RASCSI/cpp/disk_image/posix_file_handle.cpp

102 lines
2.4 KiB
C++

//---------------------------------------------------------------------------
//
// SCSI Target Emulator RaSCSI (*^..^*)
// for Raspberry Pi
//
// Copyright (C) 2022-2023 akuker
//
// [ PosixFileHandle ]
//
//---------------------------------------------------------------------------
#include "posix_file_handle.h"
#include "shared/log.h"
#include <sys/mman.h>
#include <errno.h>
#include <unistd.h>
//===========================================================================
//
// Direct file access that will map the file into virtual memory space
//
//===========================================================================
PosixFileHandle::PosixFileHandle(const string &path, int size, uint32_t blocks, off_t imgoff) : DiskImageHandle(path, size, blocks, imgoff)
{
assert(blocks > 0);
assert(imgoff >= 0);
fd = open(path.c_str(), O_RDWR);
if (fd < 0)
{
LOGWARN("Unable to open file %s. Errno:%d", path.c_str(), errno)
return;
}
struct stat sb;
if (fstat(fd, &sb) < 0)
{
LOGWARN("Unable to run fstat. Errno:%d", errno)
return;
}
LOGWARN("%s opened file of size: %d", __PRETTY_FUNCTION__, (unsigned int)sb.st_size)
initialized = true;
}
PosixFileHandle::~PosixFileHandle()
{
close(fd);
// Force the OS to save any cached data to the disk
sync();
}
bool PosixFileHandle::ReadSector(vector<uint8_t>& buf, int block)
{
if (!initialized)
{
return false;
}
assert(block < GetBlocksPerSector());
size_t sector_size_bytes = (size_t)1 << GetSectorSize();
// Calculate offset into the image file
off_t offset = GetTrackOffset(block);
offset += GetSectorOffset(block);
lseek(fd, offset, SEEK_SET);
size_t result = read(fd, buf.data(), sector_size_bytes);
if (result != sector_size_bytes)
{
LOGWARN("%s only read %d bytes but wanted %d", __PRETTY_FUNCTION__, (unsigned int)result, (unsigned int)sector_size_bytes)
}
return true;
}
bool PosixFileHandle::WriteSector(const vector<uint8_t>& buf, int block)
{
if (!initialized)
{
return false;
}
assert(block < GetBlocksPerSector());
size_t sector_size_bytes = (size_t)1 << GetSectorSize();
off_t offset = GetTrackOffset(block);
offset += GetSectorOffset(block);
lseek(fd, offset, SEEK_SET);
size_t result = write(fd, buf.data(), sector_size_bytes);
if (result != sector_size_bytes)
{
LOGWARN("%s only wrote %d bytes but wanted %d ", __PRETTY_FUNCTION__, (unsigned int)result, (unsigned int)sector_size_bytes)
}
return true;
}