/*
- * utils.c
- * exFAT file system implementation library.
- *
- * Created by Andrew Nayenko on 04.09.09.
- * This software is distributed under the GNU General Public License
- * version 3 or any later.
- */
+ utils.c (04.09.09)
+ exFAT file system implementation library.
-#include "exfat.h"
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <unistd.h>
-#define _XOPEN_SOURCE /* for timezone in Linux */
-#include <time.h>
-#include <sys/time.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, rootdir_cluster, 0);
- }
- return clusters * CLUSTER_SIZE(*ef->sb);
-}
-
-int exfat_mount(struct exfat* ef, const char* spec)
-{
- tzset();
-
- ef->sb = malloc(sizeof(struct exfat_super_block));
- if (ef->sb == NULL)
- {
- exfat_error("memory allocation failed");
- return -ENOMEM;
- }
-
- ef->fd = open(spec, O_RDONLY); /* currently read only */
- if (ef->fd < 0)
- {
- free(ef->sb);
- exfat_error("failed to open `%s'", spec);
- return -EIO;
- }
+ Copyright (C) 2009, 2010 Andrew Nayenko
- 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);
- free(ef->sb);
- exfat_error("exFAT file system is not found");
- return -EIO;
- }
+ 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.
- ef->upcase = NULL;
- ef->upcase_chars = 0;
- ef->rootdir_size = rootdir_size(ef);
+ 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.
- return 0;
-}
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
-void exfat_unmount(struct exfat* ef)
-{
- close(ef->fd);
- ef->fd = 0;
- free(ef->sb);
- ef->sb = NULL;
- free(ef->upcase);
- ef->upcase = NULL;
- ef->upcase_chars = 0;
-}
+#include "exfat.h"
+#include <string.h>
+#define _XOPEN_SOURCE /* for timezone in Linux */
+#include <time.h>
-void exfat_stat(const struct exfat_node* node, struct stat *stbuf)
+void exfat_stat(const struct exfat* ef, const struct exfat_node* node,
+ struct stat* stbuf)
{
memset(stbuf, 0, sizeof(struct stat));
if (node->flags & EXFAT_ATTRIB_DIR)
- stbuf->st_mode = S_IFDIR | 0755;
+ stbuf->st_mode = S_IFDIR | (0777 & ~ef->dmask);
else
- stbuf->st_mode = S_IFREG | 0444;
+ stbuf->st_mode = S_IFREG | (0777 & ~ef->fmask);
stbuf->st_nlink = 1;
+ stbuf->st_uid = ef->uid;
+ stbuf->st_gid = ef->gid;
stbuf->st_size = node->size;
+ stbuf->st_blocks = DIV_ROUND_UP(node->size, CLUSTER_SIZE(*ef->sb)) *
+ CLUSTER_SIZE(*ef->sb) / 512;
stbuf->st_mtime = node->mtime;
stbuf->st_atime = node->atime;
stbuf->st_ctime = 0; /* unapplicable */
#define EPOCH_DIFF_DAYS (EPOCH_DIFF_YEAR * 365 + EPOCH_DIFF_YEAR / 4)
/* number of seconds from Unix epoch to exFAT epoch (considering leap days) */
#define EPOCH_DIFF_SEC (EPOCH_DIFF_DAYS * SEC_IN_DAY)
+/* number of leap years passed from exFAT epoch to the specified year
+ (excluding the specified year itself) */
+#define LEAP_YEARS(year) ((EXFAT_EPOCH_YEAR + (year) - 1) / 4 \
+ - (EXFAT_EPOCH_YEAR - 1) / 4)
+/* checks whether the specified year is leap */
+#define IS_LEAP_YEAR(year) ((EXFAT_EPOCH_YEAR + (year)) % 4 == 0)
static const time_t days_in_year[] =
{
0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
};
-union exfat_date
-{
- uint16_t raw;
- struct
- {
- uint16_t day : 5; /* 1-31 */
- uint16_t month : 4; /* 1-12 */
- uint16_t year : 7; /* 1-127 (+1980) */
- };
-};
-
-union exfat_time
-{
- uint16_t raw;
- struct
- {
- uint16_t twosec : 5; /* 0-29 (2 sec granularity) */
- uint16_t min : 6; /* 0-59 */
- uint16_t hour : 5; /* 0-23 */
- };
-};
-
time_t exfat_exfat2unix(le16_t date, le16_t time)
{
- union exfat_date edate;
- union exfat_time etime;
time_t unix_time = EPOCH_DIFF_SEC;
+ uint16_t ndate = le16_to_cpu(date);
+ uint16_t ntime = le16_to_cpu(time);
- edate.raw = le16_to_cpu(date);
- etime.raw = le16_to_cpu(time);
+ uint16_t day = ndate & 0x1f; /* 5 bits, 1-31 */
+ uint16_t month = ndate >> 5 & 0xf; /* 4 bits, 1-12 */
+ uint16_t year = ndate >> 9; /* 7 bits, 1-127 (+1980) */
- /*
- exfat_debug("%hu-%02hu-%02hu %hu:%02hu:%02hu",
- edate.year + 1980, edate.month, edate.day,
- etime.hour, etime.min, etime.twosec * 2);
- */
+ uint16_t twosec = ntime & 0x1f; /* 5 bits, 0-29 (2 sec granularity) */
+ uint16_t min = ntime >> 5 & 0xf; /* 6 bits, 0-59 */
+ uint16_t hour = ntime >> 11; /* 5 bits, 0-23 */
- if (edate.day == 0 || edate.month == 0 || edate.month > 12)
+ if (day == 0 || month == 0 || month > 12)
