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-rw-r--r--sys/conf/files1
-rw-r--r--sys/kern/subr_fattime.c304
-rw-r--r--sys/sys/clock.h3
3 files changed, 308 insertions, 0 deletions
diff --git a/sys/conf/files b/sys/conf/files
index e255f24..c257af4 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1374,6 +1374,7 @@ kern/subr_clock.c standard
kern/subr_devstat.c standard
kern/subr_disk.c standard
kern/subr_eventhandler.c standard
+kern/subr_fattime.c standard
kern/subr_firmware.c optional firmware
kern/subr_hints.c standard
kern/subr_kdb.c standard
diff --git a/sys/kern/subr_fattime.c b/sys/kern/subr_fattime.c
new file mode 100644
index 0000000..2a280e5
--- /dev/null
+++ b/sys/kern/subr_fattime.c
@@ -0,0 +1,304 @@
+/*-
+ * Copyright (c) 2006 Poul-Henning Kamp
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ *
+ * Convert MS-DOS FAT format timestamps to and from unix timespecs
+ *
+ * FAT filestamps originally consisted of two 16 bit integers, encoded like
+ * this:
+ *
+ * yyyyyyymmmmddddd (year - 1980, month, day)
+ *
+ * hhhhhmmmmmmsssss (hour, minutes, seconds divided by two)
+ *
+ * Subsequently even Microsoft realized that files could be accessed in less
+ * than two seconds and a byte was added containing:
+ *
+ * sfffffff (second mod two, 100ths of second)
+ *
+ * FAT timestamps are in the local timezone, with no indication of which
+ * timezone much less if daylight savings time applies.
+ *
+ * Later on again, in Windows NT, timestamps were defined relative to GMT.
+ *
+ * Purists will point out that UTC replaced GMT for such uses around
+ * a century ago, already then. Ironically "NT" was an abbreviation of
+ * "New Technology". Anyway...
+ *
+ * The functions below always assume UTC time, and the calling code
+ * must apply the local timezone offset as appropriate. Unless special
+ * conditions apply, the utc_offset() function be used for this.
+ *
+ * The conversion functions below cut time into four-year leap-second
+ * cycles rather than single years and uses table lookups inside those
+ * cycles to get the months and years sorted out.
+ *
+ * Obviously we cannot calculate the correct table index going from
+ * a posix seconds count to Y/M/D, but we can get pretty close by
+ * dividing the daycount by 32 (giving a too low index), and then
+ * adjusting upwards a couple of steps if necessary.
+ *
+ * FAT timestamps have 7 bits for the year and starts at 1980, so
+ * they can represent up to 2107 which means that the non-leap-year
+ * 2100 must be handled.
+ *
+ * XXX: As long as time_t is 32 bits this is not relevant or easily
+ * XXX: testable. Revisit when time_t grows bigger.
