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* [glibc] Correct timespec implementation [BZ #26232]
@ 2020-07-14 11:43 H.J. Lu
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From: H.J. Lu @ 2020-07-14 11:43 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=f896fc0f2bfc9f3f8df0563a7c99dcbf24bab655
commit f896fc0f2bfc9f3f8df0563a7c99dcbf24bab655
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Mon Jul 13 16:15:56 2020 -0700
Correct timespec implementation [BZ #26232]
commit 04deeaa9ea74b0679dfc9d9155a37b6425f19a9f
Author: Lucas A. M. Magalhaes <lamm@linux.ibm.com>
Date: Fri Jul 10 19:41:06 2020 -0300
Fix time/tst-cpuclock1 intermitent failures
has 2 issues:
1. It assumes time_t == long which is false on x32.
2. tst-timespec.c is compiled without -fexcess-precision=standard which
generates incorrect results on i686 in support_timespec_check_in_range:
double ratio = (double)observed_norm / expected_norm;
return (lower_bound <= ratio && ratio <= upper_bound);
This patch does
1. Compile tst-timespec.c with -fexcess-precision=standard.
2. Replace long with time_t.
3. Replace LONG_MIN and LONG_MAX with TYPE_MINIMUM (time_t) and
TYPE_MAXIMUM (time_t).
Diff:
---
support/Makefile | 7 ++++
support/timespec.c | 18 ++++------
support/timespec.h | 2 +-
support/tst-timespec.c | 98 ++++++++++++++++++++++++++++----------------------
4 files changed, 71 insertions(+), 54 deletions(-)
diff --git a/support/Makefile b/support/Makefile
index e74e0dd519..93faafddf9 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -196,6 +196,13 @@ CFLAGS-support_paths.c = \
-DROOTSBINDIR_PATH=\"$(rootsbindir)\" \
-DCOMPLOCALEDIR_PATH=\"$(complocaledir)\"
+# In support_timespec_check_in_range we may be passed a very tight
+# range for which we should produce a correct result for expected
+# being withing the observed range. The code uses double internally
+# in support_timespec_check_in_range and for that computation we use
+# -fexcess-precision=standard.
+CFLAGS-timespec.c += -fexcess-precision=standard
+
ifeq (,$(CXX))
LINKS_DSO_PROGRAM = links-dso-program-c
else
diff --git a/support/timespec.c b/support/timespec.c
index 9f5449e49e..edbdb165ec 100644
--- a/support/timespec.c
+++ b/support/timespec.c
@@ -60,21 +60,17 @@ test_timespec_equal_or_after_impl (const char *file, int line,
}
}
-/* Convert TIME to nanoseconds stored in a long.
- Returns long maximum or minimum if the conversion overflows
+/* Convert TIME to nanoseconds stored in a time_t.
+ Returns time_t maximum or minimum if the conversion overflows
or underflows, respectively. */
-long
+time_t
support_timespec_ns (struct timespec time)
{
- long time_ns;
+ time_t time_ns;
if (INT_MULTIPLY_WRAPV(time.tv_sec, TIMESPEC_HZ, &time_ns))
- {
- return (time.tv_sec < 0) ? TYPE_MINIMUM(long): TYPE_MAXIMUM(long);
- }
+ return time.tv_sec < 0 ? TYPE_MINIMUM(time_t) : TYPE_MAXIMUM(time_t);
