Commit Graph

8 Commits

Author SHA1 Message Date
Alexander Mihajlovic f19787bb84 posix: Fix calculation of clock base in clock_settime
Previous version calculated rt_clock_base incorrectly by subtracting
clock_gettime from the specified time. Effectively the following
formula was used.

    rt_clock_base := new_time - clock_gettime()

This is clearly incorrect when we consider what should happen if we
call clock_settime with the result of clock_gettime. It ought to be
approximately a no-op, but instead we end up zeroing the clock.

    rt_clock_base := clock_gettime() - clock_gettime() = 0

This patch fixes clock_settime by instead using k_uptime_get to
calculate rt_clock_base, like so:

    rt_clock_base := new_time - k_uptime_get()

Trying the earlier thought experiment we get:

    rt_clock_base := clock_gettime() - k_uptime_get()

Using the definition of clock_gettime this expands to:

    rt_clock_base := (rt_clock_base + k_uptime_get()) - k_uptime_get()

The two k_uptime_get() terms cancel out, leaving:

    rt_clock_base := rt_clock_base

I.e. the no-op that we expect when calling clock_settime with
the result of clock_gettime.

Note: The bug is only observable when rt_clock_base is non-zero.
So when clock_settime is called for the first time, it will appear
to work correctly since rt_clock_base is initialized to 0.

Signed-off-by: Alexander Mihajlovic <alexander.mihajlovic@endian.se>
2019-05-21 08:24:59 -04:00
Paul Sokolovsky 81fa697f32 posix: Move gettimeofday declaration to <sys/time.h>
According to POSIX, that's the header which defines this function.
Similarly, nothing in POSIX indicates that <time.h> should have
access to struct timeval, so it's removed (it's made accessible
to <sys/time.h> via <sys/_timeval.h> introduced earlier).

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
2019-05-07 22:18:09 -04:00
Kumar Gala e96d02984c lib: posix: Fix compile issue with newer newlib
Both SDK 0.10.0-beta2 and the ARM gcc 2018q2 run into a build issue with
newlib and conflict definitions of mode_t type.

First we need to add some ifdef protection if mode_t is already defined
and set _MODE_T_DECLARED if we are the first to define it.

Secondarily, we rename include/posix/sys/types.h to
include/posix/posix_types.h so that we aren't getting a name collusion
with the system sys/types.h and that we can easily and clearily include
it (which we need to do to pull in the info from newlib).

Fixes: #12224

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>
2019-02-22 11:55:01 -06:00
David Brown 9d6f1c600f lib: posix: clock: Implement clock_settime
Set a base time, using the current uptime.

Signed-off-by: David Brown <david.brown@linaro.org>
2018-09-11 09:21:52 -04:00
David Brown 9921eb329d lib: posix: clock: Add read of CLOCK_REALTIME
Add a private variable `rt_clock_base` that can be used to determine a
real-time clock by using the `k_uptime_get` clock.  Once `clock_settime`
is added, this can allow us to have a meaningful real time clock.

Signed-off-by: David Brown <david.brown@linaro.org>
2018-09-11 09:21:52 -04:00
David Brown e0dda1b4b0 lib: posix: clock: Add gettimeofday() call
Provide an implementation of gettimeofday().  This uses clock_gettime()
with the CLOCK_REALTIME parameter, which is currently unimplemented, but
will allow clients to call this function once this functionality has
been implemented.

Signed-off-by: David Brown <david.brown@linaro.org>
2018-09-11 09:21:52 -04:00
Ramakrishna Pallala 03a3c992b8 lib: posix: clock: Use k_uptime_get() to compute tv_nsec
Use k_uptime_get() to compute both tv_sec and tv_nsec members
of timespec structure.

Fixes #8009

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
2018-06-02 16:00:23 -04:00
Ramakrishna Pallala f603e603bb lib: posix: Move posix layer from 'kernel' to 'lib'
Move posix layer from 'kernel' to 'lib' folder as it is not
a core kernel feature.

Fixed posix header file dependencies as part of the move and
also removed NEWLIBC related macros from posix headers.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
2018-04-05 16:43:05 -04:00