/*
- * mount.c
- * exFAT file system implementation library.
- *
- * Created by Andrew Nayenko on 22.10.09.
- * This software is distributed under the GNU General Public License
- * version 3 or any later.
- */
+ mount.c (22.10.09)
+ exFAT file system implementation library.
+
+ Free exFAT implementation.
+ Copyright (C) 2010-2016 Andrew Nayenko
+
+ 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 2 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, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
#include "exfat.h"
#include <string.h>
+#include <stdlib.h>
#include <errno.h>
-#include <fcntl.h>
+#include <inttypes.h>
#include <unistd.h>
-#define _XOPEN_SOURCE /* for tzset() in Linux */
-#include <time.h>
+#include <sys/types.h>
static uint64_t rootdir_size(const struct exfat* ef)
{
- uint64_t clusters = 0;
+ uint32_t clusters = 0;
+ uint32_t clusters_max = le32_to_cpu(ef->sb->cluster_count);
cluster_t rootdir_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
- while (!CLUSTER_INVALID(rootdir_cluster))
+ /* Iterate all clusters of the root directory to calculate its size.
+ It can't be contiguous because there is no flag to indicate this. */
+ do
{
+ if (clusters == clusters_max) /* infinite loop detected */
+ {
+ exfat_error("root directory cannot occupy all %d clusters",
+ clusters);
+ return 0;
+ }
+ if (CLUSTER_INVALID(rootdir_cluster))
+ {
+ exfat_error("bad cluster %#x while reading root directory",
+ rootdir_cluster);
+ return 0;
+ }
+ rootdir_cluster = exfat_next_cluster(ef, ef->root, rootdir_cluster);
clusters++;
- /* root directory cannot be contiguous because there is no flag
- to indicate this */
- rootdir_cluster = exfat_next_cluster(ef, rootdir_cluster, 0);
}
- return clusters * CLUSTER_SIZE(*ef->sb);
+ while (rootdir_cluster != EXFAT_CLUSTER_END);
+
+ return (uint64_t) clusters * CLUSTER_SIZE(*ef->sb);
+}
+
+static const char* get_option(const char* options, const char* option_name)
+{
+ const char* p;
+ size_t length = strlen(option_name);
+
+ for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
+ if ((p == options || p[-1] == ',') && p[length] == '=')
+ return p + length + 1;
+ return NULL;
+}
+
+static int get_int_option(const char* options, const char* option_name,
+ int base, int default_value)
+{
+ const char* p = get_option(options, option_name);
+
+ if (p == NULL)
+ return default_value;
+ return strtol(p, NULL, base);
+}
+
+static bool match_option(const char* options, const char* option_name)
+{
+ const char* p;
+ size_t length = strlen(option_name);
+
+ for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
+ if ((p == options || p[-1] == ',') &&
+ (p[length] == ',' || p[length] == '\0'))
+ return true;
+ return false;
+}
+
+static void parse_options(struct exfat* ef, const char* options)
+{
+ int opt_umask;
+
+ opt_umask = get_int_option(options, "umask", 8, 0);
+ ef->dmask = get_int_option(options, "dmask", 8, opt_umask);
+ ef->fmask = get_int_option(options, "fmask", 8, opt_umask);
+
+ ef->uid = get_int_option(options, "uid", 10, geteuid());
+ ef->gid = get_int_option(options, "gid", 10, getegid());
+
+ ef->noatime = match_option(options, "noatime");
+}
+
+static bool verify_vbr_checksum(struct exfat_dev* dev, void* sector,
+ off_t sector_size)
+{
+ uint32_t vbr_checksum;
+ int i;
+
+ if (exfat_pread(dev, sector, sector_size, 0) < 0)
+ {
+ exfat_error("failed to read boot sector");
+ return false;
+ }
+ vbr_checksum = exfat_vbr_start_checksum(sector, sector_size);
+ for (i = 1; i < 11; i++)
+ {
+ if (exfat_pread(dev, sector, sector_size, i * sector_size) < 0)