if (INT_ADD_WRAPV(time_ns, time.tv_nsec, &time_ns))
- {
- return (time.tv_nsec < 0) ? TYPE_MINIMUM(long): TYPE_MAXIMUM(long);
- }
+ return time.tv_nsec < 0 ? TYPE_MINIMUM(time_t) : TYPE_MAXIMUM(time_t);
return time_ns;
}
@@ -113,7 +109,7 @@ support_timespec_check_in_range (struct timespec expected, struct timespec obser
double lower_bound, double upper_bound)
{
assert (upper_bound >= lower_bound);
- long expected_norm, observed_norm;
+ time_t expected_norm, observed_norm;
expected_norm = support_timespec_ns (expected);
/* Don't divide by zero */
assert(expected_norm != 0);
diff --git a/support/timespec.h b/support/timespec.h
index fd5466745d..1a6775a882 100644
--- a/support/timespec.h
+++ b/support/timespec.h
@@ -48,7 +48,7 @@ void test_timespec_equal_or_after_impl (const char *file, int line,
const struct timespec left,
const struct timespec right);
-long support_timespec_ns (struct timespec time);
+time_t support_timespec_ns (struct timespec time);
struct timespec support_timespec_normalize (struct timespec time);
diff --git a/support/tst-timespec.c b/support/tst-timespec.c
index 71423555a9..ac5ed228ba 100644
--- a/support/tst-timespec.c
+++ b/support/tst-timespec.c
@@ -19,13 +19,14 @@
#include <support/timespec.h>
#include <support/check.h>
#include <limits.h>
+#include <intprops.h>
#define TIMESPEC_HZ 1000000000
struct timespec_ns_test_case
{
struct timespec time;
- long time_ns;
+ time_t time_ns;
};
struct timespec_norm_test_case
@@ -43,6 +44,9 @@ struct timespec_test_case
int result;
};
+#define TIME_T_MIN TYPE_MINIMUM (time_t)
+#define TIME_T_MAX TYPE_MAXIMUM (time_t)
+
/* Test cases for timespec_ns */
struct timespec_ns_test_case ns_cases[] = {
{.time = {.tv_sec = 0, .tv_nsec = 0},
@@ -73,36 +77,42 @@ struct timespec_ns_test_case ns_cases[] = {
.time_ns = -TIMESPEC_HZ + 1,
},
/* Overflow bondary by 2 */
- {.time = {.tv_sec = LONG_MAX / TIMESPEC_HZ, .tv_nsec = LONG_MAX%TIMESPEC_HZ - 1},
- .time_ns = LONG_MAX - 1,
+ {.time = {.tv_sec = TIME_T_MAX / TIMESPEC_HZ,
+ .tv_nsec = TIME_T_MAX % TIMESPEC_HZ - 1},
+ .time_ns = TIME_T_MAX - 1,
},
/* Overflow bondary */
- {.time = {.tv_sec = LONG_MAX / TIMESPEC_HZ, .tv_nsec = LONG_MAX%TIMESPEC_HZ},
- .time_ns = LONG_MAX,
+ {.time = {.tv_sec = TIME_T_MAX / TIMESPEC_HZ,
+ .tv_nsec = TIME_T_MAX % TIMESPEC_HZ},
+ .time_ns = TIME_T_MAX,
},
/* Underflow bondary by 1 */
- {.time = {.tv_sec = LONG_MIN / TIMESPEC_HZ, .tv_nsec = LONG_MIN%TIMESPEC_HZ + 1},
- .time_ns = LONG_MIN + 1,
+ {.time = {.tv_sec = TIME_T_MIN / TIMESPEC_HZ,
+ .tv_nsec = TIME_T_MIN % TIMESPEC_HZ + 1},
+ .time_ns = TIME_T_MIN + 1,
},
/* Underflow bondary */
- {.time = {.tv_sec = LONG_MIN / TIMESPEC_HZ, .tv_nsec = LONG_MIN%TIMESPEC_HZ},
- .time_ns = LONG_MIN,
+ {.time = {.tv_sec = TIME_T_MIN / TIMESPEC_HZ,
+ .tv_nsec = TIME_T_MIN % TIMESPEC_HZ},
+ .time_ns = TIME_T_MIN,
},
