luxos/Kernel/hal/vfs.c

#include <memory.h>
#include <stdlib.h>
#include <fileio.h>
#include <debugio.h>

#define MAX_FS_COUNT 64
#define BAD 0xffffffff

FileSystem* fsArray;
uint32 fsCount;

MountPoint* mpArray;
uint32 mpCount;
uint32 mpAllocated;

#define LogVfs(...) { Log("%#[Vfs] ", ColorLightBlue); Log(__VA_ARGS__); }
#define ErrorVfs(...) { Error("%#[Vfs] ", ColorLightBlue); Error(__VA_ARGS__); }

void VfsInstall ()
{
	fsArray = (FileSystem*) kmalloc(MAX_FS_COUNT * sizeof(FileSystem));
	fsCount = 0;

	mpArray = (MountPoint*) kmalloc(32 * sizeof(MountPoint));
	mpCount = 0;
	mpAllocated = 32;

	LogVfs("%#VFS now in business.\n", ColorLightGreen);
}

uint8 VfsInstallFs (FileSystem* fs)
{
	if (fsCount >= MAX_FS_COUNT) {
		ErrorVfs("%#Failed to install file system '%s': FS count reached.\n", ColorLightRed, fs->Name);
		return 0;
	}

	memcpy(&fsArray[fsCount], fs, sizeof(FileSystem));
	fsArray[fsCount].Id = fsCount;

	++fsCount;
	LogVfs("Installed file system %#.\n", ColorWhite, fs->Name);
	return 1;
}

uint32 VfsFindDevice (string dev)
{
	uint32 i;
	for (i = 0; i < mpCount; i++)
		if (strcmp(dev, mpArray[i].Name) == 0)
			return i;

	return BAD;
}


// Returns mount point index, removes dev name from path
uint32 VfsParsePath (string* path)
{
	// Sanity check
	if (!path || !(*path)) return BAD;

	string dev = *path, p = strchr(*path, ':');
	if (p == NULL) return BAD; // invalid path

	// Split string
	*path = p+1; *p = '\0';

	return VfsFindDevice(dev);
}

uint8 VfsMount (string Name, DevReadRoutine R, DevWriteRoutine W, uint32 BlockSize)
{
	uint32 i, fsId = BAD, mpIndex = BAD;

	// Try to figure out the file system
	for (i = 0; i < fsCount && fsId == BAD; i++)
		if (fsArray->Detect && fsArray->Detect(R, BlockSize)) fsId = i;

	if (fsId == BAD) {
		ErrorVfs("%#Failed to mount device %s: no file system found.\n", ColorLightRed, Name)
		return 0;			// No file system, no good
	}

	// Try to find an empty slot to fill
	for (i = 0; i < mpCount && mpIndex == BAD; i++)
		if (mpArray[i].Id == BAD) mpIndex = i;

	// No empty slots?
	if (mpIndex == BAD)
	{
		// Make sure we have enough space
		if (mpCount == mpAllocated) 		{
			mpAllocated += 4;
			mpArray = kmrealloc(mpArray, mpAllocated * sizeof(MountPoint));
		}

		mpIndex = mpCount++;
	}

	// Add to mount point list, set up data
	mpArray[mpIndex].Id = mpIndex;
	mpArray[mpIndex].FsId = fsId;
	mpArray[mpIndex].BlockSize = BlockSize;
	mpArray[mpIndex].Read = R;
	mpArray[mpIndex].Write = W;

	// Change name if it already exists
	uint32 find = VfsFindDevice(Name);
	if (find != BAD)
	{
		uint32 len = strlen(Name);
		uint8 success = 0;
		Name[len+1] = '\0';

		// Try to find a number index
		for (find = '0'; find <= '9' && !success; find++)
		{
			Name[len] = find;
			if (VfsFindDevice(Name) == BAD) success = 1;
		}

		// What? Haven't found anything yet? Try the alphabet
		for (find = 'a'; find <= 'z' && !success; find++)
		{
			Name[len] = find;
			if (VfsFindDevice(Name) == BAD) success = 1;
		}

		// Still nothing? How in the world is this even possible ?!?!?!
		if (!success) return 0;
	}

	memcpy(mpArray[mpCount].Name, Name, sizeof(char) * 128);

	LogVfs("Mounted device %#%s", ColorWhite, Name);
	return 1;
}

void VfsUnmount (uint32 dev_id)
{
	mpArray[dev_id].Id = BAD;
	mpCount--;
}

// Returns pointer to FILE structure that was inputed if success, null otherwise
FILE* VfsOpen (FILE* file, string path)
{
	if (!file) return NULL;

	// Parse string
	uint32 dev = VfsParsePath(&path);
	file->DeviceId = dev;

	// Device not found, or Open routine doesn't exist
	if (dev == BAD || !fsArray[mpArray[dev].FsId].Open) return NULL;

	// Ask the FS to do the 'opening'
	return fsArray[mpArray[dev].FsId].Open(&mpArray[dev],file,path);
}

DirectoryEntry* VfsTest (string path)
{
	// Parse string
	uint32 dev = VfsParsePath(&path);

	// Device not found, or Open routine doesn't exist
	if (dev == BAD || !fsArray[mpArray[dev].FsId].Test) return NULL;

	// Ask the FS to do the 'opening'
	return fsArray[mpArray[dev].FsId].Test(&mpArray[dev],path);
}

FILE* VfsClose (FILE* file)
{
	if (!file) return NULL;
	MountPoint* mp = &(mpArray[file->DeviceId]);

	if (!fsArray[mp->FsId].Close) return NULL;
	return fsArray[mp->FsId].Close(mp,file);
}

uint32 VfsRead (FILE* file, uint32 bsz, uint32 n, uint8* buffer)
{
	if (!file) return NULL;
	MountPoint* mp = &(mpArray[file->DeviceId]);

	if (!fsArray[mp->FsId].Read) return NULL;
	return fsArray[mp->FsId].Read(mp, file, bsz, n, buffer);
}

uint32 VfsWrite (FILE* file, uint32 bsz, uint32 n, uint8* buffer)
{
	if (!file) return NULL;
	MountPoint* mp = &(mpArray[file->DeviceId]);

	if (!fsArray[mp->FsId].Write) return NULL;
	return fsArray[mp->FsId].Write(mp, file, bsz, n, buffer);
}

DirectoryEntry* VfsReadDirectory (FILE* handle, uint32 index)
{
	if (!handle) return NULL;
	MountPoint* mp = &(mpArray[handle->DeviceId]);

	if (!fsArray[mp->FsId].ReadDirectory) return NULL;
	return fsArray[mp->FsId].ReadDirectory(mp, handle, index);
}