freebsd-dev/sys/geom/label/g_label_msdosfs.c
Pawel Jakub Dawidek e1237b285b Introduce GEOM_LABEL class.
This class is used for detecting volume labels on file systems:
UFS, MSDOSFS (FAT12, FAT16, FAT32) and ISO9660.
It also provide native labelization (there is no need for file system).

g_label_ufs.c is based on geom_vol_ffs from Gordon Tetlow.
g_label_msdos.c and g_label_iso9660.c are probably hacks, I just found
where volume labels are stored and I use those offsets here,
but with this class it should be easy to do it as it should be done by
someone who know how.
Implementing volume labels detection for other file systems also should
be trivial.

New providers are created in those directories:
/dev/ufs/ (UFS1, UFS2)
/dev/msdosfs/ (FAT12, FAT16, FAT32)
/dev/iso9660/ (ISO9660)
/dev/label/ (native labels, configured with glabel(8))

Manual page cleanups and some comments inside were submitted by
Simon L. Nielsen, who was, as always, very helpful. Thanks!
2004-07-02 19:40:36 +00:00

102 lines
3.0 KiB
C

/*-
* Copyright (c) 2004 Pawel Jakub Dawidek <pjd@FreeBSD.org>
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <geom/geom.h>
#include <geom/label/g_label.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 "
static void
g_label_msdosfs_taste(struct g_consumer *cp, char *label, size_t size)
{
struct g_provider *pp;
char *sector, *volume;
int i, error;
g_topology_assert_not();
pp = cp->provider;
label[0] = '\0';
sector = (char *)g_read_data(cp, 0, pp->sectorsize, &error);
if (sector == NULL || error != 0)
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;
}
bzero(label, size);
strlcpy(label, volume, MIN(size, VOLUME_LEN));
g_free(sector);
for (i = size - 1; i > 0; i--) {
if (label[i] == '\0')
continue;
else if (label[i] == ' ')
label[i] = '\0';
else
break;
}
}
const struct g_label_desc g_label_msdosfs = {
.ld_taste = g_label_msdosfs_taste,
.ld_dir = G_LABEL_MSDOSFS_DIR
};