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Handle MSDOS file systems properly. Before the change file systems

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created on Windows XP (and others maybe) were not detected.
We detected only those created with newfs_msdos(8).

Submitted by:		Tobias Reifenberger <treif@mayn.de>
style(9)ified by:	pjd
This commit is contained in:
Pawel Jakub Dawidek 2006-08-12 15:34:15 +00:00
parent d88fe2bfc7
commit 1894472106
2 changed files with 301 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

201
sys/geom/label/g_label_msdosfs.c
View File

@ -1,5 +1,6 @@
/*-
* Copyright (c) 2004 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* Copyright (c) 2006 Tobias Reifenberger
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@ -34,57 +35,171 @@ __FBSDID("$FreeBSD$");
#include <geom/geom.h>
#include <geom/label/g_label.h>
#include <geom/label/g_label_msdosfs.h>
#define G_LABEL_MSDOSFS_DIR "msdosfs"
#define FAT12 "FAT12 "
#define FAT16 "FAT16 "
#define FAT32 "FAT32 "
#define VOLUME_LEN 11
#define NO_NAME "NO NAME "
#define LABEL_NO_NAME "NO NAME "
static void
g_label_msdosfs_taste(struct g_consumer *cp, char *label, size_t size)
{
struct g_provider *pp;
char *sector, *volume;
int i;
FAT_BSBPB *pfat_bsbpb;
FAT32_BSBPB *pfat32_bsbpb;
FAT_DES *pfat_entry;
uint8_t *sector0, *sector;
uint32_t i;
g_topology_assert_not();
pp = cp->provider;
label[0] = '\0';
sector = (char *)g_read_data(cp, 0, pp->sectorsize, NULL);
if (sector == NULL)
return;
if (strncmp(sector + 0x36, FAT12, strlen(FAT12)) == 0) {
G_LABEL_DEBUG(1, "MSDOS (FAT12) file system detected on %s.",
pp->name);
volume = sector + 0x2b;
} else if (strncmp(sector + 0x36, FAT16, strlen(FAT16)) == 0) {
G_LABEL_DEBUG(1, "MSDOS (FAT16) file system detected on %s.",
pp->name);
volume = sector + 0x2b;
} else if (strncmp(sector + 0x52, FAT32, strlen(FAT32)) == 0) {
G_LABEL_DEBUG(1, "MSDOS (FAT32) file system detected on %s.",
pp->name);
volume = sector + 0x47;
} else {
g_free(sector);
return;
}
if (strncmp(volume, NO_NAME, VOLUME_LEN) == 0) {
g_free(sector);
return;
}
if (volume[0] == '\0') {
g_free(sector);
return;
}
sector0 = NULL;
sector = NULL;
bzero(label, size);
strlcpy(label, volume, MIN(size, VOLUME_LEN));
g_free(sector);
/* Check if the sector size of the medium is a valid FAT sector size. */
switch(pp->sectorsize) {
case 512:
case 1024:
case 2048:
case 4096:
break;
default:
G_LABEL_DEBUG(1, "MSDOSFS: %s: sector size %d not compatible.",
pp->name, pp->sectorsize);
return;
}
/* Load 1st sector with boot sector and boot parameter block. */
sector0 = (uint8_t *)g_read_data(cp, 0, pp->sectorsize, NULL);
if (sector0 == NULL)
return;
/* Check for the FAT boot sector signature. */
if (sector0[510] != 0x55 || sector0[511] != 0xaa) {
G_LABEL_DEBUG(1, "MSDOSFS: %s: no FAT signature found.",
pp->name);
goto error;
}
/*
* Test if this is really a FAT volume and determine the FAT type.
*/
pfat_bsbpb = (FAT_BSBPB *)sector0;
pfat32_bsbpb = (FAT32_BSBPB *)sector0;
if (UINT16BYTES(pfat_bsbpb->BPB_FATSz16) != 0) {
/*
* If the BPB_FATSz16 field is not zero and the string "FAT" is
