From: Amjad Alsharafi <amjadsharafi10@gmail.com>
Added several tests to verify the implementation of the vvfat driver.
We needed a way to interact with it, so created a basic `fat16.py` driver
that handled writing correct sectors for us.
Added `vvfat` to the non-generic formats, as its not a normal image format.
Signed-off-by: Amjad Alsharafi <amjadsharafi10@gmail.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <bb8149c945301aefbdf470a0924c07f69f9c087d.1721470238.git.amjadsharafi10@gmail.com>
[kwolf: Made mypy and pylint happy to unbreak 297]
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit c8f60bfb4345ea8343a53eaefe88d47b44c53f24)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff --git a/tests/qemu-iotests/check b/tests/qemu-iotests/check
index 75de1b4691..4da95cff2a 100755
--- a/tests/qemu-iotests/check
+++ b/tests/qemu-iotests/check
@@ -70,7 +70,7 @@ def make_argparser() -> argparse.ArgumentParser:
p.set_defaults(imgfmt='raw', imgproto='file')
format_list = ['raw', 'bochs', 'cloop', 'parallels', 'qcow', 'qcow2',
- 'qed', 'vdi', 'vpc', 'vhdx', 'vmdk', 'luks', 'dmg']
+ 'qed', 'vdi', 'vpc', 'vhdx', 'vmdk', 'luks', 'dmg', 'vvfat']
g_fmt = p.add_argument_group(
' image format options',
'The following options set the IMGFMT environment variable. '
diff --git a/tests/qemu-iotests/fat16.py b/tests/qemu-iotests/fat16.py
new file mode 100644
index 0000000000..7d2d052413
--- /dev/null
+++ b/tests/qemu-iotests/fat16.py
@@ -0,0 +1,690 @@
+# A simple FAT16 driver that is used to test the `vvfat` driver in QEMU.
+#
+# Copyright (C) 2024 Amjad Alsharafi <amjadsharafi10@gmail.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+from typing import Callable, List, Optional, Protocol, Set
+import string
+
+SECTOR_SIZE = 512
+DIRENTRY_SIZE = 32
+ALLOWED_FILE_CHARS = set(
+ "!#$%&'()-@^_`{}~" + string.digits + string.ascii_uppercase
+)
+
+
+class MBR:
+ def __init__(self, data: bytes):
+ assert len(data) == 512
+ self.partition_table = []
+ for i in range(4):
+ partition = data[446 + i * 16 : 446 + (i + 1) * 16]
+ self.partition_table.append(
+ {
+ "status": partition[0],
+ "start_head": partition[1],
+ "start_sector": partition[2] & 0x3F,
+ "start_cylinder": ((partition[2] & 0xC0) << 2)
+ | partition[3],
+ "type": partition[4],
+ "end_head": partition[5],
+ "end_sector": partition[6] & 0x3F,
+ "end_cylinder": ((partition[6] & 0xC0) << 2)
+ | partition[7],
+ "start_lba": int.from_bytes(partition[8:12], "little"),
+ "size": int.from_bytes(partition[12:16], "little"),
+ }
+ )
+
+ def __str__(self):
+ return "\n".join(
+ [
+ f"{i}: {partition}"
+ for i, partition in enumerate(self.partition_table)
+ ]
+ )
+
+
+class FatBootSector:
+ # pylint: disable=too-many-instance-attributes
+ def __init__(self, data: bytes):
+ assert len(data) == 512
+ self.bytes_per_sector = int.from_bytes(data[11:13], "little")
+ self.sectors_per_cluster = data[13]
+ self.reserved_sectors = int.from_bytes(data[14:16], "little")
+ self.fat_count = data[16]
+ self.root_entries = int.from_bytes(data[17:19], "little")
+ total_sectors_16 = int.from_bytes(data[19:21], "little")
+ self.media_descriptor = data[21]
+ self.sectors_per_fat = int.from_bytes(data[22:24], "little")
+ self.sectors_per_track = int.from_bytes(data[24:26], "little")
+ self.heads = int.from_bytes(data[26:28], "little")
+ self.hidden_sectors = int.from_bytes(data[28:32], "little")
+ total_sectors_32 = int.from_bytes(data[32:36], "little")
+ assert (
+ total_sectors_16 == 0 or total_sectors_32 == 0
+ ), "Both total sectors (16 and 32) fields are non-zero"
+ self.total_sectors = total_sectors_16 or total_sectors_32
+ self.drive_number = data[36]
+ self.volume_id = int.from_bytes(data[39:43], "little")
+ self.volume_label = data[43:54].decode("ascii").strip()
+ self.fs_type = data[54:62].decode("ascii").strip()
+
+ def root_dir_start(self):
+ """
+ Calculate the start sector of the root directory.
+ """
+ return self.reserved_sectors + self.fat_count * self.sectors_per_fat
+
+ def root_dir_size(self):
+ """
+ Calculate the size of the root directory in sectors.
+ """
+ return (
+ self.root_entries * DIRENTRY_SIZE + self.bytes_per_sector - 1
+ ) // self.bytes_per_sector
+
+ def data_sector_start(self):
+ """
+ Calculate the start sector of the data region.
+ """
+ return self.root_dir_start() + self.root_dir_size()
+
+ def first_sector_of_cluster(self, cluster: int) -> int:
+ """
+ Calculate the first sector of the given cluster.
+ """
+ return (
+ self.data_sector_start() + (cluster - 2) * self.sectors_per_cluster
+ )
+
+ def cluster_bytes(self):
+ """
+ Calculate the number of bytes in a cluster.
