def create_inode_table():
first_data_block = fs.bytes_to_int(
superblock.get_field(superblock.s_first_data_block))
inodetable_block = inodetable.load_inode(0)
table_number = inodetable.get_table_number(0)
inodetable_block.set_field(
table_number, inodetable_block.i_mode, inodetable.S_IFDIR
| inodetable.S_IXUSR | inodetable.S_IRUSR | inodetable.S_IWUSR
| inodetable.S_IXOTH | inodetable.S_IROTH | inodetable.S_IWOTH
| inodetable.S_IWGRP
| inodetable.S_IRGRP | inodetable.S_IXGRP)
inodetable_block.set_field(table_number, inodetable_block.i_uid, 0)
inodetable_block.set_field(table_number, inodetable_block.i_size, 0)
inodetable_block.set_field(table_number, inodetable_block.i_atime, 0)
inodetable_block.set_field(table_number, inodetable_block.i_mtime, 0)
inodetable_block.set_field(table_number, inodetable_block.i_ctime,
int(time.time()))
inodetable_block.set_field(table_number, inodetable_block.i_dtime, 0)
inodetable_block.set_field(table_number, inodetable_block.i_gid, 0)
inodetable_block.set_field(table_number, inodetable_block.i_blocks, 1)
inodetable_block.set_field(table_number, inodetable_block.i_flags, 0)
block = bytearray(inodetable_block.i_block[sysblock.SIZE_INDEX])
block[:superblock.s_first_data_block[sysblock.SIZE_INDEX]] = \
first_data_block.to_bytes(superblock.s_first_data_block[sysblock.SIZE_INDEX], 'little')
inodetable_block.set_field(table_number, inodetable_block.i_block,
bytes(block))
inodetable_block.set_field(
table_number, inodetable_block.i_pad,
bytes(inodetable_block.i_pad[sysblock.SIZE_INDEX]))
inodetable.unload_inode(0)
def auth(user, passwd):
nonlocal uid, gid
if uid != -1:
raise AuthError
uid, gid = 0, 0
fd = openfile.open_file('/etc/passwd', openfile.O_RDONLY)
inode = fdtable.get_inode(fd)
inode_tn = inodetable.get_table_number(inode)
file_inodetable_block = inodetable.load_inode(inode)
file_size = fs.bytes_to_int(
file_inodetable_block.get_field(inode_tn,
file_inodetable_block.i_size))
lines = readfile.read_by_offset(
fd, file_size).decode(encoding='ASCII').splitlines()
closefile.close_file(fd)
uid, gid = -1, -1
digest = hashlib.sha224(passwd.encode()).hexdigest()
for l in lines:
if l.lstrip()[0] != '#':
u = tuple(l.split(':'))
if u[0] == user:
if u[1] == digest and u[4] != 'nologin':
uid = int(u[2])
gid = int(u[3])
if uid == -1:
raise AuthError
return uid
def remove_file_record(offset):
inode = get_record_inode_number(offset)
inode_table_block = inodetable.load_inode(inode)
inode_tn = inodetable.get_table_number(inode)
i_block = inode_table_block.get_field(inode_tn, inode_table_block.i_block)
inodetable.free_file_blocks(inode_table_block, inode, i_block)
data_block_buffer.set_bytes(offset, fs.int_to_bytes(0, IN_FIELD_SIZE))
def write_by_offset(fd, buf, nbytes):
inode = fdtable.get_inode(fd)
offset = fdtable.get_offset(fd)
inode_tn = inodetable.get_table_number(inode)
file_inodetable_block = inodetable.load_inode(inode)
i_block = file_inodetable_block.get_field(inode_tn,
file_inodetable_block.i_block)
file_size = fs.bytes_to_int(
file_inodetable_block.get_field(inode_tn,
file_inodetable_block.i_size))
blocks_count = fs.bytes_to_int(
file_inodetable_block.get_field(inode_tn,
file_inodetable_block.i_blocks))
block_size = fs.bytes_to_int(
superblock.get_field(superblock.s_log_block_size)) * 1024
