ladybird/Userland/adjtime.cpp
Nico Weber 5fcd34b810 Userland: Add an "adjtime" utility
It's a thin userland wrapper around adjtime(2). It can be used
to view current pending time adjustments, and root can use it to
smoothly adjust the system time.

As far as I can tell, other systems don't have a userland utility
for this, but it seems useful. Useful enough that I'm adding it to
the lagom build so I can use it on my linux box too :)
2020-11-10 19:03:08 +01:00

77 lines
2.7 KiB
C++

/*
* Copyright (c) 2020, Nico Weber <thakis@chromium.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <LibCore/ArgsParser.h>
#include <math.h>
#include <sys/time.h>
int main(int argc, char** argv)
{
#ifdef __serenity__
if (pledge("stdio settime", nullptr) < 0) {
perror("pledge");
return 1;
}
#endif
Core::ArgsParser args_parser;
double delta = __builtin_nan("");
args_parser.add_option(delta, "Adjust system time by this many seconds", "set", 's', "delta_seconds");
args_parser.parse(argc, argv);
if (__builtin_isnan(delta)) {
#ifdef __serenity__
if (pledge("stdio", nullptr) < 0) {
perror("pledge");
return 1;
}
#endif
} else {
long delta_us = static_cast<long>(round(delta * 1'000'000));
timeval delta_timeval;
delta_timeval.tv_sec = delta_us / 1'000'000;
delta_timeval.tv_usec = delta_us % 1'000'000;
if (delta_timeval.tv_usec < 0) {
delta_timeval.tv_sec--;
delta_timeval.tv_usec += 1'000'000;
}
if (adjtime(&delta_timeval, nullptr) < 0) {
perror("adjtime set");
return 1;
}
}
timeval remaining_delta_timeval;
if (adjtime(nullptr, &remaining_delta_timeval) < 0) {
perror("adjtime get");
return 1;
}
double remaining_delta = remaining_delta_timeval.tv_sec + remaining_delta_timeval.tv_usec / 1'000'000.0;
printf("%f\n", remaining_delta);
return 0;
}