+ """
+ return self.bytes_per_sector * self.sectors_per_cluster
+
+ def __str__(self):
+ return (
+ f"Bytes per sector: {self.bytes_per_sector}\n"
+ f"Sectors per cluster: {self.sectors_per_cluster}\n"
+ f"Reserved sectors: {self.reserved_sectors}\n"
+ f"FAT count: {self.fat_count}\n"
+ f"Root entries: {self.root_entries}\n"
+ f"Total sectors: {self.total_sectors}\n"
+ f"Media descriptor: {self.media_descriptor}\n"
+ f"Sectors per FAT: {self.sectors_per_fat}\n"
+ f"Sectors per track: {self.sectors_per_track}\n"
+ f"Heads: {self.heads}\n"
+ f"Hidden sectors: {self.hidden_sectors}\n"
+ f"Drive number: {self.drive_number}\n"
+ f"Volume ID: {self.volume_id}\n"
+ f"Volume label: {self.volume_label}\n"
+ f"FS type: {self.fs_type}\n"
+ )
+
+
+class FatDirectoryEntry:
+ # pylint: disable=too-many-instance-attributes
+ def __init__(self, data: bytes, sector: int, offset: int):
+ self.name = data[0:8].decode("ascii").strip()
+ self.ext = data[8:11].decode("ascii").strip()
+ self.attributes = data[11]
+ self.reserved = data[12]
+ self.create_time_tenth = data[13]
+ self.create_time = int.from_bytes(data[14:16], "little")
+ self.create_date = int.from_bytes(data[16:18], "little")
+ self.last_access_date = int.from_bytes(data[18:20], "little")
+ high_cluster = int.from_bytes(data[20:22], "little")
+ self.last_mod_time = int.from_bytes(data[22:24], "little")
+ self.last_mod_date = int.from_bytes(data[24:26], "little")
+ low_cluster = int.from_bytes(data[26:28], "little")
+ self.cluster = (high_cluster << 16) | low_cluster
+ self.size_bytes = int.from_bytes(data[28:32], "little")
+
+ # extra (to help write back to disk)
+ self.sector = sector
+ self.offset = offset
+
+ def as_bytes(self) -> bytes:
+ return (
+ self.name.ljust(8, " ").encode("ascii")
+ + self.ext.ljust(3, " ").encode("ascii")
+ + self.attributes.to_bytes(1, "little")
+ + self.reserved.to_bytes(1, "little")
+ + self.create_time_tenth.to_bytes(1, "little")
+ + self.create_time.to_bytes(2, "little")
+ + self.create_date.to_bytes(2, "little")
+ + self.last_access_date.to_bytes(2, "little")
+ + (self.cluster >> 16).to_bytes(2, "little")
+ + self.last_mod_time.to_bytes(2, "little")
+ + self.last_mod_date.to_bytes(2, "little")
+ + (self.cluster & 0xFFFF).to_bytes(2, "little")
+ + self.size_bytes.to_bytes(4, "little")
+ )
+
+ def whole_name(self):
+ if self.ext:
+ return f"{self.name}.{self.ext}"
+ else:
+ return self.name
+
+ def __str__(self):
+ return (
+ f"Name: {self.name}\n"
+ f"Ext: {self.ext}\n"
+ f"Attributes: {self.attributes}\n"
+ f"Reserved: {self.reserved}\n"
+ f"Create time tenth: {self.create_time_tenth}\n"
+ f"Create time: {self.create_time}\n"
+ f"Create date: {self.create_date}\n"
+ f"Last access date: {self.last_access_date}\n"
+ f"Last mod time: {self.last_mod_time}\n"
+ f"Last mod date: {self.last_mod_date}\n"
+ f"Cluster: {self.cluster}\n"
+ f"Size: {self.size_bytes}\n"
+ )
+
+ def __repr__(self):
+ # convert to dict
+ return str(vars(self))
+
+
+class SectorReader(Protocol):
+ def __call__(self, start_sector: int, num_sectors: int = 1) -> bytes: ...
+
+# pylint: disable=broad-exception-raised
+class Fat16:
+ def __init__(
+ self,
+ start_sector: int,
+ size: int,
+ sector_reader: SectorReader,
+ sector_writer: Callable[[int, bytes], None]
+ ):
+ self.start_sector = start_sector
+ self.size_in_sectors = size
+ self.sector_reader = sector_reader
+ self.sector_writer = sector_writer
+
+ self.boot_sector = FatBootSector(self.sector_reader(start_sector, 1))
+
+ fat_size_in_sectors = (
+ self.boot_sector.sectors_per_fat * self.boot_sector.fat_count
+ )
+ self.fats = self.read_sectors(
+ self.boot_sector.reserved_sectors, fat_size_in_sectors
+ )
+ self.fats_dirty_sectors: Set[int] = set()
+
+ def read_sectors(self, start_sector: int, num_sectors: int) -> bytes:
+ return self.sector_reader(start_sector + self.start_sector,
+ num_sectors)
+
+ def write_sectors(self, start_sector: int, data: bytes) -> None:
+ return self.sector_writer(start_sector + self.start_sector, data)
+
+ def directory_from_bytes(
+ self, data: bytes, start_sector: int
+ ) -> List[FatDirectoryEntry]:
+ """
+ Convert `bytes` into a list of `FatDirectoryEntry` objects.
+ Will ignore long file names.
