#!/usr/bin/env python3 """Real AppImage shutdown capture. Run under headless-desktop; no app modifications. Normal: wmctrl orderly close. Held: stop surviving zygotes at the main process kernel exit event, exposing the post-unmount lifetime deterministically; resume survivors afterwards. All process signals target PIDs discovered beneath the launched AppImage. """ import os,sys,time,json,ctypes,signal,subprocess,threading,queue,pathlib,tkinter as tk from datetime import datetime image,side,sha,mode,outroot=sys.argv[1:] out=pathlib.Path(outroot)/(side+'-'+mode+'-'+datetime.now().strftime('%H%M%S'));out.mkdir() ctypes.CDLL(None).prctl(36,1,0,0,0) # PR_SET_CHILD_SUBREAPER q=queue.Queue(); events=[]; known={}; start=time.monotonic(); closing=None root=tk.Tk();root.title('AppImage shutdown observer');root.geometry('730x1020+1180+15');root.configure(bg='#101820') head=tk.Label(root,text=f'{side.upper()} {sha[:10]}\nLinux x86_64 · Xvfb / openbox\nFresh app state · '+('exit-boundary hold' if mode=='held' else 'normal close'),bg='#101820',fg='white',font=('DejaVu Sans',17),justify='left');head.pack(anchor='w',padx=16,pady=15) box=tk.Text(root,bg='#101820',fg='#dce9ef',font=('DejaVu Sans Mono',12),wrap='word',borderwidth=0,insertwidth=0);box.pack(fill='both',expand=True,padx=16,pady=8) status=tk.Label(root,text='Launching real AppImage…',bg='#101820',fg='#ffc866',font=('DejaVu Sans',17),wraplength=690,justify='left');status.pack(padx=16,pady=18) def emit(text,**extra): elapsed=round((time.monotonic()-start)*1000,3); ev=dict(ms=elapsed,event=text,**extra);events.append(ev);q.put(('line',f'{elapsed:10.3f} ms {text}\n')) with (out/'events.json').open('w') as f:json.dump(events,f,indent=2) def stat(pid): try: s=pathlib.Path(f'/proc/{pid}/stat').read_text(); a=s[s.rfind(')')+2:].split(); return a[0],int(a[1]) except (OSError,ValueError):return None def discover(pid): try: cmd=pathlib.Path(f'/proc/{pid}/cmdline').read_bytes().replace(b'\0',b' ').decode(errors='replace');known[pid]=cmd kids=set() for task in pathlib.Path(f'/proc/{pid}/task').iterdir(): try:kids.update(map(int,(task/'children').read_text().split())) except OSError:pass for kid in kids:discover(kid) except OSError:pass def stable_capture(label): a=out/(label+'-a.png');b=out/(label+'.png') for _ in range(10): subprocess.run(['import','-window','root',str(a)],check=True) time.sleep(.5) subprocess.run(['import','-window','root',str(b)],check=True) equal=subprocess.run(['compare','-metric','AE',str(a),str(b),'null:'],capture_output=True) if equal.returncode==0:return raise RuntimeError('Screenshot pixels did not settle: '+label) def run(): global closing wm=subprocess.Popen(['openbox'],stdout=subprocess.DEVNULL,stderr=subprocess.DEVNULL) recorder=None;app=None;tracked=[] try: time.sleep(1) recorder=subprocess.Popen(['ffmpeg','-y','-loglevel','error','-f','x11grab','-video_size','1920x1080','-framerate','12','-i',os.environ['DISPLAY'],'-c:v','libx264','-preset','ultrafast','-crf','24','-pix_fmt','yuv420p',str(out/'recording.mp4')],stdout=subprocess.DEVNULL,stderr=(out/'ffmpeg.log').open('w')) state=out/'state';state.mkdir() # Synthetic display label, so captures never expose the host's name. bindir=state/'bin';bindir.mkdir() hostlabel=bindir/'hostnamectl';hostlabel.write_text('#!/bin/sh\nprintf \'AppImage evidence\\n\'\n');hostlabel.chmod(0o755) env={k:os.environ[k] for k in ['PATH','DISPLAY','DBUS_SESSION_BUS_ADDRESS','XDG_RUNTIME_DIR','XAUTHORITY','LANG'] if k in os.environ} env['PATH']=str(bindir)+os.pathsep+env['PATH'] env.update(HOME=str(state),XDG_CONFIG_HOME=str(state/'config'),XDG_DATA_HOME=str(state/'data'),XDG_CACHE_HOME=str(state/'cache'),T3CODE_HOME=str(state/'t3'),T3CODE_DEV_SEED='0') app=subprocess.Popen([image,'--no-sandbox','--disable-gpu'],env=env,cwd=state,stdout=(out/'app.log').open('w'),stderr=subprocess.STDOUT) runtime=app.pid;emit(f'AppImage launch PID {app.pid}') deadline=time.monotonic()+90;window=None;main=None while time.monotonic()=5 and int(cols[2]) in known and 'T3' in cols[4]:window=cols[0];main=int(cols[2]);break if window:break if app.poll() is not None:raise RuntimeError('AppImage exited before its window opened') time.sleep(.1) if not window:raise RuntimeError('No app window within 90 seconds') subprocess.run(['wmctrl','-ir',window,'-b','remove,maximized_vert,maximized_horz'],check=True) subprocess.run(['wmctrl','-ir',window,'-e','0,15,35,1140,960'],check=True) time.sleep(7);discover(app.pid) # The static AppImage runtime daemon is reparented to this subreaper. runtimes=[] for proc in pathlib.Path('/proc').iterdir(): if not proc.name.isdigit():continue pid=int(proc.name);st=stat(pid) if not st or st[1]!