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/* ----------------------------------------------------------------------- *
*
* Copyright 1998-2011 H. Peter Anvin - All Rights Reserved
* Copyright 2009-2011 Intel Corporation; author H. Peter Anvin
* Copyright 2011 Paulo Alcantara <pcacjr@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
* Boston MA 02111-1307, USA; either version 2 of the License, or
* (at your option) any later version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* fs.c - Generic sanity check for FAT/NTFS-based installers
*/
#define _XOPEN_SOURCE 500 /* Required on glibc 2.x */
#define _BSD_SOURCE
#include <stdio.h>
#include <inttypes.h>
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
#include "syslinux.h"
#include "syslxint.h"
#include "syslxcom.h"
#include "syslxfs.h"
void syslinux_make_bootsect(void *bs, int fs_type)
{
if (fs_type == VFAT) {
struct fat_boot_sector *bootsect = bs;
const struct fat_boot_sector *sbs =
(const struct fat_boot_sector *)boot_sector;
memcpy(&bootsect->FAT_bsHead, &sbs->FAT_bsHead, FAT_bsHeadLen);
memcpy(&bootsect->FAT_bsCode, &sbs->FAT_bsCode, FAT_bsCodeLen);
} else if (fs_type == NTFS) {
struct ntfs_boot_sector *bootsect = bs;
const struct ntfs_boot_sector *sbs =
(const struct ntfs_boot_sector *)boot_sector;
memcpy(&bootsect->NTFS_bsHead, &sbs->NTFS_bsHead, NTFS_bsHeadLen);
memcpy(&bootsect->NTFS_bsCode, &sbs->NTFS_bsCode, NTFS_bsCodeLen);
}
}
static const char *check_fat_bootsect(const void *bs, int *fs_type)
{
int sectorsize;
const struct fat_boot_sector *sectbuf = bs;
long long sectors, fatsectors, dsectors;
long long clusters;
int rootdirents, clustersize;
sectorsize = get_16(§buf->bsBytesPerSec);
clustersize = get_8(§buf->bsSecPerClust);
if (clustersize == 0 || (clustersize & (clustersize - 1)))
return "impossible cluster size on an FAT volume";
sectors = get_16(§buf->bsSectors);
sectors = sectors ? sectors : get_32(§buf->bsHugeSectors);
dsectors = sectors - get_16(§buf->bsResSectors);
fatsectors = get_16(§buf->bsFATsecs);
fatsectors = fatsectors ? fatsectors : get_32(§buf->bs32.FATSz32);
fatsectors *= get_8(§buf->bsFATs);
dsectors -= fatsectors;
rootdirents = get_16(§buf->bsRootDirEnts);
dsectors -= (rootdirents + sectorsize / 32 - 1) / sectorsize;
if (dsectors < 0)
return "negative number of data sectors on an FAT volume";
clusters = dsectors / clustersize;
fatsectors = get_16(§buf->bsFATsecs);
fatsectors = fatsectors ? fatsectors : get_32(§buf->bs32.FATSz32);
fatsectors *= get_8(§buf->bsFATs);
if (!fatsectors)
return "zero FAT sectors";
if (clusters < 0xFFF5) {
/* FAT12 or FAT16 */
if (!get_16(§buf->bsFATsecs))
return "zero FAT sectors (FAT12/16)";
if (get_8(§buf->bs16.BootSignature) == 0x29) {
if (!memcmp(§buf->bs16.FileSysType, "FAT12 ", 8)) {
if (clusters >= 0xFF5)
return "more than 4084 clusters but claims FAT12";
} else if (!memcmp(§buf->bs16.FileSysType, "FAT16 ", 8)) {
if (clusters < 0xFF5)
return "less than 4084 clusters but claims FAT16";
} else if (!memcmp(§buf->bs16.FileSysType, "FAT32 ", 8)) {
return "less than 65525 clusters but claims FAT32";
} else if (memcmp(§buf->bs16.FileSysType, "FAT ", 8)) {
static char fserr[] = "filesystem type \"????????\" not "
"supported";
memcpy(fserr + 17, §buf->bs16.FileSysType, 8);
return fserr;
}
}
} else if (clusters < 0x0FFFFFF5) {
/*
* FAT32...
*
* Moving the FileSysType and BootSignature was a lovely stroke
* of M$ idiocy...
*/
if (get_8(§buf->bs32.BootSignature) != 0x29 ||
memcmp(§buf->bs32.FileSysType, "FAT32 ", 8))
return "missing FAT32 signature";
} else {
return "impossibly large number of clusters on an FAT volume";
}
if (fs_type)
*fs_type = VFAT;
return NULL;
}
static const char *check_ntfs_bootsect(const void *bs, int *fs_type)
{
const struct ntfs_boot_sector *sectbuf = bs;
if (memcmp(§buf->bsOemName, "NTFS ", 8) &&
memcmp(§buf->bsOemName, "MSWIN4.0", 8) &&
memcmp(§buf->bsOemName, "MSWIN4.1", 8))
return "unknown OEM name but claims NTFS";
if (fs_type)
*fs_type = NTFS;
return NULL;
}
const char *syslinux_check_bootsect(const void *bs, int *fs_type)
{
uint8_t media_sig;
int sectorsize;
const struct fat_boot_sector *sectbuf = bs;
const char *retval;
media_sig = get_8(§buf->bsMedia);
/* Must be 0xF0 or 0xF8-0xFF for FAT/NTFS volumes */
if (media_sig != 0xF0 && media_sig < 0xF8)
return "invalid media signature (not an FAT/NTFS volume?)";
sectorsize = get_16(§buf->bsBytesPerSec);
if (sectorsize == SECTOR_SIZE) ; /* ok */
else if (sectorsize >= 512 && sectorsize <= 4096 &&
(sectorsize & (sectorsize - 1)) == 0)
return "unsupported sectors size";
else
return "impossible sector size";
if (ntfs_check_zero_fields((struct ntfs_boot_sector *)bs))
retval = check_ntfs_bootsect(bs, fs_type);
else
retval = check_fat_bootsect(bs, fs_type);
return retval;
}
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