+ Will stop when it encounters a 0x00 byte.
+ """
+
+ entries = []
+ for i in range(0, len(data), DIRENTRY_SIZE):
+ entry = data[i : i + DIRENTRY_SIZE]
+
+ current_sector = start_sector + (i // SECTOR_SIZE)
+ current_offset = i % SECTOR_SIZE
+
+ if entry[0] == 0:
+ break
+
+ if entry[0] == 0xE5:
+ # Deleted file
+ continue
+
+ if entry[11] & 0xF == 0xF:
+ # Long file name
+ continue
+
+ entries.append(
+ FatDirectoryEntry(entry, current_sector, current_offset)
+ )
+ return entries
+
+ def read_root_directory(self) -> List[FatDirectoryEntry]:
+ root_dir = self.read_sectors(
+ self.boot_sector.root_dir_start(), self.boot_sector.root_dir_size()
+ )
+ return self.directory_from_bytes(
+ root_dir, self.boot_sector.root_dir_start()
+ )
+
+ def read_fat_entry(self, cluster: int) -> int:
+ """
+ Read the FAT entry for the given cluster.
+ """
+ fat_offset = cluster * 2 # FAT16
+ return int.from_bytes(self.fats[fat_offset : fat_offset + 2], "little")
+
+ def write_fat_entry(self, cluster: int, value: int) -> None:
+ """
+ Write the FAT entry for the given cluster.
+ """
+ fat_offset = cluster * 2
+ self.fats = (
+ self.fats[:fat_offset]
+ + value.to_bytes(2, "little")
+ + self.fats[fat_offset + 2 :]
+ )
+ self.fats_dirty_sectors.add(fat_offset // SECTOR_SIZE)
+
+ def flush_fats(self) -> None:
+ """
+ Write the FATs back to the disk.
+ """
+ for sector in self.fats_dirty_sectors:
+ data = self.fats[sector * SECTOR_SIZE : (sector + 1) * SECTOR_SIZE]
+ sector = self.boot_sector.reserved_sectors + sector
+ self.write_sectors(sector, data)
+ self.fats_dirty_sectors = set()
+
+ def next_cluster(self, cluster: int) -> Optional[int]:
+ """
+ Get the next cluster in the chain.
+ If its `None`, then its the last cluster.
+ The function will crash if the next cluster
+ is `FREE` (unexpected) or invalid entry.
+ """
+ fat_entry = self.read_fat_entry(cluster)
+ if fat_entry == 0:
+ raise Exception("Unexpected: FREE cluster")
+ if fat_entry == 1:
+ raise Exception("Unexpected: RESERVED cluster")
+ if fat_entry >= 0xFFF8:
+ return None
+ if fat_entry >= 0xFFF7:
+ raise Exception("Invalid FAT entry")
+
+ return fat_entry
+
+ def next_free_cluster(self) -> int:
+ """
+ Find the next free cluster.
+ """
+ # simple linear search
+ for i in range(2, 0xFFFF):
+ if self.read_fat_entry(i) == 0:
+ return i
+ raise Exception("No free clusters")
+
+ def next_free_cluster_non_continuous(self) -> int:
+ """
+ Find the next free cluster, but makes sure
+ that the cluster before and after it are not allocated.
+ """
+ # simple linear search
+ before = False
+ for i in range(2, 0xFFFF):
+ if self.read_fat_entry(i) == 0:
+ if before and self.read_fat_entry(i + 1) == 0:
+ return i
+ else:
+ before = True
+ else:
+ before = False
+
+ raise Exception("No free clusters")
+
+ def read_cluster(self, cluster: int) -> bytes:
+ """
+ Read the cluster at the given cluster.
+ """
+ return self.read_sectors(
+ self.boot_sector.first_sector_of_cluster(cluster),
+ self.boot_sector.sectors_per_cluster,
+ )
+
+ def write_cluster(self, cluster: int, data: bytes) -> None:
+ """
+ Write the cluster at the given cluster.
+ """
+ assert len(data) == self.boot_sector.cluster_bytes()
+ self.write_sectors(
+ self.boot_sector.first_sector_of_cluster(cluster),
+ data,
+ )
+
+ def read_directory(
+ self, cluster: Optional[int]
+ ) -> List[FatDirectoryEntry]:
+ """
+ Read the directory at the given cluster.
+ """
+ entries = []
+ while cluster is not None:
+ data = self.read_cluster(cluster)
+ entries.extend(
+ self.directory_from_bytes(
+ data, self.boot_sector.first_sector_of_cluster(cluster)
+ )
+ )
+ cluster = self.next_cluster(cluster)
+ return entries
+
+ def add_direntry(
+ self, cluster: Optional[int], name: str, ext: str, attributes: int
+ ) -> FatDirectoryEntry:
+ """
+ Add a new directory entry to the given cluster.
+ If the cluster is `None`, then it will be added to the root directory.
