277 lines
8.0 KiB
C
277 lines
8.0 KiB
C
/* Provide a replacement for the POSIX nanosleep function.
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Copyright (C) 1999-2000, 2002, 2004-2020 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* written by Jim Meyering
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and Bruno Haible for the native Windows part */
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#include <config.h>
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#include <time.h>
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#include "intprops.h"
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#include "sig-handler.h"
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#include "verify.h"
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#include <stdbool.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/select.h>
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#include <signal.h>
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#include <sys/time.h>
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#include <errno.h>
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#include <unistd.h>
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enum { BILLION = 1000 * 1000 * 1000 };
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#if HAVE_BUG_BIG_NANOSLEEP
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int
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nanosleep (const struct timespec *requested_delay,
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struct timespec *remaining_delay)
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# undef nanosleep
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{
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/* nanosleep mishandles large sleeps due to internal overflow problems.
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The worst known case of this is Linux 2.6.9 with glibc 2.3.4, which
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can't sleep more than 24.85 days (2^31 milliseconds). Similarly,
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cygwin 1.5.x, which can't sleep more than 49.7 days (2^32 milliseconds).
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Solve this by breaking the sleep up into smaller chunks. */
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if (requested_delay->tv_nsec < 0 || BILLION <= requested_delay->tv_nsec)
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{
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errno = EINVAL;
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return -1;
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}
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{
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/* Verify that time_t is large enough. */
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verify (TYPE_MAXIMUM (time_t) / 24 / 24 / 60 / 60);
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const time_t limit = 24 * 24 * 60 * 60;
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time_t seconds = requested_delay->tv_sec;
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struct timespec intermediate;
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intermediate.tv_nsec = requested_delay->tv_nsec;
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while (limit < seconds)
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{
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int result;
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intermediate.tv_sec = limit;
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result = nanosleep (&intermediate, remaining_delay);
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seconds -= limit;
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if (result)
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{
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if (remaining_delay)
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remaining_delay->tv_sec += seconds;
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return result;
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}
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intermediate.tv_nsec = 0;
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}
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intermediate.tv_sec = seconds;
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return nanosleep (&intermediate, remaining_delay);
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}
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}
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#elif defined _WIN32 && ! defined __CYGWIN__
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/* Native Windows platforms. */
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# define WIN32_LEAN_AND_MEAN
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# include <windows.h>
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/* The Windows API function Sleep() has a resolution of about 15 ms and takes
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at least 5 ms to execute. We use this function for longer time periods.
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Additionally, we use busy-looping over short time periods, to get a
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resolution of about 0.01 ms. In order to measure such short timespans,
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we use the QueryPerformanceCounter() function. */
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int
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nanosleep (const struct timespec *requested_delay,
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struct timespec *remaining_delay)
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{
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static bool initialized;
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/* Number of performance counter increments per nanosecond,
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or zero if it could not be determined. */
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static double ticks_per_nanosecond;
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if (requested_delay->tv_nsec < 0 || BILLION <= requested_delay->tv_nsec)
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{
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errno = EINVAL;
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return -1;
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}
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/* For requested delays of one second or more, 15ms resolution is
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sufficient. */
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if (requested_delay->tv_sec == 0)
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{
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if (!initialized)
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{
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/* Initialize ticks_per_nanosecond. */
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LARGE_INTEGER ticks_per_second;
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if (QueryPerformanceFrequency (&ticks_per_second))
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ticks_per_nanosecond =
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(double) ticks_per_second.QuadPart / 1000000000.0;
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initialized = true;
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}
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if (ticks_per_nanosecond)
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{
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/* QueryPerformanceFrequency worked. We can use
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QueryPerformanceCounter. Use a combination of Sleep and
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busy-looping. */
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/* Number of milliseconds to pass to the Sleep function.
