circuitpython/tests/extmod/vfs_fat_ilistdir_del.py
Andrew Leech 4e0964b59f extmod/vfs: Add finaliser to ilistdir to close directory handle.
When iterating over filesystem/folders with os.iterdir(), an open file
(directory) handle is used internally.  Currently this file handle is only
closed once the iterator is completely drained, eg. once all entries have
been looped over / converted into list etc.

If a program opens an iterdir but does not loop over it, or starts to loop
over the iterator but breaks out of the loop, then the handle never gets
closed.  In this state, when the iter object is cleaned up by the garbage
collector this open handle can cause corruption of the filesystem.

Fixes issues #6568 and #8506.
2022-09-13 13:00:42 +10:00

76 lines
2.0 KiB
Python

# Test ilistdir __del__ for VfsFat using a RAM device.
import gc
try:
import uos
uos.VfsFat
except (ImportError, AttributeError):
print("SKIP")
raise SystemExit
class RAMBlockDevice:
ERASE_BLOCK_SIZE = 4096
def __init__(self, blocks):
self.data = bytearray(blocks * self.ERASE_BLOCK_SIZE)
def readblocks(self, block, buf, off=0):
addr = block * self.ERASE_BLOCK_SIZE + off
for i in range(len(buf)):
buf[i] = self.data[addr + i]
def writeblocks(self, block, buf, off=0):
addr = block * self.ERASE_BLOCK_SIZE + off
for i in range(len(buf)):
self.data[addr + i] = buf[i]
def ioctl(self, op, arg):
if op == 4: # block count
return len(self.data) // self.ERASE_BLOCK_SIZE
if op == 5: # block size
return self.ERASE_BLOCK_SIZE
if op == 6: # erase block
return 0
def test(bdev, vfs_class):
vfs_class.mkfs(bdev)
vfs = vfs_class(bdev)
vfs.mkdir("/test_d1")
vfs.mkdir("/test_d2")
vfs.mkdir("/test_d3")
for i in range(10):
print(i)
# We want to partially iterate the ilistdir iterator to leave it in an
# open state, which will then test the finaliser when it's garbage collected.
idir = vfs.ilistdir("/")
print(any(idir))
# Alternate way of partially iterating the ilistdir object, modifying the
# filesystem while it's open.
for dname, *_ in vfs.ilistdir("/"):
vfs.rmdir(dname)
break
vfs.mkdir(dname)
# Also create a fully drained iterator and ensure trying to re-use it
# throws the correct exception.
idir_emptied = vfs.ilistdir("/")
l = list(idir_emptied)
print(len(l))
try:
next(idir_emptied)
except StopIteration:
pass
gc.collect()
vfs.open("/test", "w").close()
bdev = RAMBlockDevice(30)
test(bdev, uos.VfsFat)