lbn = offset // block_size
b_offset = offset % block_size
if offset + nbytes > file_size:
if b_offset + nbytes > block_size or lbn == blocks_count:
inodetable.extend_file_blocks(file_inodetable_block, inode,
i_block)
file_inodetable_block.set_field(inode_tn, file_inodetable_block.i_size,
offset + nbytes)
bn = inodetable.lbn_to_bn(lbn, i_block)
data_block_buffer.load(bn)
if b_offset + nbytes > block_size:
first_bytes_count = block_size - b_offset
if first_bytes_count != 0:
data_block_buffer.set_bytes(b_offset, buf[:first_bytes_count])
data_block_buffer.unload(bn)
bn = inodetable.lbn_to_bn(lbn + 1, i_block)
data_block_buffer.load(bn)
data_block_buffer.set_bytes(0, buf[first_bytes_count:nbytes])
else:
data_block_buffer.set_bytes(b_offset, buf)
data_block_buffer.unload(bn)
fdtable.set_offset(fd, offset + nbytes)
file_inodetable_block.set_field(inode_tn, file_inodetable_block.i_mtime,
int(time.time()))
inodetable.unload_inode(inode)
def chmod(path, mode):
fd = openfile.create_file_descriptor(path, openfile.O_RDONLY, 0)
ino = fdtable.get_inode(fd)
inode_tn = inodetable.get_table_number(ino)
inode_block = inodetable.load_inode(ino)
i_mode = fs.bytes_to_int(inode_block.get_field(inode_tn, inode_block.i_mode))
i_uid = fs.bytes_to_int(inode_block.get_field(inode_tn, inode_block.i_uid))
try:
if user.get_uid() != i_uid and user.get_uid() != 0:
raise permissions.PermissionsError(i_mode)
if i_mode & inodetable.S_IFREG == inodetable.S_IFREG:
inode_block.set_field(inode_tn, inode_block.i_mode, inodetable.S_IFREG | int(mode))
else:
inode_block.set_field(inode_tn, inode_block.i_mode, inodetable.S_IFDIR | int(mode))
finally:
inodetable.unload_inode(ino)
closefile.close_file(fd)
return 0
def write_to_end(fd, buf, nbytes):
inode = fdtable.get_inode(fd)
inode_tn = inodetable.get_table_number(inode)
file_inodetable_block = inodetable.load_inode(inode)
i_block = file_inodetable_block.get_field(inode_tn,
file_inodetable_block.i_block)
file_size = fs.bytes_to_int(
file_inodetable_block.get_field(inode_tn,
file_inodetable_block.i_size))
block_size = fs.bytes_to_int(
superblock.get_field(superblock.s_log_block_size)) * 1024
last_block_size = file_size % block_size
if last_block_size == 0:
last_bn = inodetable.extend_file_blocks(file_inodetable_block, inode,
i_block)
else:
last_bn = inodetable.get_last_file_bn(i_block)
data_block_buffer.load(last_bn)
if last_block_size + nbytes > block_size:
last_bn = inodetable.extend_file_blocks(file_inodetable_block, inode,
i_block)
remaining_bytes_count = block_size - last_block_size
data_block_buffer.set_bytes(last_block_size,
buf[:remaining_bytes_count])
data_block_buffer.unload(data_block_buffer.block_number)
data_block_buffer.load(last_bn)
data_block_buffer.set_bytes(0, buf[remaining_bytes_count:nbytes])
else:
data_block_buffer.set_bytes(last_block_size, buf[:nbytes])
file_inodetable_block.set_field(inode_tn, file_inodetable_block.i_size,
file_size + nbytes)
data_block_buffer.unload(last_bn)
file_inodetable_block.set_field(inode_tn, file_inodetable_block.i_mtime,
int(time.time()))
inodetable.unload_inode(inode)
def read_by_offset(fd, nbytes):
inode = fdtable.get_inode(fd)
offset = fdtable.get_offset(fd)
inode_tn = inodetable.get_table_number(inode)
file_inodetable_block = inodetable.load_inode(inode)
