[PATCH v4] Ensure mktime sets errno on error (bug 23789)
Paul Eggert
eggert@cs.ucla.edu
Sat Nov 10 02:01:00 GMT 2018
On 11/7/18 6:48 AM, Albert ARIBAUD wrote:
> 1. If the for-loop reaches remaining_probes==0, then it really should
> set errno = EOVERFLOW before returning -1, because remaining_probes
> is only decremented in the else clause inside the for-loop, and that
> only happens (or should only happen) when there were no failures so
> far, so if we fail then, we have to set errno.
Thanks for the diagnosis. Revised patches attached, which set errno in
that case as you suggested.
> 2. It is not normal that t, gt, t1 and t2 remain the same for all six
> iterations of the for-loop. That should be investigated and fixed.
Long ago I came up with weird scenarios involving odd combinations of
leap seconds and DST transitions all near the maximum convertible time_t
values that could involve that many iterations. None of these scenarios
will ever happen, really; the number is that large just to be safe. It
could be that I overestimated the number, but that's no big deal.
> I don't know why ranged_convert alters an argument which should be
> a pure imput. In fact, I don't know why it does not just copy this
> argument into a local time_t. Any known reason?
Because it communicates back to the caller the nearest long_int value
that is in range. This value is not obvious because it can depend on
timezone and leap second information.
After looking at the mktime implementation again I see some other things
that need fixing. These are mostly for Gnulib (when we can't assume that
localtime_r fails only due to EOVERFLOW), but there are some code
cleanups and fixes for very unlikely bugs. Proposed glibc patches attached.
-------------- next part --------------
From d7b1a2c6fda647672fd7774fc70cbe0b797af4e5 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 7 Nov 2018 07:52:17 -0800
Subject: [PATCH 1/7] mktime: fix EOVERFLOW bug
[BZ#23789]
* time/mktime.c [!_LIBC && !DEBUG_MKTIME]:
Include libc-config.h, not config.h, for __set_errno.
(guess_time_tm, __mktime_internal): Set errno to EOVERFLOW on overflow.
---
ChangeLog | 8 ++++++++
time/mktime.c | 26 +++++++++++++++++++-------
2 files changed, 27 insertions(+), 7 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index e43fd3e987..9f6d1d4edd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2018-11-09 Paul Eggert <eggert@cs.ucla.edu>
+
+ mktime: fix EOVERFLOW bug
+ [BZ#23789]
+ * time/mktime.c [!_LIBC && !DEBUG_MKTIME]:
+ Include libc-config.h, not config.h, for __set_errno.
+ (guess_time_tm, __mktime_internal): Set errno to EOVERFLOW on overflow.
+
2018-11-09 Martin Sebor <msebor@redhat.com>
* include/libc-symbols.h (__attribute_copy__): Define macro unless
diff --git a/time/mktime.c b/time/mktime.c
index 00f0dec6b4..106b4eac26 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -39,7 +39,7 @@
*/
#if !defined _LIBC && !DEBUG_MKTIME
-# include <config.h>
+# include <libc-config.h>
#endif
/* Assume that leap seconds are possible, unless told otherwise.
@@ -51,6 +51,7 @@
#include <time.h>
+#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdlib.h>
@@ -255,8 +256,9 @@ long_int_avg (long_int a, long_int b)
If TP is null, return a value not equal to T; this avoids false matches.
YEAR and YDAY must not be so large that multiplying them by three times the
number of seconds in a year (or day, respectively) would overflow long_int.
- If the returned value would be out of range, yield the minimal or
- maximal in-range value, except do not yield a value equal to T. */
+ If TP is non-null and the returned value would be out of range, set
+ errno to EOVERFLOW and yield a minimal or maximal in-range value
+ that is not equal to T. */
static long_int
guess_time_tm (long_int year, long_int yday, int hour, int min, int sec,
long_int t, const struct tm *tp)
@@ -269,9 +271,10 @@ guess_time_tm (long_int year, long_int yday, int hour, int min, int sec,
tp->tm_hour, tp->tm_min, tp->tm_sec);
if (! INT_ADD_WRAPV (t, d, &result))
return result;
+ __set_errno (EOVERFLOW);
}
- /* Overflow occurred one way or another. Return the nearest result
+ /* An error occurred, probably overflow. Return the nearest result
that is actually in range, except don't report a zero difference
if the actual difference is nonzero, as that would cause a false
match; and don't oscillate between two values, as that would
@@ -344,6 +347,8 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
Use *OFFSET to keep track of a guess at the offset of the result,
compared to what the result would be for UTC without leap seconds.
If *OFFSET's guess is correct, only one CONVERT call is needed.
+ If successful, set *TP to the canonicalized struct tm;
+ otherwise leave *TP alone, return ((time_t) -1) and set errno.
