mirror of https://github.com/vinc/moros.git
Improve FUSE driver with write and delete (#292)
* Add write to FUSE driver * Update code * Fix file creation * Remove debug print * Remove more print statements * Remove unsupported function * Fix entries * Allocate space for new dir entry * Fix dir block size computation * Add unlink * Refactor private methods * Remove debug operation
This commit is contained in:
Vincent Ollivier
GitHub
parent
512b60564b
commit
407d20c75c
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@ -2,6 +2,7 @@
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import logging
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import os
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from time import time
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from errno import ENOENT
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from fuse import FUSE, FuseOSError, Operations, LoggingMixIn
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from stat import S_IFDIR, S_IFREG
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@ -9,24 +10,22 @@ from stat import S_IFDIR, S_IFREG
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BLOCK_SIZE = 512
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SUPERBLOCK_ADDR = 4096 * BLOCK_SIZE
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BITMAP_ADDR = SUPERBLOCK_ADDR + 2 * BLOCK_SIZE
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ENTRY_SIZE = (1 + 4 + 4 + 8 + 1)
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class MorosFuse(LoggingMixIn, Operations):
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chmod = None
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chown = None
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create = None
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mkdir = None
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readlink = None
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rename = None
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rmdir = None
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symlink = None
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truncate = None
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unlink = None
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utimens = None
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write = None
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getxattr = None
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def __init__(self, path):
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self.block_size = BLOCK_SIZE
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self.image = open(path, "rb")
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self.image = open(path, "r+b")
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self.image.seek(SUPERBLOCK_ADDR)
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superblock = self.image.read(self.block_size)
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assert superblock[0:8] == b"MOROS FS" # Signature
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@ -40,39 +39,54 @@ class MorosFuse(LoggingMixIn, Operations):
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rest = (total - (BITMAP_ADDR // self.block_size)) * bs // (bs + 1)
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self.data_addr = BITMAP_ADDR + (rest // bs) * self.block_size
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def destroy(self, path):
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self.image.close()
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return
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def __next_free_addr(self):
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for bitmap_addr in range(BITMAP_ADDR, self.data_addr):
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self.image.seek(bitmap_addr)
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bitmap = self.image.read(self.block_size)
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for i in range(self.block_size):
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byte = bitmap[i]
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for bit in range(0, 8):
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if (byte >> bit & 1) == 0:
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block = (bitmap_addr - BITMAP_ADDR) * self.block_size * 8 + i * 8 + bit
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return self.data_addr + block * self.block_size
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def getattr(self, path, fh=None):
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(kind, addr, size, time, name) = self.__scan(path)
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if addr == 0:
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raise FuseOSError(ENOENT)
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mode = S_IFDIR | 0o755 if kind == 0 else S_IFREG | 0o644
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return { "st_atime": 0, "st_mtime": time, "st_uid": 0, "st_gid": 0, "st_mode": mode, "st_size": size }
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def __is_alloc(self, addr):
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block = (addr - self.data_addr) // self.block_size
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bitmap_addr = BITMAP_ADDR + (block // (self.block_size * 8))
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pos = bitmap_addr + (block // 8)
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self.image.seek(pos)
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byte = int.from_bytes(self.image.read(1), "big")
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bit = block % 8
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return (byte >> bit & 1) == 1
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def read(self, path, size, offset, fh):
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(kind, next_block_addr, size, time, name) = self.__scan(path)
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res = b""
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while next_block_addr != 0:
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self.image.seek(next_block_addr)
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next_block_addr = int.from_bytes(self.image.read(4), "big") * self.block_size
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if offset < self.block_size - 4:
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buf = self.image.read(min(self.block_size - 4, size))
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res = b"".join([res, buf[offset:]])
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offset = 0
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else:
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offset -= self.block_size - 4
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size -= self.block_size - 4
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return res
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def __alloc(self, addr):
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block = (addr - self.data_addr) // self.block_size
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bitmap_addr = BITMAP_ADDR + (block // (self.block_size * 8))
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self.image.seek(bitmap_addr + (block // 8))
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byte = int.from_bytes(self.image.read(1), "big")
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self.image.seek(-1, 1)
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bit = block % 8
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byte |= (1 << bit)
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self.image.write(bytes([byte]))
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def readdir(self, path, fh):
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files = [".", ".."]
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(_, next_block_addr, _, _, _) = self.__scan(path)
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for (kind, addr, size, time, name) in self.__read(next_block_addr):
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files.append(name)
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return files
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def __free(self, addr):
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block = (addr - self.data_addr) // self.block_size
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bitmap_addr = BITMAP_ADDR + (block // (self.block_size * 8))
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self.image.seek(bitmap_addr + (block // 8))
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byte = int.from_bytes(self.image.read(1), "big")
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self.image.seek(-1, 1)
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bit = block % 8
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byte &= ~(1 << bit)
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self.image.write(bytes([byte]))
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def __update_dir_size(self, path, entries):
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entries.remove(".")
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entries.remove("..")