+ {
+ exfat_error("failed to read VBR sector");
+ return false;
+ }
+ vbr_checksum = exfat_vbr_add_checksum(sector, sector_size,
+ vbr_checksum);
+ }
+ if (exfat_pread(dev, sector, sector_size, i * sector_size) < 0)
+ {
+ exfat_error("failed to read VBR checksum sector");
+ return false;
+ }
+ for (i = 0; i < sector_size / sizeof(vbr_checksum); i++)
+ if (le32_to_cpu(((const le32_t*) sector)[i]) != vbr_checksum)
+ {
+ exfat_error("invalid VBR checksum 0x%x (expected 0x%x)",
+ le32_to_cpu(((const le32_t*) sector)[i]), vbr_checksum);
+ return false;
+ }
+ return true;
+}
+
+static int commit_super_block(const struct exfat* ef)
+{
+ if (exfat_pwrite(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0) < 0)
+ {
+ exfat_error("failed to write super block");
+ return 1;
+ }
+ return exfat_fsync(ef->dev);
}
-int exfat_mount(struct exfat* ef, const char* spec)
+static int prepare_super_block(const struct exfat* ef)
{
- tzset();
+ if (le16_to_cpu(ef->sb->volume_state) & EXFAT_STATE_MOUNTED)
+ exfat_warn("volume was not unmounted cleanly");
+
+ if (ef->ro)
+ return 0;
+
+ ef->sb->volume_state = cpu_to_le16(
+ le16_to_cpu(ef->sb->volume_state) | EXFAT_STATE_MOUNTED);
+ return commit_super_block(ef);
+}
+
+int exfat_mount(struct exfat* ef, const char* spec, const char* options)
+{
+ int rc;
+ enum exfat_mode mode;
+
+ exfat_tzset();
+ memset(ef, 0, sizeof(struct exfat));
+
+ parse_options(ef, options);
+
+ if (match_option(options, "ro"))
+ mode = EXFAT_MODE_RO;
+ else if (match_option(options, "ro_fallback"))
+ mode = EXFAT_MODE_ANY;
+ else
+ mode = EXFAT_MODE_RW;
+ ef->dev = exfat_open(spec, mode);
+ if (ef->dev == NULL)
+ return -EIO;
+ if (exfat_get_mode(ef->dev) == EXFAT_MODE_RO)
+ {
+ if (mode == EXFAT_MODE_ANY)
+ ef->ro = -1;
+ else
+ ef->ro = 1;
+ }
ef->sb = malloc(sizeof(struct exfat_super_block));
if (ef->sb == NULL)
{
- exfat_error("memory allocation failed");
+ exfat_close(ef->dev);
+ exfat_error("failed to allocate memory for the super block");
return -ENOMEM;
}
+ memset(ef->sb, 0, sizeof(struct exfat_super_block));
- ef->fd = open(spec, O_RDWR);
- if (ef->fd < 0)
+ if (exfat_pread(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0) < 0)
{
+ exfat_close(ef->dev);
free(ef->sb);
- exfat_error("failed to open `%s'", spec);
+ exfat_error("failed to read boot sector");
return -EIO;
}
-
- exfat_read_raw(ef->sb, sizeof(struct exfat_super_block), 0, ef->fd);
if (memcmp(ef->sb->oem_name, "EXFAT ", 8) != 0)
{
- close(ef->fd);
+ exfat_close(ef->dev);
free(ef->sb);
exfat_error("exFAT file system is not found");
return -EIO;
}
-
- ef->upcase = NULL;
- ef->upcase_chars = 0;
- ef->rootdir_size = rootdir_size(ef);
+ /* sector cannot be smaller than 512 bytes */
+ if (ef->sb->sector_bits < 9)
+ {
+ exfat_close(ef->dev);
+ exfat_error("too small sector size: 2^%hhd", ef->sb->sector_bits);
+ free(ef->sb);
+ return -EIO;
+ }
+ /* officially exFAT supports cluster size up to 32 MB */
+ if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
+ {
+ exfat_close(ef->dev);
+ exfat_error("too big cluster size: 2^(%hhd+%hhd)",
+ ef->sb->sector_bits, ef->sb->spc_bits);
+ free(ef->sb);
+ return -EIO;
+ }
+ ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
+ if (ef->zero_cluster == NULL)
+ {
+ exfat_close(ef->dev);
+ free(ef->sb);
+ exfat_error("failed to allocate zero sector");
+ return -ENOMEM;
+ }
+ /* use zero_cluster as a temporary buffer for VBR checksum verification */
+ if (!verify_vbr_checksum(ef->dev, ef->zero_cluster, SECTOR_SIZE(*ef->sb)))
+ {
+ free(ef->zero_cluster);
+ exfat_close(ef->dev);
