119 lines
4.1 KiB
C
119 lines
4.1 KiB
C
/*
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* gettimeofday.c
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* Win32 gettimeofday() replacement
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*
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* src/port/gettimeofday.c
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*
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* Copyright (c) 2003 SRA, Inc.
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* Copyright (c) 2003 SKC, Inc.
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*
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* Permission to use, copy, modify, and distribute this software and
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* its documentation for any purpose, without fee, and without a
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* written agreement is hereby granted, provided that the above
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* copyright notice and this paragraph and the following two
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* paragraphs appear in all copies.
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*
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
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* INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
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* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
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* DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
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* IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
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* SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*/
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#include "c.h"
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#include <sys/time.h>
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/* FILETIME of Jan 1 1970 00:00:00, the PostgreSQL epoch */
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static const unsigned __int64 epoch = UINT64CONST(116444736000000000);
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/*
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* FILETIME represents the number of 100-nanosecond intervals since
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* January 1, 1601 (UTC).
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*/
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#define FILETIME_UNITS_PER_SEC 10000000L
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#define FILETIME_UNITS_PER_USEC 10
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/*
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* Both GetSystemTimeAsFileTime and GetSystemTimePreciseAsFileTime share a
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* signature, so we can just store a pointer to whichever we find. This
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* is the pointer's type.
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*/
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typedef VOID(WINAPI * PgGetSystemTimeFn) (LPFILETIME);
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/* One-time initializer function, must match that signature. */
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static void WINAPI init_gettimeofday(LPFILETIME lpSystemTimeAsFileTime);
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/* Storage for the function we pick at runtime */
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static PgGetSystemTimeFn pg_get_system_time = &init_gettimeofday;
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/*
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* One time initializer. Determine whether GetSystemTimePreciseAsFileTime
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* is available and if so, plan to use it; if not, fall back to
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* GetSystemTimeAsFileTime.
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*/
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static void WINAPI
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init_gettimeofday(LPFILETIME lpSystemTimeAsFileTime)
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{
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/*
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* Because it's guaranteed that kernel32.dll will be linked into our
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* address space already, we don't need to LoadLibrary it and worry about
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* closing it afterwards, so we're not using Pg's dlopen/dlsym() wrapper.
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*
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* We'll just look up the address of GetSystemTimePreciseAsFileTime if
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* present.
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*
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* While we could look up the Windows version and skip this on Windows
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* versions below Windows 8 / Windows Server 2012 there isn't much point,
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* and determining the windows version is its self somewhat Windows
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* version and development SDK specific...
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*/
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pg_get_system_time = (PgGetSystemTimeFn) GetProcAddress(GetModuleHandle(TEXT("kernel32.dll")),
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"GetSystemTimePreciseAsFileTime");
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if (pg_get_system_time == NULL)
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{
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/*
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* The expected error from GetLastError() is ERROR_PROC_NOT_FOUND, if
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* the function isn't present. No other error should occur.
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*
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* We can't report an error here because this might be running in
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* frontend code; and even if we're in the backend, it's too early to
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* elog(...) if we get some unexpected error. Also, it's not a
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* serious problem, so just silently fall back to
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* GetSystemTimeAsFileTime irrespective of why the failure occurred.
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*/
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pg_get_system_time = &GetSystemTimeAsFileTime;
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}
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(*pg_get_system_time) (lpSystemTimeAsFileTime);
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}
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/*
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* timezone information is stored outside the kernel so tzp isn't used anymore.
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*
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* Note: this function is not for Win32 high precision timing purposes. See
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* elapsed_time().
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*/
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int
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gettimeofday(struct timeval *tp, struct timezone *tzp)
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{
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FILETIME file_time;
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ULARGE_INTEGER ularge;
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(*pg_get_system_time) (&file_time);
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ularge.LowPart = file_time.dwLowDateTime;
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ularge.HighPart = file_time.dwHighDateTime;
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tp->tv_sec = (long) ((ularge.QuadPart - epoch) / FILETIME_UNITS_PER_SEC);
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tp->tv_usec = (long) (((ularge.QuadPart - epoch) % FILETIME_UNITS_PER_SEC)
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/ FILETIME_UNITS_PER_USEC);
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return 0;
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}
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