/* Reads the next directory entry in DIR and stores the name in
NAME. Returns true if successful, false if the directory
contains no more entries. */
bool
dir_readdir (struct dir *dir, char name[NAME_MAX + 1])
{
struct dir_entry e;
while (inode_read_at (dir->inode, &e, sizeof e, dir->pos) == sizeof e)
{
dir->pos += sizeof e;
if (e.in_use && strcmp(e.name,".") != 0 && strcmp(e.name,"..") != 0 )
{
strlcpy (name, e.name, NAME_MAX + 1);
return true;
}
}
return false;
}
bool dir_is_empty( struct dir *dir)
{
struct dir_entry e;
int pos = 0;
while (inode_read_at (dir->inode, &e, sizeof e, pos) == sizeof e)
{
pos += sizeof e;
if (e.in_use)
{
if (strcmp(e.name,".")==0 || strcmp(e.name,"..")==0) continue;
return false;
}
}
return true;
}
/* Adds a file named NAME to DIR, which must not already contain a
file by that name. The file's inode is in sector
INODE_SECTOR.
Returns true if successful, false on failure.
Fails if NAME is invalid (i.e. too long) or a disk or memory
error occurs. */
bool
dir_add (struct dir *dir, const char *name, block_sector_t inode_sector)
{
struct dir_entry e;
off_t ofs;
bool success = false;
name = getfilename(name);
ASSERT (dir != NULL);
ASSERT (name != NULL);
/* Check NAME for validity. */
if (*name == '\0' || strlen (name) > NAME_MAX) {
return false;
}
//lock the directory for the operation
inode_lock(dir->inode);
/* Check that NAME is not in use. */
if (lookup (dir, name, NULL, NULL))
goto done;
/* Set OFS to offset of free slot.
If there are no free slots, then it will be set to the
current end-of-file.
inode_read_at() will only return a short read at end of file.
Otherwise, we'd need to verify that we didn't get a short
read due to something intermittent such as low memory. */
for (ofs = 0; inode_read_at (dir->inode, &e, sizeof e, ofs) == sizeof e;
ofs += sizeof e)
if (!e.in_use)
break;
/* Write slot. */
e.in_use = true;
strlcpy (e.name, name, sizeof e.name);
e.inode_sector = inode_sector;
success = inode_write_at (dir->inode, &e, sizeof e, ofs) == sizeof e;
done:
//unlock the directory again
inode_unlock(dir->inode);
return success;
}
/* Adds a file named NAME to DIR, which must not already contain a
file by that name. The file's inode is in sector
INODE_SECTOR.
Returns true if successful, false on failure.
Fails if NAME is invalid (i.e. too long) or a disk or memory
error occurs. */
bool
dir_add (struct file *dir, const char *name, block_sector_t inode_sector)
{
ASSERT (file_is_dir (dir));
struct dir_entry e;
size_t ofs;
bool success = false;
ASSERT (dir != NULL);
ASSERT (name != NULL);
/* Check NAME for validity. */
if (*name == '\0' || strlen (name) > NAME_MAX)
return false;
bool locked = file_lock (dir);
/* Check that NAME is not in use. */
if (dir_lookup (dir, name) >= 0)
goto done;
/* Set OFS to offset of free slot.
If there are no free slots, then it will be set to the
current end-of-file.
inode_read_at() will only return a short read at end of file.
Otherwise, we'd need to verify that we didn't get a short
read due to something intermittent such as low memory. */
size_t dir_size = inode_length (dir->inode);
for (ofs = 0; ofs < dir_size; ofs += sizeof e)
{
inode_read_at (dir->inode, &e, sizeof e, ofs);
if (!e.in_use)
break;
}
/* Write slot. */
e.in_use = true;
strlcpy (e.name, name, sizeof e.name);
e.inode_sector = inode_sector;
success = inode_write_at (dir->inode, &e, sizeof e, ofs) == sizeof e;
done:
if (locked) file_unlock (dir);
return success;
}
/* Returns the num of entries in this directory, EXCLUDING '.' and
'..' */
static size_t
dir_size (struct dir *dir)
{
struct dir_entry e;
size_t ofs;
size_t count = 0;
ASSERT (dir != NULL);
lock_acquire (&dir->l);
for (ofs = 0; inode_read_at (dir->inode, &e, sizeof e, ofs) == sizeof e;
ofs += sizeof e)
{
if (e.in_use)
count++;
}
lock_release (&dir->l);
return count - 2;
}
static struct directory *dir_get_root(struct block *d){
struct inode *root_ino;
struct directory *root;
ASSERT(d != NULL);
// get root inode
root_ino = ext2_get_inode(d,EXT2_ROOT_INO);
// allocate memory
root = kmalloc(root_ino->i_size);
if(root == NULL) return NULL;
