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Diffstat (limited to 'src/common/compat_time.c')
| -rw-r--r-- | src/common/compat_time.c | 657 |
1 files changed, 657 insertions, 0 deletions
diff --git a/src/common/compat_time.c b/src/common/compat_time.c new file mode 100644 index 0000000000..d044bbe1d7 --- /dev/null +++ b/src/common/compat_time.c @@ -0,0 +1,657 @@ +/* Copyright (c) 2003-2004, Roger Dingledine + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2016, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file compat_time.c + * \brief Portable wrappers for finding out the current time, running + * timers, etc. + **/ + +#define COMPAT_TIME_PRIVATE +#include "compat.h" + +#ifdef _WIN32 +#include <winsock2.h> +#include <windows.h> +#endif + +#ifdef HAVE_SYS_TYPES_H +#include <sys/types.h> +#endif +#ifdef HAVE_UNISTD_H +#include <unistd.h> +#endif +#ifdef TOR_UNIT_TESTS +#if !defined(HAVE_USLEEP) && defined(HAVE_SYS_SELECT_H) +/* as fallback implementation for tor_sleep_msec */ +#include <sys/select.h> +#endif +#endif + +#ifdef __APPLE__ +#include <mach/mach_time.h> +#endif + +#include "torlog.h" +#include "util.h" +#include "container.h" + +#ifndef HAVE_GETTIMEOFDAY +#ifdef HAVE_FTIME +#include <sys/timeb.h> +#endif +#endif + +#ifdef _WIN32 +#undef HAVE_CLOCK_GETTIME +#endif + +#ifdef TOR_UNIT_TESTS +/** Delay for <b>msec</b> milliseconds. Only used in tests. */ +void +tor_sleep_msec(int msec) +{ +#ifdef _WIN32 + Sleep(msec); +#elif defined(HAVE_USLEEP) + sleep(msec / 1000); + /* Some usleep()s hate sleeping more than 1 sec */ + usleep((msec % 1000) * 1000); +#elif defined(HAVE_SYS_SELECT_H) + struct timeval tv = { msec / 1000, (msec % 1000) * 1000}; + select(0, NULL, NULL, NULL, &tv); +#else + sleep(CEIL_DIV(msec, 1000)); +#endif +} +#endif + +/** Set *timeval to the current time of day. On error, log and terminate. + * (Same as gettimeofday(timeval,NULL), but never returns -1.) + */ +void +tor_gettimeofday(struct timeval *timeval) +{ +#ifdef _WIN32 + /* Epoch bias copied from perl: number of units between windows epoch and + * Unix epoch. */ +#define EPOCH_BIAS U64_LITERAL(116444736000000000) +#define UNITS_PER_SEC U64_LITERAL(10000000) +#define USEC_PER_SEC U64_LITERAL(1000000) +#define UNITS_PER_USEC U64_LITERAL(10) + union { + uint64_t ft_64; + FILETIME ft_ft; + } ft; + /* number of 100-nsec units since Jan 1, 1601 */ + GetSystemTimeAsFileTime(&ft.ft_ft); + if (ft.ft_64 < EPOCH_BIAS) { + /* LCOV_EXCL_START */ + log_err(LD_GENERAL,"System time is before 1970; failing."); + exit(1); + /* LCOV_EXCL_STOP */ + } + ft.ft_64 -= EPOCH_BIAS; + timeval->tv_sec = (unsigned) (ft.ft_64 / UNITS_PER_SEC); + timeval->tv_usec = (unsigned) ((ft.ft_64 / UNITS_PER_USEC) % USEC_PER_SEC); +#elif defined(HAVE_GETTIMEOFDAY) + if (gettimeofday(timeval, NULL)) { + /* LCOV_EXCL_START */ + log_err(LD_GENERAL,"gettimeofday failed."); + /* If gettimeofday dies, we have either given a bad timezone (we didn't), + or segfaulted.