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	Some filesystems nowadays use 64-bit types for timestamps. So, update grub_dirhook_info struct to use an grub_int64_t type to store mtime. This also updates the grub_unixtime2datetime() function to receive a 64-bit timestamp argument and do 64-bit-safe divisions. All the remaining conversion from 32-bit to 64-bit should be safe, as 32-bit to 64-bit attributions will be implicitly casted. The most critical part in the 32-bit to 64-bit conversion is in the function grub_unixtime2datetime() where it needs to deal with the 64-bit type. So, for that, the grub_divmod64() helper has been used. These changes enables the GRUB to support dates beyond y2038. Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
		
			
				
	
	
		
			118 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			118 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* datetime.c - Module for common datetime function.  */
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/*
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 *  GRUB  --  GRand Unified Bootloader
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 *  Copyright (C) 2008  Free Software Foundation, Inc.
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 *
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 *  GRUB is free software: you can redistribute it and/or modify
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 *  it under the terms of the GNU General Public License as published by
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 *  the Free Software Foundation, either version 3 of the License, or
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 *  (at your option) any later version.
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 *
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 *  GRUB is distributed in the hope that it will be useful,
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 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *  GNU General Public License for more details.
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 *
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 *  You should have received a copy of the GNU General Public License
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 *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
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 */
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#include <grub/datetime.h>
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#include <grub/i18n.h>
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#include <grub/misc.h>
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#include <grub/mm.h>
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static const char *const grub_weekday_names[] =
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{
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  N_("Sunday"),
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  N_("Monday"),
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  N_("Tuesday"),
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  N_("Wednesday"),
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  N_("Thursday"),
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  N_("Friday"),
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  N_("Saturday"),
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};
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int
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grub_get_weekday (struct grub_datetime *datetime)
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{
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  unsigned a, y, m;
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  if (datetime->month <= 2)
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    a = 1;
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  else
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    a = 0;
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  y = datetime->year - a;
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  m = datetime->month + 12 * a - 2;
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  return (datetime->day + y + y / 4 - y / 100 + y / 400 + (31 * m / 12)) % 7;
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}
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const char *
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grub_get_weekday_name (struct grub_datetime *datetime)
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{
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  return _ (grub_weekday_names[grub_get_weekday (datetime)]);
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}
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#define SECPERMIN 60
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#define SECPERHOUR (60*SECPERMIN)
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#define SECPERDAY (24*SECPERHOUR)
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#define DAYSPERYEAR 365
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#define DAYSPER4YEARS (4*DAYSPERYEAR+1)
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void
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grub_unixtime2datetime (grub_int64_t nix, struct grub_datetime *datetime)
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{
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  int i;
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  grub_uint8_t months[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
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  /* In the period of validity of unixtime all years divisible by 4
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     are bissextile*/
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  /* Convenience: let's have 3 consecutive non-bissextile years
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     at the beginning of the counting date. So count from 1901. */
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  int days_epoch;
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  /* Number of days since 1st Januar, 1901.  */
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  unsigned days;
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  /* Seconds into current day.  */
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  unsigned secs_in_day;
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  /* Transform C divisions and modulos to mathematical ones */
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  if (nix < 0)
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    /*
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     * The result of division here shouldn't be larger than GRUB_INT_MAX.
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     * So, it's safe to store the result back in an int.
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     */
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    days_epoch = -(grub_divmod64 (((grub_int64_t) (SECPERDAY) - nix - 1), SECPERDAY, NULL));
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  else
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    days_epoch = grub_divmod64 (nix, SECPERDAY, NULL);
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  secs_in_day = nix - days_epoch * SECPERDAY;
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  days = days_epoch + 69 * DAYSPERYEAR + 17;
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  datetime->year = 1901 + 4 * (days / DAYSPER4YEARS);
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  days %= DAYSPER4YEARS;
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  /* On 31st December of bissextile years 365 days from the beginning
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     of the year elapsed but year isn't finished yet */
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  if (days / DAYSPERYEAR == 4)
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    {
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      datetime->year += 3;
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      days -= 3*DAYSPERYEAR;
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    }
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  else
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    {
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      datetime->year += days / DAYSPERYEAR;
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      days %= DAYSPERYEAR;
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    }
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  for (i = 0; i < 12
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	 && days >= (i==1 && datetime->year % 4 == 0
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		      ? 29 : months[i]); i++)
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    days -= (i==1 && datetime->year % 4 == 0
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			    ? 29 : months[i]);
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  datetime->month = i + 1;
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  datetime->day = 1 + days;
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  datetime->hour = (secs_in_day / SECPERHOUR);
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  secs_in_day %= SECPERHOUR;
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  datetime->minute = secs_in_day / SECPERMIN;
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  datetime->second = secs_in_day % SECPERMIN;
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}
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