+ * XXX: grepfodder: 64 bit time_t, y2100, y2.1k, 2100, leap year
+ *
+ */
+
+#include <sys/param.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/clock.h>
+
+#define DAY (24 * 60 * 60) /* Length of day in seconds */
+#define YEAR 365 /* Length of normal year */
+#define LYC (4 * YEAR + 1) /* Length of 4 year leap-year cycle */
+#define T1980 (10 * 365 + 2) /* Days from 1970 to 1980 */
+
+/* End of month is N days from start of (normal) year */
+#define JAN 31
+#define FEB (JAN + 28)
+#define MAR (FEB + 31)
+#define APR (MAR + 30)
+#define MAY (APR + 31)
+#define JUN (MAY + 30)
+#define JUL (JUN + 31)
+#define AUG (JUL + 31)
+#define SEP (AUG + 30)
+#define OCT (SEP + 31)
+#define NOV (OCT + 30)
+#define DEC (NOV + 31)
+
+/* Table of months in a 4 year leap-year cycle */
+
+#define ENC(y,m) (((y) << 9) | ((m) << 5))
+
+static const struct {
+ uint16_t days; /* month start in days relative to cycle */
+ uint16_t coded; /* encoded year + month information */
+} mtab[48] = {
+ { 0 + 0 * YEAR, ENC(0, 1) },
+
+ { JAN + 0 * YEAR, ENC(0, 2) }, { FEB + 0 * YEAR + 1, ENC(0, 3) },
+ { MAR + 0 * YEAR + 1, ENC(0, 4) }, { APR + 0 * YEAR + 1, ENC(0, 5) },
+ { MAY + 0 * YEAR + 1, ENC(0, 6) }, { JUN + 0 * YEAR + 1, ENC(0, 7) },
+ { JUL + 0 * YEAR + 1, ENC(0, 8) }, { AUG + 0 * YEAR + 1, ENC(0, 9) },
+ { SEP + 0 * YEAR + 1, ENC(0, 10) }, { OCT + 0 * YEAR + 1, ENC(0, 11) },
+ { NOV + 0 * YEAR + 1, ENC(0, 12) }, { DEC + 0 * YEAR + 1, ENC(1, 1) },
+
+ { JAN + 1 * YEAR + 1, ENC(1, 2) }, { FEB + 1 * YEAR + 1, ENC(1, 3) },
+ { MAR + 1 * YEAR + 1, ENC(1, 4) }, { APR + 1 * YEAR + 1, ENC(1, 5) },
+ { MAY + 1 * YEAR + 1, ENC(1, 6) }, { JUN + 1 * YEAR + 1, ENC(1, 7) },
+ { JUL + 1 * YEAR + 1, ENC(1, 8) }, { AUG + 1 * YEAR + 1, ENC(1, 9) },
+ { SEP + 1 * YEAR + 1, ENC(1, 10) }, { OCT + 1 * YEAR + 1, ENC(1, 11) },
+ { NOV + 1 * YEAR + 1, ENC(1, 12) }, { DEC + 1 * YEAR + 1, ENC(2, 1) },
+
+ { JAN + 2 * YEAR + 1, ENC(2, 2) }, { FEB + 2 * YEAR + 1, ENC(2, 3) },
+ { MAR + 2 * YEAR + 1, ENC(2, 4) }, { APR + 2 * YEAR + 1, ENC(2, 5) },
+ { MAY + 2 * YEAR + 1, ENC(2, 6) }, { JUN + 2 * YEAR + 1, ENC(2, 7) },
+ { JUL + 2 * YEAR + 1, ENC(2, 8) }, { AUG + 2 * YEAR + 1, ENC(2, 9) },
+ { SEP + 2 * YEAR + 1, ENC(2, 10) }, { OCT + 2 * YEAR + 1, ENC(2, 11) },
+ { NOV + 2 * YEAR + 1, ENC(2, 12) }, { DEC + 2 * YEAR + 1, ENC(3, 1) },
+
+ { JAN + 3 * YEAR + 1, ENC(3, 2) }, { FEB + 3 * YEAR + 1, ENC(3, 3) },
+ { MAR + 3 * YEAR + 1, ENC(3, 4) }, { APR + 3 * YEAR + 1, ENC(3, 5) },
+ { MAY + 3 * YEAR + 1, ENC(3, 6) }, { JUN + 3 * YEAR + 1, ENC(3, 7) },
+ { JUL + 3 * YEAR + 1, ENC(3, 8) }, { AUG + 3 * YEAR + 1, ENC(3, 9) },
+ { SEP + 3 * YEAR + 1, ENC(3, 10) }, { OCT + 3 * YEAR + 1, ENC(3, 11) },
+ { NOV + 3 * YEAR + 1, ENC(3, 12) }
+};
+
+
+void
+timet2fattime(struct timespec *tsp, u_int16_t *ddp, u_int16_t *dtp, u_int8_t *dhp)
+{
+ time_t t1;
+ unsigned t2, l, m;
+
+ t1 = tsp->tv_sec;
+
+ if (dhp != NULL)
+ *dhp = (tsp->tv_sec & 1) * 100 + tsp->tv_nsec / 10000000;
+ if (dtp != NULL) {
+ *dtp = (t1 / 2) % 30;
+ *dtp |= ((t1 / 60) % 60) << 5;
+ *dtp |= ((t1 / 3600) % 24) << 11;
+ }
+ if (ddp != NULL) {
+ t2 = t1 / DAY;
+ if (t2 < T1980) {
+ /* Impossible date, truncate to 1980-01-01 */
+ *ddp = 0x0021;
+ } else {
+ t2 -= T1980;
+
+ /*
+ * 2100 is not a leap year.
