blob: 027f8b0e05dd89df88a413a1c4b211d2f0048a11 [file] [log] [blame]
/*
mount.c (22.10.09)
exFAT file system implementation library.
Free exFAT implementation.
Copyright (C) 2010-2014 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 <inttypes.h>
#include <unistd.h>
#include <sys/types.h>
static uint64_t rootdir_size(const struct exfat* ef)
{
uint64_t clusters = 0;
cluster_t rootdir_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
while (!CLUSTER_INVALID(rootdir_cluster))
{
clusters++;
/* root directory cannot be contiguous because there is no flag
to indicate this */
rootdir_cluster = exfat_next_cluster(ef, ef->root, rootdir_cluster);
}
if (rootdir_cluster != EXFAT_CLUSTER_END)
{
exfat_error("bad cluster %#x while reading root directory",
rootdir_cluster);
return 0;
}
return 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 sys_umask = umask(0);
int opt_umask;
umask(sys_umask); /* restore umask */
opt_umask = get_int_option(options, "umask", 8, sys_umask);
ef->dmask = get_int_option(options, "dmask", 8, opt_umask) & 0777;
ef->fmask = get_int_option(options, "fmask", 8, opt_umask) & 0777;
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,
off64_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);
}
static int prepare_super_block(const struct exfat* ef)
{
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_close(ef->dev);
exfat_error("failed to allocate memory for the super block");
return -ENOMEM;
}
memset(ef->sb, 0, sizeof(struct exfat_super_block));
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 read boot sector");
return -EIO;
}
if (memcmp(ef->sb->oem_name, "EXFAT ", 8) != 0)
{
exfat_close(ef->dev);
free(ef->sb);
exfat_error("exFAT file system is not found");
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;
}
/* officially exFAT supports cluster size up to 32 MB */
if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
{
free(ef->zero_cluster);
exfat_close(ef->dev);
exfat_error("too big cluster size: 2^%d",
(int) ef->sb->sector_bits + (int) ef->sb->spc_bits);
free(ef->sb);
return -EIO;
}
if (le64_to_cpu(ef->sb->sector_count) * SECTOR_SIZE(*ef->sb) >
exfat_get_size(ef->dev))
{
free(ef->zero_cluster);
exfat_error("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));
exfat_close(ef->dev);
free(ef->sb);
return -EIO;
}
ef->root = malloc(sizeof(struct exfat_node));
if (ef->root == NULL)
{
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->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_flush(ef); /* ignore return code */
exfat_put_node(ef, ef->root);
exfat_reset_cache(ef);
free(ef->root);
ef->root = NULL;
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;
}