From c0667f3ce5ce09b7c8e27b08beca39818a7b05e8 Mon Sep 17 00:00:00 2001 From: pjd Date: Sat, 12 Aug 2006 15:34:15 +0000 Subject: Handle MSDOS file systems properly. Before the change file systems created on Windows XP (and others maybe) were not detected. We detected only those created with newfs_msdos(8). Submitted by: Tobias Reifenberger style(9)ified by: pjd --- sys/geom/label/g_label_msdosfs.c | 189 ++++++++++++++++++++++++++++++++------- sys/geom/label/g_label_msdosfs.h | 140 +++++++++++++++++++++++++++++ 2 files changed, 295 insertions(+), 34 deletions(-) create mode 100644 sys/geom/label/g_label_msdosfs.h (limited to 'sys/geom') diff --git a/sys/geom/label/g_label_msdosfs.c b/sys/geom/label/g_label_msdosfs.c index 5e40bd9..6137de9 100644 --- a/sys/geom/label/g_label_msdosfs.c +++ b/sys/geom/label/g_label_msdosfs.c @@ -1,5 +1,6 @@ /*- * Copyright (c) 2004 Pawel Jakub Dawidek + * 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 #include +#include #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'; + sector0 = NULL; + sector = NULL; + bzero(label, size); - sector = (char *)g_read_data(cp, 0, pp->sectorsize, NULL); - if (sector == NULL) + /* 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; - if (strncmp(sector + 0x36, FAT12, strlen(FAT12)) == 0) { - G_LABEL_DEBUG(1, "MSDOS (FAT12) file system detected on %s.", + } + + /* 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); - volume = sector + 0x2b; - } else if (strncmp(sector + 0x36, FAT16, strlen(FAT16)) == 0) { - G_LABEL_DEBUG(1, "MSDOS (FAT16) file system detected on %s.", + 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); - volume = sector + 0x2b; - } else if (strncmp(sector + 0x52, FAT32, strlen(FAT32)) == 0) { - G_LABEL_DEBUG(1, "MSDOS (FAT32) file system detected on %s.", + + /* 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); - volume = sector + 0x47; + + /* + * 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_free(sector); - return; - } - if (strncmp(volume, NO_NAME, VOLUME_LEN) == 0) { - g_free(sector); - return; - } - if (volume[0] == '\0') { - g_free(sector); - return; + G_LABEL_DEBUG(1, "MSDOSFS: %s: no FAT volume detected.", + pp->name); + goto error; } - bzero(label, size); - strlcpy(label, volume, MIN(size, VOLUME_LEN)); - g_free(sector); + +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 = { diff --git a/sys/geom/label/g_label_msdosfs.h b/sys/geom/label/g_label_msdosfs.h new file mode 100644 index 0000000..761461b --- /dev/null +++ b/sys/geom/label/g_label_msdosfs.h @@ -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 + +/* + * 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; -- cgit v1.1