Reduce the timing tests complexity
diff --git a/tests/suites/test_suite_timing.function b/tests/suites/test_suite_timing.function
index 1610155..42d3da6 100644
--- a/tests/suites/test_suite_timing.function
+++ b/tests/suites/test_suite_timing.function
@@ -1,51 +1,14 @@
/* BEGIN_HEADER */
-/* This test module exercises the timing module. One of the expected failure
- modes is for timers to never expire, which could lead to an infinite loop.
- The function timing_timer_simple is protected against this failure mode and
- checks that timers do expire. Other functions will terminate if their
- timers do expire. Therefore it is recommended to run timing_timer_simple
- first and run other test functions only if that timing_timer_simple
- succeeded. */
+/* This test module exercises the timing module. Since, depending on the
+ * underlying operating system, the timing routines are not always reliable,
+ * this suite only performs very basic sanity checks of the timing API.
+ */
#include <limits.h>
#include "mbedtls/timing.h"
-/* Wait this many milliseconds for a short timing test. This duration
- should be large enough that, in practice, if you read the timer
- value twice in a row, it won't have jumped by that much. */
-#define TIMING_SHORT_TEST_MS 100
-
-/* A loop that waits TIMING_SHORT_TEST_MS must not take more than this many
- iterations. This value needs to be large enough to accommodate fast
- platforms (e.g. at 4GHz and 10 cycles/iteration a CPU can run through 20
- million iterations in 50ms). The only motivation to keep this value low is
- to avoid having an infinite loop if the timer functions are not implemented
- correctly. Ideally this value should be based on the processor speed but we
- don't have this information! */
-#define TIMING_SHORT_TEST_ITERATIONS_MAX 1e8
-
-/* alarm(0) must fire in no longer than this amount of time. */
-#define TIMING_ALARM_0_DELAY_MS TIMING_SHORT_TEST_MS
-
-static int expected_delay_status( uint32_t int_ms, uint32_t fin_ms,
- unsigned long actual_ms )
-{
- return( fin_ms == 0 ? -1 :
- actual_ms >= fin_ms ? 2 :
- actual_ms >= int_ms ? 1 :
- 0 );
-}
-
-/* Some conditions in timing_timer_simple suggest that timers are unreliable.
- Most other test cases rely on timers to terminate, and could loop
- indefinitely if timers are too broken. So if timing_timer_simple detected a
- timer that risks not terminating (going backwards, or not reaching the
- desired count in the alloted clock cycles), set this flag to immediately
- fail those other tests without running any timers. */
-static int timers_are_badly_broken = 0;
-
/* END_HEADER */
/* BEGIN_DEPENDENCIES
@@ -54,350 +17,52 @@
*/
/* BEGIN_CASE */
-void timing_timer_simple( )
-{
- struct mbedtls_timing_hr_time timer;
- unsigned long millis = 0;
- unsigned long new_millis = 0;
- unsigned long iterations = 0;
- /* Start the timer. */
- (void) mbedtls_timing_get_timer( &timer, 1 );
- /* Busy-wait loop for a few milliseconds. */
- do
- {
- new_millis = mbedtls_timing_get_timer( &timer, 0 );
- ++iterations;
- /* Check that the timer didn't go backwards */
- TEST_ASSERT( new_millis >= millis );
- millis = new_millis;
- }
- while( millis < TIMING_SHORT_TEST_MS &&
- iterations <= TIMING_SHORT_TEST_ITERATIONS_MAX );
- /* The wait duration should have been large enough for at least a
- few runs through the loop, even on the slowest realistic platform. */
- TEST_ASSERT( iterations >= 2 );
- /* The wait duration shouldn't have overflowed the iteration count. */
- TEST_ASSERT( iterations < TIMING_SHORT_TEST_ITERATIONS_MAX );
- return;
-
-exit:
- if( iterations >= TIMING_SHORT_TEST_ITERATIONS_MAX ||
- new_millis < millis )
- {
- /* The timer was very unreliable: it didn't increment and the loop ran
- out, or it went backwards. Other tests that use timers might go
- into an infinite loop, so we'll skip them. */