*/ + exit(1); + /* LCOV_EXCL_STOP */ + } +#elif defined(HAVE_FTIME) + struct timeb tb; + ftime(&tb); + timeval->tv_sec = tb.time; + timeval->tv_usec = tb.millitm * 1000; +#else +#error "No way to get time." +#endif + return; +} + +#define ONE_MILLION ((int64_t) (1000 * 1000)) +#define ONE_BILLION ((int64_t) (1000 * 1000 * 1000)) + +/** True iff monotime_init has been called. */ +static int monotime_initialized = 0; + +static monotime_t initialized_at; +#ifdef MONOTIME_COARSE_FN_IS_DIFFERENT +static monotime_coarse_t initialized_at_coarse; +#endif + +#ifdef TOR_UNIT_TESTS +/** True if we are running unit tests and overriding the current monotonic + * time. Note that mocked monotonic time might not be monotonic. + */ +static int monotime_mocking_enabled = 0; +static monotime_t initialized_at_saved; + +static int64_t mock_time_nsec = 0; +#ifdef MONOTIME_COARSE_FN_IS_DIFFERENT +static int64_t mock_time_nsec_coarse = 0; +static monotime_coarse_t initialized_at_coarse_saved; +#endif + +void +monotime_enable_test_mocking(void) +{ + if (BUG(monotime_initialized == 0)) { + monotime_init(); + } + + tor_assert_nonfatal(monotime_mocking_enabled == 0); + monotime_mocking_enabled = 1; + memcpy(&initialized_at_saved, + &initialized_at, sizeof(monotime_t)); + memset(&initialized_at, 0, sizeof(monotime_t)); +#ifdef MONOTIME_COARSE_FN_IS_DIFFERENT + memcpy(&initialized_at_coarse_saved, + &initialized_at_coarse, sizeof(monotime_coarse_t)); + memset(&initialized_at_coarse, 0, sizeof(monotime_coarse_t)); +#endif +} + +void +monotime_disable_test_mocking(void) +{ + tor_assert_nonfatal(monotime_mocking_enabled == 1); + monotime_mocking_enabled = 0; + + memcpy(&initialized_at, + &initialized_at_saved, sizeof(monotime_t)); +#ifdef MONOTIME_COARSE_FN_IS_DIFFERENT + memcpy(&initialized_at_coarse, + &initialized_at_coarse_saved, sizeof(monotime_coarse_t)); +#endif +} + +void +monotime_set_mock_time_nsec(int64_t nsec) +{ + tor_assert_nonfatal(monotime_mocking_enabled == 1); + mock_time_nsec = nsec; +} + +#ifdef MONOTIME_COARSE_FN_IS_DIFFERENT +void +monotime_coarse_set_mock_time_nsec(int64_t nsec) +{ + tor_assert_nonfatal(monotime_mocking_enabled == 1); + mock_time_nsec_coarse = nsec; +} +#endif +#endif + +/* "ratchet" functions for monotonic time. */ + +#if defined(_WIN32) || defined(TOR_UNIT_TESTS) + +/** Protected by lock: last value returned by monotime_get(). */ +static int64_t last_pctr = 0; +/** Protected by lock: offset we must add to monotonic time values. */ +static int64_t pctr_offset = 0; +/* If we are using GetTickCount(), how many times has it rolled over? */ +static uint32_t rollover_count = 0; +/* If we are using GetTickCount(), what's the last value it returned? */ +static int64_t last_tick_count = 0; + +/** Helper for windows: Called with a sequence of times that are supposed + * to be monotonic; increments them as appropriate so that they actually + * _are_ monotonic. + * + * Caller must hold lock. */ +STATIC int64_t +ratchet_performance_counter(int64_t count_raw) +{ + /* must hold lock */ + const int64_t count_adjusted = count_raw + pctr_offset; + + if (PREDICT_UNLIKELY(count_adjusted < last_pctr)) { + /* Monotonicity failed! Pretend no time elapsed. */ + pctr_offset = last_pctr - count_raw; + return last_pctr; + } else { + last_pctr = count_adjusted; + return count_adjusted; + } +} + +STATIC int64_t +ratchet_coarse_performance_counter(const int64_t count_raw) +{ + int64_t count = count_raw + (((int64_t)rollover_count) << 32); + while (PREDICT_UNLIKELY(count < last_tick_count)) { + ++rollover_count; + count = count_raw + (((int64_t)rollover_count) << 32); + } + last_tick_count = count; + return count; +} +#endif + +#if defined(MONOTIME_USING_GETTIMEOFDAY) || defined(TOR_UNIT_TESTS) +static struct timeval last_timeofday = { 0, 0 }; +static struct timeval timeofday_offset = { 0, 0 }; + +/** Helper for