+ * XXX: a 32 bit time_t can not get us here.
+ */
+ if (t2 >= ((2100 - 1980) / 4 * LYC + FEB))
+ t2++;
+
+ /* Account for full leapyear cycles */
+ l = t2 / LYC;
+ *ddp = (l * 4) << 9;
+ t2 -= l * LYC;
+
+ /* Find approximate table entry */
+ m = t2 / 32;
+
+ /* Find correct table entry */
+ while (m < 47 && mtab[m + 1].days <= t2)
+ m++;
+
+ /* Get year + month from the table */
+ *ddp += mtab[m].coded;
+
+ /* And apply the day in the month */
+ t2 -= mtab[m].days - 1;
+ *ddp |= t2;
+ }
+ }
+}
+
+/*
+ * Table indexed by the bottom two bits of year + four bits of the month
+ * from the FAT timestamp, returning number of days into 4 year long
+ * leap-year cycle
+ */
+
+#define DCOD(m, y, l) ((m) + YEAR * (y) + (l))
+static const uint16_t daytab[64] = {
+ 0, DCOD( 0, 0, 0), DCOD(JAN, 0, 0), DCOD(FEB, 0, 1),
+ DCOD(MAR, 0, 1), DCOD(APR, 0, 1), DCOD(MAY, 0, 1), DCOD(JUN, 0, 1),
+ DCOD(JUL, 0, 1), DCOD(AUG, 0, 1), DCOD(SEP, 0, 1), DCOD(OCT, 0, 1),
+ DCOD(NOV, 0, 1), DCOD(DEC, 0, 1), 0, 0,
+ 0, DCOD( 0, 1, 1), DCOD(JAN, 1, 1), DCOD(FEB, 1, 1),
+ DCOD(MAR, 1, 1), DCOD(APR, 1, 1), DCOD(MAY, 1, 1), DCOD(JUN, 1, 1),
+ DCOD(JUL, 1, 1), DCOD(AUG, 1, 1), DCOD(SEP, 1, 1), DCOD(OCT, 1, 1),
+ DCOD(NOV, 1, 1), DCOD(DEC, 1, 1), 0, 0,
+ 0, DCOD( 0, 2, 1), DCOD(JAN, 2, 1), DCOD(FEB, 2, 1),
+ DCOD(MAR, 2, 1), DCOD(APR, 2, 1), DCOD(MAY, 2, 1), DCOD(JUN, 2, 1),
+ DCOD(JUL, 2, 1), DCOD(AUG, 2, 1), DCOD(SEP, 2, 1), DCOD(OCT, 2, 1),
+ DCOD(NOV, 2, 1), DCOD(DEC, 2, 1), 0, 0,
+ 0, DCOD( 0, 3, 1), DCOD(JAN, 3, 1), DCOD(FEB, 3, 1),
+ DCOD(MAR, 3, 1), DCOD(APR, 3, 1), DCOD(MAY, 3, 1), DCOD(JUN, 3, 1),
+ DCOD(JUL, 3, 1), DCOD(AUG, 3, 1), DCOD(SEP, 3, 1), DCOD(OCT, 3, 1),
+ DCOD(NOV, 3, 1), DCOD(DEC, 3, 1), 0, 0
+};
+
+void
+fattime2timet(unsigned dd, unsigned dt, unsigned dh, struct timespec *tsp)
+{
+ unsigned day;
+
+ /* Unpack time fields */
+ tsp->tv_sec = (dt & 0x1f) << 1;
+ tsp->tv_sec += ((dt & 0x7e0) >> 5) * 60;
+ tsp->tv_sec += ((dt & 0xf800) >> 11) * 3600;
+ tsp->tv_sec += dh / 100;
+ tsp->tv_nsec = (dh % 100) * 10000000;
+
+ /* Day of month */
+ day = (dd & 0x1f) - 1;
+
+ /* Full leap-year cycles */
+ day += LYC * ((dd >> 11) & 0x1f);
+
+ /* Month offset from leap-year cycle */
+ day += daytab[(dd >> 5) & 0x3f];
+
+ /*
+ * 2100 is not a leap year.