+ """
+
+ def find_free_entry(data: bytes) -> Optional[int]:
+ for i in range(0, len(data), DIRENTRY_SIZE):
+ entry = data[i : i + DIRENTRY_SIZE]
+ if entry[0] == 0 or entry[0] == 0xE5:
+ return i
+ return None
+
+ assert len(name) <= 8, "Name must be 8 characters or less"
+ assert len(ext) <= 3, "Ext must be 3 characters or less"
+ assert attributes % 0x15 != 0x15, "Invalid attributes"
+
+ # initial dummy data
+ new_entry = FatDirectoryEntry(b"\0" * 32, 0, 0)
+ new_entry.name = name.ljust(8, " ")
+ new_entry.ext = ext.ljust(3, " ")
+ new_entry.attributes = attributes
+ new_entry.reserved = 0
+ new_entry.create_time_tenth = 0
+ new_entry.create_time = 0
+ new_entry.create_date = 0
+ new_entry.last_access_date = 0
+ new_entry.last_mod_time = 0
+ new_entry.last_mod_date = 0
+ new_entry.cluster = self.next_free_cluster()
+ new_entry.size_bytes = 0
+
+ # mark as EOF
+ self.write_fat_entry(new_entry.cluster, 0xFFFF)
+
+ if cluster is None:
+ for i in range(self.boot_sector.root_dir_size()):
+ sector_data = self.read_sectors(
+ self.boot_sector.root_dir_start() + i, 1
+ )
+ offset = find_free_entry(sector_data)
+ if offset is not None:
+ new_entry.sector = self.boot_sector.root_dir_start() + i
+ new_entry.offset = offset
+ self.update_direntry(new_entry)
+ return new_entry
+ else:
+ while cluster is not None:
+ data = self.read_cluster(cluster)
+ offset = find_free_entry(data)
+ if offset is not None:
+ new_entry.sector = (
+ self.boot_sector.first_sector_of_cluster(cluster)
+ + (offset // SECTOR_SIZE))
+ new_entry.offset = offset % SECTOR_SIZE
+ self.update_direntry(new_entry)
+ return new_entry
+ cluster = self.next_cluster(cluster)
+
+ raise Exception("No free directory entries")
+
+ def update_direntry(self, entry: FatDirectoryEntry) -> None:
+ """
+ Write the directory entry back to the disk.
+ """
+ sector = self.read_sectors(entry.sector, 1)
+ sector = (
+ sector[: entry.offset]
+ + entry.as_bytes()
+ + sector[entry.offset + DIRENTRY_SIZE :]
+ )
+ self.write_sectors(entry.sector, sector)
+
+ def find_direntry(self, path: str) -> Optional[FatDirectoryEntry]:
+ """
+ Find the directory entry for the given path.
+ """
+ assert path[0] == "/", "Path must start with /"
+
+ path = path[1:] # remove the leading /
+ parts = path.split("/")
+ directory = self.read_root_directory()
+
+ current_entry = None
+
+ for i, part in enumerate(parts):
+ is_last = i == len(parts) - 1
+
+ for entry in directory:
+ if entry.whole_name() == part:
+ current_entry = entry
+ break
+ if current_entry is None:
+ return None
+
+ if is_last:
+ return current_entry
+
+ if current_entry.attributes & 0x10 == 0:
+ raise Exception(
+ f"{current_entry.whole_name()} is not a directory"
+ )
+
+ directory = self.read_directory(current_entry.cluster)
+
+ assert False, "Exited loop with is_last == False"
+
+ def read_file(self, entry: Optional[FatDirectoryEntry]) -> Optional[bytes]:
+ """
+ Read the content of the file at the given path.
+ """
+ if entry is None:
+ return None
+ if entry.attributes & 0x10 != 0:
+ raise Exception(f"{entry.whole_name()} is a directory")
+
+ data = b""
+ cluster: Optional[int] = entry.cluster
+ while cluster is not None and len(data) <= entry.size_bytes:
+ data += self.read_cluster(cluster)
+ cluster = self.next_cluster(cluster)
+ return data[: entry.size_bytes]
+
+ def truncate_file(
+ self,
+ entry: FatDirectoryEntry,
+ new_size: int,
+ allocate_non_continuous: bool = False,
+ ) -> None:
+ """
+ Truncate the file at the given path to the new size.
+ """
+ if entry is None:
+ raise Exception("entry is None")
+ if entry.attributes & 0x10 != 0:
+ raise Exception(f"{entry.whole_name()} is a directory")
+
+ def clusters_from_size(size: int) -> int:
+ return (
+ size + self.boot_sector.cluster_bytes() - 1
+ ) // self.boot_sector.cluster_bytes()
+
+ # First, allocate new FATs if we need to
+ required_clusters = clusters_from_size(new_size)
+ current_clusters = clusters_from_size(entry.size_bytes)
+
+ affected_clusters = set()
+
+ # Keep at least one cluster, easier to manage this way
+ if required_clusters == 0:
+ required_clusters = 1
+ if current_clusters == 0:
+ current_clusters = 1
+
+ cluster: Optional[int]
+
+ if required_clusters > current_clusters:
+ # Allocate new clusters
+ cluster = entry.cluster
+ to_add = required_clusters
+ for _ in range(current_clusters - 1):
+ to_add -= 1
+ assert cluster is not None, "Cluster is None"
+ affected_clusters.add(cluster)
+ cluster = self.next_cluster(cluster)
+ assert required_clusters > 0, "No new clusters to allocate"
+ assert cluster is not None, "Cluster is None"
+ assert (
+ self.next_cluster(cluster) is None
+ ), "Cluster is not the last cluster"
+
+ # Allocate new clusters
+ for _ in range(to_add - 1):
+ if allocate_non_continuous:
+ new_cluster = self.next_free_cluster_non_continuous()
+ else:
+ new_cluster = self.next_free_cluster()
+ self.write_fat_entry(cluster, new_cluster)
+ self.write_fat_entry(new_cluster, 0xFFFF)
+ cluster = new_cluster
+
+ elif required_clusters < current_clusters:
+ # Truncate the file
+ cluster = entry.cluster
+ for _ in range(required_clusters - 1):
+ assert cluster is not None, "Cluster is None"
+ cluster = self.next_cluster(cluster)
+ assert cluster is not None, "Cluster is None"
+
+ next_cluster = self.next_cluster(cluster)
+ # mark last as EOF
+ self.write_fat_entry(cluster, 0xFFFF)
+ # free the rest
+ while next_cluster is not None:
+ cluster = next_cluster
+ next_cluster = self.next_cluster(next_cluster)
+ self.write_fat_entry(cluster, 0)
+
+ self.flush_fats()
+
+ # verify number of clusters
+ cluster = entry.cluster
+ count = 0
+ while cluster is not None:
+ count += 1
+ affected_clusters.add(cluster)
+ cluster = self.next_cluster(cluster)
+ assert (
+ count == required_clusters
+ ), f"Expected {required_clusters} clusters, got {count}"
+
+ # update the size
+ entry.size_bytes = new_size
+ self.update_direntry(entry)
+
+ # trigger every affected cluster
+ for cluster in affected_clusters:
+ first_sector = self.boot_sector.first_sector_of_cluster(cluster)
+ first_sector_data = self.read_sectors(first_sector, 1)
+ self.write_sectors(first_sector, first_sector_data)
+
+ def write_file(self, entry: FatDirectoryEntry, data: bytes) -> None:
+ """
+ Write the content of the file at the given path.