gettimeofday(): Called with a sequence of times that are + * supposed to be monotonic; increments them as appropriate so that they + * actually _are_ monotonic. + * + * Caller must hold lock. */ +STATIC void +ratchet_timeval(const struct timeval *timeval_raw, struct timeval *out) +{ + /* must hold lock */ + timeradd(timeval_raw, &timeofday_offset, out); + if (PREDICT_UNLIKELY(timercmp(out, &last_timeofday, <))) { + /* time ran backwards. Instead, declare that no time occurred. */ + timersub(&last_timeofday, timeval_raw, &timeofday_offset); + memcpy(out, &last_timeofday, sizeof(struct timeval)); + } else { + memcpy(&last_timeofday, out, sizeof(struct timeval)); + } +} +#endif + +#ifdef TOR_UNIT_TESTS +/** For testing: reset all the ratchets */ +void +monotime_reset_ratchets_for_testing(void) +{ + last_pctr = pctr_offset = last_tick_count = 0; + rollover_count = 0; + memset(&last_timeofday, 0, sizeof(struct timeval)); + memset(&timeofday_offset, 0, sizeof(struct timeval)); +} +#endif + +#ifdef __APPLE__ + +/** Initialized on startup: tells is how to convert from ticks to + * nanoseconds. + */ +static struct mach_timebase_info mach_time_info; + +static void +monotime_init_internal(void) +{ + tor_assert(!monotime_initialized); + int r = mach_timebase_info(&mach_time_info); + tor_assert(r == 0); + tor_assert(mach_time_info.denom != 0); +} + +/** + * Set "out" to the most recent monotonic time value + */ +void +monotime_get(monotime_t *out) +{ +#ifdef TOR_UNIT_TESTS + if (monotime_mocking_enabled) { + out->abstime_ = (mock_time_nsec * mach_time_info.denom) + / mach_time_info.numer; + return; + } +#endif + out->abstime_ = mach_absolute_time(); +} + +/** + * Return the number of nanoseconds between <b>start</b> and <b>end</b>. + */ +int64_t +monotime_diff_nsec(const monotime_t *start, + const monotime_t *end) +{ + if (BUG(mach_time_info.denom == 0)) { + monotime_init(); + } + const int64_t diff_ticks = end->abstime_ - start->abstime_; + const int64_t diff_nsec = + (diff_ticks * mach_time_info.numer) / mach_time_info.denom; + return diff_nsec; +} + +/* end of "__APPLE__" */ +#elif defined(HAVE_CLOCK_GETTIME) + +#ifdef CLOCK_MONOTONIC_COARSE +/** + * Which clock should we use for coarse-grained monotonic time? By default + * this is CLOCK_MONOTONIC_COARSE, but it might not work -- for example, + * if we're compiled with newer Linux headers and then we try to run on + * an old Linux kernel. In that case, we will fall back to CLOCK_MONOTONIC. + */ +static int clock_monotonic_coarse = CLOCK_MONOTONIC_COARSE; +#endif + +static void +monotime_init_internal(void) +{ +#ifdef CLOCK_MONOTONIC_COARSE + struct timespec ts; + if (clock_gettime(CLOCK_MONOTONIC_COARSE, &ts) < 0) { + log_info(LD_GENERAL, "CLOCK_MONOTONIC_COARSE isn't working (%s); " + "falling back to CLOCK_MONOTONIC.", strerror(errno)); + clock_monotonic_coarse = CLOCK_MONOTONIC; + } +#endif +} + +void +monotime_get(monotime_t *out) +{ +#ifdef TOR_UNIT_TESTS + if (monotime_mocking_enabled) { + out->ts_.tv_sec = (time_t) (mock_time_nsec / ONE_BILLION); + out->ts_.tv_nsec = (int) (mock_time_nsec % ONE_BILLION); + return; + } +#endif + int r = clock_gettime(CLOCK_MONOTONIC, &out->ts_); + tor_assert(r == 0); +} + +#ifdef CLOCK_MONOTONIC_COARSE +void +monotime_coarse_get(monotime_coarse_t *out) +{ +#ifdef TOR_UNIT_TESTS + if (monotime_mocking_enabled) { + out->ts_.tv_sec = (time_t) (mock_time_nsec_coarse / ONE_BILLION); + out->ts_.tv_nsec = (int) (mock_time_nsec_coarse % ONE_BILLION); + return; + } +#endif + int r = clock_gettime(clock_monotonic_coarse, &out->ts_); + if (PREDICT_UNLIKELY(r < 0) && + errno == EINVAL && + clock_monotonic_coarse == CLOCK_MONOTONIC_COARSE) { + /* We should have caught this at startup in monotime_init_internal! + */ + log_warn(LD_BUG, "Falling back to non-coarse monotonic time %s initial " + "system start?", monotime_initialized?"after":"without"); + clock_monotonic_coarse = CLOCK_MONOTONIC; + r = clock_gettime(clock_monotonic_coarse, &out->ts_); + } + + tor_assert(r == 0); +} +#endif + +int64_t +monotime_diff_nsec(const monotime_t *start, + const monotime_t *end) +{ + const int64_t diff_sec = end->ts_.tv_sec - start->ts_.tv_sec; + const int64_t diff_nsec = diff_sec * ONE_BILLION + + (end->ts_.tv_nsec - start->ts_.tv_nsec); + + return diff_nsec; +} + +/* end of "HAVE_CLOCK_GETTIME" */ +#elif defined (_WIN32) + +/** Result of QueryPerformanceFrequency, in terms needed to + * convert ticks to nanoseconds. */ +static int64_t nsec_per_tick_numer = 1; +static int64_t nsec_per_tick_denom = 1; + +/** Lock to protect last_pctr and pctr_offset */ +static CRITICAL_SECTION monotime_lock; +/** Lock to protect rollover_count and last_tick_count */ +static CRITICAL_SECTION monotime_coarse_lock; + +typedef ULONGLONG (WINAPI *GetTickCount64_fn_t)(void); +static GetTickCount64_fn_t GetTickCount64_fn = NULL; + +static void +monotime_init_internal(void) +{ + tor_assert(!monotime_initialized); + BOOL ok = InitializeCriticalSectionAndSpinCount(&monotime_lock, 200); + tor_assert(ok); + ok = InitializeCriticalSectionAndSpinCount(&monotime_coarse_lock, 200); + tor_assert(ok); + LARGE_INTEGER li; + ok = QueryPerformanceFrequency(&li); + tor_assert(ok); + tor_assert(li.QuadPart); + + uint64_t n = ONE_BILLION; + uint64_t d = li.QuadPart; + /* We need to simplify this or we'll probably overflow the int64. */ + simplify_fraction64(&n, &d); + tor_assert(n <= INT64_MAX); + tor_assert(d <= INT64_MAX); + + nsec_per_tick_numer = (int64_t) n; + nsec_per_tick_denom = (int64_t) d; + + last_pctr = 0; + pctr_offset = 0; + + HANDLE h = load_windows_system_library(TEXT("kernel32.dll")); + if (h) { + GetTickCount64_fn = (GetTickCount64_fn_t) + GetProcAddress(h, "GetTickCount64"); + } + // FreeLibrary(h) ? +} + +void +monotime_get(monotime_t *out) +{ + if (BUG(monotime_initialized == 0)) { + monotime_init(); + } + +#ifdef TOR_UNIT_TESTS + if (monotime_mocking_enabled) { + out->pcount_ = (mock_time_nsec * nsec_per_tick_denom) + / nsec_per_tick_numer; + return; + } +#endif + + /* Alas, QueryPerformanceCounter is not always monotonic: see bug list at + + https://www.python.org/dev/peps/pep-0418/#windows-queryperformancecounter + */ + + EnterCriticalSection(&monotime_lock); + LARGE_INTEGER res; + BOOL ok = QueryPerformanceCounter(&res); + tor_assert(ok); + const int64_t count_raw = res.QuadPart; + out->pcount_ = ratchet_performance_counter(count_raw); + LeaveCriticalSection(&monotime_lock); +} + +void +monotime_coarse_get(monotime_coarse_t *out) +{ +#ifdef TOR_UNIT_TESTS + if (monotime_mocking_enabled) { + out->tick_count_ = mock_time_nsec_coarse / ONE_MILLION; + return; + } +#endif + + if (GetTickCount64_fn) { + out->tick_count_ = (int64_t)GetTickCount64_fn(); + } else { + EnterCriticalSection(&monotime_coarse_lock); + DWORD tick = GetTickCount(); + out->tick_count_ = ratchet_coarse_performance_counter(tick); + LeaveCriticalSection(&monotime_coarse_lock); + } +} + +int64_t +monotime_diff_nsec(const monotime_t *start, + const monotime_t *end) +{ + if (BUG(monotime_initialized == 0)) { + monotime_init(); + } + const int64_t diff_ticks = end->pcount_ - start->pcount_; + return (diff_ticks * nsec_per_tick_numer) / nsec_per_tick_denom; +} + +int64_t +monotime_coarse_diff_msec(const monotime_coarse_t *start, + const monotime_coarse_t *end) +{ + const int64_t diff_ticks = end->tick_count_ - start->tick_count_; + return diff_ticks; +} + +int64_t +monotime_coarse_diff_usec(const monotime_coarse_t *start, + const monotime_coarse_t *end) +{ + return monotime_coarse_diff_msec(start, end) * 1000; +} + +int64_t +monotime_coarse_diff_nsec(const monotime_coarse_t *start, + const monotime_coarse_t *end) +{ + return monotime_coarse_diff_msec(start, end) * ONE_MILLION; +} + +/* end of "_WIN32" */ +#elif defined(MONOTIME_USING_GETTIMEOFDAY) + +static tor_mutex_t monotime_lock; + +/** Initialize the monotonic timer subsystem. */ +static void +monotime_init_internal(void) +{ + tor_assert(!monotime_initialized); + tor_mutex_init(&monotime_lock); +} + +void +monotime_get(monotime_t *out) +{ + if (BUG(monotime_initialized == 0)) { + monotime_init(); + } + + tor_mutex_acquire(&monotime_lock); + struct timeval timeval_raw; + tor_gettimeofday(&timeval_raw); + ratchet_timeval(&timeval_raw, &out->tv_); + tor_mutex_release(&monotime_lock); +} + +int64_t +monotime_diff_nsec(const monotime_t *start, + const monotime_t *end) +{ + struct timeval diff; + timersub(&end->tv_, &start->tv_, &diff); + return (diff.tv_sec * ONE_BILLION + diff.tv_usec * 1000); +} + +/* end of "MONOTIME_USING_GETTIMEOFDAY" */ +#else +#error "No way to implement monotonic timers." +#endif + +/** + * Initialize the monotonic timer subsystem. Must be called before any + * monotonic timer functions. This function is idempotent. + */ +void +monotime_init(void) +{ + if (!monotime_initialized) { + monotime_init_internal(); + monotime_initialized = 1; + monotime_get(&initialized_at); +#ifdef MONOTIME_COARSE_FN_IS_DIFFERENT + monotime_coarse_get(&initialized_at_coarse); +#endif + } +} + +int64_t +monotime_diff_usec(const monotime_t *start, + const monotime_t *end) +{ + const int64_t nsec = monotime_diff_nsec(start, end); + return CEIL_DIV(nsec, 1000); +} + +int64_t +monotime_diff_msec(const monotime_t *start, + const monotime_t *end) +{ + const int64_t nsec = monotime_diff_nsec(start, end); + return CEIL_DIV(nsec, ONE_MILLION); +} + +uint64_t +monotime_absolute_nsec(void) +{ + monotime_t now; + if (BUG(monotime_initialized == 0)) { + monotime_init(); + } + + monotime_get(&now); + return monotime_diff_nsec(&initialized_at, &now); +} + +uint64_t +monotime_absolute_usec(void) +{ + return monotime_absolute_nsec() / 1000; +} + +uint64_t +monotime_absolute_msec(void) +{ + return monotime_absolute_nsec() / ONE_MILLION; +} + +#ifdef MONOTIME_COARSE_FN_IS_DIFFERENT +uint64_t +monotime_coarse_absolute_nsec(void) +{ + if (BUG(monotime_initialized == 0)) { + monotime_init(); + } + + monotime_coarse_t now; + monotime_coarse_get(&now); + return monotime_coarse_diff_nsec(&initialized_at_coarse, &now); +} + +uint64_t +monotime_coarse_absolute_usec(void) +{ + return monotime_coarse_absolute_nsec() / 1000; +} + +uint64_t +monotime_coarse_absolute_msec(void) +{ + return monotime_coarse_absolute_nsec() / ONE_MILLION; +} +#endif + |