win32ntdll.c

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/*-------------------------------------------------------------------------
 *
 * win32ntdll.c
 *    Dynamically loaded Windows NT functions.
 *
 * Portions Copyright (c) 2021-2022, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/port/win32ntdll.c
 *
 *-------------------------------------------------------------------------
 */
 
#include "c.h"
 
#include "port/win32ntdll.h"
 
RtlGetLastNtStatus_t pg_RtlGetLastNtStatus;
RtlNtStatusToDosError_t pg_RtlNtStatusToDosError;
NtFlushBuffersFileEx_t pg_NtFlushBuffersFileEx;
 
typedef struct NtDllRoutine
{
    const char *name;
    pg_funcptr_t *address;
} NtDllRoutine;
 
static const NtDllRoutine routines[] = {
    {"RtlGetLastNtStatus", (pg_funcptr_t *) &pg_RtlGetLastNtStatus},
    {"RtlNtStatusToDosError", (pg_funcptr_t *) &pg_RtlNtStatusToDosError},
    {"NtFlushBuffersFileEx", (pg_funcptr_t *) &pg_NtFlushBuffersFileEx}
};
 
static bool initialized;
 
int
initialize_ntdll(void)
{
    HMODULE     module;
 
    if (initialized)
        return 0;
 
    if (!(module = LoadLibraryEx("ntdll.dll", NULL, 0)))
    {
        _dosmaperr(GetLastError());
        return -1;
    }
 
    for (int i = 0; i < lengthof(routines); ++i)
    {
        pg_funcptr_t address;
 
        address = (pg_funcptr_t) GetProcAddress(module, routines[i].name);
        if (!address)
        {
            _dosmaperr(GetLastError());
            FreeLibrary(module);
 
            return -1;
        }
 
        *(pg_funcptr_t *) routines[i].address = address;
    }
 
    initialized = true;
 
    return 0;
}