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adjtime.c: Use timestamp math and simplify

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This commit is contained in:
Joel Sherrill
2014-07-18 19:46:59 -05:00
parent 8abbbdde38
commit 3b6352d2e6
1 changed files with 28 additions and 40 deletions
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68
cpukit/posix/src/adjtime.c
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@@ -1,12 +1,12 @@
/**
* @file
*
* @brief Correct the Time to Synchronize the System Clock
* @brief Adjust the Time to Synchronize the System Clock
* @ingroup POSIXAPI
*/
/*
* COPYRIGHT (c) 1989-2007.
* COPYRIGHT (c) 1989-2014.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
@@ -18,6 +18,7 @@
#include "config.h"
#endif
#define _BSD_SOURCE
#include <time.h>
#include <sys/time.h>
#include <errno.h>
@@ -30,20 +31,21 @@
/**
* This method was initially added as part of porting NTP to RTEMS.
* It is a BSD compatability function and now is available on
* GNU/Linux.
* It is a BSD compatability function and now is available on
* GNU/Linux.
*
* At one point there was a static variable named adjustment
* used by this implementation. I don't see any reason for it
* to be here based upon the GNU/Linux documentation.
* At one point there was a static variable named adjustment
* used by this implementation. I don't see any reason for it
* to be here based upon the GNU/Linux documentation.
*/
int adjtime(
int adjtime(
const struct timeval *delta,
struct timeval *olddelta
struct timeval *olddelta
)
{
struct timespec ts;
long adjustment;
Timestamp_Control delta_as_timestamp;
Timestamp_Control tod_as_timestamp;
Timestamp_Control *tod_as_timestamp_ptr;
/*
* Simple validations
@@ -51,21 +53,22 @@ int adjtime(
if ( !delta )
rtems_set_errno_and_return_minus_one( EINVAL );
if ( delta->tv_usec >= TOD_MICROSECONDS_PER_SECOND )
rtems_set_errno_and_return_minus_one( EINVAL );
/*
* Currently, RTEMS does the adjustment in one movement.
* Given interest, requirements, and sponsorship, a future
* enhancement would be to adjust the time in smaller increments
* at each clock tick. Until then, there is no outstanding
* adjustment.
*/
if ( olddelta ) {
olddelta->tv_sec = 0;
olddelta->tv_usec = 0;
}
/* convert delta to microseconds */
adjustment = (delta->tv_sec * TOD_MICROSECONDS_PER_SECOND);
adjustment += delta->tv_usec;
/* too small to account for */
if ( adjustment < rtems_configuration_get_microseconds_per_tick() )
return 0;
/*
* convert delta timeval to internal timestamp
*/
_Timestamp_Set( &delta_as_timestamp, delta->tv_sec, delta->tv_usec * 1000 );
/*
* This prevents context switches while we are adjusting the TOD
@@ -73,30 +76,15 @@ int adjtime(
_Thread_Disable_dispatch();
_TOD_Get( &ts );
tod_as_timestamp_ptr =
_TOD_Get_with_nanoseconds( &tod_as_timestamp, &_TOD.now );
ts.tv_sec += delta->tv_sec;
ts.tv_nsec += delta->tv_usec * TOD_NANOSECONDS_PER_MICROSECOND;
/* if adjustment is too much positive */
while ( ts.tv_nsec >= TOD_NANOSECONDS_PER_SECOND ) {
ts.tv_nsec -= TOD_NANOSECONDS_PER_SECOND;
ts.tv_sec++;
}
_Timestamp_Add_to( tod_as_timestamp_ptr, &delta_as_timestamp );
/* if adjustment is too much negative */
while ( ts.tv_nsec <= (-1 * TOD_NANOSECONDS_PER_SECOND) ) {
ts.tv_nsec += TOD_NANOSECONDS_PER_SECOND;
ts.tv_sec--;
}
_TOD_Set( &ts );
_TOD_Set_with_timestamp( tod_as_timestamp_ptr );
_Thread_Enable_dispatch();
/* set the user's output */
if ( olddelta )
*olddelta = *delta;
return 0;
}