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fs.c
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fs.c
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#include <assert.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
enum DATA_SIZE {
IBLOCK_CNT = 5,
DATA_CNT = 56,
BLK_CNT = 64,
FILE_CNT = 80,
INODE_SIZE = 256,
BLK_SIZE = 4096
};
enum BLOCK {
SUPER = 0,
IBMAP,
DBMAP,
IBLOCK,
DATA_REGION = 8
};
enum CMD {
WRITE = 'w',
READ = 'r',
DELETE = 'd'
};
typedef struct _Block {
unsigned char segment[4096];
} BLK;
typedef struct _Inode {
unsigned int fsize;
unsigned int blocks;
unsigned int pointer[12];
unsigned int NOT_USED_SPACE[50];
} Inode;
typedef struct _Dir {
char inum;
char name[3];
} Dir;
/****************************** NODE **********************************/
typedef struct _Node {
void *address;
struct _Node *next;
struct _Node *prev;
} Node;
/**********************************************************************/
/****************************** QUEUE *********************************/
typedef struct _Queue {
Node *head;
Node *tail;
int size;
} Queue;
void init_q(Queue **new_q) {
(*new_q) = (Queue *)malloc(sizeof(Queue));
(*new_q)->head = (Node *)malloc(sizeof(Node));
(*new_q)->tail = (Node *)malloc(sizeof(Node));
(*new_q)->head->prev = NULL;
(*new_q)->tail->next = NULL;
(*new_q)->head->next = (*new_q)->tail;
(*new_q)->tail->prev = (*new_q)->head;
(*new_q)->size = 0;
return;
}
void enqueue(Queue **q, void *address) {
Node *new_node = (Node *)malloc(sizeof(Node));
new_node->address = address;
new_node->next = NULL;
if ((*q)->size == 0) {
(*q)->size = 1;
(*q)->head = (*q)->tail = new_node;
return;
}
((*q)->size)++;
Node *prev_tail = (*q)->tail;
prev_tail->next = new_node;
(*q)->tail = new_node;
new_node->prev = prev_tail;
}
int dequeue(Queue **q, void **address) {
if ((*q)->size == 0) {
return -1;
}
*address = (*q)->head->address;
Node *prev_head = (*q)->head;
if ((*q)->size == 1) {
((*q)->size)--;
(*q)->head = (*q)->tail = NULL;
free(prev_head);
return 1;
}
((*q)->size)--;
(*q)->head = prev_head->next;
(*q)->head->prev = NULL;
free(prev_head);
return 1;
}
void push_front(Queue **q, void *address) {
Node *new_node = (Node *)malloc(sizeof(Node));
new_node->address = address;
new_node->next = NULL;
if ((*q)->size == 0) {
(*q)->size = 1;
(*q)->head = (*q)->tail = new_node;
return;
}
((*q)->size)++;
Node *prev_head = (*q)->head;
prev_head->prev = new_node;
(*q)->head = new_node;
new_node->next = prev_head;
}
/**********************************************************************/
/*
* Proto types of functions
*/
void init();
void print_EOF(unsigned const char *);
Inode *create_inode();
BLK *create_data();
int set_bitmap(BLK **);
void set_file_inode(Inode **inode, unsigned file_size, char byte);
void set_dir_inode(Inode **inode, unsigned file_size);
void read_file_inode(Inode **inode, unsigned file_size);
void remove_file_inode(int inum);
/**********************************************************************/
BLK *block;
Queue *inode_freelist;
Queue *data_freelist;
Inode *root_dir;
Queue *root_dir_freelist;
int main(int argc, char *argv[]) {
if (argc != 2) {
printf("ku_fs: Wrong number of arguments\n");
return 1;
}
FILE *fp = fopen(argv[1], "r");
if (fp == NULL) {
printf("ku_fs: Fail to open the input file\n");
return 1;
}
init();
assert(block != NULL);
char buf[512];
char f_name[3];
char cmd;
char c_size[16];
while (fgets(buf, 512, fp)) {
memcpy(f_name, buf, 2);
f_name[2] = '\0';
