bool dir_add (struct dir *directory, block_sector_t block_sec,
const char *file)
{
struct dir_entry directory_element;
off_t offset;
bool success = false;
ASSERT(directory != NULL);
ASSERT(file != NULL);
acquire_inode_lock (directory->inode);
if (*file == '\0' || strlen (file) > MAXIMUM_FILE_NAME_LENGTH)
{
release_inode_lock (directory->inode);
return success;
}
for (offset = 0;
inode_read_at (directory->inode, &directory_element,
sizeof directory_element, offset) == sizeof directory_element;
offset += sizeof directory_element)
if (directory_element.in_use
&& !strcmp (file, directory_element.name))
{
release_inode_lock (directory->inode);
return success;
}
if (!inode_add_parent (get_inumber (directory->inode), block_sec))
{
release_inode_lock (directory->inode);
return success;
}
for (offset = 0;
inode_read_at (directory->inode, &directory_element,
sizeof directory_element, offset) == sizeof directory_element;
offset += sizeof directory_element)
if (!directory_element.in_use)
break;
directory_element.in_use = true;
strlcpy (directory_element.name, file,
sizeof directory_element.name);
directory_element.inode_sector = block_sec;
success = inode_write_at (directory->inode, &directory_element,
sizeof directory_element, offset) == sizeof directory_element;
release_inode_lock (directory->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 dir *dir, const char *name, block_sector_t inode_sector)
{
struct dir_entry e;
off_t ofs;
bool success = false;
ASSERT (dir != NULL);
ASSERT (name != NULL);
inode_lock(dir_get_inode (dir));
/* Check NAME for validity. */
if (*name == '\0' || strlen (name) > NAME_MAX)
{
inode_unlock (dir_get_inode(dir));
return false;
}
/* Check that NAME is not in use. */
if (lookup (dir, name, NULL, NULL))
goto done;
if (!inode_add_parent (inode_get_inumber (dir_get_inode(dir)),inode_sector))
{
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:
inode_unlock (dir_get_inode(dir));
return success;
}