// read entire file
inode_read_at(d,root_ino,root,root_ino->i_size,0);
return root;
}
/* Reads the next directory entry in DIR and stores the name in
NAME. Returns true if successful, false if the directory
contains no more entries. */
bool
dir_readdir (struct dir *dir, char name[NAME_MAX + 1])
{
struct dir_entry e;
while (inode_read_at (dir->inode, &e, sizeof e, dir->pos) == sizeof e)
{
dir->pos += sizeof e;
if (e.in_use)
{
// printf ("readdir name:%x, name:%s, pos:%d\n", name, e.name, dir->pos);
strlcpy (name, e.name, NAME_MAX + 1);
// printf ("strlcpy end\n");
return true;
}
}
return false;
}
/* Reads the next directory entry in DIR and stores the name in
NAME. Returns true if successful, false if the directory
contains no more entries. */
bool
dir_readdir (struct dir *dir, char name[NAME_MAX + 1])
{
struct dir_entry e;
bool result = false;
lock_acquire (&dir->l);
while (!result &&
inode_read_at (dir->inode, &e, sizeof e, dir->pos) == sizeof e)
{
if (e.in_use)
{
strlcpy (name, e.name, NAME_MAX + 1);
result = true;
}
dir->pos += sizeof e;
}
lock_release (&dir->l);
return result;
}
/* Reads the next directory entry in DIR and stores the name in
NAME. Returns true if successful, false if the directory
contains no more entries. */
bool
dir_readdir (struct dir *dir, char name[NAME_MAX + 1])
{
// lock_acquire(&directory_lock);
struct dir_entry e;
bool success = false;
while (inode_read_at (dir->inode, &e, sizeof e, dir->pos) == sizeof e)
{
dir->pos += sizeof e;
if (e.in_use)
{
strlcpy (name, e.name, NAME_MAX + 1);
// return true;
success = true;
break;
}
}
// lock_release(&directory_lock);
return success;
}
bool dir_readdir (struct dir *directory,
char file [MAXIMUM_FILE_NAME_LENGTH + 1])
{
struct dir_entry directory_element;
bool success = false;
acquire_inode_lock (directory->inode);
while (inode_read_at (directory->inode, &directory_element,
sizeof directory_element, directory->pos) == sizeof directory_element)
{
directory->pos += sizeof directory_element;
if (directory_element.in_use)
{
strlcpy (file, directory_element.name,
MAXIMUM_FILE_NAME_LENGTH + 1);
success = true;
break;
}
}
release_inode_lock (directory->inode);
return success;
}
/* Searches DIR for a file with the given NAME.
If successful, returns true, sets *EP to the directory entry
if EP is non-null, and sets *OFSP to the byte offset of the
directory entry if OFSP is non-null.
otherwise, returns false and ignores EP and OFSP. */
static bool
lookup (const struct dir *dir, const char *name,
struct dir_entry *ep, off_t *ofsp)
{
struct dir_entry e;
size_t ofs;
ASSERT (dir != NULL);
ASSERT (name != NULL);
for (ofs = 0; inode_read_at (dir->inode, &e, sizeof e, ofs) == sizeof e;
ofs += sizeof e)
if (e.in_use && !strcmp (name, e.name))
{
if (ep != NULL)
*ep = e;
if (ofsp != NULL)
*ofsp = ofs;
return true;
}
return false;
}
/* Returns whether or not the given directory is empty (an empty directory is
one in which the only entries are "." and "..").
NOTE : Assumes the caller has already acquired a lock on the directory. */
bool
dir_is_empty (struct file *dir)
{
ASSERT (file_is_dir (dir));
/* Look through all the directory entries, counting up the entries that are
in use. */
size_t dir_size = inode_length (dir->inode);
struct dir_entry e;
size_t ofs;
size_t entries = 0;
for (ofs = 0; ofs < dir_size; ofs += sizeof e)
{
inode_read_at (dir->inode, &e, sizeof e, ofs);
if (e.in_use) entries++;
}
/* A directory should never have less than 2 entries. */
ASSERT (entries >= 2);
/* The directory is empty if it contains only "." and ".." - 2 entries. */
return entries == 2;
}
/*! Reads SIZE bytes from FILE into BUFFER, starting at offset FILE_OFS in the
file. Returns the number of bytes actually read, which may be less than
SIZE if end of file is reached. The file's current position is
unaffected. */
off_t file_read_at(struct file *file, void *buffer, off_t size,
off_t file_ofs) {
ASSERT(file != NULL);
ASSERT(buffer != NULL);
return inode_read_at(file->inode, buffer, size, file_ofs);
}
/* Creates a file named NAME with the given INITIAL_SIZE.
Returns true if successful, false otherwise.