- timers_are_badly_broken = 1;
- }
-
- /* No cleanup needed, but show some diagnostic iterations, because timing
- problems can be hard to reproduce. */
- mbedtls_fprintf( stdout, " Finished with millis=%lu new_millis=%lu get(timer)<=%lu iterations=%lu\n",
- millis, new_millis, mbedtls_timing_get_timer( &timer, 0 ),
- iterations );
-}
-/* END_CASE */
-
-/* BEGIN_CASE */
-void timing_timer_reset( )
-{
- struct mbedtls_timing_hr_time timer;
- unsigned long millis = 0;
- unsigned long iterations = 0;
-
- /* Skip this test if it looks like timers don't work at all, to avoid an
- infinite loop below. */
- TEST_ASSERT( !timers_are_badly_broken );
-
- /* Start the timer. Timers are always reset to 0. */
- TEST_ASSERT( mbedtls_timing_get_timer( &timer, 1 ) == 0 );
- /* Busy-wait loop for a few milliseconds */
- do
- {
- ++iterations;
- millis = mbedtls_timing_get_timer( &timer, 0 );
- }
- while( millis < TIMING_SHORT_TEST_MS );
-
- /* Reset the timer and check that it has restarted. */
- TEST_ASSERT( mbedtls_timing_get_timer( &timer, 1 ) == 0 );
- /* Read the timer immediately after reset. It should be 0 or close
- to it. */
- TEST_ASSERT( mbedtls_timing_get_timer( &timer, 0 ) < TIMING_SHORT_TEST_MS );
- return;
-
-exit:
- /* No cleanup needed, but show some diagnostic information, because timing
- problems can be hard to reproduce. */
- if( !timers_are_badly_broken )
- mbedtls_fprintf( stdout, " Finished with millis=%lu get(timer)<=%lu iterations=%lu\n",
- millis, mbedtls_timing_get_timer( &timer, 0 ),
- iterations );
-}
-/* END_CASE */
-
-/* BEGIN_CASE */
-void timing_two_timers( int delta )
-{
- struct mbedtls_timing_hr_time timer1, timer2;
- unsigned long millis1 = 0, millis2 = 0;
-
- /* Skip this test if it looks like timers don't work at all, to avoid an
- infinite loop below. */
- TEST_ASSERT( !timers_are_badly_broken );
-
- /* Start the first timer and wait for a short time. */
- (void) mbedtls_timing_get_timer( &timer1, 1 );
- do
- {
- millis1 = mbedtls_timing_get_timer( &timer1, 0 );
- }
- while( millis1 < TIMING_SHORT_TEST_MS );
-
- /* Do a short busy-wait, so that the difference between timer1 and timer2
- doesn't practically always end up being very close to a whole number of
- milliseconds. */
- while( delta > 0 )
- --delta;
-
- /* Start the second timer and compare it with the first. */
- mbedtls_timing_get_timer( &timer2, 1 );
- do
- {
- millis1 = mbedtls_timing_get_timer( &timer1, 0 );
- millis2 = mbedtls_timing_get_timer( &timer2, 0 );
- /* The first timer should always be ahead of the first. */
- TEST_ASSERT( millis1 > millis2 );
- /* The timers shouldn't drift apart, i.e. millis2-millis1 should stay
- roughly constant, but this is hard to test reliably, especially in
- a busy environment such as an overloaded continuous integration
- system, so we don't test it it. */
- }
- while( millis2 < TIMING_SHORT_TEST_MS );
-
- return;
-
-exit:
- /* No cleanup needed, but show some diagnostic iterations, because timing
- problems can be hard to reproduce. */
- if( !timers_are_badly_broken )
- mbedtls_fprintf( stdout, " Finished with millis1=%lu get(timer1)<=%lu millis2=%lu get(timer2)<=%lu\n",
- millis1, mbedtls_timing_get_timer( &timer1, 0 ),
- millis2, mbedtls_timing_get_timer( &timer2, 0 ) );
-}
-/* END_CASE */
-
-/* BEGIN_CASE */
-void timing_alarm( int seconds )
-{
- struct mbedtls_timing_hr_time timer;
- unsigned long millis = 0;
- /* We check that about the desired number of seconds has elapsed. Be
- slightly liberal with the lower bound, so as to allow platforms where
- the alarm (with second resolution) and the timer (with millisecond
- resolution) are based on different clocks. Be very liberal with the
- upper bound, because the platform might be busy. */
- unsigned long millis_min = ( seconds > 0 ?
- seconds * 900 :
- 0 );
- unsigned long millis_max = ( seconds > 0 ?
