Fix Bug #9191 "TIMESTAMP/from_unixtime() no longer accepts 2^31-1"

(4.1 version, with post-review fixes)
  
  The fix for another Bug (6439) limited FROM_UNIXTIME() to
  TIMESTAMP_MAX_VALUE which is 2145916799 or 2037-12-01 23:59:59 GMT,
  however unix timestamp in general is not considered to be limited 
  by this value. All dates up to power(2,31)-1 are valid.
  
  This patch extends allowed TIMESTAMP range so, that max
  TIMESTAMP value is power(2,31)-1. It also corrects
  FROM_UNIXTIME() and UNIX_TIMESTAMP() functions, so that
  max allowed UNIX_TIMESTAMP() is power(2,31)-1. FROM_UNIXTIME()
  is fixed accordingly to allow conversion of dates up to
  2038-01-19 03:14:07 UTC. The patch also fixes CONVERT_TZ()
  function to allow extended range of dates.
  
  The main problem solved in the patch is possible overflows
  of variables, used in broken-time representation to time_t
  conversion (required for UNIX_TIMESTAMP).


acinclude.m4:
  Add new macro to check time_t range
configure.in:
  Call the macro to check time_t range
include/my_time.h:
  Move time-related defines to proper place.
  Add a function to perform a rough check if
  a TIMESTAMP value fits into the boundaries.
  Note: it is defined as "static inline", as
  otherwise libmysql won't compile (due to the
  way how gcc handles "inline" directive).
mysql-test/r/func_time.result:
  Update test result
mysql-test/r/timezone.result:
  Update test result
mysql-test/r/timezone2.result:
  Update test result
mysql-test/t/func_time.test:
  Add test for Bug#9191 and update test to be consistent
  with new TIMESTAMP boundaries
mysql-test/t/timezone.test:
  Update old tests to be consistent
  with new TIMESTAMP boundaries
mysql-test/t/timezone2.test:
  Update tests for convert_tz to be consistent with new
  TIMESTAMP boundaries
sql/item_timefunc.cc:
  Fix convert_tz to allow dates from the new (extended)
  TIMESTAMP range
sql/mysql_priv.h:
  Move time handling defaults to my_time.h
sql-common/my_time.c:
  Because of increased TIMESTAMP_MAX_VALUE overflows in my_system_gmt_sec()
  became possible. Here we make it safe against the overflows by stepping
  back from the boundary dates which are likely to trigger them.
sql/time.cc:
  Update TIME_to_timestamp to allow conversion of
  extended date range
sql/tztime.cc:
  Fix new (4.1) implementation of broken-down time representation
  to time_t conversion routine to avoid overflows during conversion
  of boundary dates
mysql-test/r/timezone4.result:
  New BitKeeper file ``mysql-test/r/timezone4.result''
mysql-test/t/timezone4-master.opt:
  New BitKeeper file ``mysql-test/t/timezone4-master.opt''
mysql-test/t/timezone4.test:
  New BitKeeper file ``mysql-test/t/timezone4.test''

4 files changed, 75 insertions, 29 deletions

diff --git a/sql/item_timefunc.cc b/sql/item_timefunc.cc
index febc92e34f6..68eb2178804 100644
--- a/sql/item_timefunc.cc
+++ b/sql/item_timefunc.cc
@@ -1827,15 +1827,10 @@ bool Item_func_convert_tz::get_date(TIME *ltime,
     return 1;
   }
 
-  /* Check if we in range where we treat datetime values as non-UTC */
-  if (ltime->year < TIMESTAMP_MAX_YEAR && ltime->year > TIMESTAMP_MIN_YEAR ||
-      ltime->year==TIMESTAMP_MAX_YEAR && ltime->month==1 && ltime->day==1 ||
-      ltime->year==TIMESTAMP_MIN_YEAR && ltime->month==12 && ltime->day==31)
-  {
-    my_time_tmp= from_tz->TIME_to_gmt_sec(ltime, &not_used);
-    if (my_time_tmp >= TIMESTAMP_MIN_VALUE && my_time_tmp <= TIMESTAMP_MAX_VALUE)
-      to_tz->gmt_sec_to_TIME(ltime, my_time_tmp);
-  }
+  my_time_tmp= from_tz->TIME_to_gmt_sec(ltime, &not_used);
+  /* my_time_tmp is guranteed to be in the allowed range */
+  if (my_time_tmp)
+    to_tz->gmt_sec_to_TIME(ltime, my_time_tmp);
   
   null_value= 0;
   return 0;
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index 4a5658c5ccf..c0525198d4a 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -142,12 +142,6 @@ MY_LOCALE *my_locale_by_name(const char *name);
 /* Characters shown for the command in 'show processlist' */
 #define PROCESS_LIST_WIDTH 100
 
-/* Time handling defaults */
-#define TIMESTAMP_MAX_YEAR 2038
-#define YY_PART_YEAR	   70
-#define TIMESTAMP_MIN_YEAR (1900 + YY_PART_YEAR - 1)
-#define TIMESTAMP_MAX_VALUE 2145916799
-#define TIMESTAMP_MIN_VALUE 1
 #define PRECISION_FOR_DOUBLE 53
 #define PRECISION_FOR_FLOAT  24
 
diff --git a/sql/time.cc b/sql/time.cc
index ef832ac5a70..0e428e8bc40 100644
--- a/sql/time.cc
+++ b/sql/time.cc
@@ -230,14 +230,11 @@ my_time_t TIME_to_timestamp(THD *thd, const TIME *t, bool *in_dst_time_gap)
 
   *in_dst_time_gap= 0;
 
