libmocha/source/devoptab/devoptab_fsa_write.cpp

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#include "devoptab_fsa.h"
#include "logger.h"
#include <mutex>
ssize_t __fsa_write(struct _reent *r, void *fd, const char *ptr, size_t len) {
FSError status;
if (!fd || !ptr) {
r->_errno = EINVAL;
return -1;
}
// Check that the file was opened with write access
auto *file = (__fsa_file_t *) fd;
if ((file->flags & O_ACCMODE) == O_RDONLY) {
r->_errno = EBADF;
return -1;
}
// cache-aligned, cache-line-sized
__attribute__((aligned(0x40))) uint8_t alignedBuffer[0x40];
auto *deviceData = (FSADeviceData *) r->deviceData;
std::lock_guard<MutexWrapper> lock(file->mutex);
// If O_APPEND is set, we always write to the end of the file.
// When writing we file->offset to the file size to keep in sync.
if (file->flags & O_APPEND) {
file->offset = file->appendOffset;
}
size_t bytesWritten = 0;
while (bytesWritten < len) {
// only use input buffer if cache-aligned and write size is a multiple of cache line size
// otherwise write from alignedBuffer
uint8_t *tmp = (uint8_t *) ptr;
size_t size = len - bytesWritten;
if ((uintptr_t) ptr & 0x3F) {
// write partial cache-line front-end
tmp = alignedBuffer;
size = MIN(size, 0x40 - ((uintptr_t) ptr & 0x3F));
} else if (size < 0x40) {
// write partial cache-line back-end
tmp = alignedBuffer;
} else {
// write whole cache lines
size &= ~0x3F;
}
// Limit each request to 256 KiB
if (size > 0x40000) {
size = 0x40000;
}
if (tmp == alignedBuffer) {
memcpy(tmp, ptr, size);
}
status = FSAWriteFile(deviceData->clientHandle, tmp, 1, size, file->fd, 0);
if (status < 0) {
DEBUG_FUNCTION_LINE_ERR("FSAWriteFile(0x%08X, 0x%08X, 1, 0x%08X, 0x%08X, 0) (%s) failed: %s",
deviceData->clientHandle, tmp, size, file->fd, file->fullPath, FSAGetStatusStr(status));
if (bytesWritten != 0) {
return bytesWritten; // error after partial write
}
r->_errno = __fsa_translate_error(status);
return -1;
}
file->appendOffset += status;
file->offset += status;
bytesWritten += status;
ptr += status;
if ((size_t) status != size) {
return bytesWritten; // partial write
}
}
return bytesWritten;
}