/* Closes INODE and writes it to disk.
If this was the last reference to INODE, frees its memory.
If INODE was also a removed inode, frees its blocks. */
void
inode_close (struct inode *inode)
{
/* Ignore null pointer. */
if (inode == NULL)
return;
/* Release resources if this was the last opener. */
if (--inode->open_cnt == 0)
{
lock_acquire (&inode->lock);
/* Remove from inode list and release lock. */
list_remove (&inode->elem);
/* Deallocate blocks if removed. */
if (inode->removed)
{
inode_clear (inode);
free_map_release (inode->sector, 1);
}
lock_release (&inode->lock);
free (inode);
}
}
// Reads from a file, f_offset must be kept in the client to remember the last point read
unsigned int fs_read_file(int inode, char * data, int size, unsigned long * f_offset) {
inode_clear(&n); // Clear inode to take off the trash
inode_read(inode, &n); // Read the current inode
int log_block = * f_offset / FS_BLOCK_SIZE; // Current logical block
int block_index = * f_offset % FS_BLOCK_SIZE; // Current block index
int top_log_block = n.blocks / 2; // Maximum logical block
int i = 0;
if (!top_log_block && n.mode & EXT2_S_IFDIR) {
top_log_block = 1; // Directory hack
}
// If we match the conditions, start reading
if (log_block < top_log_block || log_block == top_log_block && block_index < n._last_write_offset) {
log_block_read(&n, &log_block);
char * block = (char *) &b;
// Read iteratively and easy :)
for (; i < size; i++, block_index++) {
data[i] = block[block_index];
if (top_log_block == log_block && block_index == n._last_write_offset - 1) {
break; // If it's a top, get out
}
if (block_index == FS_BLOCK_SIZE - 1) {
log_block++;
log_block_read(&n, &log_block);
block_index = -1;
}
}
* f_offset += i;
} else {
return 0; // Bad offset given
}
return i;
}
// Writes to a file, as simple as unix
unsigned int fs_write_file(int inode, char * data, int size) {
inode_clear(&n); // Clear the inode to take off the trash
inode_read(inode, &n); // Read the current inode.
int log_block = n.blocks / 2;
block_clear(&b); // Prepare to read the data, clear it.
int i = 0;
int block_index = n._last_write_offset;
log_block_read(&n, &log_block); // Set up the point where we'll write
char * block = (char *) &b;
// Write until we reach end
for (; i < size; i++) {
block[block_index] = data[i];
if (block_index == FS_BLOCK_SIZE - 1) {
log_block_write(&n, &log_block);
log_block++; // Iterate if necessary.
log_block_read(&n, &log_block);
block_index = 0;
} else {
block_index++;
}
}
n._last_write_offset = block_index;
log_block_write(&n, &log_block); // Save the last bits
n.blocks = log_block * 2; // Update the inodes
inode_write(inode,&n);
fs_bitmaps_write_all(); // Persist the changes in the FS
return i;
}
// Makes a new directory
unsigned int fs_mkdir(char * name, unsigned int parent_inode) {
unsigned int inode_id = 0;
if ((inode_id = fs_indir(name, parent_inode))) {
return 0;
}
inode_id = bitmap_first_valued(bm_inodes, FS_INODE_BITMAP_SIZE, 0) + 1;
if (!parent_inode) {
parent_inode = inode_id;
}
int log_block;
if (parent_inode != inode_id) {
inode_read(parent_inode, &n);
if(!fs_has_perms(&n, ACTION_WRITE)) {
return ERR_PERMS;
}
log_block = n.blocks / 2;
block_clear(&b);
dir_op_offset = 0;
log_block_read(&n, &log_block);
add_dir_entry(&n, EXT2_FT_DIR, inode_id, name, &log_block);
log_block_write(&n, &log_block);
inode_write(parent_inode, &n);
}
bitmap_write(bm_inodes, inode_id - 1, 1);
inode_clear(&n);
if(!fs_done)
{
n.uid = 0;
} else {
n.uid = current_ttyc()->uid;
}
n.mode = EXT2_S_IFDIR;
n.size = 0;
n.blocks = 0; // Beware! This represents the SECTORS!
log_block = n.blocks / 2;
block_clear(&b);
dir_op_offset = 0;
add_dir_entry(&n, EXT2_FT_DIR, inode_id, ".", &log_block);
add_dir_entry(&n, EXT2_FT_DIR, parent_inode, "..", &log_block);
log_block_write(&n, &log_block);
n.blocks = (log_block) * 2;
n.i_file_acl = 511;
n._dir_inode = parent_inode;
n._last_write_offset = dir_op_offset;
inode_write(inode_id, &n);
fs_bitmaps_write_all();
return inode_id;
}
// Opens a file
unsigned int fs_open_file(char * name, unsigned int folder_inode, int mode, int type) {
unsigned int inode_id = 0;
if(strcmp(name, "/") == 0 && strlen(name) == strlen("/")) {
return 1; // root
}
if(name[0] == 0)
{
inode_id = current_ttyc()->pwd;
} else {
inode_id = fs_indir(name, folder_inode);
}
if (inode_id) {
if (mode & O_CREAT) {
int _rm_res = fs_rm(inode_id, 0);
if(_rm_res < 0) {
return _rm_res;
}
} else if(mode & O_NEW) {
inode_read(inode_id, &n);
if(n.mode == EXT2_S_IFLNK) {
return n.data_blocks[0];
}
return inode_id;
}
else {
inode_read(inode_id, &n);
int can = 1;
if((mode & O_RD) && !fs_has_perms(&n, ACTION_READ)) {
can = 0;
}
if((mode & O_WR) && !fs_has_perms(&n, ACTION_WRITE)) {
can = 0;
}
if(can || !fs_done) {
if(n.mode == EXT2_S_IFLNK) {
return n.data_blocks[0];
}
return inode_id;
} else {
return ERR_PERMS;
}
}
} else if (!(mode & (O_NEW | O_CREAT))) {
return ERR_NO_EXIST;
}
inode_id = bitmap_first_valued(bm_inodes, FS_INODE_BITMAP_SIZE, 0) + 1;
if (!folder_inode) {
folder_inode = inode_id;
}
int log_block;
if (folder_inode != inode_id) {
inode_read(folder_inode, &n);
if(!fs_has_perms(&n, ACTION_WRITE)) {
return ERR_PERMS;
}
log_block = n.blocks / 2;
block_clear(&b);
dir_op_offset = 0;
log_block_read(&n, &log_block);
add_dir_entry(&n, EXT2_FT_DIR, inode_id, name, &log_block);
log_block_write(&n, &log_block);
inode_write(folder_inode, &n);
}
bitmap_write(bm_inodes, inode_id - 1, 1);
inode_clear(&n);
if(!fs_done)
{
n.uid = 0;
} else {
n.uid = current_ttyc()->uid;
}
n.mode = type;
n.size = 0;
n.blocks = 0; // Beware! This represents the SECTORS!
n._last_write_offset = 0;
n.i_file_acl = 511;
n._dir_inode = folder_inode;
inode_write(inode_id, &n);
inode_clear(&n);
if(n.mode == EXT2_S_IFLNK) {
return n.data_blocks[0];
}
return inode_id;
}