1 files changed, 441 insertions, 0 deletions

diff --git a/libparted/fs/r/fat/bootsector.c b/libparted/fs/r/fat/bootsector.c
new file mode 100644
index 0000000..85ccc0f
--- /dev/null
+++ b/libparted/fs/r/fat/bootsector.c
@@ -0,0 +1,441 @@
+/*
+    libparted
+    Copyright (C) 1998-2000, 2002, 2004, 2007, 2009-2014, 2019-2023 Free
+    Software Foundation, Inc.
+
+    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; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <config.h>
+#include "fat.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+
+/* Reads in the boot sector (superblock), and does a minimum of sanity
+ * checking.  The goals are:
+ *	- to detect fat file systems, even if they are damaged [i.e. not
+ * return an error / throw an exception]
+ *	- to fail detection if there's not enough information for
+ * fat_boot_sector_probe_type() to work (or possibly crash on a divide-by-zero)
+ */
+int
+fat_boot_sector_read (FatBootSector** bsp, const PedGeometry *geom)
+{
+	PED_ASSERT (bsp != NULL);
+	PED_ASSERT (geom != NULL);
+
+	if (!ped_geometry_read_alloc (geom, (void **)bsp, 0, 1))
+		return 0;
+	FatBootSector *bs = *bsp;
+	if (PED_LE16_TO_CPU (bs->boot_sign) != 0xAA55) {
+		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
+			_("File system has an invalid signature for a FAT "
+			  "file system."));
+		return 0;
+	}
+
+	if (!bs->sector_size
+            || PED_LE16_TO_CPU (bs->sector_size) % PED_SECTOR_SIZE_DEFAULT) {
+		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
+			_("File system has an invalid sector size for a FAT "
+			  "file system."));
+		return 0;
+	}
+
+	if (!bs->cluster_size) {
+		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
+			_("File system has an invalid cluster size for a FAT "
+			  "file system."));
+		return 0;
+	}
+
+	if (!bs->reserved) {
+		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
+			_("File system has an invalid number of reserved "
+			  "sectors for a FAT file system."));
+		return 0;
+	}
+
+	if (bs->fats < 1 || bs->fats > 4) {
+		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
+			_("File system has an invalid number of FATs."));
+		return 0;
+	}
+
+	return 1;
+}
+
+/*
+    Don't trust the FAT12, FAT16 or FAT32 label string.
+ */
+FatType _GL_ATTRIBUTE_PURE
+fat_boot_sector_probe_type (const FatBootSector* bs, const PedGeometry* geom)
+{
+	PedSector	logical_sector_size;
+	PedSector	first_cluster_sector;
+	FatCluster	cluster_count;
+
+	if (!PED_LE16_TO_CPU (bs->dir_entries))
+		return FAT_TYPE_FAT32;
+
+	logical_sector_size = PED_LE16_TO_CPU (bs->sector_size) / 512;
+
+	first_cluster_sector
+		= PED_LE16_TO_CPU (bs->reserved) * logical_sector_size
+		  + 2 * PED_LE16_TO_CPU (bs->fat_length) * logical_sector_size
+		  + PED_LE16_TO_CPU (bs->dir_entries)
+			/ (512 / sizeof (FatDirEntry));
+	cluster_count = (geom->length - first_cluster_sector)
+			/ bs->cluster_size / logical_sector_size;
+	if (cluster_count > MAX_FAT12_CLUSTERS)
+		return FAT_TYPE_FAT16;
+	else
+		return FAT_TYPE_FAT12;
+}
+
+/* Analyses the boot sector, and sticks appropriate numbers in
+   fs->type_specific.
