filesystem.cpp

LINUX 设计一个简单的二级文件系统

#include <iostream.h>
#include <stdio.h>
#include <string.h>
#include "FileSystem.h"
#include "string2"
#include "Util.h"

SuperBlock sb;
FILE* fd;
hinode hinode[NHINO];
SysOFile sys_ofile[100];

unsigned long FileSystem::mapAddr(unsigned int id) {
	unsigned long addr;
	addr = this->IN_Start+sizeof(DInode)*(id-1);
	return addr;
}
void FileSystem::SaveSuperBlock() {
	fseek(fd, 0, 0);
	fwrite(&sb, 1, sizeof(SuperBlock), fd);
}
FileSystem::~FileSystem() {}
FileSystem::FileSystem() {
	strcpy(this->Disk_Name, "FileSystem.disk");
	this->LoginNum = 0;
	this->IN_Start = BlockSize * 2;
	this->Data_Start = BlockSize * (2 + 400);
	this->GroupSize = 50;
}

void FileSystem::ShowList(const char* usn) {
	if (!this->CheckLogin(usn)) return;
	unsigned int curDir = this->LoginUser[this->UNameI(usn)].CurDirInodeID;
	INode* inode = this->IGet(curDir);
	Direct dir;
	fseek(fd, inode->addr[0]*BlockSize, 0);
	fread(&dir, 1, sizeof(Direct), fd);
	this->IPut(inode);
	int i = 0;
	if (curDir != this->LoginUser[this->UNameI(usn)].user.Dino) {
		i = 1;
		cout << "文件总数: " << dir.size-1 << endl;
	} else {
		cout << "文件总数: " << dir.size << endl;
	}

	for (; i<dir.size; i++) {
		cout << "名称：" << dir.files[i].name << '\t';
		inode = this->IGet(dir.files[i].Dino);
		if (inode->size == 0)
			cout << "物理地址：" << this->mapAddr(inode->Dino) << "\t大小：" << "1 KB";
		else
			cout << "物理地址：" << inode->addr[0]*BlockSize << "\t大小：" << inode->size << " KB";
		cout << "\t保护码：" << inode->type;
		int di_mode, one;
		for (int j=0; j<4; j++) {
			di_mode = inode->mode;
			one = di_mode % 2;
			di_mode = di_mode / 2;
			if (one) cout << 'x';
			else cout << '*';
		}
		cout << endl;
	}
}

void FileSystem::MakeDir(const char *usn, const char *name) {
	if (!this->CheckLogin(usn)) return;
	if (!u.regTest("^[a-zA-Z0-9._]{1,16}$", name)) {
		cout << "目录名称只能是1至16位字母或数字或点号下划线组成！" << endl;
		return;
	}
	unsigned int dinodeid = this->NameI(usn, name);
	if (dinodeid != 0) {
		cout << "相同名称的文件或目录已经存在！" << endl;
		return;
	}
	Direct dir;
	dir.size = 1;
	strcpy(dir.files[0].name, "..");
	dir.files[0].Dino = this->LoginUser[this->UNameI(usn)].CurDirInodeID;
	unsigned int Bid = this->BAlloc();
	if (Bid == 0) {
		return;
	}
	INode* inode = this->IAlloc();
	if (inode == NULL) {
		this->BFree(Bid);
		return;
	}
	fseek(fd, Bid*BlockSize, 0);
	fwrite(&dir, 1, sizeof(Direct), fd);
	inode->size = 1;
	inode->addr[0] = Bid;
	inode->type = 'd';
	inode->mode = '0';
	Bid = inode->Dino;
	this->IPut(inode);
	File file;
	strcpy(file.name, name);
	file.Dino = Bid;
	unsigned int curDir = this->LoginUser[this->UNameI(usn)].CurDirInodeID;
	INode* inode2 = this->IGet(curDir);
	fseek(fd, inode2->addr[0]*BlockSize, 0);
	fread(&dir, 1, sizeof(Direct), fd);
	dir.files[dir.size] = file;
	dir.size++;
	fseek(fd, inode2->addr[0]*BlockSize, 0);
	fwrite(&dir, 1, sizeof(Direct), fd);
	this->IPut(inode2);

