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-rw-r--r--libparted/fs/r/fat/table.c481
1 files changed, 481 insertions, 0 deletions
diff --git a/libparted/fs/r/fat/table.c b/libparted/fs/r/fat/table.c
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+++ b/libparted/fs/r/fat/table.c
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+/*
+ libparted
+ Copyright (C) 1998-2000, 2007-2014, 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 <parted/endian.h>
+#include "fat.h"
+
+#ifndef DISCOVER_ONLY
+
+FatTable*
+fat_table_new (FatType fat_type, FatCluster size)
+{
+ FatTable* ft;
+ int entry_size = fat_table_entry_size (fat_type);
+
+ ft = (FatTable*) ped_malloc (sizeof (FatTable));
+ if (!ft) return NULL;
+
+ ft->cluster_count = ft->free_cluster_count = size - 2;
+
+/* ensure there's some free room on the end, to finish off the sector */
+ ft->size = ped_div_round_up (size * entry_size, 512) * 512 / entry_size;
+ ft->fat_type = fat_type;
+ ft->raw_size = ft->size * entry_size;
+
+ ft->table = ped_malloc (ft->raw_size);
+ if (!ft->table) {
+ free (ft);
+ return NULL;
+ }
+
+ fat_table_clear (ft);
+ return ft;
+}
+
+void
+fat_table_destroy (FatTable* ft)
+{
+ free (ft->table);
+ free (ft);
+}
+
+FatTable*
+fat_table_duplicate (const FatTable* ft)
+{
+ FatTable* dup_ft;
+
+ dup_ft = fat_table_new (ft->fat_type, ft->size);
+ if (!dup_ft) return NULL;
+
+ dup_ft->cluster_count = ft->cluster_count;
+ dup_ft->free_cluster_count = ft->free_cluster_count;
+ dup_ft->bad_cluster_count = ft->bad_cluster_count;
+ dup_ft->last_alloc = ft->last_alloc;
+
+ memcpy (dup_ft->table, ft->table, ft->raw_size);
+
+ return dup_ft;
+}
+
+void
+fat_table_clear (FatTable* ft)
+{
+ memset (ft->table, 0, ft->raw_size);
+
+ fat_table_set (ft, 0, 0x0ffffff8);
+ fat_table_set (ft, 1, 0x0fffffff);
+
+ ft->free_cluster_count = ft->cluster_count;
+ ft->bad_cluster_count = 0;
+ ft->last_alloc = 1;
+}
+
+int
+fat_table_set_cluster_count (FatTable* ft, FatCluster new_cluster_count)
+{
+ PED_ASSERT (new_cluster_count + 2 <= ft->size);
+
+ ft->cluster_count = new_cluster_count;
+ return fat_table_count_stats (ft);
+}
+
+int
+fat_table_count_stats (FatTable* ft)
+{
+ FatCluster i;
+
+ PED_ASSERT (ft->cluster_count + 2 <= ft->size);
+
+ ft->free_cluster_count = 0;
+ ft->bad_cluster_count = 0;
+
+ for (i=2; i < ft->cluster_count + 2; i++) {
+ if (fat_table_is_available (ft, i))
+ ft->free_cluster_count++;
+ if (fat_table_is_bad (ft, i))
+ ft->bad_cluster_count++;
+ }
+ return 1;
+}
+
+int
+fat_table_read (FatTable* ft, const PedFileSystem* fs, int table_num)
+{
+ FatSpecific* fs_info = FAT_SPECIFIC (fs);
+
+ PED_ASSERT (ft->raw_size >= fs_info->fat_sectors * 512);
+
+ memset (ft->table, 0, ft->raw_size);
+
+ if (!ped_geometry_read (fs->geom, (void *) ft->table,
+ fs_info->fat_offset
+ + table_num * fs_info->fat_sectors,
+ fs_info->fat_sectors))
+ return 0;
+
+ if ( *((unsigned char*) ft->table) != fs_info->boot_sector->media) {
+ if (ped_exception_throw (
+ PED_EXCEPTION_ERROR,
+ PED_EXCEPTION_IGNORE_CANCEL,
+ _("FAT %d media %x doesn't match the boot sector's "
+ "media %x. You should probably run scandisk."),
+ (int) table_num + 1,
+ (int) *((unsigned char*) ft->table),
+ (int) fs_info->boot_sector->media)
+ != PED_EXCEPTION_IGNORE)
+ return 0;
+ }
+
+ ft->cluster_count = fs_info->cluster_count;