+
+   Note: you need to subtract (2 * cluster_sectors) off cluster offset,
+   because the first cluster is number 2.  (0 and 1 are not real clusters,
+   and referencing them is a bug)
+ */
+int
+fat_boot_sector_analyse (FatBootSector* bs, PedFileSystem* fs)
+{
+	FatSpecific*		fs_info = FAT_SPECIFIC (fs);
+	int			fat_entry_size;
+
+	PED_ASSERT (bs != NULL);
+
+	fs_info->logical_sector_size = PED_LE16_TO_CPU (bs->sector_size) / 512;
+
+	fs_info->sectors_per_track = PED_LE16_TO_CPU (bs->secs_track);
+	fs_info->heads = PED_LE16_TO_CPU (bs->heads);
+	if (fs_info->sectors_per_track < 1 || fs_info->sectors_per_track > 63
+	    || fs_info->heads < 1 || fs_info->heads > 255) {
+		PedCHSGeometry* bios_geom = &fs->geom->dev->bios_geom;
+		int cyl_count = 0;
+
+		if (fs_info->heads > 0 && fs_info->sectors_per_track > 0)
+			cyl_count = fs->geom->dev->length / fs_info->heads
+					/ fs_info->sectors_per_track;
+
+		switch (ped_exception_throw (
+			PED_EXCEPTION_ERROR,
+			PED_EXCEPTION_FIX + PED_EXCEPTION_IGNORE
+			+ PED_EXCEPTION_CANCEL,
+			_("The file system's CHS geometry is (%d, %d, %d), "
+			  "which is invalid.  The partition table's CHS "
+			  "geometry is (%d, %d, %d).  If you select Ignore, "
+			  "the file system's CHS geometry will be left "
+			  "unchanged.  If you select Fix, the file system's "
+			  "CHS geometry will be set to match the partition "
+			  "table's CHS geometry."),
+			 cyl_count, fs_info->heads, fs_info->sectors_per_track,
+			 bios_geom->cylinders, bios_geom->heads,
+			 bios_geom->sectors)) {
+
+		case PED_EXCEPTION_FIX:
+			fs_info->sectors_per_track = bios_geom->sectors;
+			fs_info->heads = bios_geom->heads;
+			bs->secs_track
+				= PED_CPU_TO_LE16 (fs_info->sectors_per_track);
+			bs->heads = PED_CPU_TO_LE16 (fs_info->heads);
+			if (!fat_boot_sector_write (bs, fs))
+				return 0;
+			break;
+
+		case PED_EXCEPTION_CANCEL:
+			return 0;
+
+		case PED_EXCEPTION_IGNORE:
+			break;
+
+                default:
+                        break;
+		}
+	}
+
+	if (bs->sectors)
+		fs_info->sector_count = PED_LE16_TO_CPU (bs->sectors)
+						* fs_info->logical_sector_size;
+	else
+		fs_info->sector_count = PED_LE32_TO_CPU (bs->sector_count)
+						* fs_info->logical_sector_size;
+
+	fs_info->fat_table_count = bs->fats;
+	fs_info->root_dir_entry_count = PED_LE16_TO_CPU (bs->dir_entries);
+	fs_info->fat_offset = PED_LE16_TO_CPU (bs->reserved)
+					* fs_info->logical_sector_size;
+	fs_info->cluster_sectors = bs->cluster_size
+				   * fs_info->logical_sector_size;
+	fs_info->cluster_size = fs_info->cluster_sectors * 512;
+
+	if (fs_info->logical_sector_size == 0) {
+		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
+			_("FAT boot sector says logical sector size is 0.  "
+			  "This is weird. "));
+		return 0;
+	}
+	if (fs_info->fat_table_count == 0) {
+		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
+			_("FAT boot sector says there are no FAT tables.  This "
+			  "is weird. "));
+		return 0;
+	}
+	if (fs_info->cluster_sectors == 0) {
+		ped_exception_throw (PED_EXCEPTION_ERROR, PED_EXCEPTION_CANCEL,
+			_("FAT boot sector says clusters are 0 sectors.  This "
+			  "is weird. "));
+		return 0;
+	}
+
+	fs_info->fat_type = fat_boot_sector_probe_type (bs, fs->geom);
+	if (fs_info->fat_type == FAT_TYPE_FAT12) {
+		ped_exception_throw (
+			PED_EXCEPTION_NO_FEATURE,
+			PED_EXCEPTION_CANCEL,
+			_("File system is FAT12, which is unsupported."));
+		return 0;
+	}
+	if (fs_info->fat_type == FAT_TYPE_FAT16) {