+ """
+ if entry is None:
+ raise Exception("entry is None")
+ if entry.attributes & 0x10 != 0:
+ raise Exception(f"{entry.whole_name()} is a directory")
+
+ data_len = len(data)
+
+ self.truncate_file(entry, data_len)
+
+ cluster: Optional[int] = entry.cluster
+ while cluster is not None:
+ data_to_write = data[: self.boot_sector.cluster_bytes()]
+ if len(data_to_write) < self.boot_sector.cluster_bytes():
+ old_data = self.read_cluster(cluster)
+ data_to_write += old_data[len(data_to_write) :]
+
+ self.write_cluster(cluster, data_to_write)
+ data = data[self.boot_sector.cluster_bytes() :]
+ if len(data) == 0:
+ break
+ cluster = self.next_cluster(cluster)
+
+ assert (
+ len(data) == 0
+ ), "Data was not written completely, clusters missing"
+
+ def create_file(self, path: str) -> Optional[FatDirectoryEntry]:
+ """
+ Create a new file at the given path.
+ """
+ assert path[0] == "/", "Path must start with /"
+
+ path = path[1:] # remove the leading /
+
+ parts = path.split("/")
+
+ directory_cluster = None
+ directory = self.read_root_directory()
+
+ parts, filename = parts[:-1], parts[-1]
+
+ for _, part in enumerate(parts):
+ current_entry = None
+ for entry in directory:
+ if entry.whole_name() == part:
+ current_entry = entry
+ break
+ if current_entry is None:
+ return None
+
+ if current_entry.attributes & 0x10 == 0:
+ raise Exception(
+ f"{current_entry.whole_name()} is not a directory"
+ )
+
+ directory = self.read_directory(current_entry.cluster)
+ directory_cluster = current_entry.cluster
+
+ # add new entry to the directory
+
+ filename, ext = filename.split(".")
+
+ if len(ext) > 3:
+ raise Exception("Ext must be 3 characters or less")
+ if len(filename) > 8:
+ raise Exception("Name must be 8 characters or less")
+
+ for c in filename + ext:
+
+ if c not in ALLOWED_FILE_CHARS:
+ raise Exception("Invalid character in filename")
+
+ return self.add_direntry(directory_cluster, filename, ext, 0)
diff --git a/tests/qemu-iotests/testenv.py b/tests/qemu-iotests/testenv.py
index a864c74b12..23307fa2f4 100644
--- a/tests/qemu-iotests/testenv.py
+++ b/tests/qemu-iotests/testenv.py
@@ -250,7 +250,7 @@ def __init__(self, imgfmt: str, imgproto: str, aiomode: str,
self.qemu_img_options = os.getenv('QEMU_IMG_OPTIONS')
self.qemu_nbd_options = os.getenv('QEMU_NBD_OPTIONS')
- is_generic = self.imgfmt not in ['bochs', 'cloop', 'dmg']
+ is_generic = self.imgfmt not in ['bochs', 'cloop', 'dmg', 'vvfat']
self.imgfmt_generic = 'true' if is_generic else 'false'
self.qemu_io_options = f'--cache {self.cachemode} --aio {self.aiomode}'
diff --git a/tests/qemu-iotests/tests/vvfat b/tests/qemu-iotests/tests/vvfat
new file mode 100755
index 0000000000..acdc6ce8ff
--- /dev/null
+++ b/tests/qemu-iotests/tests/vvfat
@@ -0,0 +1,485 @@
+#!/usr/bin/env python3
+# group: rw vvfat
+#
+# Test vvfat driver implementation
+# Here, we use a simple FAT16 implementation and check the behavior of
+# the vvfat driver.