This function is external because it is used also by timegm.c. */
time_t
__mktime_internal (struct tm *tp,
@@ -435,7 +440,10 @@ __mktime_internal (struct tm *tp,
useful than returning -1. */
goto offset_found;
else if (--remaining_probes == 0)
- return -1;
+ {
+ __set_errno (EOVERFLOW);
+ return -1;
+ }
/* We have a match. Check whether tm.tm_isdst has the requested
value, if any. */
@@ -505,8 +513,12 @@ __mktime_internal (struct tm *tp,
sec_adjustment -= sec;
sec_adjustment += sec_requested;
if (INT_ADD_WRAPV (t, sec_adjustment, &t)
- || ! (mktime_min <= t && t <= mktime_max)
- || ! convert_time (convert, t, &tm))
+ || ! (mktime_min <= t && t <= mktime_max))
+ {
+ __set_errno (EOVERFLOW);
+ return -1;
+ }
+ if (! convert_time (convert, t, &tm))
return -1;
}
--
2.19.1
-------------- next part --------------
From 423a60057ac9b775f964f7686c0f61000e0a4b03 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 7 Nov 2018 07:52:18 -0800
Subject: [PATCH 2/7] mktime: new test for mktime failure
[BZ#23789]
Based on a test suggested by Albert Aribaud in:
https://www.sourceware.org/ml/libc-alpha/2018-10/msg00662.html
* time/Makefile (tests): Add bug-mktime4.
* time/bug-mktime4.c: New file.
---
ChangeLog | 7 ++++
time/Makefile | 2 +-
time/bug-mktime4.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 100 insertions(+), 1 deletion(-)
create mode 100644 time/bug-mktime4.c
diff --git a/ChangeLog b/ChangeLog
index 9f6d1d4edd..e92ce16df9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2018-11-09 Paul Eggert <eggert@cs.ucla.edu>
+ mktime: new test for mktime failure
+ [BZ#23789]
+ Based on a test suggested by Albert Aribaud in:
+ https://www.sourceware.org/ml/libc-alpha/2018-10/msg00662.html
+ * time/Makefile (tests): Add bug-mktime4.
+ * time/bug-mktime4.c: New file.
+
mktime: fix EOVERFLOW bug
[BZ#23789]
* time/mktime.c [!_LIBC && !DEBUG_MKTIME]:
diff --git a/time/Makefile b/time/Makefile
index ec3e39dcea..743bd99f18 100644
--- a/time/Makefile
+++ b/time/Makefile
@@ -43,7 +43,7 @@ tests := test_time clocktest tst-posixtz tst-strptime tst_wcsftime \
tst-getdate tst-mktime tst-mktime2 tst-ftime_l tst-strftime \
tst-mktime3 tst-strptime2 bug-asctime bug-asctime_r bug-mktime1 \
tst-strptime3 bug-getdate1 tst-strptime-whitespace tst-ftime \
- tst-tzname tst-y2039
+ tst-tzname tst-y2039 bug-mktime4
include ../Rules
diff --git a/time/bug-mktime4.c b/time/bug-mktime4.c
new file mode 100644
index 0000000000..9c076eb623
--- /dev/null
+++ b/time/bug-mktime4.c
@@ -0,0 +1,92 @@
+#include <time.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+
+static bool
+equal_tm (struct tm const *t, struct tm const *u)
+{
+ return (t->tm_sec == u->tm_sec && t->tm_min == u->tm_min
+ && t->tm_hour == u->tm_hour && t->tm_mday == u->tm_mday
+ && t->tm_mon == u->tm_mon && t->tm_year == u->tm_year
+ && t->tm_wday == u->tm_wday && t->tm_yday == u->tm_yday
+ && t->tm_isdst == u->tm_isdst && t->tm_gmtoff == u->tm_gmtoff
+ && t->tm_zone == u->tm_zone);
+}
+
+static int
+do_test (void)
+{
+ /* Calculate minimum time_t value. This would be simpler with C11,
+ which has _Generic, but we cannot assume C11. It would also
+ be simpler with intprops.h, which has TYPE_MINIMUM, but it's
+ better not to use glibc internals. */
+ time_t time_t_min = -1;
+ time_t_min = (0 < time_t_min ? 0
+ : sizeof time_t_min == sizeof (long int) ? LONG_MIN
+ : sizeof time_t_min == sizeof (long long int) ? LLONG_MIN
+ : 1);
+ if (time_t_min == 1)
+ {
+ printf ("unknown time type\n");
+ return 1;
+ }
+ time_t ymin = time_t_min / 60 / 60 / 24 / 366;
+ bool mktime_should_fail = ymin == 0 || INT_MIN + 1900 < ymin + 1970;
+