+		fs_info->fat_sectors = PED_LE16_TO_CPU (bs->fat_length)
+				       * fs_info->logical_sector_size;
+		fs_info->serial_number
+			= PED_LE32_TO_CPU (bs->u.fat16.serial_number);
+		fs_info->root_cluster = 0;
+		fs_info->root_dir_offset
+			= fs_info->fat_offset
+			  + fs_info->fat_sectors * fs_info->fat_table_count;
+		fs_info->root_dir_sector_count
+			= fs_info->root_dir_entry_count * sizeof (FatDirEntry)
+			  / (512 * fs_info->logical_sector_size);
+		fs_info->cluster_offset
+			= fs_info->root_dir_offset
+			  + fs_info->root_dir_sector_count;
+	}
+	if (fs_info->fat_type == FAT_TYPE_FAT32) {
+		fs_info->fat_sectors = PED_LE32_TO_CPU (bs->u.fat32.fat_length)
+					* fs_info->logical_sector_size;
+		fs_info->serial_number
+			= PED_LE32_TO_CPU (bs->u.fat32.serial_number);
+		fs_info->info_sector_offset
+		    = PED_LE16_TO_CPU (fs_info->boot_sector->u.fat32.info_sector)
+			  * fs_info->logical_sector_size;
+		fs_info->boot_sector_backup_offset
+		  = PED_LE16_TO_CPU (fs_info->boot_sector->u.fat32.backup_sector)
+			  * fs_info->logical_sector_size;
+		fs_info->root_cluster
+			= PED_LE32_TO_CPU (bs->u.fat32.root_dir_cluster);
+		fs_info->root_dir_offset = 0;
+		fs_info->root_dir_sector_count = 0;
+		fs_info->cluster_offset
+			= fs_info->fat_offset
+			  + fs_info->fat_sectors * fs_info->fat_table_count;
+	}
+
+	fs_info->cluster_count
+		= (fs_info->sector_count - fs_info->cluster_offset)
+		  / fs_info->cluster_sectors;
+
+	fat_entry_size = fat_table_entry_size (fs_info->fat_type);
+	if (fs_info->cluster_count + 2
+			> fs_info->fat_sectors * 512 / fat_entry_size)
+		fs_info->cluster_count
+			= fs_info->fat_sectors * 512 / fat_entry_size - 2;
+
+	fs_info->dir_entries_per_cluster
+		= fs_info->cluster_size / sizeof (FatDirEntry);
+	return 1;
+}
+
+#ifndef DISCOVER_ONLY
+int
+fat_boot_sector_set_boot_code (FatBootSector** bsp, const PedFileSystem* fs)
+{
+	PED_ASSERT (bsp != NULL);
+	*bsp = ped_malloc (fs->geom->dev->sector_size);
+	FatBootSector *bs = *bsp;
+	PED_ASSERT (bs != NULL);
+
+	memset (bs, 0, 512);
+	memcpy (bs->boot_jump, FAT_BOOT_JUMP, 3);
+	PED_ASSERT (sizeof(FAT_BOOT_CODE) < sizeof(bs->u.fat32.boot_code));
+	strcpy (bs->u.fat32.boot_code, FAT_BOOT_CODE);
+	return 1;
+}
+
+int
+fat_boot_sector_generate (FatBootSector** bsp, const PedFileSystem* fs)
+{
+	FatSpecific*	fs_info = FAT_SPECIFIC (fs);
+
+	PED_ASSERT (bsp != NULL);
+	FatBootSector *bs = *bsp;
+	PED_ASSERT (bs != NULL);
+
+	memcpy (bs->system_id, "MSWIN4.1", 8);
+	bs->sector_size = PED_CPU_TO_LE16 (fs_info->logical_sector_size * 512);
+	bs->cluster_size = fs_info->cluster_sectors
+				/ fs_info->logical_sector_size;
+	bs->reserved = PED_CPU_TO_LE16 (fs_info->fat_offset
+					/ fs_info->logical_sector_size);
+	bs->fats = fs_info->fat_table_count;
+
+	bs->dir_entries = (fs_info->fat_type == FAT_TYPE_FAT16)
+			  ? PED_CPU_TO_LE16 (fs_info->root_dir_entry_count)
+			  : 0;
+
+	if (fs_info->sector_count / fs_info->logical_sector_size > 0xffff
+		|| fs_info->fat_type == FAT_TYPE_FAT32) {
+		bs->sectors = 0;
+		bs->sector_count = PED_CPU_TO_LE32 (fs_info->sector_count
+						/ fs_info->logical_sector_size);
+	} else {
+		bs->sectors = PED_CPU_TO_LE16 (fs_info->sector_count
+					       / fs_info->logical_sector_size);
+		bs->sector_count = 0;
+	}
+
+	bs->media = 0xf8;
+
+	bs->secs_track = PED_CPU_TO_LE16 (fs_info->sectors_per_track);
+	bs->heads = PED_CPU_TO_LE16 (fs_info->heads);
+	bs->hidden = PED_CPU_TO_LE32 (fs->geom->start);
+
+	if (fs_info->fat_type == FAT_TYPE_FAT32) {