/* Multiplication overflow */
- {.time = {.tv_sec = LONG_MAX / TIMESPEC_HZ + 1, .tv_nsec = 1},
- .time_ns = LONG_MAX,
+ {.time = {.tv_sec = TIME_T_MAX / TIMESPEC_HZ + 1, .tv_nsec = 1},
+ .time_ns = TIME_T_MAX,
},
/* Multiplication underflow */
- {.time = {.tv_sec = LONG_MIN / TIMESPEC_HZ - 1, .tv_nsec = -1},
- .time_ns = LONG_MIN,
+ {.time = {.tv_sec = TIME_T_MIN / TIMESPEC_HZ - 1, .tv_nsec = -1},
+ .time_ns = TIME_T_MIN,
},
/* Sum overflows */
- {.time = {.tv_sec = LONG_MAX / TIMESPEC_HZ, .tv_nsec = LONG_MAX%TIMESPEC_HZ + 1},
- .time_ns = LONG_MAX,
+ {.time = {.tv_sec = TIME_T_MAX / TIMESPEC_HZ,
+ .tv_nsec = TIME_T_MAX % TIMESPEC_HZ + 1},
+ .time_ns = TIME_T_MAX,
},
/* Sum underflow */
- {.time = {.tv_sec = LONG_MIN / TIMESPEC_HZ, .tv_nsec = LONG_MIN%TIMESPEC_HZ - 1},
- .time_ns = LONG_MIN,
+ {.time = {.tv_sec = TIME_T_MIN / TIMESPEC_HZ,
+ .tv_nsec = TIME_T_MIN % TIMESPEC_HZ - 1},
+ .time_ns = TIME_T_MIN,
}
};
@@ -144,28 +154,28 @@ struct timespec_norm_test_case norm_cases[] = {
.norm = {.tv_sec = -2, .tv_nsec = -1}
},
/* Overflow bondary by 2 */
- {.time = {.tv_sec = LONG_MAX - 2, .tv_nsec = TIMESPEC_HZ + 1},
- .norm = {.tv_sec = LONG_MAX - 1, 1},
+ {.time = {.tv_sec = TIME_T_MAX - 2, .tv_nsec = TIMESPEC_HZ + 1},
+ .norm = {.tv_sec = TIME_T_MAX - 1, 1},
},
/* Overflow bondary by 1 */
- {.time = {.tv_sec = LONG_MAX - 1, .tv_nsec = TIMESPEC_HZ + 1},
- .norm = {.tv_sec = LONG_MAX, .tv_nsec = 1},
+ {.time = {.tv_sec = TIME_T_MAX - 1, .tv_nsec = TIMESPEC_HZ + 1},
+ .norm = {.tv_sec = TIME_T_MAX, .tv_nsec = 1},
},
/* Underflow bondary by 2 */
- {.time = {.tv_sec = LONG_MIN + 2, .tv_nsec = -TIMESPEC_HZ - 1},
- .norm = {.tv_sec = LONG_MIN + 1, -1},
+ {.time = {.tv_sec = TIME_T_MIN + 2, .tv_nsec = -TIMESPEC_HZ - 1},
+ .norm = {.tv_sec = TIME_T_MIN + 1, -1},
},
/* Underflow bondary by 1 */
- {.time = {.tv_sec = LONG_MIN + 1, .tv_nsec = -TIMESPEC_HZ - 1},
- .norm = {.tv_sec = LONG_MIN, .tv_nsec = -1},
+ {.time = {.tv_sec = TIME_T_MIN + 1, .tv_nsec = -TIMESPEC_HZ - 1},
+ .norm = {.tv_sec = TIME_T_MIN, .tv_nsec = -1},
},
/* SUM overflow */
- {.time = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ},
- .norm = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ - 1},
+ {.time = {.tv_sec = TIME_T_MAX, .tv_nsec = TIMESPEC_HZ},
+ .norm = {.tv_sec = TIME_T_MAX, .tv_nsec = TIMESPEC_HZ - 1},
},
/* SUM underflow */
- {.time = {.tv_sec = LONG_MIN, .tv_nsec = -TIMESPEC_HZ},
- .norm = {.tv_sec = LONG_MIN, .tv_nsec = -1 * (TIMESPEC_HZ - 1)},
+ {.time = {.tv_sec = TIME_T_MIN, .tv_nsec = -TIMESPEC_HZ},
+ .norm = {.tv_sec = TIME_T_MIN, .tv_nsec = -1 * (TIMESPEC_HZ - 1)},
}
};
@@ -243,39 +253,41 @@ struct timespec_test_case check_cases[] = {
},
/* Maximum/Minimum long values */
/* 14 */
- {.expected = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ - 1},
- .observed = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ - 2},