i_block = file_inodetable_block.get_field(inode_tn,
file_inodetable_block.i_block)
file_size = fs.bytes_to_int(
file_inodetable_block.get_field(inode_tn,
file_inodetable_block.i_size))
block_size = fs.bytes_to_int(
superblock.get_field(superblock.s_log_block_size)) * 1024
if offset >= file_size:
raise OffsetError(offset)
lbn = offset // block_size
b_offset = offset % block_size
buf = bytearray()
if b_offset + nbytes > block_size:
first_bytes_count = block_size - b_offset
data_block_buffer.load(inodetable.lbn_to_bn(lbn, i_block))
buf[:first_bytes_count] = data_block_buffer.get_bytes(
b_offset, first_bytes_count)
data_block_buffer.load(inodetable.lbn_to_bn(lbn + 1, i_block))
buf[first_bytes_count:nbytes] = data_block_buffer.get_bytes(
0, nbytes - first_bytes_count)
else:
data_block_buffer.load(inodetable.lbn_to_bn(lbn, i_block))
buf[:] = data_block_buffer.get_bytes(b_offset, nbytes)
fdtable.set_offset(fd, offset + nbytes)
file_inodetable_block.set_field(inode_tn, file_inodetable_block.i_atime,
int(time.time()))
inodetable.unload_inode(inode)
return bytes(buf)
def stat(path):
fd = openfile.create_file_descriptor(path, openfile.O_STAT, 0)
ino = fdtable.get_inode(fd)
inode_tn = inodetable.get_table_number(ino)
inode_block = inodetable.load_inode(ino)
mode = fs.bytes_to_int(inode_block.get_field(inode_tn, inode_block.i_mode))
uid = fs.bytes_to_int(inode_block.get_field(inode_tn, inode_block.i_uid))
gid = fs.bytes_to_int(inode_block.get_field(inode_tn, inode_block.i_gid))
size = fs.bytes_to_int(inode_block.get_field(inode_tn, inode_block.i_size))
atime = fs.bytes_to_int(
inode_block.get_field(inode_tn, inode_block.i_atime))
mtime = fs.bytes_to_int(
inode_block.get_field(inode_tn, inode_block.i_mtime))
ctime = fs.bytes_to_int(
inode_block.get_field(inode_tn, inode_block.i_ctime))
blocks = fs.bytes_to_int(
inode_block.get_field(inode_tn, inode_block.i_blocks))
inodetable.unload_inode(ino)
closefile.close_file(fd)
return ino, mode, uid, gid, size, atime, mtime, ctime, blocks
def create_file_descriptor(path, oflag, mode):
names = [n for n in path.split('/') if n != '']
dir_table_in = 0
dir_inodetable_block = inodetable.load_inode(dir_table_in)
dir_in = 0
perm = inodetable.S_IRUSR | inodetable.S_IRGRP | inodetable.S_IROTH
if not permissions.check_file_permissions(dir_inodetable_block, dir_in,
perm):
raise permissions.PermissionsError(perm)
if path != '/':
if len(names) > 1:
for n in names[:-1]:
offset = filerecord.find_file_record(dir_inodetable_block,
dir_table_in, n)
inodetable.unload_inode(dir_in)
if offset is None:
raise createfile.DirNotFoundError(n)
dir_in = filerecord.get_record_inode_number(offset)
dir_table_in = inodetable.get_table_number(dir_in)
dir_inodetable_block = inodetable.load_inode(dir_in)
if not permissions.check_file_permissions(
dir_inodetable_block, dir_in, perm):
raise permissions.PermissionsError(perm)
if fs.bytes_to_int(
dir_inodetable_block.get_field(
dir_table_in, dir_inodetable_block.i_mode)
) & inodetable.S_IFDIR != inodetable.S_IFDIR:
raise createfile.DirNotFoundError(n)
offset = filerecord.find_file_record(dir_inodetable_block,
dir_table_in, names[-1])
if oflag == O_WRONLY:
perm = inodetable.S_IWUSR | inodetable.S_IWGRP | inodetable.S_IWOTH
if oflag == O_RDWR:
perm |= inodetable.S_IWUSR | inodetable.S_IWGRP | inodetable.S_IWOTH
if offset is None:
raise deletefile.FileNotExistsError(names[-1])
inode_n = filerecord.get_record_inode_number(offset)
inode_table_n = inodetable.get_table_number(inode_n)
file_inodetable_block = inodetable.load_inode(inode_n)
else:
if oflag == O_WRONLY:
perm = inodetable.S_IWUSR | inodetable.S_IWGRP | inodetable.S_IWOTH
if oflag == O_RDWR:
perm |= inodetable.S_IWUSR | inodetable.S_IWGRP | inodetable.S_IWOTH
inode_n = dir_in
inode_table_n = dir_table_in
file_inodetable_block = dir_inodetable_block
if fs.bytes_to_int(
file_inodetable_block.get_field(
inode_table_n, file_inodetable_block.i_mode)) & mode != mode:
raise deletefile.WrongFileTypeError(names[-1])
if oflag != O_STAT:
if not permissions.check_file_permissions(file_inodetable_block,
inode_n, perm):
raise permissions.PermissionsError(perm)
inodetable.unload_inode(dir_in)
inodetable.unload_inode(0)
return fdtable.reserve_fd(inode_n)
def create_file_record(path, mode):
if path == '/':
raise FileAlreadyExistsError('/')
names = [n for n in path.split('/') if n != '']
bg_block = gdtable.get_gdtableblock(0)
inodebitmap.inode_bitmap.load(
fs.bytes_to_int(bg_block.get_field(0, bg_block.bg_inode_bitmap)))
inode_ign = inodebitmap.find_first_free_inode()
inode_n = fs.ign_to_in(
0,
fs.bytes_to_int(superblock.get_field(superblock.s_inodes_per_group)),
inode_ign)
dir_table_in = 0
dir_inodetable_block = inodetable.load_inode(dir_table_in)
dir_in = 0
perm = inodetable.S_IRUSR | inodetable.S_IRGRP | inodetable.S_IROTH
if not permissions.check_file_permissions(dir_inodetable_block, dir_in,
perm):
raise permissions.PermissionsError(perm)
if len(names) > 1:
for n in names[:-1]:
offset = filerecord.find_file_record(dir_inodetable_block,
dir_table_in, n)
inodetable.unload_inode(dir_in)
if offset is None:
raise DirNotFoundError(n)
dir_in = filerecord.get_record_inode_number(offset)
dir_table_in = inodetable.get_table_number(dir_in)
dir_inodetable_block = inodetable.load_inode(dir_in)
if not permissions.check_file_permissions(dir_inodetable_block,
dir_in, perm):
raise permissions.PermissionsError(perm)
if fs.bytes_to_int(
dir_inodetable_block.get_field(dir_table_in,
dir_inodetable_block.i_mode)
) & inodetable.S_IFDIR != inodetable.S_IFDIR:
raise DirNotFoundError(n)
perm = inodetable.S_IWUSR | inodetable.S_IWGRP | inodetable.S_IWOTH
if not permissions.check_file_permissions(dir_inodetable_block, dir_in,
perm):
raise permissions.PermissionsError(perm)
offset = filerecord.find_file_record(dir_inodetable_block, dir_table_in,
names[-1])
if offset is None:
filerecord.create_file_record(dir_inodetable_block, dir_table_in,
inode_n, names[-1])
dir_inodetable_block.set_field(dir_table_in,
dir_inodetable_block.i_mtime,
int(time.time()))
else:
raise FileAlreadyExistsError(names[-1])
inodetable_block = inodetable.load_inode(inode_n)
inodetable_block.set_field(inode_ign, inodetable_block.i_mode, mode)
inodetable_block.set_field(inode_ign, inodetable_block.i_uid,
user.get_uid())
inodetable_block.set_field(inode_ign, inodetable_block.i_size, 0)
inodetable_block.set_field(inode_ign, inodetable_block.i_atime, 0)
inodetable_block.set_field(inode_ign, inodetable_block.i_mtime, 0)
inodetable_block.set_field(inode_ign, inodetable_block.i_ctime,