+ struct tm tm0 = { .tm_year = INT_MIN, .tm_mday = 1, .tm_wday = -1 };
+ struct tm tm = tm0;
+ errno = 0;
+ time_t t = mktime (&tm);
+ long long int llt = t;
+ bool mktime_failed = tm.tm_wday == tm0.tm_wday;
+
+ if (mktime_failed)
+ {
+ if (! mktime_should_fail)
+ {
+ printf ("mktime failed but should have succeeded\n");
+ return 1;
+ }
+ if (errno == 0)
+ {
+ printf ("mktime failed without setting errno");
+ return 1;
+ }
+ if (t != (time_t) -1)
+ {
+ printf ("mktime returned %lld but did not set tm_wday\n", llt);
+ return 1;
+ }
+ if (! equal_tm (&tm, &tm0))
+ {
+ printf ("mktime (P) failed but modified *P\n");
+ return 1;
+ }
+ }
+ else
+ {
+ if (mktime_should_fail)
+ {
+ printf ("mktime succeeded but should have failed\n");
+ return 1;
+ }
+ struct tm *lt = localtime (&t);
+ if (lt == NULL)
+ {
+ printf ("mktime returned a value rejected by localtime\n");
+ return 1;
+ }
+ if (! equal_tm (lt, &tm))
+ {
+ printf ("mktime result does not match localtime result\n");
+ return 1;
+ }
+ }
+ return 0;
+}
+
+#define TIMEOUT 1000
+#include "support/test-driver.c"
--
2.19.1
-------------- next part --------------
From 48c1f7c67e85c9a23f8ae365627b6210426399fb Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 8 Nov 2018 08:26:21 -0800
Subject: [PATCH 3/7] mktime: simplify offset guess
[BZ#23789]
* time/mktime.c (__mktime_internal): Omit excess precision.
---
ChangeLog | 4 ++++
time/mktime.c | 6 +++---
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index e92ce16df9..b7008a8972 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
2018-11-09 Paul Eggert <eggert@cs.ucla.edu>
+ mktime: simplify offset guess
+ [BZ#23789]
+ * time/mktime.c (__mktime_internal): Omit excess precision.
+
mktime: new test for mktime failure
[BZ#23789]
Based on a test suggested by Albert Aribaud in:
diff --git a/time/mktime.c b/time/mktime.c
index 106b4eac26..0f905eb8fe 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -355,7 +355,7 @@ __mktime_internal (struct tm *tp,
struct tm *(*convert) (const time_t *, struct tm *),
mktime_offset_t *offset)
{
- long_int t, gt, t0, t1, t2, dt;
+ long_int t, gt, t0, t1, t2;
struct tm tm;
/* The maximum number of probes (calls to CONVERT) should be enough
@@ -502,8 +502,8 @@ __mktime_internal (struct tm *tp,
/* Set *OFFSET to the low-order bits of T - T0 - NEGATIVE_OFFSET_GUESS.
This is just a heuristic to speed up the next mktime call, and
correctness is unaffected if integer overflow occurs here. */
- INT_SUBTRACT_WRAPV (t, t0, &dt);
- INT_SUBTRACT_WRAPV (dt, negative_offset_guess, offset);
+ INT_SUBTRACT_WRAPV (t, t0, offset);
+ INT_SUBTRACT_WRAPV (*offset, negative_offset_guess, offset);
if (LEAP_SECONDS_POSSIBLE && sec_requested != tm.tm_sec)
{
--
2.19.1
-------------- next part --------------
From 7678c7757fdf133db5edf17c7b3f6097b76e6ade Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 8 Nov 2018 10:20:50 -0800
Subject: [PATCH 4/7] mktime: make more room for overflow
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
[BZ#23789]
* time/mktime.c (long_int): Now 4⨯ int, not just 3⨯.
This is so that we can add tm_diff results to a previous guess,
which will be useful in a later patch.
---
ChangeLog | 6 ++++++
time/mktime.c | 20 +++++++++++---------
2 files changed, 17 insertions(+), 9 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index b7008a8972..82cdd795ab 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2018-11-09 Paul Eggert <eggert@cs.ucla.edu>
+ mktime: make more room for overflow
+ [BZ#23789]
+ * time/mktime.c (long_int): Now 4⨯ int, not just 3⨯.
+ This is so that we can add tm_diff results to a previous guess,
+ which will be useful in a later patch.
