bool is_parent_directory (struct dir* directory)
{
if (!directory)
return false;
if (ROOT_DIR_SECTOR == get_inumber (directory->inode))
return true;
return false;
}
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;
}
/* Stores the current working directory, as a null-terminated
string, in the CWD_SIZE bytes in CWD.
Returns true if successful, false on error. Errors include
system errors, directory trees deeper than MAX_LEVEL levels,
and insufficient space in CWD. */
static bool
getcwd (char *cwd, size_t cwd_size)
{
size_t cwd_len = 0;
#define MAX_LEVEL 20
char name[MAX_LEVEL * 3 + 1 + READDIR_MAX_LEN + 1];
char *namep;
int child_inum;
/* Make sure there's enough space for at least "/". */
if (cwd_size < 2)
return false;
/* Get inumber for current directory. */
if (!get_inumber (".", &child_inum))
return false;
namep = name;
for (;;)
{
int parent_inum, parent_fd;
/* Compose "../../../..", etc., in NAME. */
if ((namep - name) > MAX_LEVEL * 3)
return false;
*namep++ = '.';
*namep++ = '.';
*namep = '\0';
/* Open directory. */
parent_fd = open (name);
if (parent_fd < 0)
return false;
*namep++ = '/';
/* If parent and child have the same inumber,
then we've arrived at the root. */
parent_inum = inumber (parent_fd);
if (parent_inum == child_inum)
break;
/* Find name of file in parent directory with the child's
inumber. */
for (;;)
{
int test_inum;
if (!readdir (parent_fd, namep) || !get_inumber (name, &test_inum))
{
close (parent_fd);
return false;
}
if (test_inum == child_inum)
break;
}
close (parent_fd);
/* Prepend "/name" to CWD. */
if (!prepend (namep - 1, cwd, &cwd_len, cwd_size))
return false;
/* Move up. */
child_inum = parent_inum;
}
/* Finalize CWD. */
if (cwd_len > 0)
{
/* Move the string to the beginning of CWD,
and null-terminate it. */
memmove (cwd, (cwd + cwd_size) - cwd_len, cwd_len);
cwd[cwd_len] = '\0';
}
else
{
/* Special case for the root. */
strlcpy (cwd, "/", cwd_size);
}
return true;
}
