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/error.h>
  20 #include <common/macros.h>
  21 #include <common/error.h>
  22 #include <stddef.h>
  23 #include <stdint.h>
  24 #include <limits.h>
  25 #include <errno.h>
  26 #include <pthread.h>
  27 #include <locale.h>
  28 #include <string.h>
  29
  30 static bool utf8_output_supported;
  31
  32 LTTNG_HIDDEN
  33 bool locale_supports_utf8(void)
  34 {
  35         return utf8_output_supported;
  36 }
  37
  38 LTTNG_HIDDEN
  39 int timespec_to_ms(struct timespec ts, unsigned long *ms)
  40 {
  41         unsigned long res, remain_ms;
  42
  43         if (ts.tv_sec > ULONG_MAX / MSEC_PER_SEC) {
  44                 errno = EOVERFLOW;
  45                 return -1;      /* multiplication overflow */
  46         }
  47         res = ts.tv_sec * MSEC_PER_SEC;
  48         remain_ms = ULONG_MAX - res;
  49         if (ts.tv_nsec / NSEC_PER_MSEC > remain_ms) {
  50                 errno = EOVERFLOW;
  51                 return -1;      /* addition overflow */
  52         }
  53         res += ts.tv_nsec / NSEC_PER_MSEC;
  54         *ms = res;
  55         return 0;
  56 }
  57
  58 LTTNG_HIDDEN
  59 struct timespec timespec_abs_diff(struct timespec t1, struct timespec t2)
  60 {
  61         uint64_t ts1 = (uint64_t) t1.tv_sec * (uint64_t) NSEC_PER_SEC +
  62                         (uint64_t) t1.tv_nsec;
  63         uint64_t ts2 = (uint64_t) t2.tv_sec * (uint64_t) NSEC_PER_SEC +
  64                         (uint64_t) t2.tv_nsec;
  65         uint64_t diff = max(ts1, ts2) - min(ts1, ts2);
  66         struct timespec res;
  67
  68         res.tv_sec = diff / (uint64_t) NSEC_PER_SEC;
  69         res.tv_nsec = diff % (uint64_t) NSEC_PER_SEC;
  70         return res;
  71 }
  72
  73 static
  74 void __attribute__((constructor)) init_locale_utf8_support(void)
  75 {
  76         const char *program_locale = setlocale(LC_ALL, NULL);
  77         const char *lang = getenv("LANG");
  78
  79         if (program_locale && strstr(program_locale, "utf8")) {
  80                 utf8_output_supported = true;
  81         } else if (lang && strstr(lang, "utf8")) {
  82                 utf8_output_supported = true;
  83         }
  84 }
  85
  86 LTTNG_HIDDEN
  87 int time_to_iso8601_str(time_t time, char *str, size_t len)
  88 {
  89         int ret = 0;
  90         struct tm *tm_result;
  91         struct tm tm_storage;
  92         size_t strf_ret;
  93
  94         if (len < ISO8601_STR_LEN) {
  95                 ERR("Buffer too short to format ISO 8601 timestamp: %zu bytes provided when at least %zu are needed",
  96                                 len, ISO8601_STR_LEN);
  97                 ret = -1;
  98                 goto end;
  99         }
 100
 101         tm_result = localtime_r(&time, &tm_storage);
 102         if (!tm_result) {
 103                 ret = -1;
 104                 PERROR("Failed to break down timestamp to tm structure");
 105                 goto end;
 106         }
 107
 108         strf_ret = strftime(str, len, "%Y%m%dT%H%M%S%z", tm_result);
 109         if (strf_ret == 0) {
 110                 ret = -1;
 111                 ERR("Failed to format timestamp as local time");
 112                 goto end;
 113         }
 114 end:
 115         return ret;
 116 }