+		bs->fat_length = 0;
+		bs->u.fat32.fat_length = PED_CPU_TO_LE32 (fs_info->fat_sectors
+						/ fs_info->logical_sector_size);
+		bs->u.fat32.flags = 0;	/* FIXME: what the hell are these? */
+		bs->u.fat32.version = 0;  /* must be 0, for Win98 bootstrap */
+		bs->u.fat32.root_dir_cluster
+			= PED_CPU_TO_LE32 (fs_info->root_cluster);
+		bs->u.fat32.info_sector
+			= PED_CPU_TO_LE16 (fs_info->info_sector_offset
+					   / fs_info->logical_sector_size);
+		bs->u.fat32.backup_sector
+			= PED_CPU_TO_LE16 (fs_info->boot_sector_backup_offset
+					   / fs_info->logical_sector_size);
+
+		bs->u.fat32.drive_num = 0x80;	/* _ALWAYS_ 0x80.  silly DOS */
+
+		memset (bs->u.fat32.empty_1, 0, 12);
+
+		bs->u.fat32.ext_signature = 0x29;
+		bs->u.fat32.serial_number
+			= PED_CPU_TO_LE32 (fs_info->serial_number);
+		memcpy (bs->u.fat32.volume_name, "NO NAME    ", 11);
+		memcpy (bs->u.fat32.fat_name, "FAT32   ", 8);
+	} else {
+		bs->fat_length
+			= PED_CPU_TO_LE16 (fs_info->fat_sectors
+					   / fs_info->logical_sector_size);
+
+		bs->u.fat16.drive_num = 0x80;	/* _ALWAYS_ 0x80.  silly DOS */
+
+		bs->u.fat16.ext_signature = 0x29;
+		bs->u.fat16.serial_number
+			= PED_CPU_TO_LE32 (fs_info->serial_number);
+		memcpy (bs->u.fat16.volume_name, "NO NAME    ", 11);
+		memcpy (bs->u.fat16.fat_name, "FAT16   ", 8);
+	}
+
+	bs->boot_sign = PED_CPU_TO_LE16 (0xaa55);
+
+	return 1;
+}
+
+int
+fat_boot_sector_write (const FatBootSector* bs, PedFileSystem* fs)
+{
+	FatSpecific*	fs_info = FAT_SPECIFIC (fs);
+
+	PED_ASSERT (bs != NULL);
+
+	if (!ped_geometry_write (fs->geom, bs, 0, 1))
+		return 0;
+	if (fs_info->fat_type == FAT_TYPE_FAT32) {
+		if (!ped_geometry_write (fs->geom, bs,
+					 fs_info->boot_sector_backup_offset, 1))
+			return 0;
+	}
+	return ped_geometry_sync (fs->geom);
+}
+
+int
+fat_info_sector_read (FatInfoSector** isp, const PedFileSystem* fs)
+{
+	FatSpecific*	fs_info = FAT_SPECIFIC (fs);
+	int		status;
+
+	PED_ASSERT (isp != NULL);
+
+	if (!ped_geometry_read_alloc (fs->geom, (void **)isp, fs_info->info_sector_offset, 1))
+		return 0;
+	FatInfoSector *is = *isp;
+	if (PED_LE32_TO_CPU (is->signature_2) != FAT32_INFO_MAGIC2) {
+		status = ped_exception_throw (PED_EXCEPTION_WARNING,
+				PED_EXCEPTION_IGNORE_CANCEL,
+				_("The information sector has the wrong "
+				"signature (%x).  Select cancel for now, "
+				"and send in a bug report.  If you're "
+				"desperate, it's probably safe to ignore."),
+				PED_LE32_TO_CPU (is->signature_2));
+		if (status == PED_EXCEPTION_CANCEL) return 0;
+	}
+	return 1;
+}
+
+int
+fat_info_sector_generate (FatInfoSector** isp, const PedFileSystem* fs)
+{
+	FatSpecific*	fs_info = FAT_SPECIFIC (fs);
+
+	PED_ASSERT (isp != NULL);
+	*isp = ped_malloc (fs->geom->dev->sector_size);
+	FatInfoSector *is = *isp;
+
+	fat_table_count_stats (fs_info->fat);
+
+	memset (is, 0, 512);
+
+	is->signature_1 = PED_CPU_TO_LE32 (FAT32_INFO_MAGIC1);
+	is->signature_2 = PED_CPU_TO_LE32 (FAT32_INFO_MAGIC2);
+	is->free_clusters = PED_CPU_TO_LE32 (fs_info->fat->free_cluster_count);
+	is->next_cluster = PED_CPU_TO_LE32 (fs_info->fat->last_alloc);
+	is->signature_3 = PED_CPU_TO_LE16 (FAT32_INFO_MAGIC3);
+
+	return 1;
+}
+
+int
+fat_info_sector_write (const FatInfoSector* is, PedFileSystem *fs)
+{
+	FatSpecific*	fs_info = FAT_SPECIFIC (fs);
+
+	PED_ASSERT (is != NULL);
+
+	if (!ped_geometry_write (fs->geom, is, fs_info->info_sector_offset, 1))
+		return 0;
+	return ped_geometry_sync (fs->geom);
+}
+#endif /* !DISCOVER_ONLY */