-  if (t->year < TIMESTAMP_MAX_YEAR && t->year > TIMESTAMP_MIN_YEAR ||
-      t->year == TIMESTAMP_MAX_YEAR && t->month == 1 && t->day == 1 ||
-      t->year == TIMESTAMP_MIN_YEAR && t->month == 12 && t->day == 31)
+  timestamp= thd->variables.time_zone->TIME_to_gmt_sec(t, in_dst_time_gap);
+  if (timestamp)
   {
     thd->time_zone_used= 1;
-    timestamp= thd->variables.time_zone->TIME_to_gmt_sec(t, in_dst_time_gap);
-    if (timestamp >= TIMESTAMP_MIN_VALUE && timestamp <= TIMESTAMP_MAX_VALUE)
-      return timestamp;
+    return timestamp;
   }
 
   /* If we are here we have range error. */
diff --git a/sql/tztime.cc b/sql/tztime.cc
index b0a32748998..60c5e8efd71 100644
--- a/sql/tztime.cc
+++ b/sql/tztime.cc
@@ -885,9 +885,14 @@ TIME_to_gmt_sec(const TIME *t, const TIME_ZONE_INFO *sp, bool *in_dst_time_gap)
   my_time_t local_t;
   uint saved_seconds;
   uint i;
+  int shift= 0;
 
   DBUG_ENTER("TIME_to_gmt_sec");
 
+  if (!validate_timestamp_range(t))
+    return 0;
+
+
   /* We need this for correct leap seconds handling */
   if (t->second < SECS_PER_MIN)
     saved_seconds= 0;
@@ -895,11 +900,29 @@ TIME_to_gmt_sec(const TIME *t, const TIME_ZONE_INFO *sp, bool *in_dst_time_gap)
     saved_seconds= t->second;
 
   /*
-    NOTE If we want to convert full my_time_t range without MySQL
-    restrictions we should catch overflow here somehow.
+    NOTE: to convert full my_time_t range we do a shift of the
+    boundary dates here to avoid overflow of my_time_t.
+    We use alike approach in my_system_gmt_sec().
+
+    However in that function we also have to take into account
+    overflow near 0 on some platforms. That's because my_system_gmt_sec
+    uses localtime_r(), which doesn't work with negative values correctly
+    on platforms with unsigned time_t (QNX). Here we don't use localtime()
+    => we negative values of local_t are ok.
   */
 
-  local_t= sec_since_epoch(t->year, t->month, t->day,
+  if ((t->year == TIMESTAMP_MAX_YEAR) && (t->month == 1) && t->day > 4)
+  {
+    /*
+      We will pass (t->day - shift) to sec_since_epoch(), and
+      want this value to be a positive number, so we shift
+      only dates > 4.01.2038 (to avoid owerflow).
+    */
+    shift= 2;
+  }
+
+
+  local_t= sec_since_epoch(t->year, t->month, (t->day - shift),
                            t->hour, t->minute,
                            saved_seconds ? 0 : t->second);
 
@@ -918,6 +941,22 @@ TIME_to_gmt_sec(const TIME *t, const TIME_ZONE_INFO *sp, bool *in_dst_time_gap)
   /* binary search for our range */
   i= find_time_range(local_t, sp->revts, sp->revcnt);
 
+  /*
+    As there are no offset switches at the end of TIMESTAMP range,
+    we could simply check for overflow here (and don't need to bother
+    about DST gaps etc)
+  */
+  if (shift)
+  {
+    if (local_t > (TIMESTAMP_MAX_VALUE - shift*86400L +
+                   sp->revtis[i].rt_offset - saved_seconds))
+    {
+      DBUG_RETURN(0);                           /* my_time_t overflow */
+    }
+    else
+     local_t+= shift*86400L;
+  }
+
   if (sp->revtis[i].rt_type)
   {
     /*
@@ -927,10 +966,16 @@ TIME_to_gmt_sec(const TIME *t, const TIME_ZONE_INFO *sp, bool *in_dst_time_gap)
       beginning of the gap.
     */
     *in_dst_time_gap= 1;
-    DBUG_RETURN(sp->revts[i] - sp->revtis[i].rt_offset + saved_seconds);
+    local_t= sp->revts[i] - sp->revtis[i].rt_offset + saved_seconds;
   }
   else
-    DBUG_RETURN(local_t - sp->revtis[i].rt_offset + saved_seconds);
+    local_t= local_t - sp->revtis[i].rt_offset + saved_seconds;
+
+  /* check for TIMESTAMP_MAX_VALUE was already done above */
+  if (local_t < TIMESTAMP_MIN_VALUE)
+    local_t= 0;
+
+  DBUG_RETURN(local_t);
 }
 
 
@@ -1294,9 +1339,24 @@ Time_zone_offset::Time_zone_offset(long tz_offset_arg):
 my_time_t
 Time_zone_offset::TIME_to_gmt_sec(const TIME *t, bool *in_dst_time_gap) const
 {
-  return sec_since_epoch(t->year, t->month, t->day,
-                         t->hour, t->minute, t->second) -
-         offset;
+  my_time_t local_t;
+
+  /*
+    Check timestamp range.we have to do this as calling function relies on
+    us to make all validation checks here.
+  */
+  if (!validate_timestamp_range(t))
+    return 0;
+
+  local_t= sec_since_epoch(t->year, t->month, t->day,
+                           t->hour, t->minute, t->second) -
+           offset;
+
+  if (local_t >= TIMESTAMP_MIN_VALUE && local_t <= TIMESTAMP_MAX_VALUE)
+    return local_t;
+
+  /* range error*/
+  return 0;
 }