Fails if a file named NAME already exists,
or if internal memory allocation fails. */
static bool
_filesys_create (const char *full_path, off_t initial_size,
bool is_dir)
{
block_sector_t cwd = thread_current ()->cwd_sector;
bool found = true;
if (cwd != (block_sector_t) ROOT_DIR_SECTOR)
{
struct inode *curr = NULL;
curr = inode_open (cwd);
struct dir *p;
p = dir_open (inode_open (curr->data.parent_dir_sector));
struct dir_entry e;
size_t ofs;
ASSERT (p != NULL);
found = false;
for (ofs = 0;
inode_read_at (p->inode, &e, sizeof e, ofs) == sizeof e;
ofs += sizeof e)
{
if (e.inode_sector == cwd && e.in_use)
{
found = true;
break;
}
}
}
if (!found)
return false;
char leaf_name[NAME_MAX + 1];
if (!dir_get_leaf_name (full_path, leaf_name))
return false;
struct dir *parent_dir = dir_get_parent_dir (full_path);
if (parent_dir == NULL)
return false;
block_sector_t inode_sector = 0;
if (!free_map_allocate_one (&inode_sector))
{
dir_close (parent_dir);
return false;
}
bool success = is_dir? dir_create (inode_sector, BLOCK_SECTOR_SIZE /
sizeof (struct dir_entry)) :
inode_create (inode_sector, initial_size);
if (!success)
{
free_map_release (inode_sector, 1);
dir_close (parent_dir);
return false;
}
if (!dir_add (parent_dir, leaf_name, inode_sector))
{
inode_remove (inode_open (inode_sector));
free_map_release (inode_sector, 1);
dir_close (parent_dir);
return false;
}
dir_close (parent_dir);
return true;
}
bool dir_remove (struct dir *directory, const char *file)
{
struct dir_entry directory_element_1, directory_element_2;
struct inode *inode = NULL;
bool present = false;
off_t offset_1, offset_2;
int count;
ASSERT(directory != NULL);
ASSERT(file != NULL);
acquire_inode_lock (directory->inode);
for (offset_2 = 0;
inode_read_at (directory->inode, &directory_element_2,
sizeof directory_element_2, offset_2) == sizeof directory_element_2;
offset_2 += sizeof directory_element_2)
if (directory_element_2.in_use
&& !strcmp (file, directory_element_2.name))
{
directory_element_1 = directory_element_2;
offset_1 = offset_2;
present = true;
}
if (!present)
{
inode_close (inode);
release_inode_lock (directory->inode);
return false;
}
inode = inode_open (directory_element_1.inode_sector);
if (inode == NULL)
{
inode_close (inode);
release_inode_lock (directory->inode);
return false;
}
if (is_inode_dir (inode) && get_inode_open_cnt (inode) > 1)
{
inode_close (inode);
release_inode_lock (directory->inode);
return false;
}
if (is_inode_dir (inode) && !dir_is_empty (inode))
{
inode_close (inode);
release_inode_lock (directory->inode);
return false;
}
directory_element_1.in_use = false;
offset_2 = inode_write_at (directory->inode, &directory_element_1,
sizeof directory_element_1, offset_1);
if (sizeof directory_element_1 != offset_2)
{
inode_close (inode);
release_inode_lock (directory->inode);
return false;
}
inode_remove (inode);
inode_close (inode);
release_inode_lock (directory->inode);
return true;
}
/* Reads SIZE bytes from FILE into BUFFER,
starting at offset FILE_OFS in the file.
Returns the number of bytes actually read,
which may be less than SIZE if end of file is reached.
The file's current position is unaffected. */
off_t
file_read_at (struct file *file, void *buffer, off_t size, off_t file_ofs)
{
return inode_read_at (file->inode, buffer, size, file_ofs);
}
struct directory *dir_lookup(struct block *d, const char *path){
char *path_copy, *token, *save_ptr;
struct directory *cur,*next,*last,*file_ptr;
struct directory *found = NULL;
ASSERT(path != NULL);
// copy path
path_copy = kmalloc(strlen(path)+1);
memcpy(path_copy,path,strlen(path)+1);
// start from root
last = NULL;
cur = dir_get_root(d);
ASSERT(cur != NULL);
// search path
for(token = strtok_r(path_copy,"/",&save_ptr); token != NULL;
token = strtok_r(NULL,"/",&save_ptr)){
// check if current directory is the same as the last
if(cur == last) {
file_ptr = NULL;
break;
}
// look up current directory
file_ptr = dir_lookup_current(cur,token);
last = cur; //save current directory
// if file is directory
if(file_ptr != NULL && file_ptr->inode != 0 && file_ptr->file_type == EXT2_FT_DIR){
// get file inode, it is temporary
struct inode *file_ino = ext2_get_inode(d,file_ptr->inode);
if(file_ino == NULL || (file_ino->i_mode & EXT2_S_IFDIR) == 0){
file_ptr = NULL;
if(file_ino != NULL) kfree(file_ino);
break;
}
// read directory file
next = kmalloc(file_ino->i_size);
if(next == NULL) {
file_ptr = NULL;
kfree(file_ino);
break;
}
inode_read_at(d,file_ino,next,file_ino->i_size,0);
// free temporary memory and switch directory
kfree(file_ino);
kfree(cur);
cur = next;
}
}
// file found
if(file_ptr != NULL && file_ptr->inode != 0){
found = kmalloc(sizeof(struct directory));
memcpy(found,file_ptr,sizeof(struct directory));
}
kfree(cur);
kfree(path_copy);
return found;
}
