Files

208 lines
9.4 KiB
Python

"""Migrate the recognized pre-package desktop console without replacing its Bash."""
from __future__ import annotations
import hashlib
import json
import os
from pathlib import Path
import pwd
import re
import stat
import subprocess
import tempfile
RECORD = "console-desktop.json"
LEGACY_WRAPPER_SHA256 = "71a6436d7411606312b009aee62a6d736a0d31a31194abb445f600740d8174f5"
def _need(value, error):
if not value:
raise ValueError(error)
def _owned(path, *, directory=False):
path = Path(path)
for parent in [path, *path.parents]:
_need(not parent.is_symlink(), "CONSOLE_DESKTOP_SYMLINK_REFUSED")
info = path.lstat()
kind = stat.S_ISDIR if directory else stat.S_ISREG
_need(kind(info.st_mode) and info.st_uid == os.getuid() and not info.st_mode & 0o022,
"CONSOLE_DESKTOP_PATH_NOT_OWNED")
return info
def _snapshot(path):
_owned(path)
fd = os.open(path, os.O_RDONLY | os.O_NOFOLLOW | os.O_NONBLOCK)
with os.fdopen(fd, "rb") as stream:
info = os.fstat(stream.fileno())
_need(stat.S_ISREG(info.st_mode) and info.st_uid == os.getuid()
and not info.st_mode & 0o022 and info.st_size <= 32768,
"CONSOLE_DESKTOP_FILE_UNTRUSTED")
return stream.read(), stat.S_IMODE(info.st_mode)
def _atomic(path, data, mode=0o600):
fd, temporary = tempfile.mkstemp(prefix=".fb-desktop-", dir=path.parent)
try:
with os.fdopen(fd, "wb") as stream:
os.fchmod(stream.fileno(), mode)
stream.write(data)
stream.flush()
os.fsync(stream.fileno())
os.replace(temporary, path)
finally:
try:
os.unlink(temporary)
except FileNotFoundError:
pass
def _legacy_entry(home):
return ("[Desktop Entry]\nVersion=1.0\nType=Application\nName=FrameBridge Console\n"
"Comment=Open the persistent local Bash and FBTERM activity console\n"
"Exec=" + str(home / ".local/bin/framebridge-console") + "\n"
"Icon=utilities-terminal\nTerminal=false\nCategories=System;TerminalEmulator;\n"
"StartupWMClass=Gnome-terminal\n").encode()
def _new_entry(state):
# Desktop Entry Exec quoting, without a shell or environment expansion.
_need(not any(ord(char) < 32 or ord(char) == 127 for char in str(state)),
"CONSOLE_DESKTOP_STATE_PATH_INVALID")
quoted = str(state).replace("%", "%%").replace("\\", "\\\\").replace('"', '\\"').replace("`", "\\`").replace("$", "\\$")
return ("[Desktop Entry]\nVersion=1.0\nType=Application\nName=FrameBridge Console\n"
"Comment=Open the persistent local Bash and FBTERM activity console\n"
'Exec=/usr/bin/fb --state-dir "' + quoted + '" console\n'
"Icon=utilities-terminal\nTerminal=false\nCategories=System;TerminalEmulator;\n"
"StartupWMClass=Gnome-terminal\n").encode()
def _new_wrapper(state):
command = ["/usr/bin/fb", "--state-dir", str(state), "console"]
return ("#!/usr/bin/python3\n"
'"""Open the packaged FrameBridge console using the retained local profile."""\n'
"import os\nimport sys\n"
"command = " + repr(command) + "\n"
"if sys.argv[1:] == ['--inside']:\n"
" command += ['--inside', '--mode', 'gui']\n"
"elif sys.argv[1:]:\n"
" raise SystemExit('Usage: framebridge-console')\n"
"os.execv(command[0], command)\n").encode()
def _migrate_wrapper(state, home):
path = home / ".local/bin/framebridge-console"
before, mode = _snapshot(path)
after = _new_wrapper(state)
if before == after:
return False
_need(hashlib.sha256(before).hexdigest() == LEGACY_WRAPPER_SHA256,
"CONSOLE_DESKTOP_LEGACY_WRAPPER_CHANGED")
backup = state / "console-wrapper-legacy.backup"
if backup.exists() or backup.is_symlink():
data, backup_mode = _snapshot(backup)
_need(data == before and backup_mode == 0o600, "CONSOLE_DESKTOP_WRAPPER_BACKUP_CHANGED")
else:
_atomic(backup, before)
_need(_snapshot(path)[0] == before, "CONSOLE_DESKTOP_WRAPPER_CHANGED_DURING_MIGRATION")
_atomic(path, after, mode)
return True
def _legacy_identity(node, runtime):
return {"socket": runtime / (node.lower() + "-tty1") / "console.sock",
"session": node.upper() + "-FBTERM"}
def legacy_context(state, node, runtime):
"""Return a user-approved legacy binding; ordinary profiles remain isolated."""