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(_, parent_addr, parent_size, _, parent_name) = self.__scan(path)
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parent_size = ENTRY_SIZE * len(entries) + len("".join(entries))
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self.image.seek(-(4 + 8 + 1 + len(parent_name)), 1)
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self.image.write(parent_size.to_bytes(4, "big"))
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return parent_addr
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def __scan(self, path):
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next_block_addr = self.data_addr
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@ -107,6 +121,133 @@ class MorosFuse(LoggingMixIn, Operations):
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if addr > 0:
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yield (kind, addr, size, time, name)
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def destroy(self, path):
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self.image.close()
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return
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def getattr(self, path, fh=None):
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(kind, addr, size, time, name) = self.__scan(path)
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if addr == 0:
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raise FuseOSError(ENOENT)
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mode = S_IFDIR | 0o755 if kind == 0 else S_IFREG | 0o644
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return { "st_atime": 0, "st_mtime": time, "st_uid": 0, "st_gid": 0, "st_mode": mode, "st_size": size }
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def read(self, path, size, offset, fh):
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(kind, next_block_addr, size, time, name) = self.__scan(path)
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res = b""
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while next_block_addr != 0 and size > 0:
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self.image.seek(next_block_addr)
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next_block_addr = int.from_bytes(self.image.read(4), "big") * self.block_size
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if offset < self.block_size - 4:
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buf = self.image.read(max(0, min(self.block_size - 4, size)))
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res = b"".join([res, buf[offset:]])
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offset = 0
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else:
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offset -= self.block_size - 4
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size -= self.block_size - 4
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return res
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def readdir(self, path, fh):
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files = [".", ".."]
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(_, next_block_addr, _, _, _) = self.__scan(path)
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for (kind, addr, size, time, name) in self.__read(next_block_addr):
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files.append(name)
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return files
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def mkdir(self, path, mode):
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self.create(path, S_IFDIR | mode)
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def create(self, path, mode):
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(path, _, name) = path.rpartition("/")
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entries = self.readdir(path + "/", 0)
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entries.append(name)
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pos = self.image.tell()
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parent_addr = self.__update_dir_size(path, entries)
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# Allocate space for the new dir entry if needed
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blocks = 0
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addr = parent_addr
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next_addr = parent_addr
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while next_addr != 0:
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addr = next_addr
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blocks += 1
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self.image.seek(addr)
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next_addr = int.from_bytes(self.image.read(4), "big") * self.block_size
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free_size = (self.block_size - 4) - (pos - addr)
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if free_size < ENTRY_SIZE + len(name):
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pos = self.image.tell() - 4
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addr = self.__next_free_addr()
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self.__alloc(addr)
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self.image.seek(pos)
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self.image.write((addr // self.block_size).to_bytes(4, "big"))
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pos = addr + 4
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# Allocate space for the new file
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kind = int((mode & S_IFDIR) != S_IFDIR)
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size = 0
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addr = self.__next_free_addr()
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self.__alloc(addr)
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# Add dir entry
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self.image.seek(pos)
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self.image.write(kind.to_bytes(1, "big"))
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self.image.write((addr // self.block_size).to_bytes(4, "big"))
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self.image.write(size.to_bytes(4, "big"))
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self.image.write(int(time()).to_bytes(8, "big"))
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self.image.write(len(name).to_bytes(1, "big"))
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self.image.write(name.encode("utf-8"))
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return 0
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def write(self, path, data, offset, fh):
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(_, addr, size, _, name) = self.__scan(path)
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n = self.block_size - 4 # Space available for data in blocks
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j = size % n # Start of space available in last block
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# Update file size
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self.image.seek(-(4 + 8 + 1 + len(name)), 1)
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size = max(size, offset + len(data))
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self.image.write(size.to_bytes(4, "big"))
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for i in range(0, offset, n):
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self.image.seek(addr)
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next_addr = int.from_bytes(self.image.read(4), "big") * self.block_size
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if i + n >= offset:
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self.image.seek(addr + 4 + j)
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self.image.write(data[0:(n - j)])
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if next_addr == 0:
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next_addr = self.__next_free_addr()
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self.__alloc(next_addr)
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self.image.seek(addr)
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self.image.write((next_addr // self.block_size).to_bytes(4, "big"))
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addr = next_addr
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for i in range(n - j if j > 0 else 0, len(data), n):
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next_addr = 0
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if i + n < len(data): # TODO: check for off by one error
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next_addr = self.__next_free_addr()
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self.__alloc(next_addr)
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self.image.seek(addr)
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self.image.write((next_addr // self.block_size).to_bytes(4, "big"))
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self.image.write(data[i:min(i + n, len(data))])
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addr = next_addr
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return len(data)
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def unlink(self, path):
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# Unlink and free blocs
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(_, addr, size, _, name) = self.__scan(path)
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self.image.seek(-(4 + 4 + 8 + 1 + len(name)), 1)
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self.image.write((0).to_bytes(4, "big"))
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while addr != 0:
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self.__free(addr)
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self.image.seek(addr)
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addr = int.from_bytes(self.image.read(4), "big") * self.block_size
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# Update parent dir size
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(path, _, _) = path.rpartition("/")
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entries = self.readdir(path + "/", 0)
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self.__update_dir_size(path, entries)
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if __name__ == '__main__':
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import argparse
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parser = argparse.ArgumentParser()
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@ -114,4 +255,4 @@ if __name__ == '__main__':
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parser.add_argument('mount')
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args = parser.parse_args()
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#logging.basicConfig(level=logging.DEBUG)
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fuse = FUSE(MorosFuse(args.image), args.mount, ro=True, foreground=True, allow_other=True)
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fuse = FUSE(MorosFuse(args.image), args.mount, ro=False, foreground=True, allow_other=True)
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