+
mktime: simplify offset guess
[BZ#23789]
* time/mktime.c (__mktime_internal): Omit excess precision.
diff --git a/time/mktime.c b/time/mktime.c
index 0f905eb8fe..ffbb5ea171 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -120,11 +120,12 @@ my_tzset (void)
#if defined _LIBC || NEED_MKTIME_WORKING || NEED_MKTIME_INTERNAL
/* A signed type that can represent an integer number of years
- multiplied by three times the number of seconds in a year. It is
+ multiplied by four times the number of seconds in a year. It is
needed when converting a tm_year value times the number of seconds
- in a year. The factor of three comes because these products need
+ in a year. The factor of four comes because these products need
to be subtracted from each other, and sometimes with an offset
- added to them, without worrying about overflow.
+ added to them, and then with another timestamp added, without
+ worrying about overflow.
Much of the code uses long_int to represent time_t values, to
lessen the hassle of dealing with platforms where time_t is
@@ -132,12 +133,12 @@ my_tzset (void)
time_t values that mktime can generate even on platforms where
time_t is excessively wide. */
-#if INT_MAX <= LONG_MAX / 3 / 366 / 24 / 60 / 60
+#if INT_MAX <= LONG_MAX / 4 / 366 / 24 / 60 / 60
typedef long int long_int;
#else
typedef long long int long_int;
#endif
-verify (INT_MAX <= TYPE_MAXIMUM (long_int) / 3 / 366 / 24 / 60 / 60);
+verify (INT_MAX <= TYPE_MAXIMUM (long_int) / 4 / 366 / 24 / 60 / 60);
/* Shift A right by B bits portably, by dividing A by 2**B and
truncating towards minus infinity. B should be in the range 0 <= B
@@ -211,9 +212,10 @@ isdst_differ (int a, int b)
were not adjusted between the timestamps.
The YEAR values uses the same numbering as TP->tm_year. Values
- need not be in the usual range. However, YEAR1 must not overflow
- when multiplied by three times the number of seconds in a year, and
- likewise for YDAY1 and three times the number of seconds in a day. */
+ need not be in the usual range. However, YEAR1 - YEAR0 must not
+ overflow even when multiplied by three times the number of seconds
+ in a year, and likewise for YDAY1 - YDAY0 and three times the
+ number of seconds in a day. */
static long_int
ydhms_diff (long_int year1, long_int yday1, int hour1, int min1, int sec1,
@@ -403,7 +405,7 @@ __mktime_internal (struct tm *tp,
if (LEAP_SECONDS_POSSIBLE)
{
/* Handle out-of-range seconds specially,
- since ydhms_tm_diff assumes every minute has 60 seconds. */
+ since ydhms_diff assumes every minute has 60 seconds. */
if (sec < 0)
sec = 0;
if (59 < sec)
--
2.19.1
-------------- next part --------------
From 19a49e00d5fab2ac24d36900dc810407fd05d12a Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 8 Nov 2018 10:30:36 -0800
Subject: [PATCH 5/7] mktime: fix bug with Y2038 DST transition
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
[BZ#23789]
* time/mktime.c (ranged_convert): On 32-bit platforms, don’t
mishandle a DST transition that jumps over the Y2038 boundary.
No such DST transitions are known so this is only a theoretical
bug, but we might as well do things right.
---
ChangeLog | 7 +++++++
time/mktime.c | 4 +++-
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/ChangeLog b/ChangeLog
index 82cdd795ab..939ca140ef 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2018-11-09 Paul Eggert <eggert@cs.ucla.edu>
+ mktime: fix bug with Y2038 DST transition
+ [BZ#23789]
+ * time/mktime.c (ranged_convert): On 32-bit platforms, don’t
+ mishandle a DST transition that jumps over the Y2038 boundary.
+ No such DST transitions are known so this is only a theoretical
+ bug, but we might as well do things right.
+
mktime: make more room for overflow
[BZ#23789]
* time/mktime.c (long_int): Now 4⨯ int, not just 3⨯.
diff --git a/time/mktime.c b/time/mktime.c
index ffbb5ea171..6d5b8cf838 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -323,7 +323,7 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
while (true)
{
long_int mid = long_int_avg (ok, bad);
- if (mid != ok && mid != bad)
+ if (mid == ok || mid == bad)
break;
r = convert_time (convert, mid, tp);
if (r)
@@ -332,6 +332,8 @@ ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
bad = mid;
}
+ *t = ok;
+
if (!r && ok)
{
/* The last conversion attempt failed;
--
2.19.1
-------------- next part --------------
From 67ece14d68a5b086f2b4a04d27b0d48f3f47bea3 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri, 9 Nov 2018 17:33:24 -0800
Subject: [PATCH 6/7] mktime: fix non-EOVERFLOW errno handling
[BZ#23789]
mktime was not properly reporting failures when the underlying
localtime_r fails with errno != EOVERFLOW; it incorrectly treated
them like EOVERFLOW failures, and set errno to EOVERFLOW.
The problem could happen on non-glibc platforms, with Gnulib.
