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Fix integer overflow problems in times()

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An integer overflow may still happen, however, only after 68 years of
system uptime.

Close #2135.
This commit is contained in:
Sebastian Huber
2017-09-06 07:42:25 +02:00
parent 3663be5352
commit 731e68a39a
1 changed files with 15 additions and 33 deletions
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cpukit/libcsupport/src/__times.c
+15 -33
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@@ -43,19 +43,23 @@ clock_t _times(
struct tms *ptms
)
{
rtems_interval ticks, us_per_tick;
uint32_t tick_interval;
struct bintime binuptime;
sbintime_t uptime;
struct bintime bin_cpu_time_used;
sbintime_t cpu_time_used;
if ( !ptms )
rtems_set_errno_and_return_minus_one( EFAULT );
memset( ptms, 0, sizeof( *ptms ) );
tick_interval = (uint32_t)
(SBT_1US * rtems_configuration_get_microseconds_per_tick());
/*
* This call does not depend on TOD being initialized and can't fail.
*/
ptms = memset( ptms, 0, sizeof( *ptms ) );
ticks = rtems_clock_get_ticks_since_boot();
us_per_tick = rtems_configuration_get_microseconds_per_tick();
_TOD_Get_zero_based_uptime( &binuptime );
uptime = bttosbt( binuptime );
ptms->tms_stime = ((clock_t) uptime) / tick_interval;
/*
* RTEMS technically has no notion of system versus user time
@@ -64,33 +68,11 @@ clock_t _times(
* of ticks since boot and the number of ticks executed by this
* this thread.
*/
{
Timestamp_Control cpu_time_used;
Timestamp_Control per_tick;
uint32_t ticks_of_executing;
uint32_t fractional_ticks;
_Thread_Get_CPU_time_used( _Thread_Get_executing(), &bin_cpu_time_used );
cpu_time_used = bttosbt( bin_cpu_time_used );
ptms->tms_utime = ((clock_t) cpu_time_used) / tick_interval;
_Thread_Get_CPU_time_used( _Thread_Get_executing(), &cpu_time_used );
_Timestamp_Set(
&per_tick,
rtems_configuration_get_microseconds_per_tick() /
TOD_MICROSECONDS_PER_SECOND,
(rtems_configuration_get_nanoseconds_per_tick() %
TOD_NANOSECONDS_PER_SECOND)
);
_Timestamp_Divide(
&cpu_time_used,
&per_tick,
&ticks_of_executing,
&fractional_ticks
);
ptms->tms_utime = ticks_of_executing * us_per_tick;
}
ptms->tms_stime = ticks * us_per_tick;
return ticks * us_per_tick;
return ptms->tms_stime;
}
/**