1 files changed, 352 insertions, 0 deletions
diff --git a/CS3871/filesystem/tfs.c b/CS3871/filesystem/tfs.c
new file mode 100644
index 0000000..fe2d94c
--- /dev/null
+++ b/CS3871/filesystem/tfs.c
@@ -0,0 +1,352 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/time.h>
+#include "disk.h"
+
+#define MAX_INODES 1000
+#define INODE_START (TRACKS * SECTORS) / (8 * 512)
+#define MAX_FILES 50
+
+struct block_ptr {
+	char track;
+	short sector; 
+};
+struct blockll{
+	struct block_ptr data;
+	struct blockll *next;
+};
+
+struct meta_data{ 
+	char name[8];
+	int size;
+	int read;
+	int write;
+	int create;
+};
+
+struct inode {
+	struct meta_data info;
+	struct block_ptr data[20];
+};
+
+
+struct inode_list{
+	struct inode *node;
+	struct inode_list *next;
+};
+
+struct file {
+	struct inode *node;
+	int mode;
+	int next_sec;
+	int free;
+};
+
+
+int inode_list_size = 0;
+struct inode_list *root, *end;
+
+char bitmap[TRACKS][SECTORS/8];
+
+struct file files[MAX_FILES];
+int size;
+
+
+
+int check_bitmap(t,s)
+int t,s;
+{
+	char tmp;
+	tmp = bitmap[t][s/8];
+	tmp &= (1 << (s % 8));
+	return (int) tmp;
+}
+
+void set_bitmap(t,s)
+int t,s;
+{
+	bitmap[t][s/8] |= (1 << (s % 8));
+	return;
+}
+
+void print_bitmap()
+{
+	int i,j;
+	for(i = 0; i < 128; i++){
+
+		printf("\n%4d  ", i);
+		for (j = 0; j < 4096/8; j++) {
+			printf("%02x", bitmap[i][j]);
+			if (j %31 == 0) {
+				printf("\n%4d  ",i);
+			}
+		}
+	}
+}
+
+
+/*  TODO
+ *  Implement inode table as binary tree to speedup searches
+ */
+struct inode* inode_search(name)
+char *name;
+{
+	if (strcmp(name,"") == 0) {
+		return -1;
+	}
+	int i;
+	struct inode_list *tmp = root;
+
+	for(i = 0; i < MAX_INODES && i < inode_list_size; i++){
+		tmp = tmp->next;
+		if(strcmp(name, tmp->node->info.name) == 0) 
+			return tmp->node;
+	}
+	return -2;
+}
+
+struct blockll* get_blocks(size)
+int size;
+{
+	int i, t, s;
+	struct blockll *root, *current = malloc(sizeof(struct blockll));
+	root = current;
+
+	for (i = 0; size > 0 && i < (4096 * 128); i++) {
+		t = i / 4096;
+		s = i % 4096;
+
+		if (!check_bitmap(t, s)) {
+			current->next = malloc(sizeof(struct blockll));
+			current = current->next;
+			current-> next = NULL;
+			current->data.track = (char) t;
+			current->data.sector = (short) s;
+
+			set_bitmap(t,s);
+			size-= 512;
+		}
+	}
+
+	return i <(4096 * 128) ? root : NULL;
+}
+
+struct inode_list* inode_create(name)
+char *name;
+{
+	struct timeval *tmp_time = malloc(sizeof(struct timeval));
+
+	struct inode_list *tmp = malloc(sizeof(struct inode_list));
+	struct inode *tmp_node = malloc(sizeof(struct inode));
+
+
+	tmp->node = tmp_node;
+	
+	memcpy(&(tmp->node->info.name), name, strlen(name));
+
+	gettimeofday(tmp_time, NULL);
+
+	tmp->node->info.create = tmp_time->tv_sec;
+	tmp->node->info.read = tmp_time->tv_sec;
+	tmp->node->info.write = tmp_time->tv_sec;
+
+	end->next = tmp;
+	end = tmp;
+	inode_list_size++;
+
+	return tmp;
+}
+
+int inode_init()
+{
+	int n = MAX_INODES / 4;
+	int i;
+	char *ptr;
+	struct inode_list *tmp;
+
+	if (MAX_INODES % 4 > 0)
+		n++;
+
+	char *buf = malloc(512 * n);