+#
+# Copyright (C) 2024 Amjad Alsharafi <amjadsharafi10@gmail.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import shutil
+import iotests
+from iotests import imgfmt, QMPTestCase
+from fat16 import MBR, Fat16, DIRENTRY_SIZE
+
+filesystem = os.path.join(iotests.test_dir, "filesystem")
+
+nbd_sock = iotests.file_path("nbd.sock", base_dir=iotests.sock_dir)
+nbd_uri = "nbd+unix:///disk?socket=" + nbd_sock
+
+SECTOR_SIZE = 512
+
+
+class TestVVFatDriver(QMPTestCase):
+ # pylint: disable=broad-exception-raised
+ def setUp(self) -> None:
+ if os.path.exists(filesystem):
+ if os.path.isdir(filesystem):
+ shutil.rmtree(filesystem)
+ else:
+ raise Exception(f"{filesystem} exists and is not a directory")
+
+ os.mkdir(filesystem)
+
+ # Add some text files to the filesystem
+ for i in range(10):
+ with open(os.path.join(filesystem, f"file{i}.txt"),
+ "w", encoding="ascii") as f:
+ f.write(f"Hello, world! {i}\n")
+
+ # Add 2 large files, above the cluster size (8KB)
+ with open(os.path.join(filesystem, "large1.txt"), "wb") as f:
+ # write 'A' * 1KB, 'B' * 1KB, 'C' * 1KB, ...
+ for i in range(8 * 2): # two clusters
+ f.write(bytes([0x41 + i] * 1024))
+
+ with open(os.path.join(filesystem, "large2.txt"), "wb") as f:
+ # write 'A' * 1KB, 'B' * 1KB, 'C' * 1KB, ...
+ for i in range(8 * 3): # 3 clusters
+ f.write(bytes([0x41 + i] * 1024))
+
+ self.vm = iotests.VM()
+
+ self.vm.add_blockdev(
+ self.vm.qmp_to_opts(
+ {
+ "driver": imgfmt,
+ "node-name": "disk",
+ "rw": "true",
+ "fat-type": "16",
+ "dir": filesystem,
+ }
+ )
+ )
+
+ self.vm.launch()
+
+ self.vm.qmp_log("block-dirty-bitmap-add", **{
+ "node": "disk",
+ "name": "bitmap0",
+ })
+
+ # attach nbd server
+ self.vm.qmp_log(
+ "nbd-server-start",
+ **{"addr": {"type": "unix", "data": {"path": nbd_sock}}},
+ filters=[],
+ )
+
+ self.vm.qmp_log(
+ "nbd-server-add",
+ **{"device": "disk", "writable": True, "bitmap": "bitmap0"},
+ )
+
+ self.qio = iotests.QemuIoInteractive("-f", "raw", nbd_uri)
+
+ def tearDown(self) -> None:
+ self.qio.close()
+ self.vm.shutdown()
+ # print(self.vm.get_log())
+ shutil.rmtree(filesystem)
+
+ def read_sectors(self, sector: int, num: int = 1) -> bytes:
+ """
+ Read `num` sectors starting from `sector` from the `disk`.
+ This uses `QemuIoInteractive` to read the sectors into `stdout` and
+ then parse the output.
+ """
+ self.assertGreater(num, 0)
+
+ # The output contains the content of the sector in hex dump format
+ # We need to extract the content from it
+ output = self.qio.cmd(
+ f"read -v {sector * SECTOR_SIZE} {num * SECTOR_SIZE}")
+
+ # Each row is 16 bytes long, and we are writing `num` sectors
+ rows = num * SECTOR_SIZE // 16
+ output_rows = output.split("\n")[:rows]
+
+ hex_content = "".join(
+ [(row.split(": ")[1]).split(" ")[0] for row in output_rows]
+ )
+ bytes_content = bytes.fromhex(hex_content)
+
+ self.assertEqual(len(bytes_content), num * SECTOR_SIZE)
+
+ return bytes_content
+
+ def write_sectors(self, sector: int, data: bytes) -> None:
+ """
+ Write `data` to the `disk` starting from `sector`.
+ This uses `QemuIoInteractive` to write the data into the disk.
+ """
+
+ self.assertGreater(len(data), 0)
+ self.assertEqual(len(data) % SECTOR_SIZE, 0)
+
+ temp_file = os.path.join(iotests.test_dir, "temp.bin")
+ with open(temp_file, "wb") as f:
+ f.write(data)
+
+ self.qio.cmd(
+ f"write -s {temp_file} {sector * SECTOR_SIZE} {len(data)}"
+ )
+
+ os.remove(temp_file)
+
+ def init_fat16(self):
+ mbr = MBR(self.read_sectors(0))
+ return Fat16(
+ mbr.partition_table[0]["start_lba"],
+ mbr.partition_table[0]["size"],
+ self.read_sectors,
+ self.write_sectors,
+ )
+
+ # Tests
+
+ def test_fat_filesystem(self):
+ """
+ Test that vvfat produce a valid FAT16 and MBR sectors
+ """
+ mbr = MBR(self.read_sectors(0))
+
+ self.assertEqual(mbr.partition_table[0]["status"], 0x80)
+ self.assertEqual(mbr.partition_table[0]["type"], 6)
+
+ fat16 = Fat16(
+ mbr.partition_table[0]["start_lba"],
+ mbr.partition_table[0]["size"],
+ self.read_sectors,
+ self.write_sectors,
+ )
+ self.assertEqual(fat16.boot_sector.bytes_per_sector, 512)
+ self.assertEqual(fat16.boot_sector.volume_label, "QEMU VVFAT")
+
+ def test_read_root_directory(self):
+ """
+ Test the content of the root directory
+ """
+ fat16 = self.init_fat16()
+
+ root_dir = fat16.read_root_directory()
+
+ self.assertEqual(len(root_dir), 13) # 12 + 1 special file
+
+ files = {
+ "QEMU VVF.AT": 0, # special empty file
+ "FILE0.TXT": 16,
+ "FILE1.TXT": 16,
+ "FILE2.TXT": 16,
+ "FILE3.TXT": 16,
+ "FILE4.TXT": 16,
+ "FILE5.TXT": 16,
+ "FILE6.TXT": 16,
+ "FILE7.TXT": 16,
+ "FILE8.TXT": 16,
+ "FILE9.TXT": 16,
+ "LARGE1.TXT": 0x2000 * 2,
+ "LARGE2.TXT": 0x2000 * 3,
+ }
+
+ for entry in root_dir:
+ self.assertIn(entry.whole_name(), files)
+ self.assertEqual(entry.size_bytes, files[entry.whole_name()])
+
+ def test_direntry_as_bytes(self):
+ """
+ Test if we can convert Direntry back to bytes, so that we can write it
+ back to the disk safely.
