sortix--sortix/sortix/filesystem.cpp

/******************************************************************************

	COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.

	This file is part of Sortix.

	Sortix is free software: you can redistribute it and/or modify it under the
	terms of the GNU General Public License as published by the Free Software
	Foundation, either version 3 of the License, or (at your option) any later
	version.

	Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
	WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
	FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
	details.

	You should have received a copy of the GNU General Public License along
	with Sortix. If not, see <http://www.gnu.org/licenses/>.

	filesystem.cpp
	Allows access to stored sequences of bytes in an orderly fashion.

******************************************************************************/

#include "platform.h"
#include <libmaxsi/memory.h>
#include <libmaxsi/string.h>
#include "syscall.h"
#include "process.h"
#include "filesystem.h"
#include "mount.h"

using namespace Maxsi;

namespace Sortix
{
	namespace FileSystem
	{
		Device* Open(const char* path, int flags, mode_t mode)
		{
			const char* workingdir = "/";
			char* fullpath = NULL;
			if ( *path != '/' )
			{
				size_t len = String::Length(workingdir) + String::Length(path);
				fullpath = new char[len+1];
				if ( !fullpath ) { return NULL; }
				String::Copy(fullpath, workingdir);
				String::Cat(fullpath, path);
				path = fullpath;
			}
			size_t pathoffset = 0;
			DevFileSystem* fs = Mount::WhichFileSystem(path, &pathoffset);
			if ( !fs ) { delete[] fullpath; return NULL; }
			Device* result = fs->Open(path + pathoffset, flags, mode);
			delete[] fullpath;
			return result;
		}

		int SysOpen(const char* path, int flags, mode_t mode)
		{
			Process* process = CurrentProcess();
			Device* dev = Open(path, flags, mode);
			if ( !dev ) { return -1; /* TODO: errno */ }
			int fd = process->descriptors.Allocate(dev);
			if ( fd < 0 ) { dev->Unref(); }
			return fd;
		}

		void Init()
		{
			Syscall::Register(SYSCALL_OPEN, (void*) SysOpen);
		}
	}

	DevFileWrapper::DevFileWrapper(DevBuffer* buffer, int flags)
	{
		this->buffer = buffer;
		this->flags = flags;
		this->offset = 0;
		this->buffer->Refer();
	}

	DevFileWrapper::~DevFileWrapper()
	{
		buffer->Unref();
	}

	size_t DevFileWrapper::BlockSize()
	{
		return buffer->BlockSize();
	}

	uintmax_t DevFileWrapper::Size()
	{
		return buffer->Size();
	}

	uintmax_t DevFileWrapper::Position()
	{
		return offset;
	}

	bool DevFileWrapper::Seek(uintmax_t position)
	{
		if ( !buffer->Seek(position) ) { return false; }
		offset = position;
		return true;
	}

	bool DevFileWrapper::Resize(uintmax_t size)
	{
		return buffer->Resize(size);
	}

	ssize_t DevFileWrapper::Read(byte* dest, size_t count)
	{
		// TODO: Enforce read permission!
		if ( !buffer->Seek(offset) ) { return -1; }
		ssize_t result = buffer->Read(dest, count);
		if ( result < 0 ) { return result; }
		offset += result;
		return result;
	}

	ssize_t DevFileWrapper::Write(const byte* src, size_t count)
	{
		// TODO: Enforce write permission!
		if ( !buffer->Seek(offset) ) { return -1; }
		ssize_t result = buffer->Write(src, count);
		if ( result < 0 ) { return result; }
		offset += result;
		return result;
	}

	bool DevFileWrapper::IsReadable()
	{
		// TODO: Enforce read permission!
		return true;
	}

	bool DevFileWrapper::IsWritable()
	{
		// TODO: Enforce write permission!
		return true;
	}
}