forked from Dniel97/segatools
97 lines
2.4 KiB
C
97 lines
2.4 KiB
C
#include <windows.h>
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#include <assert.h>
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#include <stddef.h>
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#include <stdint.h>
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#include "amex/nvram.h"
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#include "util/dprintf.h"
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HRESULT nvram_open_file(HANDLE *out, const wchar_t *path, size_t size)
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{
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LARGE_INTEGER cur_size;
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LARGE_INTEGER pos;
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HANDLE file;
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HRESULT hr;
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BOOL ok;
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assert(out != NULL);
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assert(path != NULL);
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*out = NULL;
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/* This is somewhat sloppy: allow multiple processes to open the backing
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store simultaneously. Multiple processes don't actually need to open
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the backing store simultaneously, but it allows use to reuse the same
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chunihook.dll for both chuniApp.exe and aimeReaderHost.exe, since a
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backing store fd gets opened during process init and subsequentely
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re-used for all device open operations on that NVRAM.
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We could defer the file open until it is actually needed instead, but
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this requires some messy locking; naive solutions would be racy or would
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effectively block all but one thread at a time in the process from
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performing any I/O.
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Hopefully some day Chunithm will move to the new amdaemon-based system
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architecture. */
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file = CreateFileW(
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path,
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GENERIC_READ | GENERIC_WRITE,
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FILE_SHARE_READ | FILE_SHARE_WRITE,
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NULL,
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OPEN_ALWAYS,
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FILE_ATTRIBUTE_NORMAL,
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NULL);
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if (file == INVALID_HANDLE_VALUE) {
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hr = HRESULT_FROM_WIN32(GetLastError());
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dprintf("%S: Error opening backing store: %x\n", path, (int) hr);
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goto end;
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}
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ok = GetFileSizeEx(file, &cur_size);
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if (!ok) {
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hr = HRESULT_FROM_WIN32(GetLastError());
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dprintf("%S: GetFileSizeEx failed: %x\n", path, (int) hr);
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goto end;
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}
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if (cur_size.QuadPart != (uint64_t) size) {
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pos.QuadPart = (uint64_t) size;
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ok = SetFilePointerEx(file, pos, NULL, FILE_BEGIN);
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if (!ok) {
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hr = HRESULT_FROM_WIN32(GetLastError());
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dprintf("%S: SetFilePointerEx failed: %x\n", path, (int) hr);
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goto end;
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}
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ok = SetEndOfFile(file);
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if (!ok) {
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hr = HRESULT_FROM_WIN32(GetLastError());
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dprintf("%S: SetEndOfFile failed: %x\n", path, (int) hr);
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goto end;
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}
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}
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*out = file;
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file = INVALID_HANDLE_VALUE;
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hr = S_OK;
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end:
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if (file != INVALID_HANDLE_VALUE) {
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CloseHandle(file);
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}
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return hr;
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}
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