+ """
+ fat16 = self.init_fat16()
+
+ root_dir = fat16.read_root_directory()
+ first_entry_bytes = fat16.read_sectors(
+ fat16.boot_sector.root_dir_start(), 1)
+
+ # The first entry won't be deleted, so we can compare it with the first
+ # entry in the root directory
+ self.assertEqual(root_dir[0].as_bytes(),
+ first_entry_bytes[:DIRENTRY_SIZE])
+
+ def test_read_files(self):
+ """
+ Test reading the content of the files
+ """
+ fat16 = self.init_fat16()
+
+ for i in range(10):
+ file = fat16.find_direntry(f"/FILE{i}.TXT")
+ self.assertIsNotNone(file)
+ self.assertEqual(
+ fat16.read_file(file), f"Hello, world! {i}\n".encode("ascii")
+ )
+
+ # test large files
+ large1 = fat16.find_direntry("/LARGE1.TXT")
+ with open(os.path.join(filesystem, "large1.txt"), "rb") as f:
+ self.assertEqual(fat16.read_file(large1), f.read())
+
+ large2 = fat16.find_direntry("/LARGE2.TXT")
+ self.assertIsNotNone(large2)
+ with open(os.path.join(filesystem, "large2.txt"), "rb") as f:
+ self.assertEqual(fat16.read_file(large2), f.read())
+
+ def test_write_file_same_content_direct(self):
+ """
+ Similar to `test_write_file_in_same_content`, but we write the file
+ directly clusters and thus we don't go through the modification of
+ direntry.
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/FILE0.TXT")
+ self.assertIsNotNone(file)
+
+ data = fat16.read_cluster(file.cluster)
+ fat16.write_cluster(file.cluster, data)
+
+ with open(os.path.join(filesystem, "file0.txt"), "rb") as f:
+ self.assertEqual(fat16.read_file(file), f.read())
+
+ def test_write_file_in_same_content(self):
+ """
+ Test writing the same content to the file back to it
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/FILE0.TXT")
+ self.assertIsNotNone(file)
+
+ self.assertEqual(fat16.read_file(file), b"Hello, world! 0\n")
+
+ fat16.write_file(file, b"Hello, world! 0\n")
+ self.assertEqual(fat16.read_file(file), b"Hello, world! 0\n")
+
+ with open(os.path.join(filesystem, "file0.txt"), "rb") as f:
+ self.assertEqual(f.read(), b"Hello, world! 0\n")
+
+ def test_modify_content_same_clusters(self):
+ """
+ Test modifying the content of the file without changing the number of
+ clusters
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/FILE0.TXT")
+ self.assertIsNotNone(file)
+
+ new_content = b"Hello, world! Modified\n"
+ self.assertEqual(fat16.read_file(file), b"Hello, world! 0\n")
+
+ fat16.write_file(file, new_content)
+ self.assertEqual(fat16.read_file(file), new_content)
+
+ with open(os.path.join(filesystem, "file0.txt"), "rb") as f:
+ self.assertEqual(f.read(), new_content)
+
+ def test_truncate_file_same_clusters_less(self):
+ """
+ Test truncating the file without changing number of clusters
+ Test decreasing the file size
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/FILE0.TXT")
+ self.assertIsNotNone(file)
+
+ self.assertEqual(fat16.read_file(file), b"Hello, world! 0\n")
+
+ fat16.truncate_file(file, 5)
+ new_content = fat16.read_file(file)
+ self.assertEqual(new_content, b"Hello")
+
+ with open(os.path.join(filesystem, "file0.txt"), "rb") as f:
+ self.assertEqual(f.read(), new_content)
+
+ def test_truncate_file_same_clusters_more(self):
+ """
+ Test truncating the file without changing number of clusters
+ Test increase the file size
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/FILE0.TXT")
+ self.assertIsNotNone(file)
+
+ self.assertEqual(fat16.read_file(file), b"Hello, world! 0\n")
+
+ fat16.truncate_file(file, 20)
+ new_content = fat16.read_file(file)
+ self.assertIsNotNone(new_content)
+
+ # random pattern will be appended to the file, and its not always the
+ # same
+ self.assertEqual(new_content[:16], b"Hello, world! 0\n")
+ self.assertEqual(len(new_content), 20)
+
+ with open(os.path.join(filesystem, "file0.txt"), "rb") as f:
+ self.assertEqual(f.read(), new_content)
+
+ def test_write_large_file(self):
+ """
+ Test writing a large file
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/LARGE1.TXT")
+ self.assertIsNotNone(file)
+
+ # The content of LARGE1 is A * 1KB, B * 1KB, C * 1KB, ..., P * 1KB
+ # Lets change it to be Z * 1KB, Y * 1KB, X * 1KB, ..., K * 1KB
+ # without changing the number of clusters or filesize
+ new_content = b"".join([bytes([0x5A - i] * 1024) for i in range(16)])