{
exfat_error("bad date %hu-%02hu-%02hu",
- edate.year + EXFAT_EPOCH_YEAR, edate.month, edate.day);
+ year + EXFAT_EPOCH_YEAR, month, day);
return 0;
}
- if (etime.hour > 23 || etime.min > 59 || etime.twosec > 29)
+ if (hour > 23 || min > 59 || twosec > 29)
{
exfat_error("bad time %hu:%02hu:%02hu",
- etime.hour, etime.min, etime.twosec * 2);
+ hour, min, twosec * 2);
return 0;
}
/* every 4th year between 1904 and 2096 is leap */
- unix_time += edate.year * SEC_IN_YEAR
- + ((EXFAT_EPOCH_YEAR + edate.year - 1) / 4 - (EXFAT_EPOCH_YEAR - 1) / 4)
- * SEC_IN_DAY;
- unix_time += days_in_year[edate.month] * SEC_IN_DAY;
+ unix_time += year * SEC_IN_YEAR + LEAP_YEARS(year) * SEC_IN_DAY;
+ unix_time += days_in_year[month] * SEC_IN_DAY;
/* if it's leap year and February has passed we should add 1 day */
- if ((EXFAT_EPOCH_YEAR + edate.year) % 4 == 0 && edate.month > 2)
+ if ((EXFAT_EPOCH_YEAR + year) % 4 == 0 && month > 2)
unix_time += SEC_IN_DAY;
- unix_time += (edate.day - 1) * SEC_IN_DAY;
+ unix_time += (day - 1) * SEC_IN_DAY;
- unix_time += etime.hour * SEC_IN_HOUR;
- unix_time += etime.min * SEC_IN_MIN;
+ unix_time += hour * SEC_IN_HOUR;
+ unix_time += min * SEC_IN_MIN;
/* exFAT represents time with 2 sec granularity */
- unix_time += etime.twosec * 2;
+ unix_time += twosec * 2;
/* exFAT stores timestamps in local time, so we correct it to UTC */
unix_time += timezone;
return unix_time;
}
+void exfat_unix2exfat(time_t unix_time, le16_t* date, le16_t* time)
+{
+ time_t shift = EPOCH_DIFF_SEC + timezone;
+ uint16_t day, month, year;
+ uint16_t twosec, min, hour;
+ int days;
+ int i;
+
+ /* time before exFAT epoch cannot be represented */
+ if (unix_time < shift)
+ unix_time = shift;
+
+ unix_time -= shift;
+
+ days = unix_time / SEC_IN_DAY;
+ year = (4 * days) / (4 * 365 + 1);
+ days -= year * 365 + LEAP_YEARS(year);
+ month = 0;
+ for (i = 1; i <= 12; i++)
+ {
+ int leap_day = (IS_LEAP_YEAR(year) && i == 2);
+ int leap_sub = (IS_LEAP_YEAR(year) && i >= 3);
+
+ if (i == 12 || days - leap_sub < days_in_year[i + 1] + leap_day)
+ {
+ month = i;
+ days -= days_in_year[i] + leap_sub;
+ break;
+ }
+ }
+ day = days + 1;
+
+ hour = (unix_time % SEC_IN_DAY) / SEC_IN_HOUR;
+ min = (unix_time % SEC_IN_HOUR) / SEC_IN_MIN;
+ twosec = (unix_time % SEC_IN_MIN) / 2;
+
+ *date = cpu_to_le16(day | (month << 5) | (year << 9));
+ *time = cpu_to_le16(twosec | (min << 5) | (hour << 11));
+}
+
void exfat_get_name(const struct exfat_node* node, char* buffer, size_t n)
{
if (utf16_to_utf8(buffer, node->name, n, EXFAT_NAME_MAX) != 0)
exfat_bug("failed to convert name to UTF-8");
}
+
+uint16_t exfat_start_checksum(const struct exfat_entry_meta1* entry)
+{
+ uint16_t sum = 0;
+ int i;
+
+ for (i = 0; i < sizeof(struct exfat_entry); i++)
+ if (i != 2 && i != 3) /* skip checksum field itself */
+ sum = ((sum << 15) | (sum >> 1)) + ((const uint8_t*) entry)[i];
+ return sum;
+}
+
+uint16_t exfat_add_checksum(const void* entry, uint16_t sum)
+{
+ int i;
+
+ for (i = 0; i < sizeof(struct exfat_entry); i++)
+ sum = ((sum << 15) | (sum >> 1)) + ((const uint8_t*) entry)[i];
+ return sum;
+}
+
+le16_t exfat_calc_checksum(const struct exfat_entry_meta1* meta1,
+ const struct exfat_entry_meta2* meta2, const le16_t* name)
+{
+ uint16_t checksum;
+ const int name_entries = DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX);
+ int i;
+
+ checksum = exfat_start_checksum(meta1);
+ checksum = exfat_add_checksum(meta2, checksum);
+ for (i = 0; i < name_entries; i++)
+ {
+ struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
+ memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
+ EXFAT_ENAME_MAX * sizeof(le16_t));
+ checksum = exfat_add_checksum(&name_entry, checksum);
+ }
+ return cpu_to_le16(checksum);
+}
+
+le16_t exfat_calc_name_hash(const struct exfat* ef, const le16_t* name)
+{
+ size_t i;
+ size_t length = utf16_length(name);
+ uint16_t hash = 0;
+
+ for (i = 0; i < length; i++)
+ {
+ uint16_t c = le16_to_cpu(name[i]);
+
+ /* convert to upper case */
+ if (c < ef->upcase_chars)
+ c = le16_to_cpu(ef->upcase[c]);
+
+ hash = ((hash << 15) | (hash >> 1)) + (c & 0xff);
+ hash = ((hash << 15) | (hash >> 1)) + (c >> 8);
+ }
+ return cpu_to_le16(hash);
+}
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