cmd = buf[3];
int i = 0;
for (char *ptr = buf + 5; i + 5 < strlen(buf); ptr++) {
c_size[i++] = *ptr;
}
c_size[i] = '\0';
switch (cmd) {
case (WRITE): {
int flag = 0;
Dir *dirs = (Dir *)(block + DATA_REGION + (root_dir->pointer)[0]);
for (int i = 0; i < 80 - root_dir_freelist->size; i++) {
if (strcmp(dirs[i].name, f_name) == 0) {
flag = 1;
break;
}
}
if (flag) {
printf("Already exists\n");
break;
}
Inode *new_inode;
if ((new_inode = create_inode()) == NULL) {
break;
}
int inode_num = new_inode - (Inode *)(block + IBLOCK);
Dir *dir;
if (dequeue(&root_dir_freelist, (void *)&dir) == -1) {
perror("Error in root dir queue\n");
exit(0);
}
dir->inum = inode_num;
strcpy(dir->name, f_name);
set_file_inode(&new_inode, atoi(c_size), f_name[0]);
break;
}
case (READ): {
Dir *dirs = (Dir *)(block + DATA_REGION + (root_dir->pointer)[0]);
Inode *file = NULL;
for (int i = 0; i < 80 - root_dir_freelist->size; i++) {
if (strcmp(dirs[i].name, f_name) == 0) {
file = ((Inode *)(block + IBLOCK)) + dirs[i].inum;
break;
}
}
if (file != NULL) {
read_file_inode(&file, atoi(c_size));
} else {
printf("No such file\n");
}
break;
}
case (DELETE): {
int flag = 0;
Dir *dirs = (Dir *)(block + DATA_REGION + (root_dir->pointer)[0]);
int inum;
for (int i = 0; i < 80 - root_dir_freelist->size; i++) {
if (strcmp(dirs[i].name, f_name) == 0) {
// inum 0으로 바꾸고 block초기화같은건 아래 remove 함수에서
inum = dirs[i].inum;
dirs[i].inum = 0;
flag = 1;
break;
}
}
if (flag == 0) {
printf("No such file\n");
break;
}
remove_file_inode(inum);
break;
}
default:
perror("Invalid cmd\n");
exit(0);
break;
}
}
print_EOF((unsigned char *)block);
// printf("%.2x\n", (block + IBMAP)->segment[0]);
// printf("%.2x\n", (block + DBMAP)->segment[0]);
// for (int i = 0; i < BLK_CNT; i++) {
// printf("%.2x\n", (block + i)->segment[0]);
// }
}
/**********************************************************************/
void init() {
block = (BLK *)calloc(sizeof(BLK), 64);
init_q(&inode_freelist);
init_q(&data_freelist);
init_q(&root_dir_freelist);
for (int i = DATA_REGION; i < BLK_CNT; i++) {
enqueue(&data_freelist, block + i);
}
Inode *inode_entry = (Inode *)(block + IBLOCK);
for (int i = 0; i < FILE_CNT; i++) {
enqueue(&inode_freelist, inode_entry + i);
}
create_inode(); // no inode
create_inode(); // bad block
root_dir = (void *)create_inode(); // root dir
//init root
set_dir_inode(&root_dir, 80 * 4);
Dir *root_dir_entry = (Dir *)(block + DATA_REGION + (root_dir->pointer)[0]);
for (int i = 0; i < FILE_CNT; i++) {
enqueue(&root_dir_freelist, root_dir_entry + i);
}
}
Inode *create_inode() {
BLK *ibmap_entry = block + IBMAP;
int inode_num = set_bitmap(&ibmap_entry);
// 만약 중간에 inode가 없어졌다면 그거 가져다가 쓰기
// // ibmap은 1110111... 인 경우
if (inode_num < FILE_CNT - inode_freelist->size) {
return (Inode *)(block + IBLOCK) + inode_num;
}
// ibmap은 빽빽하게 11111... 인 경우
void *dequeued;
if (dequeue(&inode_freelist, &dequeued) == -1) {
printf("No space\n");
return NULL;
}
return dequeued;
}
BLK *create_data() {
BLK *dbmap_entry = block + DBMAP;
int data_blk_num = set_bitmap(&dbmap_entry);
// 만약 중간에 iblock가 없어졌다면 그거 가져다가 쓰기
// // dbmap은 1110111... 인 경우
if (data_blk_num < DATA_CNT - data_freelist->size) {
return block + DATA_REGION + data_blk_num;
}
// dbmap은 빽빽하게 11111... 인 경우
void *dequeued;
if (dequeue(&data_freelist, &dequeued) == -1) {
return NULL;
}
return dequeued;
}
int set_bitmap(BLK **bmap) {
/*
* bitmap block을 4096행 8열의 행렬로 생각.
* 1행은 `unsigned char`라서 8열
* 비트가 0인곳 발견하면 바로 loop break.
