int search_inode(int node_number, char **node_names)
{
int result = -1;
if (node_number >= 0 && node_names != NULL)
{
if (*node_names == NULL)
{
result = node_number;
}
else
{
int next_node_number = search_inode_in_folder(node_number, *node_names);
if (next_node_number > 0)
{
result = search_inode(next_node_number, node_names + 1);
}
}
}
return result;
}
int main(int argc, char const *argv[]){
if(argc != 4) {
fprintf(stderr, "Usage: ext2_cp <formatted virtual disk> <local path> <absolute disk path>\n");
exit(1);
}
int fd = open(argv[1], O_RDWR);
disk = mmap(NULL, 128 * EXT2_BLOCK_SIZE, PROT_READ
| PROT_WRITE, MAP_SHARED, fd, 0);
if(disk == MAP_FAILED) {
perror("mmap");
exit(1);
}
FILE * fp;
fp = fopen(argv[2], "r");
if (fp == NULL) {
printf("File not found\n");
exit(ENOENT);
}
//get file size
fseek(fp, 0L, SEEK_END);
int file_sz = ftell(fp);
fseek(fp, 0L, SEEK_SET);
//number of blocks needed to copy file
int num_blocks_needed = (int) (file_sz / EXT2_BLOCK_SIZE) + 1;
//get the superblock
struct ext2_super_block *superblock = (struct ext2_super_block *)
(disk + EXT2_BLOCK_SIZE);
int first_data_block = superblock->s_first_data_block;
if (num_blocks_needed > superblock->s_free_blocks_count){
fprintf(stderr, "No space left on device\n");
exit(ENOSPC);
}
// get the group descriptor table
// we know that this table always start at third datablock (index 2)
struct ext2_group_desc *group_des_table = (struct ext2_group_desc*)
(disk + EXT2_BLOCK_SIZE * 2);
int inode_bitmap = group_des_table->bg_inode_bitmap;
int block_bitmap = group_des_table->bg_block_bitmap;
int inode_table = group_des_table->bg_inode_table;
void *tablestart = disk + EXT2_BLOCK_SIZE * inode_table;
//check that the path does not already exist
int found_inode;
found_inode = search_inode(argv[3]);
if (found_inode != -1){ // has to be not found
fprintf(stderr, "File exists\n");
exit(EEXIST);
}
//get the parent directory into which to copy the file
int parent_inode_num = parent_conversion(argv[3]);
if (parent_inode_num == -1){
fprintf(stderr, "No such file or directory\n");
exit(ENOENT);
}
//get the inode of that parent directory
struct ext2_inode *parent_inode = (struct ext2_inode*)
(tablestart) + (parent_inode_num - 1);
if (parent_inode->i_mode & EXT2_S_IFREG){
fprintf(stderr, "No such file or directory\n");
exit(ENOENT);
}
//get block bitmap
int block_bitmap_block = block_bitmap * EXT2_BLOCK_SIZE;
void * block_bits = (void *)(disk + block_bitmap_block);
//get inode bitmap
unsigned long inode_bitmap_block = inode_bitmap * EXT2_BLOCK_SIZE;
void * inode_bits = (void *)(disk + inode_bitmap_block);
//find free inode
int inode_indx = get_free_inode(inode_bits);
if (inode_indx == -1){
fprintf(stderr, "No space left on device\n");
exit(ENOSPC);
}
//update superblock
superblock->s_free_inodes_count = superblock->s_free_inodes_count - 1;
//init new inode
struct ext2_inode *new_inode = (struct ext2_inode*)(tablestart)
+ (inode_indx);
new_inode->i_mode = 32768; //is file
new_inode->i_size = file_sz;
new_inode->i_blocks = 1;
new_inode->i_links_count = 1;
//global variables for indirect block if necessary
void *indirect_block;
unsigned int indr_block[15];
void *data_block;
int i;
for (i = 0; i < num_blocks_needed; i++){
if (i < 12){
int free_block_num = get_free_block(block_bits);
if (free_block_num == -1){
fprintf(stderr, "No space left on device\n");
exit(ENOSPC);
}
superblock->s_free_blocks_count = superblock->s_free_blocks_count - 1;
new_inode->i_blocks += 1;
new_inode->i_block[i] = first_data_block + free_block_num -1;
data_block = (void *)(disk + (EXT2_BLOCK_SIZE *
new_inode->i_block[i]));
}
else if (i == 12){
//i_blocks[12] entry is the 13th entry in the array
//It holds the block number of the indirect block
//- this block contains an array of block numbers
//for the next data blocks of the file.
//get free block for indirect block
int indirect_block_num = get_free_block(block_bits);
if (indirect_block_num == -1){
fprintf(stderr, "No space left on device\n");
exit(ENOSPC);
}
new_inode->i_block[i] = first_data_block + indirect_block_num;
//initialize indirect block
indirect_block = (void *)(disk + (EXT2_BLOCK_SIZE
* new_inode->i_block[i]));
//get data block
int free_block_num = get_free_block(block_bits);
if (free_block_num == -1){
fprintf(stderr, "No space left on device\n");
exit(ENOSPC);
}
superblock->s_free_blocks_count = superblock->s_free_blocks_count - 1;
new_inode->i_blocks += 1;
indr_block[i - 12] = first_data_block + free_block_num -1;
memcpy(indirect_block, (void *) indr_block, 16);
data_block = (void *)(disk + (EXT2_BLOCK_SIZE * indr_block[i - 12]));
}
else if (i > 12){
int free_block_num = get_free_block(block_bits);
if (free_block_num == -1){
fprintf(stderr, "No space left on device\n");
exit(ENOSPC);
}
superblock->s_free_blocks_count = superblock->s_free_blocks_count - 1;
new_inode->i_blocks += 1;
indr_block[i - 12] = first_data_block + free_block_num -1;
memcpy(indirect_block, (void *) indr_block, 16);
data_block = (void *)(disk + (EXT2_BLOCK_SIZE * indr_block[i - 12]));
}
//read data from file to data block
int num_read = fread(data_block, 1, EXT2_BLOCK_SIZE, fp);
if (num_read == 0){
perror("Error reading file");
}
}
fclose(fp);
//add this new file's directory entry to the parent directory
int c;
//loop through directory entries to get to the last entry
for (c = 0; c < EXT2_BLOCK_SIZE;){
struct ext2_dir_entry_2 *node_dir = (struct ext2_dir_entry_2 *)
(disk + (EXT2_BLOCK_SIZE * parent_inode->i_block[0]) + c);
if (c + node_dir->rec_len == EXT2_BLOCK_SIZE){
//this is the last block in the directory
int new_rec_len = node_dir->rec_len - node_dir->name_len - 8;
node_dir->rec_len = node_dir->name_len + 8;
//create directory entry
struct ext2_dir_entry_2 *par_dir = (struct ext2_dir_entry_2 *)
(disk + (EXT2_BLOCK_SIZE * parent_inode->i_block[0]
+ c + node_dir->rec_len));
par_dir->inode = inode_indx + 1;
par_dir->file_type = 1;
//get name of new file
char dup_path[strlen(argv[3])];
strcpy(dup_path, argv[3]);
char *ret;
ret = strrchr(dup_path, '/');
if (ret[0] == '/'){
ret++;
}
par_dir->rec_len = new_rec_len;
par_dir->name_len = strlen(ret);
strcpy(par_dir->name, ret);
break;
}
c += node_dir->rec_len;
}
return 0;
}