+
+ fat_table_count_stats (ft);
+
+ return 1;
+}
+
+int
+fat_table_write (const FatTable* ft, PedFileSystem* fs, int table_num)
+{
+ FatSpecific* fs_info = FAT_SPECIFIC (fs);
+
+ PED_ASSERT (ft->raw_size >= fs_info->fat_sectors * 512);
+
+ if (!ped_geometry_write (fs->geom, (void *) ft->table,
+ fs_info->fat_offset
+ + table_num * fs_info->fat_sectors,
+ fs_info->fat_sectors))
+ return 0;
+ if (!ped_geometry_sync (fs->geom))
+ return 0;
+
+ return 1;
+}
+
+int
+fat_table_write_all (const FatTable* ft, PedFileSystem* fs)
+{
+ FatSpecific* fs_info = FAT_SPECIFIC (fs);
+ int i;
+
+ for (i = 0; i < fs_info->fat_table_count; i++) {
+ if (!fat_table_write (ft, fs, i))
+ return 0;
+ }
+
+ return 1;
+}
+
+int
+fat_table_compare (const FatTable* a, const FatTable* b)
+{
+ FatCluster i;
+
+ if (a->cluster_count != b->cluster_count)
+ return 0;
+
+ for (i = 0; i < a->cluster_count + 2; i++) {
+ if (fat_table_get (a, i) != fat_table_get (b, i))
+ return 0;
+ }
+
+ return 1;
+}
+
+static int
+_test_code_available (const FatTable* ft, FatCluster code)
+{
+ return code == 0;
+}
+
+static int
+_test_code_bad (const FatTable* ft, FatCluster code)
+{
+ switch (ft->fat_type) {
+ case FAT_TYPE_FAT12:
+ if (code == 0xff7) return 1;
+ break;
+
+ case FAT_TYPE_FAT16:
+ if (code == 0xfff7) return 1;
+ break;
+
+ case FAT_TYPE_FAT32:
+ if (code == 0x0ffffff7) return 1;
+ break;
+ }
+ return 0;
+}
+
+static int
+_test_code_eof (const FatTable* ft, FatCluster code)
+{
+ switch (ft->fat_type) {
+ case FAT_TYPE_FAT12:
+ if (code >= 0xff7) return 1;
+ break;
+
+ case FAT_TYPE_FAT16:
+ if (code >= 0xfff7) return 1;
+ break;
+
+ case FAT_TYPE_FAT32:
+ if (code >= 0x0ffffff7) return 1;
+ break;
+ }
+ return 0;
+}
+
+void
+_update_stats (FatTable* ft, FatCluster cluster, FatCluster value)
+{
+ if (_test_code_available (ft, value)
+ && !fat_table_is_available (ft, cluster)) {
+ ft->free_cluster_count++;
+ if (fat_table_is_bad (ft, cluster))
+ ft->bad_cluster_count--;
+ }
+
+ if (!_test_code_available (ft, value)
+ && fat_table_is_available (ft, cluster)) {
+ ft->free_cluster_count--;
+ if (_test_code_bad (ft, cluster))
+ ft->bad_cluster_count--;
+ }
+}
+
+int
+fat_table_set (FatTable* ft, FatCluster cluster, FatCluster value)
+{
+ if (cluster >= ft->cluster_count + 2) {
+ ped_exception_throw (PED_EXCEPTION_BUG,
+ PED_EXCEPTION_CANCEL,
+ _("fat_table_set: cluster %ld outside "
+ "file system"),
+ (long) cluster);
+ return 0;
+ }
+
+ _update_stats (ft, cluster, value);
+
+ switch (ft->fat_type) {
+ case FAT_TYPE_FAT12:
+ PED_ASSERT (0);
+ break;
+
+ case FAT_TYPE_FAT16:
+ ((unsigned short *) ft->table) [cluster]
+ = PED_CPU_TO_LE16 (value);
+ break;
+
+ case FAT_TYPE_FAT32:
+ ((unsigned int *) ft->table) [cluster]
+ = PED_CPU_TO_LE32 (value);
+ break;
+ }
+ return 1;
+}
+
+FatCluster
+fat_table_get (const FatTable* ft, FatCluster cluster)
+{
+ if (cluster >= ft->cluster_count + 2) {
+ ped_exception_throw (PED_EXCEPTION_BUG,
+ PED_EXCEPTION_CANCEL,
+ _("fat_table_get: cluster %ld outside "
+ "file system"),
+ (long) cluster);
+ exit (EXIT_FAILURE); /* FIXME */
+ }
+
+ switch (ft->fat_type) {
+ case FAT_TYPE_FAT12:
+ PED_ASSERT (0);
+ break;
+
+ case FAT_TYPE_FAT16:
+ return PED_LE16_TO_CPU
+ (((unsigned short *) ft->table) [cluster]);
+
+ case FAT_TYPE_FAT32:
+ return PED_LE32_TO_CPU