path = Path(state) / RECORD
if not path.exists() and not path.is_symlink():
return None
state_info = _owned(Path(state), directory=True)
_need(not state_info.st_mode & 0o077, "CONSOLE_DESKTOP_STATE_NOT_PRIVATE")
raw, mode = _snapshot(path)
_need(mode == 0o600, "CONSOLE_DESKTOP_RECORD_NOT_PRIVATE")
try:
record = json.loads(raw)
except (ValueError, TypeError):
raise ValueError("CONSOLE_DESKTOP_RECORD_INVALID") from None
expected = _legacy_identity(node, Path(runtime))
_need(type(record) is dict and record.get("schema") == 1
and record.get("state") == str(state) and record.get("node") == node
and record.get("socket") == str(expected["socket"])
and record.get("session") == expected["session"], "CONSOLE_DESKTOP_RECORD_INVALID")
return expected
def migrate_legacy(state, *, home=None, node=None, runtime=None):
"""Change only the exact known legacy entry; called under the profile owner's UID."""
from .config import private_dir, state_path
import socket
uid = os.getuid()
_need(uid != 0 and os.geteuid() == uid, "CONSOLE_DESKTOP_USER_REQUIRED")
state = state_path(state)
home = Path(home if home is not None else pwd.getpwuid(uid).pw_dir)
node = node or re.sub(r"[^A-Za-z0-9_-]", "_", socket.gethostname())[:64] or "NODE"
runtime = Path(runtime if runtime is not None else Path("/run/user") / str(uid))
desktop = home / ".local/share/applications/framebridge-console.desktop"
if not desktop.exists() and not desktop.is_symlink():
return {"ok": True, "changed": False, "reason": "NO_LEGACY_DESKTOP_ENTRY"}
_owned(home, directory=True)
_owned(desktop.parent, directory=True)
before, mode = _snapshot(desktop)
after = _new_entry(state)
if before == after:
_need(legacy_context(state, node, runtime) is not None, "CONSOLE_DESKTOP_RECORD_MISSING")
wrapper_changed = _migrate_wrapper(state, home)
return {"ok": True, "changed": wrapper_changed, "reason": "ALREADY_MIGRATED",
"wrapper_changed": wrapper_changed}
if before != _legacy_entry(home):
return {"ok": True, "changed": False, "reason": "CUSTOM_DESKTOP_ENTRY_PRESERVED"}
wrapper, _ = _snapshot(home / ".local/bin/framebridge-console")
_need(hashlib.sha256(wrapper).hexdigest() == LEGACY_WRAPPER_SHA256,
"CONSOLE_DESKTOP_LEGACY_WRAPPER_CHANGED")
identity = _legacy_identity(node, runtime)
parent = identity["socket"].parent
_owned(runtime, directory=True)
_owned(parent, directory=True)
info = identity["socket"].lstat()
_need(stat.S_ISSOCK(info.st_mode) and info.st_uid == uid and not info.st_mode & 0o077,
"CONSOLE_DESKTOP_LEGACY_SOCKET_UNTRUSTED")
result = subprocess.run(["/usr/bin/tmux", "-S", str(identity["socket"]), "list-windows",
"-t", "=" + identity["session"], "-F", "#{window_id}|#{window_name}"],
capture_output=True, text=True, timeout=5)
rows = result.stdout.splitlines()
_need(result.returncode == 0 and len([row for row in rows
if re.fullmatch(r"@[0-9]+\|Console", row)]) == 1,
"CONSOLE_DESKTOP_LEGACY_WINDOW_UNVERIFIED")
window = next(row.split("|", 1)[0] for row in rows if re.fullmatch(r"@[0-9]+\|Console", row))
panes = subprocess.run(["/usr/bin/tmux", "-S", str(identity["socket"]), "list-panes",
"-t", window, "-F", "#{pane_current_command}|#{pane_dead}|#{@framebridge_role}"],
capture_output=True, text=True, timeout=5)
pane_rows = [row.split("|") for row in panes.stdout.splitlines()]
_need(panes.returncode == 0 and len(pane_rows) == 2
and all(len(row) == 3 and row[1] == "0" for row in pane_rows)
and {row[2] for row in pane_rows} == {"shell", "monitor"}
and any(row == ["bash", "0", "shell"] for row in pane_rows),
"CONSOLE_DESKTOP_LEGACY_PANES_UNVERIFIED")
private_dir(state)
backup = state / "console-desktop-legacy.backup"
if backup.exists() or backup.is_symlink():
old, backup_mode = _snapshot(backup)
_need(old == before and backup_mode == 0o600, "CONSOLE_DESKTOP_BACKUP_CHANGED")
else:
_atomic(backup, before)
record = {"schema": 1, "state": str(state), "node": node,
"socket": str(identity["socket"]), "session": identity["session"],
"desktop_before_sha256": hashlib.sha256(before).hexdigest()}
_atomic(state / RECORD, (json.dumps(record, sort_keys=True, indent=2) + "\n").encode())
_need(_snapshot(desktop)[0] == before, "CONSOLE_DESKTOP_CHANGED_DURING_MIGRATION")
_atomic(desktop, after, mode)
wrapper_changed = _migrate_wrapper(state, home)
return {"ok": True, "changed": True, "desktop": str(desktop),
"wrapper_changed": wrapper_changed,
"session": identity["session"], "socket": str(identity["socket"]),
"backup": str(backup), "runtime_changed": False}