int(time.time()))
inodetable_block.set_field(inode_ign, inodetable_block.i_dtime, 0)
inodetable_block.set_field(inode_ign, inodetable_block.i_gid,
user.get_gid())
inodetable_block.set_field(inode_ign, inodetable_block.i_blocks, 0)
inodetable_block.set_field(inode_ign, inodetable_block.i_flags, 0)
inodetable_block.set_field(inode_ign, inodetable_block.i_block, bytes(60))
inodetable_block.set_field(
inode_ign, inodetable_block.i_pad,
bytes(inodetable_block.i_pad[sysblock.SIZE_INDEX]))
inodebitmap.set_used_inode(inode_ign)
inodebitmap.inode_bitmap.unload(
fs.bytes_to_int(bg_block.get_field(0, bg_block.bg_inode_bitmap)))
inodetable.unload_inode(inode_n)
inodetable.unload_inode(0)
return fdtable.reserve_fd(inode_n)
def delete_file_record(path, mode):
if path == '/':
raise WrongFileTypeError(path)
names = [n for n in path.split('/') if n != '']
bg_block = gdtable.get_gdtableblock(0)
inodebitmap.inode_bitmap.load(
fs.bytes_to_int(bg_block.get_field(0, bg_block.bg_inode_bitmap)))
dir_table_in = 0
dir_inodetable_block = inodetable.load_inode(dir_table_in)
dir_in = 0
perm = inodetable.S_IRUSR | inodetable.S_IRGRP | inodetable.S_IROTH
if not permissions.check_file_permissions(dir_inodetable_block, dir_in,
perm):
raise permissions.PermissionsError(perm)
if len(names) > 1:
for n in names[:-1]:
offset = filerecord.find_file_record(dir_inodetable_block,
dir_table_in, n)
if dir_in != 0:
inodetable.unload_inode(dir_in)
if offset is None:
raise createfile.DirNotFoundError(n)
dir_in = filerecord.get_record_inode_number(offset)
dir_table_in = inodetable.get_table_number(dir_in)
dir_inodetable_block = inodetable.load_inode(dir_in)
if not permissions.check_file_permissions(dir_inodetable_block,
dir_in, perm):
raise permissions.PermissionsError(perm)
if fs.bytes_to_int(
dir_inodetable_block.get_field(dir_table_in,
dir_inodetable_block.i_mode)
) & inodetable.S_IFDIR != inodetable.S_IFDIR:
raise createfile.DirNotFoundError(n)
perm = inodetable.S_IWUSR | inodetable.S_IWGRP | inodetable.S_IWOTH
if not permissions.check_file_permissions(dir_inodetable_block, dir_in,
perm):
raise permissions.PermissionsError(perm)
offset = filerecord.find_file_record(dir_inodetable_block, dir_table_in,
names[-1])
bn = data_block_buffer.block_number
if offset is None:
raise FileNotExistsError(names[-1])
inode_n = filerecord.get_record_inode_number(offset)
inode_table_n = inodetable.get_table_number(inode_n)
file_inodetable_block = inodetable.load_inode(inode_n)
if fs.bytes_to_int(
file_inodetable_block.get_field(
inode_table_n, file_inodetable_block.i_mode)) & mode != mode:
raise WrongFileTypeError(names[-1])
if mode & inodetable.S_IFDIR == inodetable.S_IFDIR:
fd = opendir.opendir(path)
try:
readdir.readdir(fd)
raise DirIsNotEmpty(path)
except readfile.OffsetError:
pass
finally:
closedir.closedir(fd)
data_block_buffer.load(bn)
filerecord.remove_file_record(offset)
dir_inodetable_block.set_field(dir_table_in, dir_inodetable_block.i_mtime,
int(time.time()))
inodebitmap.set_free_inode(inode_table_n)
inodebitmap.inode_bitmap.unload(
fs.bytes_to_int(bg_block.get_field(0, bg_block.bg_inode_bitmap)))
inodetable.unload_inode(inode_n)
inodetable.unload_inode(dir_in)
inodetable.unload_inode(0)
data_block_buffer.unload(data_block_buffer.block_number)