* at the right place, this should be a FAT12 or FAT16 volume.
*/
if (strncmp(pfat_bsbpb->BS_FilSysType, "FAT", 3) != 0) {
G_LABEL_DEBUG(1,
"MSDOSFS: %s: FAT12/16 volume not valid.",
pp->name);
goto error;
}
G_LABEL_DEBUG(1, "MSDOSFS: %s: FAT12/FAT16 volume detected.",
pp->name);
/* A volume with no name should have "NO NAME " as label. */
if (strncmp(pfat_bsbpb->BS_VolLab, LABEL_NO_NAME,
sizeof(pfat_bsbpb->BS_VolLab)) == 0) {
G_LABEL_DEBUG(1,
"MSDOSFS: %s: FAT12/16 volume has no name.",
pp->name);
goto error;
}
strlcpy(label, pfat_bsbpb->BS_VolLab,
MIN(size, sizeof(pfat_bsbpb->BS_VolLab) + 1));
} else if (UINT32BYTES(pfat32_bsbpb->BPB_FATSz32) != 0) {
uint32_t fat_FirstDataSector, fat_BytesPerSector, offset;
/*
* If the BPB_FATSz32 field is not zero and the string "FAT" is
* at the right place, this should be a FAT32 volume.
*/
if (strncmp(pfat32_bsbpb->BS_FilSysType, "FAT", 3) != 0) {
G_LABEL_DEBUG(1, "MSDOSFS: %s: FAT32 volume not valid.",
pp->name);
goto error;
}
G_LABEL_DEBUG(1, "MSDOSFS: %s: FAT32 volume detected.",
pp->name);
/*
* If the volume label is not "NO NAME " we're done.
*/
if (strncmp(pfat32_bsbpb->BS_VolLab, LABEL_NO_NAME,
sizeof(pfat32_bsbpb->BS_VolLab)) != 0) {
strlcpy(label, pfat32_bsbpb->BS_VolLab,
MIN(size, sizeof(pfat32_bsbpb->BS_VolLab) + 1));
goto endofchecks;
}
/*
* If the volume label "NO NAME " is in the boot sector, the
* label of FAT32 volumes may be stored as a special entry in
* the root directory.
*/
fat_FirstDataSector =
UINT16BYTES(pfat32_bsbpb->BPB_RsvdSecCnt) +
(pfat32_bsbpb->BPB_NumFATs *
UINT32BYTES(pfat32_bsbpb->BPB_FATSz32));
fat_BytesPerSector = UINT16BYTES(pfat32_bsbpb->BPB_BytsPerSec);
G_LABEL_DEBUG(2,
"MSDOSFS: FAT_FirstDataSector=0x%x, FAT_BytesPerSector=%d",
fat_FirstDataSector, fat_BytesPerSector);
for (offset = fat_BytesPerSector * fat_FirstDataSector;;
offset += fat_BytesPerSector) {
sector = (uint8_t *)g_read_data(cp, offset,
fat_BytesPerSector, NULL);
if (sector == NULL)
goto error;
pfat_entry = (FAT_DES *)sector;
do {
/* No more entries available. */
if (pfat_entry->DIR_Name[0] == 0) {
G_LABEL_DEBUG(1, "MSDOSFS: %s: "
"FAT32 volume has no name.",
pp->name);
goto error;
}
/* Skip empty or long name entries. */
if (pfat_entry->DIR_Name[0] == 0xe5 ||
(pfat_entry->DIR_Attr &
FAT_DES_ATTR_LONG_NAME) ==
FAT_DES_ATTR_LONG_NAME) {
continue;
}
/*
* The name of the entry is the volume label if
* ATTR_VOLUME_ID is set.
*/
if (pfat_entry->DIR_Attr &
FAT_DES_ATTR_VOLUME_ID) {
strlcpy(label, pfat_entry->DIR_Name,
MIN(size,
sizeof(pfat_bsbpb->BS_VolLab) + 1));
goto endofchecks;
}
} while((uint8_t *)(++pfat_entry) <
(uint8_t *)(sector + fat_BytesPerSector));
g_free(sector);
}
} else {
G_LABEL_DEBUG(1, "MSDOSFS: %s: no FAT volume detected.",
pp->name);
goto error;
}
endofchecks:
for (i = size - 1; i > 0; i--) {
if (label[i] == '\0')
continue;
@ -93,6 +208,12 @@ g_label_msdosfs_taste(struct g_consumer *cp, char *label, size_t size)
else
break;
}
error:
if (sector0 != NULL)
g_free(sector0);
if (sector != NULL)
g_free(sector);
}
const struct g_label_desc g_label_msdosfs = {

