src/common/time.c

   1 /*
   2  * Copyright (C) 2013 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License, version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, write to the Free Software Foundation, Inc., 51
  15  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  16  */
  17
  18 #include <common/time.h>
  19 #include <common/macros.h>
  20 #include <common/error.h>
  21 #include <stddef.h>
  22 #include <stdint.h>
  23 #include <limits.h>
  24 #include <errno.h>
  25 #include <pthread.h>
  26 #include <locale.h>
  27 #include <string.h>
  28
  29 static bool utf8_output_supported;
  30
  31 LTTNG_HIDDEN
  32 bool locale_supports_utf8(void)
  33 {
  34         return utf8_output_supported;
  35 }
  36
  37 LTTNG_HIDDEN
  38 int timespec_to_ms(struct timespec ts, unsigned long *ms)
  39 {
  40         unsigned long res, remain_ms;
  41
  42         if (ts.tv_sec > ULONG_MAX / MSEC_PER_SEC) {
  43                 errno = EOVERFLOW;
  44                 return -1;      /* multiplication overflow */
  45         }
  46         res = ts.tv_sec * MSEC_PER_SEC;
  47         remain_ms = ULONG_MAX - res;
  48         if (ts.tv_nsec / NSEC_PER_MSEC > remain_ms) {
  49                 errno = EOVERFLOW;
  50                 return -1;      /* addition overflow */
  51         }
  52         res += ts.tv_nsec / NSEC_PER_MSEC;
  53         *ms = res;
  54         return 0;
  55 }
  56
  57 LTTNG_HIDDEN
  58 struct timespec timespec_abs_diff(struct timespec t1, struct timespec t2)
  59 {
  60         uint64_t ts1 = (uint64_t) t1.tv_sec * (uint64_t) NSEC_PER_SEC +
  61                         (uint64_t) t1.tv_nsec;
  62         uint64_t ts2 = (uint64_t) t2.tv_sec * (uint64_t) NSEC_PER_SEC +
  63                         (uint64_t) t2.tv_nsec;
  64         uint64_t diff = max(ts1, ts2) - min(ts1, ts2);
  65         struct timespec res;
  66
  67         res.tv_sec = diff / (uint64_t) NSEC_PER_SEC;
  68         res.tv_nsec = diff % (uint64_t) NSEC_PER_SEC;
  69         return res;
  70 }
  71
  72 static
  73 void __attribute__((constructor)) init_locale_utf8_support(void)
  74 {
  75         const char *program_locale = setlocale(LC_ALL, NULL);
  76         const char *lang = getenv("LANG");
  77
  78         if (program_locale && strstr(program_locale, "utf8")) {
  79                 utf8_output_supported = true;
  80         } else if (lang && strstr(lang, "utf8")) {
  81                 utf8_output_supported = true;
  82         }
  83 }
  84
  85 LTTNG_HIDDEN
  86 int time_to_iso8601_str(time_t time, char *str, size_t len)
  87 {
  88         int ret = 0;
  89         struct tm *tm_result;
  90         struct tm tm_storage;
  91         size_t strf_ret;
  92
  93         if (len < ISO8601_STR_LEN) {
  94                 ERR("Buffer too short to format ISO 8601 timestamp: %zu bytes provided when at least %zu are needed",
  95                                 len, ISO8601_STR_LEN);
  96                 ret = -1;
  97                 goto end;
  98         }
  99
 100         tm_result = localtime_r(&time, &tm_storage);
 101         if (!tm_result) {
 102                 ret = -1;
 103                 PERROR("Failed to break down timestamp to tm structure");
 104                 goto end;
 105         }
 106
 107         strf_ret = strftime(str, len, "%Y%m%dT%H%M%S%z", tm_result);
 108         if (strf_ret == 0) {
 109                 ret = -1;
 110                 ERR("Failed to format timestamp as local time");
 111                 goto end;
 112         }
 113 end:
 114         return ret;
 115 }