lib/getrusage.c

   1 /* getrusage replacement for systems which lack it.
   2
   3    Copyright (C) 2012-2020 Free Software Foundation, Inc.
   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 <https://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Bruno Haible, 2012.  */
  19
  20 #include <config.h>
  21
  22 /* Specification.  */
  23 #include <sys/resource.h>
  24
  25 #include <errno.h>
  26 #include <string.h>
  27
  28 /* Get uint64_t.  */
  29 #include <stdint.h>
  30
  31 #if defined _WIN32 && ! defined __CYGWIN__
  32
  33 # define WIN32_LEAN_AND_MEAN
  34 # include <windows.h>
  35
  36 #else
  37
  38 # include <sys/times.h>
  39 # include <unistd.h>
  40 #endif
  41
  42 int
  43 getrusage (int who, struct rusage *usage_p)
  44 {
  45   if (who == RUSAGE_SELF || who == RUSAGE_CHILDREN)
  46     {
  47       /* Clear all unsupported members of 'struct rusage'.  */
  48       memset (usage_p, '\0', sizeof (struct rusage));
  49
  50 #if defined _WIN32 && ! defined __CYGWIN__
  51       if (who == RUSAGE_SELF)
  52         {
  53           /* Fill in the ru_utime and ru_stime members.  */
  54           FILETIME creation_time;
  55           FILETIME exit_time;
  56           FILETIME kernel_time;
  57           FILETIME user_time;
  58
  59           if (GetProcessTimes (GetCurrentProcess (),
  60                                &creation_time, &exit_time,
  61                                &kernel_time, &user_time))
  62             {
  63               /* Convert to microseconds, rounding.  */
  64               uint64_t kernel_usec =
  65                 ((((uint64_t) kernel_time.dwHighDateTime << 32)
  66                   | (uint64_t) kernel_time.dwLowDateTime)
  67                  + 5) / 10;
  68               uint64_t user_usec =
  69                 ((((uint64_t) user_time.dwHighDateTime << 32)
  70                   | (uint64_t) user_time.dwLowDateTime)
  71                  + 5) / 10;
  72
  73               usage_p->ru_utime.tv_sec = user_usec / 1000000U;
  74               usage_p->ru_utime.tv_usec = user_usec % 1000000U;
  75               usage_p->ru_stime.tv_sec = kernel_usec / 1000000U;
  76               usage_p->ru_stime.tv_usec = kernel_usec % 1000000U;
  77             }
  78         }
  79 #else
  80       /* Fill in the ru_utime and ru_stime members.  */
  81       {
  82         struct tms time;
  83
  84         if (times (&time) != (clock_t) -1)
  85           {
  86             /* Number of clock ticks per second.  */
  87             unsigned int clocks_per_second = sysconf (_SC_CLK_TCK);
  88
  89             if (clocks_per_second > 0)
  90               {
  91                 clock_t user_ticks;
  92                 clock_t system_ticks;
  93
  94                 uint64_t user_usec;
  95                 uint64_t system_usec;
  96
  97                 if (who == RUSAGE_CHILDREN)
  98                   {
  99                     user_ticks   = time.tms_cutime;
 100                     system_ticks = time.tms_cstime;
 101                   }
 102                 else
 103                   {
 104                     user_ticks   = time.tms_utime;
 105                     system_ticks = time.tms_stime;
 106                   }
 107
 108                 user_usec =
 109                   (((uint64_t) user_ticks * (uint64_t) 1000000U)
 110                    + clocks_per_second / 2) / clocks_per_second;
 111                 system_usec =
 112                   (((uint64_t) system_ticks * (uint64_t) 1000000U)
 113                    + clocks_per_second / 2) / clocks_per_second;
 114
 115                 usage_p->ru_utime.tv_sec = user_usec / 1000000U;
 116                 usage_p->ru_utime.tv_usec = user_usec % 1000000U;
 117                 usage_p->ru_stime.tv_sec = system_usec / 1000000U;
 118                 usage_p->ru_stime.tv_usec = system_usec % 1000000U;
 119               }
 120           }
 121       }
 122 #endif
 123
 124       return 0;
 125     }
 126   else
 127     {
 128       errno = EINVAL;
 129       return -1;
 130     }
 131 }