* time/mktime.c (guess_time_tm): Remove, replacing with ...
(tm_diff): ... this simpler function, which does not change errno.
All callers changed to deal with errno themselves.
(ranged_convert, __mktime_internal): Return failure immediately if
the underlying function reports any failure other than EOVERFLOW.
(__mktime_internal): Set errno to EOVERFLOW if the spring-forward
gap code fails.
---
ChangeLog | 14 ++++
time/mktime.c | 197 +++++++++++++++++++++++++-------------------------
2 files changed, 113 insertions(+), 98 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 939ca140ef..9f62ab865e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,19 @@
2018-11-09 Paul Eggert <eggert@cs.ucla.edu>
+ mktime: fix non-EOVERFLOW errno handling
+ [BZ#23789]
+ mktime was not properly reporting failures when the underlying
+ localtime_r fails with errno != EOVERFLOW; it incorrectly treated
+ them like EOVERFLOW failures, and set errno to EOVERFLOW.
+ The problem could happen on non-glibc platforms, with Gnulib.
+ * time/mktime.c (guess_time_tm): Remove, replacing with ...
+ (tm_diff): ... this simpler function, which does not change errno.
+ All callers changed to deal with errno themselves.
+ (ranged_convert, __mktime_internal): Return failure immediately if
+ the underlying function reports any failure other than EOVERFLOW.
+ (__mktime_internal): Set errno to EOVERFLOW if the spring-forward
+ gap code fails.
+
mktime: fix bug with Y2038 DST transition
[BZ#23789]
* time/mktime.c (ranged_convert): On 32-bit platforms, don’t
diff --git a/time/mktime.c b/time/mktime.c
index 6d5b8cf838..dc83985bbd 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -250,45 +250,25 @@ long_int_avg (long_int a, long_int b)
return shr (a, 1) + shr (b, 1) + ((a | b) & 1);
}
-/* Return a time_t value corresponding to (YEAR-YDAY HOUR:MIN:SEC),
- assuming that T corresponds to *TP and that no clock adjustments
- occurred between *TP and the desired time.
- Although T and the returned value are of type long_int,
- they represent time_t values and must be in time_t range.
- If TP is null, return a value not equal to T; this avoids false matches.
+/* Return a long_int value corresponding to (YEAR-YDAY HOUR:MIN:SEC)
+ minus *TP seconds, assuming no clock adjustments occurred between
+ the two timestamps.
+
YEAR and YDAY must not be so large that multiplying them by three times the
number of seconds in a year (or day, respectively) would overflow long_int.
- If TP is non-null and the returned value would be out of range, set
- errno to EOVERFLOW and yield a minimal or maximal in-range value
- that is not equal to T. */
+ *TP should be in the usual range. */
static long_int
-guess_time_tm (long_int year, long_int yday, int hour, int min, int sec,
- long_int t, const struct tm *tp)
+tm_diff (long_int year, long_int yday, int hour, int min, int sec,
+ struct tm const *tp)
{
- if (tp)
- {
- long_int result;
- long_int d = ydhms_diff (year, yday, hour, min, sec,
- tp->tm_year, tp->tm_yday,
- tp->tm_hour, tp->tm_min, tp->tm_sec);
- if (! INT_ADD_WRAPV (t, d, &result))
- return result;
- __set_errno (EOVERFLOW);
- }
-
- /* An error occurred, probably overflow. Return the nearest result
- that is actually in range, except don't report a zero difference
- if the actual difference is nonzero, as that would cause a false
- match; and don't oscillate between two values, as that would
- confuse the spring-forward gap detector. */
- return (t < long_int_avg (mktime_min, mktime_max)
- ? (t <= mktime_min + 1 ? t + 1 : mktime_min)
- : (mktime_max - 1 <= t ? t - 1 : mktime_max));
+ return ydhms_diff (year, yday, hour, min, sec,
+ tp->tm_year, tp->tm_yday,
+ tp->tm_hour, tp->tm_min, tp->tm_sec);
}
/* Use CONVERT to convert T to a struct tm value in *TM. T must be in
- range for time_t. Return TM if successful, NULL if T is out of
- range for CONVERT. */
+ range for time_t. Return TM if successful, NULL (setting errno) on
+ failure. */
static struct tm *
convert_time (struct tm *(*convert) (const time_t *, struct tm *),
long_int t, struct tm *tm)
@@ -300,49 +280,48 @@ convert_time (struct tm *(*convert) (const time_t *, struct tm *),
/* Use CONVERT to convert *T to a broken down time in *TP.
If *T is out of range for conversion, adjust it so that
it is the nearest in-range value and then convert that.
- A value is in range if it fits in both time_t and long_int. */
+ A value is in range if it fits in both time_t and long_int.
