Line data    Source code

       1             : /*
       2             :     Mosh: the mobile shell
       3             :     Copyright 2012 Keith Winstein
       4             : 
       5             :     This program is free software: you can redistribute it and/or modify
       6             :     it under the terms of the GNU General Public License as published by
       7             :     the Free Software Foundation, either version 3 of the License, or
       8             :     (at your option) any later version.
       9             : 
      10             :     This program 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
      13             :     GNU General Public License for more details.
      14             : 
      15             :     You should have received a copy of the GNU General Public License
      16             :     along with this program.  If not, see <http://www.gnu.org/licenses/>.
      17             : 
      18             :     In addition, as a special exception, the copyright holders give
      19             :     permission to link the code of portions of this program with the
      20             :     OpenSSL library under certain conditions as described in each
      21             :     individual source file, and distribute linked combinations including
      22             :     the two.
      23             : 
      24             :     You must obey the GNU General Public License in all respects for all
      25             :     of the code used other than OpenSSL. If you modify file(s) with this
      26             :     exception, you may extend this exception to your version of the
      27             :     file(s), but you are not obligated to do so. If you do not wish to do
      28             :     so, delete this exception statement from your version. If you delete
      29             :     this exception statement from all source files in the program, then
      30             :     also delete it here.
      31             : */
      32             : 
      33             : #include "config.h"
      34             : 
      35             : #include "timestamp.h"
      36             : 
      37             : #include <errno.h>
      38             : 
      39             : #if HAVE_CLOCK_GETTIME
      40             : #include <time.h>
      41             : #endif
      42             : #if HAVE_MACH_ABSOLUTE_TIME
      43             : #include <mach/error.h>
      44             : #include <mach/mach_time.h>
      45             : #endif
      46             : #if HAVE_GETTIMEOFDAY
      47             : #include <sys/time.h>
      48             : #include <stdio.h>
      49             : #endif
      50             : 
      51             : // On Apple systems CLOCK_MONOTONIC is unfortunately able to go
      52             : // backwards in time. This breaks mosh when system is returning from
      53             : // suspend as described in ticket #1014. To avoid this issue prefer
      54             : // CLOCK_MONOTONIC_RAW on Apple systems when available.
      55             : #if defined(__APPLE__) && defined(CLOCK_MONOTONIC_RAW)
      56             : #define CLOCKTYPE CLOCK_MONOTONIC_RAW
      57             : #else
      58             : #define CLOCKTYPE CLOCK_MONOTONIC
      59             : #endif
      60             : 
      61             : static uint64_t millis_cache = -1;
      62             : 
      63      335721 : uint64_t frozen_timestamp( void )
      64             : {
      65      335721 :   if ( millis_cache == uint64_t( -1 ) ) {
      66         900 :     freeze_timestamp();
      67             :   }
      68             : 
      69      335721 :   return millis_cache;
      70             : }
      71             : 
      72       34032 : void freeze_timestamp( void )
      73             : {
      74             :   // Try all our clock sources till we get something.  This could
      75             :   // break if a source only sometimes works in a given process.
      76             : #if HAVE_CLOCK_GETTIME
      77             :   // Preferred clock source-- portable, monotonic, (should be)
      78             :   // adjusted after system sleep
      79       34032 :   struct timespec tp;
      80             : 
      81       34032 :   if (
      82             : #if defined(__APPLE__) && defined(__MACH__)
      83             :       // Check for presence, for OS X SDK >= 10.12 and runtime < 10.12
      84             :       &clock_gettime != NULL &&
      85             : #endif
      86       34032 :       clock_gettime( CLOCKTYPE, &tp ) == 0 ) {
      87       34032 :     uint64_t millis = tp.tv_nsec / 1000000;
      88       34032 :     millis += uint64_t( tp.tv_sec ) * 1000;
      89             : 
      90       34032 :     millis_cache = millis;
      91       34032 :     return;
      92             :   }
      93             : #endif
      94             : #if HAVE_MACH_ABSOLUTE_TIME
      95             :   // Monotonic, not adjusted after system sleep.  OS X 10.12 has
      96             :   // mach_continuous_time(), but also has clock_gettime().
      97             :   static mach_timebase_info_data_t s_timebase_info;
      98             :   static double absolute_to_millis = 0.0;
      99             : 
     100             :   if (absolute_to_millis == 0.0) {
     101             :     if (ERR_SUCCESS == mach_timebase_info(&s_timebase_info)) {
     102             :       absolute_to_millis = 1e-6 * s_timebase_info.numer / s_timebase_info.denom;
     103             :     } else
     104             :       absolute_to_millis = -1.0;
     105             :   }
     106             : 
     107             :   // NB: mach_absolute_time() returns "absolute time units"
     108             :   // We need to apply a conversion to get milliseconds.
     109             :   if (absolute_to_millis > 0.0) {
     110             :     millis_cache = mach_absolute_time() * absolute_to_millis;
     111             :     return;
     112             :   }
     113             : #endif
     114             : #if HAVE_GETTIMEOFDAY
     115             :   // Not monotonic.
     116             :   // NOTE: If time steps backwards, timeouts may be confused.
     117           0 :   struct timeval tv;
     118           0 :   if ( gettimeofday(&tv, NULL) ) {
     119           0 :     perror( "gettimeofday" );
     120             :   } else {
     121           0 :     uint64_t millis = tv.tv_usec / 1000;
     122           0 :     millis += uint64_t( tv.tv_sec ) * 1000;
     123             : 
     124           0 :     millis_cache = millis;
     125           0 :     return;
     126             :   }
     127             : #else
     128             : # error "gettimeofday() unavailable-- required as timer of last resort"
     129             : #endif
     130             : }