+ * XXX: a 32 bit time_t can not get us here.
+ */
+ if (day >= ((2100 - 1980) / 4 * LYC + FEB))
+ day--;
+
+ /* Align with time_t epoch */
+ day += T1980;
+
+ tsp->tv_sec += DAY * day;
+}
+
+#ifdef TEST_DRIVER
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+int
+main(int argc __unused, char **argv __unused)
+{
+ int i;
+ struct timespec ts;
+ struct tm tm;
+ double a;
+ u_int16_t d, t;
+ u_int8_t p;
+ char buf[100];
+
+ for (i = 0; i < 10000; i++) {
+ do {
+ ts.tv_sec = random();
+ } while (ts.tv_sec < T1980 * 86400);
+ ts.tv_nsec = random() % 1000000000;
+
+ printf("%10d.%03ld -- ", ts.tv_sec, ts.tv_nsec / 1000000);
+
+ gmtime_r(&ts.tv_sec, &tm);
+ strftime(buf, sizeof buf, "%Y %m %d %H %M %S", &tm);
+ printf("%s -- ", buf);
+
+ a = ts.tv_sec + ts.tv_nsec * 1e-9;
+ d = t = p = 0;
+ timet2fattime(&ts, &d, &t, &p);
+ printf("%04x %04x %02x -- ", d, t, p);
+ printf("%3d %02d %02d %02d %02d %02d -- ",
+ ((d >> 9) & 0x7f) + 1980,
+ (d >> 5) & 0x0f,
+ (d >> 0) & 0x1f,
+ (t >> 11) & 0x1f,
+ (t >> 5) & 0x3f,
+ ((t >> 0) & 0x1f) * 2);
+
+ ts.tv_sec = ts.tv_nsec = 0;
+ fattime2timet(d, t, p, &ts);
+ printf("%10d.%03ld == ", ts.tv_sec, ts.tv_nsec / 1000000);
+ gmtime_r(&ts.tv_sec, &tm);
+ strftime(buf, sizeof buf, "%Y %m %d %H %M %S", &tm);
+ printf("%s -- ", buf);
+ a -= ts.tv_sec + ts.tv_nsec * 1e-9;
+ printf("%.3f", a);
+ printf("\n");
+ }
+ return (0);
+}
+
+#endif /* TEST_DRIVER */
diff --git a/sys/sys/clock.h b/sys/sys/clock.h
index 072328d..5c0252d 100644
--- a/sys/sys/clock.h
+++ b/sys/sys/clock.h
@@ -93,6 +93,9 @@ void clock_register(device_t, long);
/* Traditional POSIX base year */
#define POSIX_BASE_YEAR 1970
+void timet2fattime(struct timespec *tsp, u_int16_t *ddp, u_int16_t *dtp, u_int8_t *dhp);
+void fattime2timet(unsigned dd, unsigned dt, unsigned dh, struct timespec *tsp);
+
#endif /* _KERNEL */
#endif /* !_SYS_CLOCK_H_ */
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