	cout << "目录创建成功！" << endl;
}

// 创建文件
void FileSystem::MakeFile(const char *usn, const char *filename) {
	if (!this->CheckLogin(usn)) return; // 用户登录检测
	if (!u.regTest("^[a-zA-Z0-9._]{1,16}$", filename)) { // 文件名合法性检测
		cout << "文件名称只能是1至16位字母或数字或点号下划线组成！" << endl;
		return;
	}
	// 调用 NameI 方法通过名称找到索引节点编号
	unsigned int dinodeid = this->NameI(usn, filename);
	if (dinodeid != 0) {
		cout << "相同名称的文件或目录已经存在!" << endl;
		return;
	}
	// 分配 索引节点
	INode* inode = this->IAlloc();
	if (inode == NULL) return;
	// 填入初始化信息
	inode->size = 0;
	inode->type = 'f';
	inode->mode = '1';
	// 初始化文件
	File file;
	strcpy(file.name, filename);
	file.Dino = inode->Dino;
	this->IPut(inode);
	// 将新文件插入目录表中
	unsigned int curDir = this->LoginUser[this->UNameI(usn)].CurDirInodeID;
	INode* inode2 = this->IGet(curDir);
	Direct dir;
	fseek(fd, inode2->addr[0]*BlockSize, 0);
	fread(&dir, 1, sizeof(Direct), fd);
	dir.files[dir.size] = file;
	dir.size++;
	fseek(fd, inode2->addr[0]*BlockSize, 0);
	fwrite(&dir, 1, sizeof(Direct), fd);
	this->IPut(inode2);
	cout << "文件创建成功！" << endl;
}


void FileSystem::IFree(unsigned int dinodeid) {
	unsigned int id;
	unsigned long addr;
	DInode dino;
	if (sb.pFI == 100) { // 栈满
		for (int i=0; i<50; i++) { // 取一半存盘
			id = sb.FIS[sb.pFI-1];
			addr = this->mapAddr(id);
			fseek(fd, addr, 0);
			fread(&dino, 1, sizeof(DInode), fd);
			dino.type = 's';
			fwrite(&dino, 1, sizeof(DInode), fd);
		}
	}
	sb.FIS[sb.pFI] = dinodeid;
	sb.FINum++;
	sb.pFI++;
}

INode* FileSystem::IAlloc() {
	INode* temp_inode;
	int i, count;
	unsigned long addr;
	if (sb.FINum == 0) {
		cout << "无法再分配更多的 I 结点!" << endl;
		return NULL;
	}
	if (sb.pFI == 0) { // 栈空, 补栈
		i = 0;
		count = 0;
		DInode in;
		for (i=0; i<IBlockNum*BlockSize/sizeof(DInode); i++) {
			addr = this->mapAddr(i);
			fseek(fd, addr, 0);
			fread(&in, 1, sizeof(DInode), fd);
			if (in.type == 'e') {
				sb.FIS[sb.pFI] = in.no;
				in.type = 's';
				fseek(fd, addr, 0);
				fwrite(&in, 1, sizeof(DInode), fd);
				sb.pFI++;
				count++;
				if (count == 50) {
					break;
				}
			}
		}
	}
	unsigned int id = sb.FIS[sb.pFI-1];
	temp_inode = this->IGet(id);
	//temp_inode->type = 's';
	addr = this->mapAddr(id);
	fseek(fd, addr, 0);
	fwrite(&temp_inode->di_number, 1, sizeof(DInode), fd);
	sb.pFI--;
	sb.FINum--;
	sb.SysMod = 0;
	this->SaveSuperBlock();
	return temp_inode;
}


INode* FileSystem::IGet(unsigned int dinodeid) {
	int inodeid = dinodeid % NHINO;
	int existed = 0;
	long addr;
	INode *temp, *newinode;

	if (hinode[inodeid].iForw != NULL) {
		// 如果 HASH 表中该 HASH 队列不为空, 查找节点
		temp = hinode[inodeid].iForw;
		while (temp) {
			if (temp->i_ino == inodeid) {
				// 如果找到该索引节点
				existed = 1;
				temp->Icount++;
				return temp;
			} else {
				temp = temp->iForw;
			}
		}
	}
	// HASH 表中不存在该节点, 则计算对应磁盘 I节点 地址
	addr = this->mapAddr(dinodeid);

	// 分配内存, 并从磁盘载入信息
	newinode = (INode*)malloc(sizeof(INode));
	fseek(fd, addr, 0);
	fread(&newinode->di_number, 1, sizeof(DInode), fd);

	// 将该节点置入 HASH 表中
	newinode->iForw = hinode[inodeid].iForw;
	newinode->iBack = newinode;
	if (newinode->iForw != NULL) {
		newinode->iForw->iBack = newinode;
	}
	hinode[inodeid].iForw = newinode;
	
	// 填好初始化信息
	newinode->Icount = 1;
	newinode->flag = 0;				// 标记是否被更新
	newinode->i_ino = inodeid;