+ Return TP on success, NULL (setting errno) on failure. */
static struct tm *
ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
long_int *t, struct tm *tp)
{
- struct tm *r;
- if (*t < mktime_min)
- *t = mktime_min;
- else if (mktime_max < *t)
- *t = mktime_max;
- r = convert_time (convert, *t, tp);
-
- if (!r && *t)
+ long_int t1 = (*t < mktime_min ? mktime_min
+ : *t <= mktime_max ? *t : mktime_max);
+ struct tm *r = convert_time (convert, t1, tp);
+ if (r)
{
- long_int bad = *t;
- long_int ok = 0;
-
- /* BAD is a known unconvertible value, and OK is a known good one.
- Use binary search to narrow the range between BAD and OK until
- they differ by 1. */
- while (true)
- {
- long_int mid = long_int_avg (ok, bad);
- if (mid == ok || mid == bad)
- break;
- r = convert_time (convert, mid, tp);
- if (r)
- ok = mid;
- else
- bad = mid;
- }
+ *t = t1;
+ return r;
+ }
+ if (errno != EOVERFLOW)
+ return NULL;
- *t = ok;
+ long_int bad = t1;
+ long_int ok = 0;
+ struct tm oktm; oktm.tm_sec = -1;
- if (!r && ok)
- {
- /* The last conversion attempt failed;
- revert to the most recent successful attempt. */
- r = convert_time (convert, ok, tp);
- }
+ /* BAD is a known out-of-range value, and OK is a known in-range one.
+ Use binary search to narrow the range between BAD and OK until
+ they differ by 1. */
+ while (true)
+ {
+ long_int mid = long_int_avg (ok, bad);
+ if (mid == ok || mid == bad)
+ break;
+ if (convert_time (convert, mid, tp))
+ ok = mid, oktm = *tp;
+ else if (errno != EOVERFLOW)
+ return NULL;
+ else
+ bad = mid;
}
- return r;
+ if (oktm.tm_sec < 0)
+ return NULL;
+ *t = ok;
+ *tp = oktm;
+ return tp;
}
@@ -359,7 +338,6 @@ __mktime_internal (struct tm *tp,
struct tm *(*convert) (const time_t *, struct tm *),
mktime_offset_t *offset)
{
- long_int t, gt, t0, t1, t2;
struct tm tm;
/* The maximum number of probes (calls to CONVERT) should be enough
@@ -379,7 +357,7 @@ __mktime_internal (struct tm *tp,
int isdst = tp->tm_isdst;
/* 1 if the previous probe was DST. */
- int dst2;
+ int dst2 = 0;
/* Ensure that mon is in range, and set year accordingly. */
int mon_remainder = mon % 12;
@@ -418,36 +396,46 @@ __mktime_internal (struct tm *tp,
time. */
INT_SUBTRACT_WRAPV (0, off, &negative_offset_guess);
- t0 = ydhms_diff (year, yday, hour, min, sec,
- EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0, negative_offset_guess);
+ long_int t0 = ydhms_diff (year, yday, hour, min, sec,
+ EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0,
+ negative_offset_guess);
+ long_int t = t0, t1 = t0, t2 = t0;
/* Repeatedly use the error to improve the guess. */
- for (t = t1 = t2 = t0, dst2 = 0;
- (gt = guess_time_tm (year, yday, hour, min, sec, t,
- ranged_convert (convert, &t, &tm)),
- t != gt);
- t1 = t2, t2 = t, t = gt, dst2 = tm.tm_isdst != 0)
- if (t == t1 && t != t2
- && (tm.tm_isdst < 0
- || (isdst < 0
- ? dst2 <= (tm.tm_isdst != 0)
- : (isdst != 0) != (tm.tm_isdst != 0))))
- /* We can't possibly find a match, as we are oscillating
- between two values. The requested time probably falls
- within a spring-forward gap of size GT - T. Follow the common
- practice in this case, which is to return a time that is GT - T
- away from the requested time, preferring a time whose
- tm_isdst differs from the requested value. (If no tm_isdst
- was requested and only one of the two values has a nonzero
- tm_isdst, prefer that value.) In practice, this is more
- useful than returning -1. */
- goto offset_found;
- else if (--remaining_probes == 0)
- {
- __set_errno (EOVERFLOW);
+ while (true)
+ {
+ if (! ranged_convert (convert, &t, &tm))
return -1;
- }
+ long_int dt = tm_diff (year, yday, hour, min, sec, &tm);
+ if (dt == 0)
+ break;
+
+ if (t == t1 && t != t2
+ && (tm.tm_isdst < 0
+ || (isdst < 0
+ ? dst2 <= (tm.tm_isdst != 0)
+ : (isdst != 0) != (tm.tm_isdst != 0))))
+ /* We can't possibly find a match, as we are oscillating
+ between two values. The requested time probably falls
+ within a spring-forward gap of size DT. Follow the common
+ practice in this case, which is to return a time that is DT
+ away from the requested time, preferring a time whose
+ tm_isdst differs from the requested value. (If no tm_isdst
+ was requested and only one of the two values has a nonzero
+ tm_isdst, prefer that value.) In practice, this is more
+ useful than returning -1. */
+ goto offset_found;
+
+ remaining_probes--;
+ if (remaining_probes == 0)
+ {
+ __set_errno (EOVERFLOW);
+ return -1;
+ }
+
+ t1 = t2, t2 = t, t += dt, dst2 = tm.tm_isdst != 0;
+ }
/* We have a match. Check whether tm.tm_isdst has the requested
value, if any. */
@@ -489,17 +477,30 @@ __mktime_internal (struct tm *tp,
if (! INT_ADD_WRAPV (t, delta * direction, &ot))
{
struct tm otm;
- ranged_convert (convert, &ot, &otm);
+ if (! ranged_convert (convert, &ot, &otm))
+ return -1;
if (! isdst_differ (isdst, otm.tm_isdst))
{
/* We found the desired tm_isdst.
