scripts/qom-fuse: move to python/qemu/qmp/qom_fuse.py

Move qom-fuse over to the python package now that it passes the
linter. Update the import paradigms so that it continues to pass in the
context of the Python package.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20210603003719.1321369-18-jsnow@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>

1 files changed, 206 insertions, 0 deletions

diff --git a/python/qemu/qmp/qom_fuse.py b/python/qemu/qmp/qom_fuse.py
new file mode 100644
index 0000000..43f4671
--- /dev/null
+++ b/python/qemu/qmp/qom_fuse.py
@@ -0,0 +1,206 @@
+"""
+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 . import QMPResponseError
+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 QMPResponseError:
+            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 QMPResponseError:
+            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 QMPResponseError:
+            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 QMPResponseError 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