+
+	for (i =0; i < n; i++) {
+		rsector(0, i, buf + (512 * i));
+	}
+	ptr = buf;
+
+	tmp = root;
+
+	for(i=0; i< MAX_INODES; i++) {
+		tmp->next = malloc(sizeof(struct inode_list));
+		memcpy(&tmp->node, ptr, 64);
+		ptr += 64;
+		tmp = tmp->next;
+		inode_list_size++;
+	}
+}
+
+/*save inodes to first n sectors on disk*/
+void inode_save()
+{
+	int i, j;
+	char *buf = malloc(512);
+	struct inode_list *tmp = root;
+
+	for (i = 0; i < MAX_INODES && tmp->next;i++) {
+		for (j = 0; j < 4; j++){
+			tmp = tmp->next;
+			memcpy(buf + j, tmp->node, sizeof(struct inode));
+		}
+		wsector(0, INODE_START + i, buf);
+	}
+}
+
+struct inode* inode_from_fd(fd) 
+int fd;
+{
+	int i;
+	struct inode_list *tmp = root;
+
+	for (i = 0; i < fd; i++) {
+		tmp = tmp->next;
+	}
+
+	return tmp->node;
+}
+
+int find_fd()
+{
+	int i;
+	for (i = 0; i < size; i++) {
+		if (files[i].free)
+			return i;
+	}
+}
+
+int tfs_init()
+{
+	int i;
+	root = malloc(sizeof(struct inode_list));
+	end = root;
+
+	dinit();
+	/*
+	 *
+	 * has issue if inodes have not been written to disk i.e. first run
+	inode_init();
+	*/
+	for (i = 0; i < MAX_FILES; i++) {
+		files[i].free = 1;
+	}
+}
+
+
+int open(fname, mode)
+char *fname, *mode;
+{
+	struct inode *fnode = inode_search(fname);
+	int fd;
+
+	if (fnode == -1)
+		return -1;
+	
+	if (fnode == -2){
+		fnode = inode_create(fname)->node;
+	}
+	fd = find_fd();
+
+	files[fd].node = fnode;
+	files[fd].mode = *mode;
+	files[fd].next_sec = 0;
+	files[fd].free = 0;
+	size++;
+
+	return fd;
+}
+
+int close(fd)
+int fd;
+{
+	if (files[fd].free)
+		return -1;
+
+	files[fd].free = 1;
+	return 1;
+}
+
+int read(fd, buf)
+int fd;
+char *buf;
+{
+	if (files[fd].free || files[fd].mode || (files[fd].next_sec == 20))
+		return -1;
+	
+	
+	rsector(files[fd].node->data[files[fd].next_sec].track, files[fd].node->data[files[fd].next_sec].sector, buf);
+	files[fd].next_sec++;
+	return 512;
+}
+
+int write(fd, buf)
+int fd;
+char *buf;
+{
+	if ((files[fd].next_sec == 20) || !files[fd].mode)
+		return 0;
+
+	struct blockll *tmp = get_blocks(500);
+	files[fd].node->data[files[fd].next_sec].track = tmp->data.track;
+	files[fd].node->data[files[fd].next_sec].sector = tmp->data.sector;
+
+	wsector(files[fd].node->data[files[fd].next_sec].track, files[fd].node->data[files[fd].next_sec].sector, buf);
+	return 1;
+}
+
+int ulink(fname)
+char *fname;
+{
+	struct inode_list *tmp = root;
+	struct inode *d;
+	int i;
+
+	for(i = 0; i < MAX_INODES && i < inode_list_size; i++){
+		tmp = tmp->next;
+		if(strcmp(fname, tmp->next->node->info.name) == 0) 
+			break;;
+	}
+	
+	d = tmp->next->node;
+	tmp->next = tmp->next->next;
+	free(d);
+	return 1;
+	}
+
+int main() 
+{
+	tfs_init();
+
+	/*
+	 *Test Writing
+	 */
+	int mode = 1;
+	int fd = open("test", &mode);
+
+	char buf[512];
+	memcpy(&buf, "Hello Filesystem", strlen("Hello Filesystem"));
+
+	int test = write(fd, &buf);
+	close(fd);
+	
+	/*
+	 *Test reading
+	 */
+	mode = 0;
+	fd = open("test", &mode);
+	char buf2[512];
+	read(fd, &buf2);
+	printf("wrote: %s\n", buf);
+
+	printf("read: %s\n", buf2);
+
+}