Extrapolate back to the desired time. */
- t = guess_time_tm (year, yday, hour, min, sec, ot, &otm);
- ranged_convert (convert, &t, &tm);
- goto offset_found;
+ long_int gt = ot + tm_diff (year, yday, hour, min, sec,
+ &otm);
+ if (mktime_min <= gt && gt <= mktime_max)
+ {
+ if (convert_time (convert, gt, &tm))
+ {
+ t = gt;
+ goto offset_found;
+ }
+ if (errno != EOVERFLOW)
+ return -1;
+ }
}
}
}
+
+ __set_errno (EOVERFLOW);
+ return -1;
}
offset_found:
--
2.19.1
-------------- next part --------------
From c1d348099f2253e18437e711c4de3d886f9bb8ca Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri, 9 Nov 2018 17:43:48 -0800
Subject: [PATCH 7/7] mktime: DEBUG_MKTIME cleanup
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
The DEBUG_MKTIME code no longer works in glibc or in Gnulib.
And it’s no longer needed now that glibc and Gnulib both have
their own testing mechanisms for mktime.
* time/mktime.c (DEBUG_MKTIME): Remove. All uses removed.
---
ChangeLog | 6 ++
time/mktime.c | 162 +-------------------------------------------------
2 files changed, 8 insertions(+), 160 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 9f62ab865e..e039728000 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2018-11-09 Paul Eggert <eggert@cs.ucla.edu>
+ mktime: DEBUG_MKTIME cleanup
+ The DEBUG_MKTIME code no longer works in glibc or in Gnulib.
+ And it’s no longer needed now that glibc and Gnulib both have
+ their own testing mechanisms for mktime.
+ * time/mktime.c (DEBUG_MKTIME): Remove. All uses removed.
+
mktime: fix non-EOVERFLOW errno handling
[BZ#23789]
mktime was not properly reporting failures when the underlying
diff --git a/time/mktime.c b/time/mktime.c
index dc83985bbd..8faa9bc93d 100644
--- a/time/mktime.c
+++ b/time/mktime.c
@@ -17,12 +17,6 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-/* Define this to 1 to have a standalone program to test this implementation of
- mktime. */
-#ifndef DEBUG_MKTIME
-# define DEBUG_MKTIME 0
-#endif
-
/* The following macros influence what gets defined when this file is compiled:
Macro/expression Which gnulib module This compilation unit
@@ -34,11 +28,9 @@
|| NEED_MKTIME_WINDOWS
NEED_MKTIME_INTERNAL mktime-internal mktime_internal
-
- DEBUG_MKTIME (defined manually) my_mktime, main
*/
-#if !defined _LIBC && !DEBUG_MKTIME
+#ifndef _LIBC
# include <libc-config.h>
#endif
@@ -60,13 +52,6 @@
#include <intprops.h>
#include <verify.h>
-#if DEBUG_MKTIME
-# include <stdio.h>
-/* Make it work even if the system's libc has its own mktime routine. */
-# undef mktime
-# define mktime my_mktime
-#endif /* DEBUG_MKTIME */
-
#ifndef NEED_MKTIME_INTERNAL
# define NEED_MKTIME_INTERNAL 0
#endif
@@ -74,7 +59,7 @@
# define NEED_MKTIME_WINDOWS 0
#endif
#ifndef NEED_MKTIME_WORKING
-# define NEED_MKTIME_WORKING DEBUG_MKTIME
+# define NEED_MKTIME_WORKING 0
#endif
#include "mktime-internal.h"
@@ -562,146 +547,3 @@ weak_alias (mktime, timelocal)
libc_hidden_def (mktime)
libc_hidden_weak (timelocal)
#endif
-
-#if DEBUG_MKTIME
-
-static int
-not_equal_tm (const struct tm *a, const struct tm *b)