+ free(ef->sb);
+ return -EIO;
+ }
+ memset(ef->zero_cluster, 0, CLUSTER_SIZE(*ef->sb));
+ if (ef->sb->version.major != 1 || ef->sb->version.minor != 0)
+ {
+ free(ef->zero_cluster);
+ exfat_close(ef->dev);
+ exfat_error("unsupported exFAT version: %hhu.%hhu",
+ ef->sb->version.major, ef->sb->version.minor);
+ free(ef->sb);
+ return -EIO;
+ }
+ if (ef->sb->fat_count != 1)
+ {
+ free(ef->zero_cluster);
+ exfat_close(ef->dev);
+ exfat_error("unsupported FAT count: %hhu", ef->sb->fat_count);
+ free(ef->sb);
+ return -EIO;
+ }
+ if (le64_to_cpu(ef->sb->sector_count) * SECTOR_SIZE(*ef->sb) >
+ exfat_get_size(ef->dev))
+ {
+ /* this can cause I/O errors later but we don't fail mounting to let
+ user rescue data */
+ exfat_warn("file system is larger than underlying device: "
+ "%"PRIu64" > %"PRIu64,
+ le64_to_cpu(ef->sb->sector_count) * SECTOR_SIZE(*ef->sb),
+ exfat_get_size(ef->dev));
+ }
ef->root = malloc(sizeof(struct exfat_node));
if (ef->root == NULL)
{
- close(ef->fd);
+ free(ef->zero_cluster);
+ exfat_close(ef->dev);
free(ef->sb);
exfat_error("failed to allocate root node");
return -ENOMEM;
}
memset(ef->root, 0, sizeof(struct exfat_node));
- ef->root->flags = EXFAT_ATTRIB_DIR;
- ef->root->size = ef->rootdir_size;
+ ef->root->attrib = EXFAT_ATTRIB_DIR;
ef->root->start_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
+ ef->root->fptr_cluster = ef->root->start_cluster;
ef->root->name[0] = cpu_to_le16('\0');
+ ef->root->size = rootdir_size(ef);
+ if (ef->root->size == 0)
+ {
+ free(ef->root);
+ free(ef->zero_cluster);
+ exfat_close(ef->dev);
+ free(ef->sb);
+ return -EIO;
+ }
/* exFAT does not have time attributes for the root directory */
ef->root->mtime = 0;
ef->root->atime = 0;
/* always keep at least 1 reference to the root node */
exfat_get_node(ef->root);
+ rc = exfat_cache_directory(ef, ef->root);
+ if (rc != 0)
+ goto error;
+ if (ef->upcase == NULL)
+ {
+ exfat_error("upcase table is not found");
+ goto error;
+ }
+ if (ef->cmap.chunk == NULL)
+ {
+ exfat_error("clusters bitmap is not found");
+ goto error;
+ }
+
+ if (prepare_super_block(ef) != 0)
+ goto error;
+
return 0;
+
+error:
+ exfat_put_node(ef, ef->root);
+ exfat_reset_cache(ef);
+ free(ef->root);
+ free(ef->zero_cluster);
+ exfat_close(ef->dev);
+ free(ef->sb);
+ return -EIO;
+}
+
+static void finalize_super_block(struct exfat* ef)
+{
+ if (ef->ro)
+ return;
+
+ ef->sb->volume_state = cpu_to_le16(
+ le16_to_cpu(ef->sb->volume_state) & ~EXFAT_STATE_MOUNTED);
+
+ /* Some implementations set the percentage of allocated space to 0xff
+ on FS creation and never update it. In this case leave it as is. */
+ if (ef->sb->allocated_percent != 0xff)
+ {
+ uint32_t free, total;
+
+ free = exfat_count_free_clusters(ef);
+ total = le32_to_cpu(ef->sb->cluster_count);
+ ef->sb->allocated_percent = ((total - free) * 100 + total / 2) / total;
+ }
+
+ commit_super_block(ef); /* ignore return code */
}
void exfat_unmount(struct exfat* ef)
{
- exfat_put_node(ef->root);
+ exfat_flush_nodes(ef); /* ignore return code */
+ exfat_flush(ef); /* ignore return code */
+ exfat_put_node(ef, ef->root);
exfat_reset_cache(ef);
+ free(ef->root);
ef->root = NULL;
- close(ef->fd);
- ef->fd = 0;
+ finalize_super_block(ef);
+ exfat_close(ef->dev); /* close descriptor immediately after fsync */
+ ef->dev = NULL;
+ free(ef->zero_cluster);
+ ef->zero_cluster = NULL;
+ free(ef->cmap.chunk);
+ ef->cmap.chunk = NULL;
free(ef->sb);
ef->sb = NULL;
free(ef->upcase);
ef->upcase = NULL;
- ef->upcase_chars = 0;
}
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