+ {.expected = {.tv_sec = TIME_T_MAX, .tv_nsec = TIMESPEC_HZ - 1},
+ .observed = {.tv_sec = TIME_T_MAX, .tv_nsec = TIMESPEC_HZ - 2},
.upper_bound = 1, .lower_bound = .9, .result = 1,
},
/* 15 - support_timespec_ns overflow */
- {.expected = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ},
- .observed = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ},
+ {.expected = {.tv_sec = TIME_T_MAX, .tv_nsec = TIMESPEC_HZ},
+ .observed = {.tv_sec = TIME_T_MAX, .tv_nsec = TIMESPEC_HZ},
.upper_bound = 1, .lower_bound = 1, .result = 1,
},
/* 16 - support_timespec_ns overflow + underflow */
- {.expected = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ},
- .observed = {.tv_sec = LONG_MIN, .tv_nsec = -TIMESPEC_HZ},
+ {.expected = {.tv_sec = TIME_T_MAX, .tv_nsec = TIMESPEC_HZ},
+ .observed = {.tv_sec = TIME_T_MIN, .tv_nsec = -TIMESPEC_HZ},
.upper_bound = 1, .lower_bound = 1, .result = 0,
},
/* 17 - support_timespec_ns underflow */
- {.expected = {.tv_sec = LONG_MIN, .tv_nsec = -TIMESPEC_HZ},
- .observed = {.tv_sec = LONG_MIN, .tv_nsec = -TIMESPEC_HZ},
+ {.expected = {.tv_sec = TIME_T_MIN, .tv_nsec = -TIMESPEC_HZ},
+ .observed = {.tv_sec = TIME_T_MIN, .tv_nsec = -TIMESPEC_HZ},
.upper_bound = 1, .lower_bound = 1, .result = 1,
},
/* 18 - support_timespec_ns underflow + overflow */
- {.expected = {.tv_sec = LONG_MIN, .tv_nsec = -TIMESPEC_HZ},
- .observed = {.tv_sec = LONG_MAX, .tv_nsec = TIMESPEC_HZ},
+ {.expected = {.tv_sec = TIME_T_MIN, .tv_nsec = -TIMESPEC_HZ},
+ .observed = {.tv_sec = TIME_T_MAX, .tv_nsec = TIMESPEC_HZ},
.upper_bound = 1, .lower_bound = 1, .result = 0,
},
/* 19 - Biggest division */
- {.expected = {.tv_sec = LONG_MAX / TIMESPEC_HZ , .tv_nsec = TIMESPEC_HZ - 1},
+ {.expected = {.tv_sec = TIME_T_MAX / TIMESPEC_HZ,
+ .tv_nsec = TIMESPEC_HZ - 1},
.observed = {.tv_sec = 0, .tv_nsec = 1},
.upper_bound = 1, .lower_bound = 1.0842021724855044e-19, .result = 1,
},
/* 20 - Lowest division */
{.expected = {.tv_sec = 0, .tv_nsec = 1},
- .observed = {.tv_sec = LONG_MAX / TIMESPEC_HZ , .tv_nsec = TIMESPEC_HZ - 1},
- .upper_bound = LONG_MAX, .lower_bound = 1, .result = 1,
+ .observed = {.tv_sec = TIME_T_MAX / TIMESPEC_HZ,
+ .tv_nsec = TIMESPEC_HZ - 1},
+ .upper_bound = TIME_T_MAX, .lower_bound = 1, .result = 1,
},
};
@@ -288,6 +300,7 @@ do_test (void)
printf("Testing support_timespec_ns\n");
for (i = 0; i < ntests; i++)
{
+ printf("Test case %d\n", i);
TEST_COMPARE (support_timespec_ns (ns_cases[i].time),
ns_cases[i].time_ns);
}
@@ -297,6 +310,7 @@ do_test (void)
printf("Testing support_timespec_normalize\n");
for (i = 0; i < ntests; i++)
{
+ printf("Test case %d\n", i);
result = support_timespec_normalize (norm_cases[i].time);
TEST_COMPARE (norm_cases[i].norm.tv_sec, result.tv_sec);
TEST_COMPARE (norm_cases[i].norm.tv_nsec, result.tv_nsec);
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