*/
int row;
int col;
unsigned char check_mask = 0b10000000;
for (row = 0;; row++) {
int flag = 0;
int cnt = 0;
unsigned char curr_bit = (*bmap)->segment[row];
while (cnt != 8) {
// & 연산자보다 ==연산자가 우선순위 높아서 괄호 안붙이면 무한루프
if ((check_mask & curr_bit) == 0) {
col = cnt;
flag = 1;
break;
}
curr_bit <<= 1;
cnt++;
}
if (flag) {
break;
}
}
/*
* 위에서 구한 비트가 비어있는 위치에 1 OR 연산으로 삽입.
*/
unsigned char mark = 0b10000000;
unsigned char len = mark >>= col;
unsigned char row_full = 0b11111111;
(*bmap)->segment[row] |= len;
return row * 8 + col;
}
void print_EOF(const unsigned char *block) {
for (int i = 0; i < BLK_CNT * BLK_SIZE; i++, block++) {
printf("%.2x ", *block);
}
}
void set_file_inode(Inode **inode, unsigned int file_size, char byte) {
(*inode)->fsize = file_size;
// file 크기가 disk total초과할 수 있음. blocks count
int blocks_cnt = 0;
// block 받아오기
// 8192 사이즈면 블록2개인데 3개 받아옴. mod연산으로 반복횟수 맞추기
int it = file_size % 4096 == 0 ? file_size / 4096 : file_size / 4096 + 1;
BLK *temp;
for (int i = 0; i < it; i++) {
if ((temp = create_data()) == NULL) {
printf("No space\n");
(*inode)->fsize = BLK_SIZE * blocks_cnt;
break;
}
blocks_cnt++;
((*inode)->pointer)[i] = temp - (block + DATA_REGION);
}
(*inode)->blocks = blocks_cnt;
//block에 쓰기
for (int i = 0; i < (*inode)->blocks; i++) {
int iteration = (i == (*inode)->blocks - 1 ? file_size - ((*inode)->blocks - 1) * 4096 : 4096);
// file size가 너무 크면 마지막에 segfault
// j는 segment 최대크기인 4095로 추가 for문 종료조건 설정
for (int j = 0; j < iteration && j < BLK_SIZE; j++) {
((BLK *)(block + DATA_REGION + ((*inode)->pointer)[i]))->segment[j] = byte;
}
}
// if given file size is bigger than previous one, blocks size has to be changed
}
void set_dir_inode(Inode **inode, unsigned file_size) {
(*inode)->fsize = file_size;
void *address = create_data();
if (address == NULL) {
printf("No space\n");
return;
}
((*inode)->pointer)[0] = (int)(address - (void *)(block + DATA_REGION));
(*inode)->blocks = 1;
}
void read_file_inode(Inode **inode, unsigned file_size) {
int read_bytes = ((*inode)->fsize < file_size ? (*inode)->fsize : file_size);
int read_blocks = ((file_size / 4096 + 1) < (*inode)->blocks ? (file_size / 4096 + 1) : (*inode)->blocks);
for (int i = 0; i < read_blocks; i++) {
int iteration = (i == read_blocks - 1 ? read_bytes - (read_blocks - 1) * 4096 : 4096);
for (int j = 0; j < iteration; j++) {
printf("%c", ((BLK *)(block + DATA_REGION + ((*inode)->pointer)[i]))->segment[j]);
}
}
printf("\n");
}
void remove_file_inode(int inum) {
int segment_idx = inum / 8;
int bit_idx = inum % 8;
unsigned char mark = 0b00000001;
unsigned char full_mask = 0b11111111;
mark <<= (7 - bit_idx);
unsigned char mask = mark ^ full_mask; // mask랑 &연산
// ibmap 0으로
BLK *ibmap = block + IBMAP;
ibmap->segment[segment_idx] &= mask;
// block 초기화
Inode *inode = (Inode *)(block + IBLOCK) + inum;
for (int i = 0; i < inode->blocks; i++) {
BLK *blk = block + DATA_REGION + inode->pointer[i];
memset(blk, 0, BLK_SIZE);
}
// dbmap 0으로
BLK *dbmap = block + DBMAP;
for (int i = 0; inode->pointer[i] != 0; i++) {
mark = 0b00000001;
segment_idx = inode->pointer[i] / 8;
bit_idx = inode->pointer[i] % 8;
mask = (mark << (7 - bit_idx)) ^ full_mask;
dbmap->segment[segment_idx] &= mask;
}
// inode 초기화
memset(inode, 0, sizeof(Inode));
}