-{
- return ((a->tm_sec ^ b->tm_sec)
- | (a->tm_min ^ b->tm_min)
- | (a->tm_hour ^ b->tm_hour)
- | (a->tm_mday ^ b->tm_mday)
- | (a->tm_mon ^ b->tm_mon)
- | (a->tm_year ^ b->tm_year)
- | (a->tm_yday ^ b->tm_yday)
- | isdst_differ (a->tm_isdst, b->tm_isdst));
-}
-
-static void
-print_tm (const struct tm *tp)
-{
- if (tp)
- printf ("%04d-%02d-%02d %02d:%02d:%02d yday %03d wday %d isdst %d",
- tp->tm_year + TM_YEAR_BASE, tp->tm_mon + 1, tp->tm_mday,
- tp->tm_hour, tp->tm_min, tp->tm_sec,
- tp->tm_yday, tp->tm_wday, tp->tm_isdst);
- else
- printf ("0");
-}
-
-static int
-check_result (time_t tk, struct tm tmk, time_t tl, const struct tm *lt)
-{
- if (tk != tl || !lt || not_equal_tm (&tmk, lt))
- {
- printf ("mktime (");
- print_tm (lt);
- printf (")\nyields (");
- print_tm (&tmk);
- printf (") == %ld, should be %ld\n", (long int) tk, (long int) tl);
- return 1;
- }
-
- return 0;
-}
-
-int
-main (int argc, char **argv)
-{
- int status = 0;
- struct tm tm, tmk, tml;
- struct tm *lt;
- time_t tk, tl, tl1;
- char trailer;
-
- /* Sanity check, plus call tzset. */
- tl = 0;
- if (! localtime (&tl))
- {
- printf ("localtime (0) fails\n");
- status = 1;
- }
-
- if ((argc == 3 || argc == 4)
- && (sscanf (argv[1], "%d-%d-%d%c",
- &tm.tm_year, &tm.tm_mon, &tm.tm_mday, &trailer)
- == 3)
- && (sscanf (argv[2], "%d:%d:%d%c",
- &tm.tm_hour, &tm.tm_min, &tm.tm_sec, &trailer)
- == 3))
- {
- tm.tm_year -= TM_YEAR_BASE;
- tm.tm_mon--;
- tm.tm_isdst = argc == 3 ? -1 : atoi (argv[3]);
- tmk = tm;
- tl = mktime (&tmk);
- lt = localtime_r (&tl, &tml);
- printf ("mktime returns %ld == ", (long int) tl);
- print_tm (&tmk);
- printf ("\n");
- status = check_result (tl, tmk, tl, lt);
- }
- else if (argc == 4 || (argc == 5 && strcmp (argv[4], "-") == 0))
- {
- time_t from = atol (argv[1]);
- time_t by = atol (argv[2]);
- time_t to = atol (argv[3]);
-
- if (argc == 4)
- for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)
- {
- lt = localtime_r (&tl, &tml);
- if (lt)
- {
- tmk = tml;
- tk = mktime (&tmk);
- status |= check_result (tk, tmk, tl, &tml);
- }
- else
- {
- printf ("localtime_r (%ld) yields 0\n", (long int) tl);
- status = 1;
- }
- tl1 = tl + by;
- if ((tl1 < tl) != (by < 0))
- break;
- }
- else
- for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)
- {
- /* Null benchmark. */
- lt = localtime_r (&tl, &tml);
- if (lt)
- {
- tmk = tml;
- tk = tl;
- status |= check_result (tk, tmk, tl, &tml);
- }
- else
- {
- printf ("localtime_r (%ld) yields 0\n", (long int) tl);
- status = 1;
- }
- tl1 = tl + by;
- if ((tl1 < tl) != (by < 0))
- break;
- }
- }
- else
- printf ("Usage:\
-\t%s YYYY-MM-DD HH:MM:SS [ISDST] # Test given time.\n\
-\t%s FROM BY TO # Test values FROM, FROM+BY, ..., TO.\n\
-\t%s FROM BY TO - # Do not test those values (for benchmark).\n",
- argv[0], argv[0], argv[0]);
-
- return status;
-}
-
-#endif /* DEBUG_MKTIME */
-
-/*
-Local Variables:
-compile-command: "gcc -DDEBUG_MKTIME -I. -Wall -W -O2 -g mktime.c -o mktime"
-End:
-*/
--
2.19.1
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