sysdeps/mach/clock_nanosleep.c

   1 /* clock_nanosleep - high-resolution sleep with specifiable clock.
   2    Copyright (C) 2002-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <mach.h>
  21 #include <time.h>
  22 #include <unistd.h>
  23 #include <posix-timer.h>
  24 #include <shlib-compat.h>
  25 #include <sysdep-cancel.h>
  26
  27 static int
  28 nanosleep_call (const struct timespec *req, struct timespec *rem)
  29 {
  30   mach_port_t recv;
  31   struct timespec before;
  32   error_t err;
  33
  34   const mach_msg_timeout_t ms
  35     = req->tv_sec * 1000
  36     + (req->tv_nsec + 999999) / 1000000;
  37
  38   recv = __mach_reply_port ();
  39
  40   if (rem != NULL)
  41     __clock_gettime (CLOCK_REALTIME, &before);
  42
  43   int cancel_oldtype = LIBC_CANCEL_ASYNC();
  44   err = __mach_msg (NULL, MACH_RCV_MSG|MACH_RCV_TIMEOUT|MACH_RCV_INTERRUPT,
  45                     0, 0, recv, ms, MACH_PORT_NULL);
  46   LIBC_CANCEL_RESET (cancel_oldtype);
  47
  48   __mach_port_destroy (mach_task_self (), recv);
  49
  50   if (err == EMACH_RCV_INTERRUPTED)
  51     {
  52       if (rem != NULL)
  53         {
  54           struct timespec after, elapsed;
  55           __clock_gettime (CLOCK_REALTIME, &after);
  56           timespec_sub (&elapsed, &after, &before);
  57           timespec_sub (rem, req, &elapsed);
  58         }
  59
  60       return EINTR;
  61     }
  62
  63   return 0;
  64 }
  65
  66 int
  67 __clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req,
  68                    struct timespec *rem)
  69 {
  70   if (clock_id != CLOCK_REALTIME
  71       || !valid_nanoseconds (req->tv_nsec)
  72       || (flags != 0 && flags != TIMER_ABSTIME))
  73     return EINVAL;
  74
  75   struct timespec now;
  76
  77   /* If we got an absolute time, remap it.  */
  78   if (flags == TIMER_ABSTIME)
  79     {
  80       long int nsec;
  81       long int sec;
  82
  83       /* Make sure we use safe data types.  */
  84       assert (sizeof (sec) >= sizeof (now.tv_sec));
  85
  86       /* Get the current time for this clock.  */
  87       if (__clock_gettime (clock_id, &now) != 0)
  88         return errno;
  89
  90       /* Compute the difference.  */
  91       nsec = req->tv_nsec - now.tv_nsec;
  92       sec = req->tv_sec - now.tv_sec - (nsec < 0);
  93       if (sec < 0)
  94         /* The time has already elapsed.  */
  95         return 0;
  96
  97       now.tv_sec = sec;
  98       now.tv_nsec = nsec + (nsec < 0 ? 1000000000 : 0);
  99
 100       /* From now on this is our time.  */
 101       req = &now;
 102
 103       /* Make sure we are not modifying the struct pointed to by REM.  */
 104       rem = NULL;
 105     }
 106
 107   return nanosleep_call (req, rem);
 108 }
 109 libc_hidden_def (__clock_nanosleep)
 110 versioned_symbol (libc, __clock_nanosleep, clock_nanosleep, GLIBC_2_17);
 111 /* clock_nanosleep moved to libc in version 2.17;
 112    old binaries may expect the symbol version it had in librt.  */
 113 #if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_17)
 114 strong_alias (__clock_nanosleep, __clock_nanosleep_2);
 115 compat_symbol (libc, __clock_nanosleep_2, clock_nanosleep, GLIBC_2_2);
 116 #endif