140
sys/geom/label/g_label_msdosfs.h Normal file
View File

@ -0,0 +1,140 @@
/*-
* Copyright (c) 2006 Tobias Reifenberger
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*
* $FreeBSD$
*/
#include <sys/types.h>
/*
* Conversion macros for little endian encoded unsigned integers
* in byte streams to the local unsigned integer format.
*/
#define UINT16BYTES(p) ((uint32_t)((p)[0] + (256*(p)[1])))
#define UINT32BYTES(p) ((uint32_t)((p)[0] + (256*(p)[1]) + \
(65536*(p)[2]) + (16777216*(p)[3])))
/*
* All following structures are according to:
*
* Microsoft Extensible Firmware Initiative FAT32 File System Specification
* FAT: General Overview of On-Disk Format
* Version 1.03, December 6, 2000
* Microsoft Corporation
*/
/*
* FAT boot sector and boot parameter block for
* FAT12 and FAT16 volumes
*/
typedef struct fat_bsbpb {
/* common fields */
uint8_t BS_jmpBoot[3];
uint8_t BS_OEMName[8];
uint8_t BPB_BytsPerSec[2];
uint8_t BPB_SecPerClus;
uint8_t BPB_RsvdSecCnt[2];
uint8_t BPB_NumFATs;
uint8_t BPB_RootEntCnt[2];
uint8_t BPB_TotSec16[2];
uint8_t BPB_Media;
uint8_t BPB_FATSz16[2];
uint8_t BPB_SecPerTrack[2];
uint8_t BPB_NumHeads[2];
uint8_t BPB_HiddSec[4];
uint8_t BPB_TotSec32[4];
/* FAT12/FAT16 only fields */
uint8_t BS_DrvNum;
uint8_t BS_Reserved1;
uint8_t BS_BootSig;
uint8_t BS_VolID[4];
uint8_t BS_VolLab[11];
uint8_t BS_FilSysType[8];
} FAT_BSBPB; /* 62 bytes */
/*
* FAT boot sector and boot parameter block for
* FAT32 volumes
*/
typedef struct fat32_bsbpb {
/* common fields */
uint8_t BS_jmpBoot[3];
uint8_t BS_OEMName[8];
uint8_t BPB_BytsPerSec[2];
uint8_t BPB_SecPerClus;
uint8_t BPB_RsvdSecCnt[2];
uint8_t BPB_NumFATs;
uint8_t BPB_RootEntCnt[2];
uint8_t BPB_TotSec16[2];
uint8_t BPB_Media;
uint8_t BPB_FATSz16[2];
uint8_t BPB_SecPerTrack[2];
uint8_t BPB_NumHeads[2];
uint8_t BPB_HiddSec[4];
uint8_t BPB_TotSec32[4];
/* FAT32 only fields */
uint8_t BPB_FATSz32[4];
uint8_t BPB_ExtFlags[2];
uint8_t BPB_FSVer[2];
uint8_t BPB_RootClus[4];
uint8_t BPB_FSInfo[2];
uint8_t BPB_BkBootSec[2];
uint8_t BPB_Reserved[12];
uint8_t BS_DrvNum;
uint8_t BS_Reserved1;
uint8_t BS_BootSig;
uint8_t BS_VolID[4];
uint8_t BS_VolLab[11];
uint8_t BS_FilSysType[8];
} FAT32_BSBPB; /* 90 bytes */
/*
* FAT directory entry structure
*/
#define FAT_DES_ATTR_READ_ONLY 0x01
#define FAT_DES_ATTR_HIDDEN 0x02
#define FAT_DES_ATTR_SYSTEM 0x04
#define FAT_DES_ATTR_VOLUME_ID 0x08
#define FAT_DES_ATTR_DIRECTORY 0x10
#define FAT_DES_ATTR_ARCHIVE 0x20
#define FAT_DES_ATTR_LONG_NAME (FAT_DES_ATTR_READ_ONLY | \
FAT_DES_ATTR_HIDDEN | \
FAT_DES_ATTR_SYSTEM | \
FAT_DES_ATTR_VOLUME_ID)
typedef struct fat_des {
uint8_t DIR_Name[11];
uint8_t DIR_Attr;
uint8_t DIR_NTRes;
uint8_t DIR_CrtTimeTenth;
uint8_t DIR_CrtTime[2];
uint8_t DIR_CrtDate[2];
uint8_t DIR_LstAccDate[2];
uint8_t DIR_FstClusHI[2];
uint8_t DIR_WrtTime[2];
uint8_t DIR_WrtDate[2];
uint8_t DIR_FstClusLO[2];
uint8_t DIR_FileSize[4];
} FAT_DES;