- seconds * 1100 + 400 :
- TIMING_ALARM_0_DELAY_MS );
- unsigned long iterations = 0;
-
- /* Skip this test if it looks like timers don't work at all, to avoid an
- infinite loop below. */
- TEST_ASSERT( !timers_are_badly_broken );
-
- /* Set an alarm and count how long it takes with a timer. */
- (void) mbedtls_timing_get_timer( &timer, 1 );
- mbedtls_set_alarm( seconds );
-
- if( seconds > 0 )
- {
- /* We set the alarm for at least 1 second. It should not have fired
- immediately, even on a slow and busy platform. */
- TEST_ASSERT( !mbedtls_timing_alarmed );
- }
- /* A 0-second alarm should fire quickly, but we don't guarantee that it
- fires immediately, so mbedtls_timing_alarmed may or may not be set at
- this point. */
-
- /* Busy-wait until the alarm rings */
- do
- {
- ++iterations;
- millis = mbedtls_timing_get_timer( &timer, 0 );
- }
- while( !mbedtls_timing_alarmed && millis <= millis_max );
-
- TEST_ASSERT( mbedtls_timing_alarmed );
- TEST_ASSERT( millis >= millis_min );
- TEST_ASSERT( millis <= millis_max );
-
- mbedtls_timing_alarmed = 0;
- return;
-
-exit:
- /* Show some diagnostic iterations, because timing
- problems can be hard to reproduce. */
- if( !timers_are_badly_broken )
- mbedtls_fprintf( stdout, " Finished with alarmed=%d millis=%lu get(timer)<=%lu iterations=%lu\n",
- mbedtls_timing_alarmed,
- millis, mbedtls_timing_get_timer( &timer, 0 ),
- iterations );
- /* Cleanup */
- mbedtls_timing_alarmed = 0;
-}
-/* END_CASE */
-
-/* BEGIN_CASE */
-void timing_delay( int int_ms, int fin_ms )
-{
- /* This function assumes that if int_ms is nonzero then it is large
- enough that we have time to read all timers at least once in an
- interval of time lasting int_ms milliseconds, and likewise for (fin_ms
- - int_ms). So don't call it with arguments that are too small. */
-
- mbedtls_timing_delay_context delay;
- struct mbedtls_timing_hr_time timer;
- unsigned long delta = 0; /* delay started between timer=0 and timer=delta */
- unsigned long before = 0, after = 0;
- unsigned long iterations = 0;
- int status = -2;
- int saw_status_1 = 0;
- int warn_inconclusive = 0;
-
- assert( int_ms >= 0 );
- assert( fin_ms >= 0 );
-
- /* Skip this test if it looks like timers don't work at all, to avoid an
- infinite loop below. */
- TEST_ASSERT( !timers_are_badly_broken );
-
- /* Start a reference timer. Program a delay, and verify that the status of
- the delay is consistent with the time given by the reference timer. */
- (void) mbedtls_timing_get_timer( &timer, 1 );
- mbedtls_timing_set_delay( &delay, int_ms, fin_ms );
- /* Set delta to an upper bound for the interval between the start of timer
- and the start of delay. Reading timer after starting delay gives us an
- upper bound for the interval, rounded to a 1ms precision. Since this
- might have been rounded down, but we need an upper bound, we add 1. */
- delta = mbedtls_timing_get_timer( &timer, 0 ) + 1;
-
- status = mbedtls_timing_get_delay( &delay );
- if( fin_ms == 0 )
- {
- /* Cancelled timer. Just check the correct status for this case. */
- TEST_ASSERT( status == -1 );
- return;
- }
-
- /* Initially, none of the delays must be passed yet if they're nonzero.
- This could fail for very small values of int_ms and fin_ms, where "very
- small" depends how fast and how busy the platform is. */
- if( int_ms > 0 )
- {
- TEST_ASSERT( status == 0 );
- }
- else
- {
- TEST_ASSERT( status == 1 );
- }
-
- do
- {
- unsigned long delay_min, delay_max;
- int status_min, status_max;
- ++iterations;
- before = mbedtls_timing_get_timer( &timer, 0 );
- status = mbedtls_timing_get_delay( &delay );
- after = mbedtls_timing_get_timer( &timer, 0 );
- /* At a time between before and after, the delay's status was status.
- Check that this is consistent given that the delay was started
- between times 0 and delta. */
- delay_min = ( before > delta ? before - delta : 0 );
- status_min = expected_delay_status( int_ms, fin_ms, delay_min );
- delay_max = after;
- status_max = expected_delay_status( int_ms, fin_ms, delay_max );
- TEST_ASSERT( status >= status_min );
- TEST_ASSERT( status <= status_max );
- if( status == 1 )
- saw_status_1 = 1;
- }
- while ( before <= fin_ms + delta && status != 2 );
-
- /* Since we've waited at least fin_ms, the delay must have fully
- expired. */
- TEST_ASSERT( status == 2 );
-
- /* If the second delay is more than the first, then there must have been a
- point in time when the first delay was passed but not the second delay.