	// newinode->di_size=3*(DIRSIZ+2);
	// if(dinodeid == 3) newinode->di_size=BLOCKSIZ;
	return newinode;
}

void FileSystem::IPut(INode* pinode) {
	unsigned long addr;
	addr = this->mapAddr(pinode->Dino);
	fseek(fd, addr, 0);
	fwrite(&pinode->di_number, 1, sizeof(DInode), fd);
	if (pinode->Icount > 1) {
		pinode->Icount--;
		return;
	}

	if (pinode->iForw == NULL) {
		pinode->iBack->iForw = NULL;
	} else {
		pinode->iForw->iBack = pinode->iBack;
		pinode->iBack->iForw = pinode->iForw;
	}
	/*
	if (pinode->di_number != 0) {
		addr = this->mapAddr(pinode->Dino);
		fseek(fd, addr, 0);
		fwrite(&pinode->di_number, 1, sizeof(DInode), fd);
	} else {
		for (int i=0; i<pinode->size; i++) {
			this->BFree(pinode->addr[i]);
		}
		//this->IFree(pinode->Dino);
	}
	if (pinode->iForw == NULL) {
		pinode->iBack->iForw = NULL;
	} else {
		pinode->iForw->iBack = pinode->iBack;
		pinode->iBack->iForw = pinode->iForw;
	}
	this->IFree(pinode->Dino);*/
}

unsigned int FileSystem::NameI(const char *usn, const char *name) {
	if (0==strcmp("/", name)) {
		return this->LoginUser[this->UNameI(usn)].user.Dino;
	} else if (0==strcmp(".", name)) {
		return this->LoginUser[this->UNameI(usn)].CurDirInodeID;
	} else {
		unsigned int curDir = this->LoginUser[this->UNameI(usn)].CurDirInodeID;
		INode* inode = this->IGet(curDir);
		Direct dir;
		fseek(fd, inode->addr[0] * BlockSize, 0);
		fread(&dir, 1, sizeof(Direct), fd);
		this->IPut(inode);
		for (int i=0; i<dir.size; i++) {
			if (strcmp(dir.files[i].name, name)==0) {
				return dir.files[i].Dino;
			}
		}
		return 0;
	}
}

void FileSystem::ChangeDir(const char *usn, const char *name) {
	if (!this->CheckLogin(usn)) return;
	int dinodeid = this->NameI(usn, name);
	if (dinodeid==0) {
		cout << "目录不存在！" << endl;
		return;
	}
	INode* inode = this->IGet(dinodeid);
	if (inode == NULL) {
		cout << "目录不存在！" << endl;
		return;
	}
	if (inode->type != 'd') {
		cout << "目录不存在！" << endl;
		return;
	}
	// cout << "当前目录：" << name << endl;
	int uid = this->UNameI(usn);
	this->LoginUser[uid].CurDirInodeID = dinodeid;
}

bool FileSystem::Login(const char *usn, const char *pwd) {
	if (this->LoginNum > 3) {
		cout << "当前系统太多人登录,请稍后登录!" << endl;
		return 0;
	}
	int i;
	for (i=0; i<this->LoginNum; i++) {
		if (strcmp(usn, this->LoginUser[i].user.usn)==0) {
			cout << "您已经登陆,不用重复登录!" << endl;
			return 0;
		}
	}
	for (i=0; i<4; i++) {
		if (strcmp(this->AllUser[i].usn, usn)==0 && strcmp(this->AllUser[i].pwd, pwd)==0) {
			cout << "登录成功!" << endl;
			this->LoginUser[this->LoginNum].user = this->AllUser[i];
			this->LoginNum++;
			LoginUser[this->LoginNum].CurDirInodeID = this->AllUser[i].Dino;
			this->ChangeDir(usn, "/");
			return 1;
		}
	}
	cout << "你输入的用户名或者密码不正确!" << endl;
	return 0;
}

void FileSystem::Logout(const char *usn) {
	if (!this->CheckLogin(usn)) return;
	int j, k;
	for (int i=0; i<this->LoginNum; i++) {
		if (strcmp(this->LoginUser[i].user.usn, usn)==0) {
			int uid = this->UNameI(usn);
			for (k=0; k<100; k++) {
				if (sys_ofile[k].f_count > 0 && sys_ofile[k].uid == uid) {
					this->Close(usn, k);
				}
			}
			for (j=i; j<3; j++) {
				this->LoginUser[j] = this->LoginUser[j+1];
			}
			this->LoginNum--;
			cout << "登出成功!" << endl;
			return;
		}
	}
}

int FileSystem::CheckLogin(const char *usn) {
	for (int i=0; i<this->LoginNum; i++) {
		if (strcmp(this->LoginUser[i].user.usn, usn)==0) {
			return 1;
		}
	}
	cout << "对不起,您还未登录,请先登录!" << endl;
	return 0;
}

void FileSystem::Load() {
	fd = fopen(this->Disk_Name, "r+w+b");
	if (fd == NULL) {
		cout << "文件系统无法加载!" << endl;
		exit(0);