segatools/util/clock.c

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4.4 KiB
C
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#include <windows.h>
#include <stdint.h>
#include "hook/table.h"
#include "util/dprintf.h"
static void WINAPI my_GetSystemTimeAsFileTime(FILETIME *out);
static BOOL WINAPI my_GetLocalTime(SYSTEMTIME *out);
static BOOL WINAPI my_GetSystemTime(SYSTEMTIME *out);
static DWORD WINAPI my_GetTimeZoneInformation(TIME_ZONE_INFORMATION *tzinfo);
static BOOL WINAPI my_SetSystemTime(SYSTEMTIME *in);
static BOOL WINAPI my_SetTimeZoneInformation(TIME_ZONE_INFORMATION *tzinfo);
static BOOL (WINAPI * next_GetSystemTimeAsFileTime)(FILETIME *out);
static int64_t clock_current_day;
static const struct hook_symbol clock_hook_syms[] = {
{
.name = "GetSystemTimeAsFileTime",
.patch = my_GetSystemTimeAsFileTime,
.link = (void **) &next_GetSystemTimeAsFileTime,
}, {
.name = "GetLocalTime",
.patch = my_GetLocalTime,
}, {
.name = "GetSystemTime",
.patch = my_GetSystemTime,
}, {
.name = "GetTimeZoneInformation",
.patch = my_GetTimeZoneInformation,
}, {
.name = "SetSystemTime",
.patch = my_SetSystemTime,
}, {
.name = "SetTimeZoneInformation",
.patch = my_SetTimeZoneInformation,
},
};
/* FILETIME is expressed in 100ns i.e. 0.1us i.e. 10^-7 sec units.
No official name for these units is given so let's call them "jiffies". */
#define jiffies_per_sec 10000000LL
#define jiffies_per_hour (jiffies_per_sec * 3600LL)
#define jiffies_per_day (jiffies_per_hour * 24LL)
static void WINAPI my_GetSystemTimeAsFileTime(FILETIME *out)
{
FILETIME in;
int64_t day;
int64_t real_jiffies;
int64_t real_jiffies_biased;
int64_t real_time;
int64_t fake_time;
int64_t fake_jiffies_biased;
int64_t fake_jiffies;
if (out == NULL) {
SetLastError(ERROR_INVALID_PARAMETER);
return;
}
/* Get and convert real jiffies */
next_GetSystemTimeAsFileTime(&in);
real_jiffies = (((int64_t) in.dwHighDateTime) << 32) | in.dwLowDateTime;
/* Apply bias: shift [02:00, 07:00) to [19:00, 24:00) */
real_jiffies_biased = real_jiffies + 17LL * jiffies_per_hour;
/* Split date and time */
day = real_jiffies_biased / jiffies_per_day;
real_time = real_jiffies_biased % jiffies_per_day;
/* Debug log */
if (clock_current_day != 0 && clock_current_day != day) {
dprintf("\n*** CLOCK JUMP! ***\n\n");
}
clock_current_day = day;
/* We want to skip the final five hours, so scale time-of-day by 19/24. */
fake_time = (real_time * 19LL) / 24LL;
/* Un-split date and time */
fake_jiffies_biased = day * jiffies_per_day + fake_time;
/* Remove bias */
fake_jiffies = fake_jiffies_biased - 17LL * jiffies_per_hour;
/* Return result */
out->dwLowDateTime = fake_jiffies;
out->dwHighDateTime = fake_jiffies >> 32;
}
static BOOL WINAPI my_GetLocalTime(SYSTEMTIME *out)
{
/* Use UTC to simplify things */
return my_GetSystemTime(out);
}
static BOOL WINAPI my_GetSystemTime(SYSTEMTIME *out)
{
FILETIME linear;
BOOL ok;
my_GetSystemTimeAsFileTime(&linear);
ok = FileTimeToSystemTime(&linear, out);
if (!ok) {
return ok;
}
#if 0
static int last_second;
if (out->wSecond != last_second) {
dprintf("%04i/%02i/%02i %02i:%02i:%02i\n",
out->wYear,
out->wMonth,
out->wDay,
out->wHour,
out->wMinute,
out->wSecond);
}
last_second = out->wSecond;
#endif
return TRUE;
}
static DWORD WINAPI my_GetTimeZoneInformation(TIME_ZONE_INFORMATION *tzinfo)
{
/* Use UTC to simplify things */
dprintf("%s\n", __func__);
if (tzinfo != NULL) {
memset(tzinfo, 0, sizeof(*tzinfo));
SetLastError(ERROR_SUCCESS);
return TIME_ZONE_ID_UNKNOWN;
} else {
SetLastError(ERROR_INVALID_PARAMETER);
return TIME_ZONE_ID_INVALID;
}
}
static BOOL WINAPI my_SetSystemTime(SYSTEMTIME *in)
{
dprintf("Prevented application from screwing with the system clock\n");
return TRUE;
}
static BOOL WINAPI my_SetTimeZoneInformation(TIME_ZONE_INFORMATION *in)
{
dprintf("Prevented application from screwing with the timezone\n");
return TRUE;
}
void clock_hook_init(void)
{
hook_table_apply(
NULL,
"kernel32.dll",
clock_hook_syms,
_countof(clock_hook_syms));
}