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Diffstat (limited to 'shared/nm-utils/nm-time-utils.c')
| -rw-r--r-- | shared/nm-utils/nm-time-utils.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/shared/nm-utils/nm-time-utils.c b/shared/nm-utils/nm-time-utils.c new file mode 100644 index 0000000000..26b982246b --- /dev/null +++ b/shared/nm-utils/nm-time-utils.c @@ -0,0 +1,227 @@ +/* NetworkManager -- Network link manager + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the + * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, + * Boston, MA 02110-1301 USA. + * + * (C) Copyright 2018 Red Hat, Inc. + */ + +#include "nm-default.h" + +#include "nm-time-utils.h" + +/*****************************************************************************/ + +static gint64 monotonic_timestamp_offset_sec; +static int monotonic_timestamp_clock_mode = 0; + +static void +monotonic_timestamp_get (struct timespec *tp) +{ + int clock_mode = 0; + int err = 0; + + switch (monotonic_timestamp_clock_mode) { + case 0: + /* the clock is not yet initialized (first run) */ + err = clock_gettime (CLOCK_BOOTTIME, tp); + if (err == -1 && errno == EINVAL) { + clock_mode = 2; + err = clock_gettime (CLOCK_MONOTONIC, tp); + } else + clock_mode = 1; + break; + case 1: + /* default, return CLOCK_BOOTTIME */ + err = clock_gettime (CLOCK_BOOTTIME, tp); + break; + case 2: + /* fallback, return CLOCK_MONOTONIC. Kernels prior to 2.6.39 + * (released on 18 May, 2011) don't support CLOCK_BOOTTIME. */ + err = clock_gettime (CLOCK_MONOTONIC, tp); + break; + } + + g_assert (err == 0); (void)err; + g_assert (tp->tv_nsec >= 0 && tp->tv_nsec < NM_UTILS_NS_PER_SECOND); + + if (G_LIKELY (clock_mode == 0)) + return; + + /* Calculate an offset for the time stamp. + * + * We always want positive values, because then we can initialize + * a timestamp with 0 and be sure, that it will be less then any + * value nm_utils_get_monotonic_timestamp_*() might return. + * For this to be true also for nm_utils_get_monotonic_timestamp_s() at + * early boot, we have to shift the timestamp to start counting at + * least from 1 second onward. + * + * Another advantage of shifting is, that this way we make use of the whole 31 bit + * range of signed int, before the time stamp for nm_utils_get_monotonic_timestamp_s() + * wraps (~68 years). + **/ + monotonic_timestamp_offset_sec = (- ((gint64) tp->tv_sec)) + 1; + monotonic_timestamp_clock_mode = clock_mode; + + _nm_utils_monotonic_timestamp_initialized (tp, monotonic_timestamp_offset_sec, clock_mode == 1); +} + +/** + * nm_utils_get_monotonic_timestamp_ns: + * + * Returns: a monotonically increasing time stamp in nanoseconds, + * starting at an unspecified offset. See clock_gettime(), %CLOCK_BOOTTIME. + * + * The returned value will start counting at an undefined point + * in the past and will always be positive. + * + * All the nm_utils_get_monotonic_timestamp_*s functions return the same + * timestamp but in different scales (nsec, usec, msec, sec). + **/ +gint64 +nm_utils_get_monotonic_timestamp_ns (void) +{ + struct timespec tp = { 0 }; + + monotonic_timestamp_get (&tp); + + /* Although the result will always be positive, we return a signed + * integer, which makes it easier to calculate time differences (when + * you want to subtract signed values). + **/ + return (((gint64) tp.tv_sec) + monotonic_timestamp_offset_sec) * NM_UTILS_NS_PER_SECOND + + tp.tv_nsec; +} + +/** + * nm_utils_get_monotonic_timestamp_us: + * + * Returns: a monotonically increasing time stamp in microseconds, + * starting at an unspecified offset. See clock_gettime(), %CLOCK_BOOTTIME. + * + * The returned value will start counting at an undefined point + * in the past and will always be positive. + * + * All the nm_utils_get_monotonic_timestamp_*s functions return the same + * timestamp but in different scales (nsec, usec, msec, sec). + **/ +gint64 +nm_utils_get_monotonic_timestamp_us (void) +{ + struct timespec tp = { 0 }; + + monotonic_timestamp_get (&tp); + + /* Although the result will always be positive, we return a signed + * integer, which makes it easier to calculate time differences (when + * you want to subtract signed values). + **/ + return (((gint64) tp.tv_sec) + monotonic_timestamp_offset_sec) * ((gint64) G_USEC_PER_SEC) + + (tp.tv_nsec / (NM_UTILS_NS_PER_SECOND/G_USEC_PER_SEC)); +} + +/** + * nm_utils_get_monotonic_timestamp_ms: + * + * Returns: a monotonically increasing time stamp in milliseconds, + * starting at an unspecified offset. See clock_gettime(), %CLOCK_BOOTTIME. + * + * The returned value will start counting at an undefined point + * in the past and will always be positive. + * + * All the nm_utils_get_monotonic_timestamp_*s functions return the same + * timestamp but in different scales (nsec, usec, msec, sec). + **/ +gint64 +nm_utils_get_monotonic_timestamp_ms (void) +{ + struct timespec tp = { 0 }; + + monotonic_timestamp_get (&tp); + + /* Although the result will always be positive, we return a signed + * integer, which makes it easier to calculate time differences (when + * you want to subtract signed values). + **/ + return (((gint64) tp.tv_sec) + monotonic_timestamp_offset_sec) * ((gint64) 1000) + + (tp.tv_nsec / (NM_UTILS_NS_PER_SECOND/1000)); +} + +/** + * nm_utils_get_monotonic_timestamp_s: + * + * Returns: nm_utils_get_monotonic_timestamp_ms() in seconds (throwing + * away sub second parts). The returned value will always be positive. + * + * This value wraps after roughly 68 years which should be fine for any + * practical purpose. + * + * All the nm_utils_get_monotonic_timestamp_*s functions return the same + * timestamp but in different scales (nsec, usec, msec, sec). + **/ +gint32 +nm_utils_get_monotonic_timestamp_s (void) +{ + struct timespec tp = { 0 }; + + monotonic_timestamp_get (&tp); + return (((gint64) tp.tv_sec) + monotonic_timestamp_offset_sec); +} + +/** + * nm_utils_monotonic_timestamp_as_boottime: + * @timestamp: the monotonic-timestamp that should be converted into CLOCK_BOOTTIME. + * @timestamp_ns_per_tick: How many nano seconds make one unit of @timestamp? E.g. if + * @timestamp is in unit seconds, pass %NM_UTILS_NS_PER_SECOND; @timestamp in nano + * seconds, pass 1; @timestamp in milli seconds, pass %NM_UTILS_NS_PER_SECOND/1000; etc. + * + * Returns: the monotonic-timestamp as CLOCK_BOOTTIME, as returned by clock_gettime(). + * The unit is the same as the passed in @timestamp basd on @timestamp_ns_per_tick. + * E.g. if you passed @timestamp in as seconds, it will return boottime in seconds. + * If @timestamp is a non-positive, it returns -1. Note that a (valid) monotonic-timestamp + * is always positive. + * + * On older kernels that don't support CLOCK_BOOTTIME, the returned time is instead CLOCK_MONOTONIC. + **/ +gint64 +nm_utils_monotonic_timestamp_as_boottime (gint64 timestamp, gint64 timestamp_ns_per_tick) +{ + gint64 offset; + + /* only support ns-per-tick being a multiple of 10. */ + g_return_val_if_fail (timestamp_ns_per_tick == 1 + || (timestamp_ns_per_tick > 0 && + timestamp_ns_per_tick <= NM_UTILS_NS_PER_SECOND && + timestamp_ns_per_tick % 10 == 0), + -1); + + /* Check that the timestamp is in a valid range. */ + g_return_val_if_fail (timestamp >= 0, -1); + + /* if the caller didn't yet ever fetch a monotonic-timestamp, he cannot pass any meaningful + * value (because he has no idea what these timestamps would be). That would be a bug. */ + g_return_val_if_fail (monotonic_timestamp_clock_mode != 0, -1); + + /* calculate the offset of monotonic-timestamp to boottime. offset_s is <= 1. */ + offset = monotonic_timestamp_offset_sec * (NM_UTILS_NS_PER_SECOND / timestamp_ns_per_tick); + + /* check for overflow. */ + g_return_val_if_fail (offset > 0 || timestamp < G_MAXINT64 + offset, G_MAXINT64); + + return timestamp - offset; +} + + |