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Diffstat (limited to 'python/qemu/utils/qom_fuse.py')
| -rw-r--r-- | python/qemu/utils/qom_fuse.py | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/python/qemu/utils/qom_fuse.py b/python/qemu/utils/qom_fuse.py new file mode 100644 index 0000000000..653a76b93b --- /dev/null +++ b/python/qemu/utils/qom_fuse.py @@ -0,0 +1,207 @@ +""" +QEMU Object Model FUSE filesystem tool + +This script offers a simple FUSE filesystem within which the QOM tree +may be browsed, queried and edited using traditional shell tooling. + +This script requires the 'fusepy' python package. + + +usage: qom-fuse [-h] [--socket SOCKET] <mount> + +Mount a QOM tree as a FUSE filesystem + +positional arguments: + <mount> Mount point + +optional arguments: + -h, --help show this help message and exit + --socket SOCKET, -s SOCKET + QMP socket path or address (addr:port). May also be + set via QMP_SOCKET environment variable. +""" +## +# Copyright IBM, Corp. 2012 +# Copyright (C) 2020 Red Hat, Inc. +# +# Authors: +# Anthony Liguori <aliguori@us.ibm.com> +# Markus Armbruster <armbru@redhat.com> +# +# This work is licensed under the terms of the GNU GPL, version 2 or later. +# See the COPYING file in the top-level directory. +## + +import argparse +from errno import ENOENT, EPERM +import stat +import sys +from typing import ( + IO, + Dict, + Iterator, + Mapping, + Optional, + Union, +) + +import fuse +from fuse import FUSE, FuseOSError, Operations + +from qemu.aqmp import ExecuteError + +from .qom_common import QOMCommand + + +fuse.fuse_python_api = (0, 2) + + +class QOMFuse(QOMCommand, Operations): + """ + QOMFuse implements both fuse.Operations and QOMCommand. + + Operations implements the FS, and QOMCommand implements the CLI command. + """ + name = 'fuse' + help = 'Mount a QOM tree as a FUSE filesystem' + fuse: FUSE + + @classmethod + def configure_parser(cls, parser: argparse.ArgumentParser) -> None: + super().configure_parser(parser) + parser.add_argument( + 'mount', + metavar='<mount>', + action='store', + help="Mount point", + ) + + def __init__(self, args: argparse.Namespace): + super().__init__(args) + self.mount = args.mount + self.ino_map: Dict[str, int] = {} + self.ino_count = 1 + + def run(self) -> int: + print(f"Mounting QOMFS to '{self.mount}'", file=sys.stderr) + self.fuse = FUSE(self, self.mount, foreground=True) + return 0 + + def get_ino(self, path: str) -> int: + """Get an inode number for a given QOM path.""" + if path in self.ino_map: + return self.ino_map[path] + self.ino_map[path] = self.ino_count + self.ino_count += 1 + return self.ino_map[path] + + def is_object(self, path: str) -> bool: + """Is the given QOM path an object?""" + try: + self.qom_list(path) + return True + except ExecuteError: + return False + + def is_property(self, path: str) -> bool: + """Is the given QOM path a property?""" + path, prop = path.rsplit('/', 1) + if path == '': + path = '/' + try: + for item in self.qom_list(path): + if item.name == prop: + return True + return False + except ExecuteError: + return False + + def is_link(self, path: str) -> bool: + """Is the given QOM path a link?""" + path, prop = path.rsplit('/', 1) + if path == '': + path = '/' + try: + for item in self.qom_list(path): + if item.name == prop and item.link: + return True + return False + except ExecuteError: + return False + + def read(self, path: str, size: int, offset: int, fh: IO[bytes]) -> bytes: + if not self.is_property(path): + raise FuseOSError(ENOENT) + + path, prop = path.rsplit('/', 1) + if path == '': + path = '/' + try: + data = str(self.qmp.command('qom-get', path=path, property=prop)) + data += '\n' # make values shell friendly + except ExecuteError as err: + raise FuseOSError(EPERM) from err + + if offset > len(data): + return b'' + + return bytes(data[offset:][:size], encoding='utf-8') + + def readlink(self, path: str) -> Union[bool, str]: + if not self.is_link(path): + return False + path, prop = path.rsplit('/', 1) + prefix = '/'.join(['..'] * (len(path.split('/')) - 1)) + return prefix + str(self.qmp.command('qom-get', path=path, + property=prop)) + + def getattr(self, path: str, + fh: Optional[IO[bytes]] = None) -> Mapping[str, object]: + if self.is_link(path): + value = { + 'st_mode': 0o755 | stat.S_IFLNK, + 'st_ino': self.get_ino(path), + 'st_dev': 0, + 'st_nlink': 2, + 'st_uid': 1000, + 'st_gid': 1000, + 'st_size': 4096, + 'st_atime': 0, + 'st_mtime': 0, + 'st_ctime': 0 + } + elif self.is_object(path): + value = { + 'st_mode': 0o755 | stat.S_IFDIR, + 'st_ino': self.get_ino(path), + 'st_dev': 0, + 'st_nlink': 2, + 'st_uid': 1000, + 'st_gid': 1000, + 'st_size': 4096, + 'st_atime': 0, + 'st_mtime': 0, + 'st_ctime': 0 + } + elif self.is_property(path): + value = { + 'st_mode': 0o644 | stat.S_IFREG, + 'st_ino': self.get_ino(path), + 'st_dev': 0, + 'st_nlink': 1, + 'st_uid': 1000, + 'st_gid': 1000, + 'st_size': 4096, + 'st_atime': 0, + 'st_mtime': 0, + 'st_ctime': 0 + } + else: + raise FuseOSError(ENOENT) + return value + + def readdir(self, path: str, fh: IO[bytes]) -> Iterator[str]: + yield '.' + yield '..' + for item in self.qom_list(path): + yield item.name |