot->Sectors = boot->NumSectors;
block[19] = boot->NumSectors & 0xFF;
block[20] = (boot->NumSectors >> 8) & 0xFF;
} else {
boot->HugeSectors = boot->NumSectors;
block[32] = boot->NumSectors & 0xFF;
block[33] = (boot->NumSectors >> 8) & 0xFF;
block[34] = (boot->NumSectors >> 16) & 0xFF;
block[35] = (boot->NumSectors >> 24) & 0xFF;
}
if (lseek(dosfs, 0, SEEK_SET) != 0 ||
write(dosfs, block, boot->BytesPerSec) != boot->BytesPerSec)
{
perr("could not write boot sector");
return FSFATAL;
}
ret |= FSBOOTMOD;
} else {
pwarn("Continuing, assuming %u clusters\n", boot->NumFatEntries-2);
}
}
boot->ClusterSize = boot->BytesPerSec * boot->SecPerClust;
boot->NumFree = 0;
return ret;
}
int
writefsinfo(dosfs, boot)
int dosfs;
struct bootblock *boot;
{
u_char fsinfo[MAX_SECTOR_SIZE];
if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
!= boot->FSInfo * boot->BytesPerSec
|| read(dosfs, fsinfo, boot->BytesPerSec) != boot->BytesPerSec) {
perr("could not read fsinfo block");
return FSFATAL;
}
fsinfo[0x1e8] = (u_char)boot->FSFree;
fsinfo[0x1e9] = (u_char)(boot->FSFree >> 8);
fsinfo[0x1ea] = (u_char)(boot->FSFree >> 16);
fsinfo[0x1eb] = (u_char)(boot->FSFree >> 24);
fsinfo[0x1ec] = (u_char)boot->FSNext;
fsinfo[0x1ed] = (u_char)(boot->FSNext >> 8);
fsinfo[0x1ee] = (u_char)(boot->FSNext >> 16);
fsinfo[0x1ef] = (u_char)(boot->FSNext >> 24);
if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET)
!= boot->FSInfo * boot->BytesPerSec
|| write(dosfs, fsinfo, boot->BytesPerSec)
!= boot->BytesPerSec) {
perr("Unable to write FSInfo");
return FSFATAL;
}
return 0;
}