+ (((unsigned int *) ft->table) [cluster]);
+ }
+
+ return 0;
+}
+
+FatCluster
+fat_table_alloc_cluster (FatTable* ft)
+{
+ FatCluster i;
+ FatCluster cluster;
+
+/* hack: assumes the first two FAT entries are marked as used (which they
+ * always should be)
+ */
+ for (i=1; i < ft->cluster_count + 1; i++) {
+ cluster = (i + ft->last_alloc) % ft->cluster_count;
+ if (fat_table_is_available (ft, cluster)) {
+ ft->last_alloc = cluster;
+ return cluster;
+ }
+ }
+
+ ped_exception_throw (PED_EXCEPTION_ERROR,
+ PED_EXCEPTION_CANCEL,
+ _("fat_table_alloc_cluster: no free clusters"));
+ return 0;
+}
+
+FatCluster
+fat_table_alloc_check_cluster (FatTable* ft, PedFileSystem* fs)
+{
+ FatSpecific* fs_info = FAT_SPECIFIC (fs);
+ FatCluster result;
+
+ while (1) {
+ result = fat_table_alloc_cluster (ft);
+ if (!result)
+ return 0;
+ if (fat_read_cluster (fs, fs_info->buffer, result))
+ return result;
+ fat_table_set_bad (ft, result);
+ }
+}
+
+/*
+ returns true if <cluster> is marked as bad
+*/
+int
+fat_table_is_bad (const FatTable* ft, FatCluster cluster)
+{
+ return _test_code_bad (ft, fat_table_get (ft, cluster));
+}
+
+/*
+ returns true if <cluster> represents an EOF marker
+*/
+int _GL_ATTRIBUTE_PURE
+fat_table_is_eof (const FatTable* ft, FatCluster cluster)
+{
+ return _test_code_eof (ft, cluster);
+}
+
+/*
+ returns true if <cluster> is available.
+*/
+int
+fat_table_is_available (const FatTable* ft, FatCluster cluster)
+{
+ return _test_code_available (ft, fat_table_get (ft, cluster));
+}
+
+/*
+ returns true if <cluster> is empty. Note that this includes bad clusters.
+*/
+int
+fat_table_is_empty (const FatTable* ft, FatCluster cluster)
+{
+ return fat_table_is_available (ft, cluster)
+ || fat_table_is_bad (ft, cluster);
+}
+
+/*
+ returns true if <cluster> is being used for something constructive.
+*/
+int
+fat_table_is_active (const FatTable* ft, FatCluster cluster)
+{
+ return !fat_table_is_bad (ft, cluster)
+ && !fat_table_is_available (ft, cluster);
+}
+
+/*
+ marks <cluster> as the last cluster in the chain
+*/
+int
+fat_table_set_eof (FatTable* ft, FatCluster cluster)
+{
+
+ switch (ft->fat_type) {
+ case FAT_TYPE_FAT12:
+ PED_ASSERT (0);
+ break;
+
+ case FAT_TYPE_FAT16:
+ return fat_table_set (ft, cluster, 0xfff8);
+
+ case FAT_TYPE_FAT32:
+ return fat_table_set (ft, cluster, 0x0fffffff);
+ }
+
+ return 0;
+}
+
+/*
+ Marks a clusters as unusable, due to physical disk damage.
+*/
+int
+fat_table_set_bad (FatTable* ft, FatCluster cluster)
+{
+ if (!fat_table_is_bad (ft, cluster))
+ ft->bad_cluster_count++;
+
+ switch (ft->fat_type) {
+ case FAT_TYPE_FAT12:
+ return fat_table_set (ft, cluster, 0xff7);
+
+ case FAT_TYPE_FAT16:
+ return fat_table_set (ft, cluster, 0xfff7);
+
+ case FAT_TYPE_FAT32:
+ return fat_table_set (ft, cluster, 0x0ffffff7);
+ }
+
+ return 0;
+}
+
+/*
+ marks <cluster> as unused/free/available
+*/
+int
+fat_table_set_avail (FatTable* ft, FatCluster cluster)
+{
+ return fat_table_set (ft, cluster, 0);
+}
+
+#endif /* !DISCOVER_ONLY */
+
+int _GL_ATTRIBUTE_CONST
+fat_table_entry_size (FatType fat_type)
+{
+ switch (fat_type) {
+ case FAT_TYPE_FAT12:
+ return 2; /* FIXME: how? */
+
+ case FAT_TYPE_FAT16:
+ return 2;
+
+ case FAT_TYPE_FAT32:
+ return 4;
+ }
+
+ return 0;
+}
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