- This could fail for very small values of (fin_ms - int_ms), where "very
- small" depends how fast and how busy the platform is. In practice, this
- is the test that's most likely to fail on a heavily loaded machine. */
- if( fin_ms > int_ms )
- {
- warn_inconclusive = 1;
- TEST_ASSERT( saw_status_1 );
- }
-
- return;
-
-exit:
- /* No cleanup needed, but show some diagnostic iterations, because timing
- problems can be hard to reproduce. */
- if( !timers_are_badly_broken )
- mbedtls_fprintf( stdout, " Finished with delta=%lu before=%lu after=%lu status=%d iterations=%lu\n",
- delta, before, after, status, iterations );
- if( warn_inconclusive )
- mbedtls_fprintf( stdout, " Inconclusive test, try running it on a less heavily loaded machine.\n" );
- }
-/* END_CASE */
-
-/* BEGIN_CASE */
void timing_hardclock( )
{
- /* We make very few guarantees about mbedtls_timing_hardclock: its rate is
- platform-dependent, it can wrap around. So there isn't much we can
- test. But we do at least test that it doesn't crash, stall or return
- completely nonsensical values. */
+ (void) mbedtls_timing_hardclock();
+ /* This goto is added to avoid warnings from the generated code. */
+ goto exit;
+}
+/* END_CASE */
- struct mbedtls_timing_hr_time timer;
- unsigned long hardclock0 = -1, hardclock1 = -1, delta1 = -1;
+/* BEGIN_CASE */
+void timing_get_timer( )
+{
+ struct mbedtls_timing_hr_time time;
+ (void) mbedtls_timing_get_timer( &time, 1 );
+ (void) mbedtls_timing_get_timer( &time, 0 );
+ /* This goto is added to avoid warnings from the generated code. */
+ goto exit;
+}
+/* END_CASE */
- /* Skip this test if it looks like timers don't work at all, to avoid an
- infinite loop below. */
- TEST_ASSERT( !timers_are_badly_broken );
+/* BEGIN_CASE */
+void timing_set_alarm( int seconds )
+{
+ if( seconds == 0 ) {
+ mbedtls_set_alarm( seconds );
+ TEST_ASSERT( mbedtls_timing_alarmed == 1 );
+ } else {
+ mbedtls_set_alarm( seconds );
+ TEST_ASSERT( mbedtls_timing_alarmed == 0 ||
+ mbedtls_timing_alarmed == 1 );
+ }
+}
+/* END_CASE */
- hardclock0 = mbedtls_timing_hardclock( );
- /* Wait 2ms to ensure a nonzero delay. Since the timer interface has 1ms
- resolution and unspecified precision, waiting 1ms might be a very small
- delay that's rounded up. */
- (void) mbedtls_timing_get_timer( &timer, 1 );
- while( mbedtls_timing_get_timer( &timer, 0 ) < 2 )
- /*busy-wait loop*/;
- hardclock1 = mbedtls_timing_hardclock( );
-
- /* Although the hardclock counter can wrap around, the difference
- (hardclock1 - hardclock0) is taken modulo the type size, so it is
- correct as long as the counter only wrapped around at most once. We
- further require the difference to be nonzero (after a wait of more than
- 1ms, the counter must have changed), and not to be overly large (after
- a wait of less than 3ms, plus time lost because other processes were
- scheduled on the CPU). If the hardclock counter runs at 4GHz, then
- 1000000000 (which is 1/4 of the counter wraparound on a 32-bit machine)
- allows 250ms. */
- delta1 = hardclock1 - hardclock0;
- TEST_ASSERT( delta1 > 0 );
- TEST_ASSERT( delta1 < 1000000000 );
- return;
-
-exit:
- /* No cleanup needed, but show some diagnostic iterations, because timing
- problems can be hard to reproduce. */
- if( !timers_are_badly_broken )
- mbedtls_fprintf( stdout, " Finished with hardclock=%lu,%lu\n",
- hardclock0, hardclock1 );
+/* BEGIN_CASE */
+void timing_delay( int fin_ms )
+{
+ mbedtls_timing_delay_context ctx;
+ int result;
+ if( fin_ms == 0 ) {
+ mbedtls_timing_set_delay( &ctx, 0, 0 );
+ result = mbedtls_timing_get_delay( &ctx );
+ TEST_ASSERT( result == -1 );
+ } else {
+ mbedtls_timing_set_delay( &ctx, fin_ms / 2, fin_ms );
+ result = mbedtls_timing_get_delay( &ctx );
+ TEST_ASSERT( result >= 0 && result <= 2 );
+ }
}
/* END_CASE */