+ fat16.write_file(file, new_content)
+ self.assertEqual(fat16.read_file(file), new_content)
+
+ with open(os.path.join(filesystem, "large1.txt"), "rb") as f:
+ self.assertEqual(f.read(), new_content)
+
+ def test_truncate_file_change_clusters_less(self):
+ """
+ Test truncating a file by reducing the number of clusters
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/LARGE1.TXT")
+ self.assertIsNotNone(file)
+
+ fat16.truncate_file(file, 1)
+ self.assertEqual(fat16.read_file(file), b"A")
+
+ with open(os.path.join(filesystem, "large1.txt"), "rb") as f:
+ self.assertEqual(f.read(), b"A")
+
+ def test_write_file_change_clusters_less(self):
+ """
+ Test truncating a file by reducing the number of clusters
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/LARGE2.TXT")
+ self.assertIsNotNone(file)
+
+ new_content = b"X" * 8 * 1024 + b"Y" * 8 * 1024
+ fat16.write_file(file, new_content)
+ self.assertEqual(fat16.read_file(file), new_content)
+
+ with open(os.path.join(filesystem, "large2.txt"), "rb") as f:
+ self.assertEqual(f.read(), new_content)
+
+ def test_write_file_change_clusters_more(self):
+ """
+ Test truncating a file by increasing the number of clusters
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/LARGE2.TXT")
+ self.assertIsNotNone(file)
+
+ # from 3 clusters to 4 clusters
+ new_content = (
+ b"W" * 8 * 1024 +
+ b"X" * 8 * 1024 +
+ b"Y" * 8 * 1024 +
+ b"Z" * 8 * 1024
+ )
+ fat16.write_file(file, new_content)
+ self.assertEqual(fat16.read_file(file), new_content)
+
+ with open(os.path.join(filesystem, "large2.txt"), "rb") as f:
+ self.assertEqual(f.read(), new_content)
+
+ def test_write_file_change_clusters_more_non_contiguous_2_mappings(self):
+ """
+ Test truncating a file by increasing the number of clusters Here we
+ allocate the new clusters in a way that makes them non-contiguous so
+ that we will get 2 cluster mappings for the file
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/LARGE1.TXT")
+ self.assertIsNotNone(file)
+
+ # from 2 clusters to 3 clusters with non-contiguous allocation
+ fat16.truncate_file(file, 3 * 0x2000, allocate_non_continuous=True)
+ new_content = b"X" * 8 * 1024 + b"Y" * 8 * 1024 + b"Z" * 8 * 1024
+ fat16.write_file(file, new_content)
+ self.assertEqual(fat16.read_file(file), new_content)
+
+ with open(os.path.join(filesystem, "large1.txt"), "rb") as f:
+ self.assertEqual(f.read(), new_content)
+
+ def test_write_file_change_clusters_more_non_contiguous_3_mappings(self):
+ """
+ Test truncating a file by increasing the number of clusters Here we
+ allocate the new clusters in a way that makes them non-contiguous so
+ that we will get 3 cluster mappings for the file
+ """
+ fat16 = self.init_fat16()
+
+ file = fat16.find_direntry("/LARGE1.TXT")
+ self.assertIsNotNone(file)
+
+ # from 2 clusters to 4 clusters with non-contiguous allocation
+ fat16.truncate_file(file, 4 * 0x2000, allocate_non_continuous=True)
+ new_content = (
+ b"W" * 8 * 1024 +
+ b"X" * 8 * 1024 +
+ b"Y" * 8 * 1024 +
+ b"Z" * 8 * 1024
+ )
+ fat16.write_file(file, new_content)
+ self.assertEqual(fat16.read_file(file), new_content)
+
+ with open(os.path.join(filesystem, "large1.txt"), "rb") as f:
+ self.assertEqual(f.read(), new_content)
+
+ def test_create_file(self):
+ """
+ Test creating a new file
+ """
+ fat16 = self.init_fat16()
+
+ new_file = fat16.create_file("/NEWFILE.TXT")
+
+ self.assertIsNotNone(new_file)
+ self.assertEqual(new_file.size_bytes, 0)
+
+ new_content = b"Hello, world! New file\n"
+ fat16.write_file(new_file, new_content)
+ self.assertEqual(fat16.read_file(new_file), new_content)
+
+ with open(os.path.join(filesystem, "newfile.txt"), "rb") as f:
+ self.assertEqual(f.read(), new_content)
+
+ # TODO: support deleting files
+
+
+if __name__ == "__main__":
+ # This is a specific test for vvfat driver
+ iotests.main(supported_fmts=["vvfat"], supported_protocols=["file"])
diff --git a/tests/qemu-iotests/tests/vvfat.out b/tests/qemu-iotests/tests/vvfat.out
new file mode 100755
index 0000000000..b6f257674e
--- /dev/null
+++ b/tests/qemu-iotests/tests/vvfat.out
@@ -0,0 +1,5 @@
+................
+----------------------------------------------------------------------
+Ran 16 tests
+
+OK
--
2.39.2© 2016 - 2024 Red Hat, Inc.