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Since Sleep can take up to 8 ms less or 8 ms more than requested
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(or maybe more if the system is loaded), we subtract 10 ms. */
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int sleep_millis = (int) requested_delay->tv_nsec / 1000000 - 10;
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/* Determine how many ticks to delay. */
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LONGLONG wait_ticks = requested_delay->tv_nsec * ticks_per_nanosecond;
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/* Start. */
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LARGE_INTEGER counter_before;
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if (QueryPerformanceCounter (&counter_before))
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{
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/* Wait until the performance counter has reached this value.
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We don't need to worry about overflow, because the performance
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counter is reset at reboot, and with a frequency of 3.6E6
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ticks per second 63 bits suffice for over 80000 years. */
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LONGLONG wait_until = counter_before.QuadPart + wait_ticks;
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/* Use Sleep for the longest part. */
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if (sleep_millis > 0)
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Sleep (sleep_millis);
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/* Busy-loop for the rest. */
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for (;;)
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{
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LARGE_INTEGER counter_after;
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if (!QueryPerformanceCounter (&counter_after))
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/* QueryPerformanceCounter failed, but succeeded earlier.
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Should not happen. */
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break;
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if (counter_after.QuadPart >= wait_until)
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/* The requested time has elapsed. */
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break;
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}
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goto done;
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}
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}
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}
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/* Implementation for long delays and as fallback. */
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Sleep (requested_delay->tv_sec * 1000 + requested_delay->tv_nsec / 1000000);
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done:
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/* Sleep is not interruptible. So there is no remaining delay. */
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if (remaining_delay != NULL)
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{
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remaining_delay->tv_sec = 0;
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remaining_delay->tv_nsec = 0;
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}
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return 0;
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}
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#else
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/* Unix platforms lacking nanosleep. */
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/* Some systems (MSDOS) don't have SIGCONT.
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Using SIGTERM here turns the signal-handling code below
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into a no-op on such systems. */
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# ifndef SIGCONT
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# define SIGCONT SIGTERM
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# endif
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static sig_atomic_t volatile suspended;
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/* Handle SIGCONT. */
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static _GL_ASYNC_SAFE void
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sighandler (int sig)
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{
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suspended = 1;
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}
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/* Suspend execution for at least *TS_DELAY seconds. */
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static int
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my_usleep (const struct timespec *ts_delay)
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{
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struct timeval tv_delay;
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tv_delay.tv_sec = ts_delay->tv_sec;
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tv_delay.tv_usec = (ts_delay->tv_nsec + 999) / 1000;
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if (tv_delay.tv_usec == 1000000)
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{
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if (tv_delay.tv_sec == TYPE_MAXIMUM (time_t))
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tv_delay.tv_usec = 1000000 - 1; /* close enough */
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else
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{
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tv_delay.tv_sec++;
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tv_delay.tv_usec = 0;
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}
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}
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return select (0, NULL, NULL, NULL, &tv_delay);
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}
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/* Suspend execution for at least *REQUESTED_DELAY seconds. The
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*REMAINING_DELAY part isn't implemented yet. */
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int
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nanosleep (const struct timespec *requested_delay,
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struct timespec *remaining_delay)
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{
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static bool initialized;
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if (requested_delay->tv_nsec < 0 || BILLION <= requested_delay->tv_nsec)
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{
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errno = EINVAL;
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return -1;
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}
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/* set up sig handler */
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if (! initialized)
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{
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struct sigaction oldact;
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sigaction (SIGCONT, NULL, &oldact);
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if (get_handler (&oldact) != SIG_IGN)
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{
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struct sigaction newact;
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newact.sa_handler = sighandler;
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sigemptyset (&newact.sa_mask);
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newact.sa_flags = 0;
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sigaction (SIGCONT, &newact, NULL);
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}
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initialized = true;
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}
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suspended = 0;
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if (my_usleep (requested_delay) == -1)
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{
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if (suspended)
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{
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/* Calculate time remaining. */
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/* FIXME: the code in sleep doesn't use this, so there's no
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rush to implement it. */
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errno = EINTR;
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}
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return -1;
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}
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/* FIXME: Restore sig handler? */
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return 0;
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}
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#endif
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