=os.getpid() or pid==app.pid:continue try:cmd=(proc/'cmdline').read_bytes().split(b'\0')[0].decode() except OSError:continue if cmd==image:runtimes.append(pid);known[pid]=cmd if len(runtimes)!=1:raise RuntimeError(f'Expected 1 AppImage mount runtime, found {runtimes}') runtime=runtimes[0];emit(f'AppImage mount runtime PID {runtime}') zygotes=[pid for pid,cmd in known.items() if '--type=zygote' in cmd] tracked=list(known);emit(f'Real app window ready; Electron main PID {main}') emit(f'Chromium zygotes: {zygotes}');q.put(('status','App running; close follows')) if len(zygotes)!=2:raise RuntimeError(f'Expected 2 zygotes, got {len(zygotes)}') exe=os.readlink(f'/proc/{main}/exe');mount=exe.split('/')[1:3];mount='/'+ '/'.join(mount) emit('AppImage executable is on a mounted squashfs') mounted=lambda: any(mount in s for s in pathlib.Path('/proc/self/mountinfo').read_text().splitlines()) if not mounted():raise RuntimeError('AppImage mount not visible') time.sleep(3) stable_capture('app-open') lib=ctypes.CDLL(None,use_errno=True) if mode=='held': # PTRACE_O_TRACEEXIT observes the boundary after userspace exit hooks. if lib.ptrace(0x4206,main,0,0x40)!=0:raise OSError(ctypes.get_errno(),'PTRACE_SEIZE') emit('Observe main kernel exit; then hold surviving zygotes') q.put(('status','Closing last app window…'));emit('wmctrl WM_DELETE_WINDOW: close last app window') closing=time.monotonic();subprocess.run(['wmctrl','-ic',window],check=True) observed=set();runtime_done=False;deadline=time.monotonic()+25 while time.monotonic()>16==6: held=[] for z in zygotes: st=stat(z) if st and st[0] not in 'ZX': os.kill(z,signal.SIGSTOP);held.append(z) lib.ptrace(7,main,0,0) # PTRACE_CONT: let main complete its exit. emit(f'Main kernel exit: held {len(held)} live zygotes',held=held) continue if os.WIFSTOPPED(statuscode) and p==main: lib.ptrace(7,main,0,os.WSTOPSIG(statuscode)) continue if p in known: code=os.waitstatus_to_exitcode(statuscode);emit(f'reaped PID {p}: exit {code}'+(f' ({signal.Signals(-code).name})' if code<0 else ''),pid=p,exit=code,coreDumped=bool(os.WCOREDUMP(statuscode))) if p==runtime:runtime_done=True if p==app.pid:app.returncode=code if runtime_done: alive={p:stat(p) for p in zygotes};alive={p:s for p,s in alive.items() if s and s[0] not in 'ZX'} emit(f'Runtime exited; AppImage mount present: {mounted()}') emit(f'Zygotes still alive after runtime exit: {len(alive)}',survivors=alive) verdict='BUG: zygotes outlive the unmounted image' if alive else 'Zygotes released before runtime exit' q.put(('status',verdict)) if mode=='held': time.sleep(5) if len(alive)==2: victim,survivor=list(alive) os.kill(victim,signal.SIGKILL) emit(f'Pressure probe: kill companion zygote {victim}') (out/'survivor-maps.txt').write_text(pathlib.Path(f'/proc/{survivor}/maps').read_text()) probe=subprocess.run(['sudo','-n','python3',str(pathlib.Path(__file__).with_name('pageout.py')),str(survivor)],capture_output=True,text=True) (out/'pageout.json').write_text(probe.stdout) detail=json.loads(probe.stdout) if probe.returncode==0 else [] emit(f'MADV_PAGEOUT: {sum(x["result"] for x in detail if x["result"]>0)} bytes; {sum(x["result"]<0 for x in detail)} errors',returncode=probe.returncode) if probe.returncode:emit('Page-out probe unavailable: '+probe.stderr.strip()) else: emit('Pressure probe: no surviving zygote to page out') for p in alive: try:os.kill(p,signal.SIGCONT) except ProcessLookupError:pass emit('SIGCONT surviving zygote after page-out probe') end=time.monotonic()+3 while time.monotonic()