segatools/nu/sram.c

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#include <windows.h>
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#include <assert.h>
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#include "hook/iohook.h"
#include "nu/sram.h"
#include "nu/nvram.h"
#include "util/dprintf.h"
#include "util/setupapi.h"
static HRESULT sram_handle_irp(struct irp *irp);
static HRESULT sram_handle_open(struct irp *irp);
static HRESULT sram_handle_close(struct irp *irp);
static HRESULT sram_handle_ioctl(struct irp *irp);
static HRESULT sram_ioctl_get_geometry(struct irp *irp);
static HANDLE sram_file;
HRESULT sram_hook_init(void)
{
HRESULT hr;
hr = nvram_open_file(&sram_file, L"DEVICE\\sram.bin", 0x80000);
if (FAILED(hr)) {
return hr;
}
hr = iohook_push_handler(sram_handle_irp);
if (FAILED(hr)) {
return hr;
}
hr = setupapi_add_phantom_dev(&sram_guid, L"$sram");
if (FAILED(hr)) {
return hr;
}
return S_OK;
}
static HRESULT sram_handle_irp(struct irp *irp)
{
assert(irp != NULL);
if (irp->op != IRP_OP_OPEN && irp->fd != sram_file) {
return iohook_invoke_next(irp);
}
switch (irp->op) {
case IRP_OP_OPEN: return sram_handle_open(irp);
case IRP_OP_CLOSE: return sram_handle_close(irp);
case IRP_OP_IOCTL: return sram_handle_ioctl(irp);
default: return iohook_invoke_next(irp);
}
}
static HRESULT sram_handle_open(struct irp *irp)
{
if (wcscmp(irp->open_filename, L"$sram") != 0) {
return iohook_invoke_next(irp);
}
dprintf("SRAM: Open device\n");
irp->fd = sram_file;
return S_OK;
}
static HRESULT sram_handle_close(struct irp *irp)
{
dprintf("SRAM: Close device\n");
return S_OK;
}
static HRESULT sram_handle_ioctl(struct irp *irp)
{
switch (irp->ioctl) {
case IOCTL_DISK_GET_DRIVE_GEOMETRY:
return sram_ioctl_get_geometry(irp);
default:
dprintf("SRAM: Unknown ioctl %x, write %i read %i\n",
irp->ioctl,
irp->write.nbytes,
irp->read.nbytes);
return HRESULT_FROM_WIN32(ERROR_INVALID_FUNCTION);
}
}
static HRESULT sram_ioctl_get_geometry(struct irp *irp)
{
DISK_GEOMETRY *out;
if (irp->read.nbytes < sizeof(*out)) {
dprintf("SRAM: Invalid ioctl response buffer size\n");
return HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER);
}
dprintf("SRAM: Get geometry\n");
out = (DISK_GEOMETRY *) irp->read.bytes;
out->Cylinders.QuadPart = 0x20000;
out->MediaType = 0;
out->TracksPerCylinder = 1;
out->SectorsPerTrack = 1;
out->BytesPerSector = 4;
irp->read.pos = sizeof(*out);
return S_OK;
}