async def _setup_stub(
thread: Thread,
bootstrap_sock: FileDescriptor,
) -> t.Tuple[t.List[str], Thread]:
"Setup a stub thread"
[(access_syscall_sock, passed_syscall_sock),
(access_data_sock, passed_data_sock)
] = await thread.open_async_channels(2)
# memfd for setting up the futex
futex_memfd = await thread.task.memfd_create(await thread.ram.ptr(
Path("child_robust_futex_list")))
# send the fds to the new process
connection_fd, make_connection = await thread.connection.prep_fd_transfer()
async def sendmsg_op(sem: RAM) -> WrittenPointer[SendMsghdr]:
iovec = await sem.ptr(IovecList([await sem.malloc(bytes, 1)]))
cmsgs = await sem.ptr(
CmsgList([
CmsgSCMRights([
passed_syscall_sock, passed_data_sock, futex_memfd,
connection_fd
])
]))
return await sem.ptr(SendMsghdr(None, iovec, cmsgs))
_, [] = await bootstrap_sock.sendmsg(
await thread.ram.perform_batch(sendmsg_op), SendmsgFlags.NONE)
# close our reference to fds that only the new process needs
await passed_syscall_sock.invalidate()
await passed_data_sock.invalidate()
# close the socketpair
await bootstrap_sock.invalidate()
#### read describe to get all the information we need from the new process
describe_buf = AsyncReadBuffer(access_data_sock)
describe_struct = await describe_buf.read_cffi('struct rsyscall_unix_stub')
argv_raw = await describe_buf.read_length_prefixed_array(
describe_struct.argc)
argv = [os.fsdecode(arg) for arg in argv_raw]
environ = await describe_buf.read_envp(describe_struct.envp_count)
#### build the new task
pid = describe_struct.pid
fd_table = handle.FDTable(pid)
address_space = far.AddressSpace(pid)
# we assume pid namespace is shared
pidns = thread.task.pidns
process = near.Process(pid)
# we assume net namespace is shared - that's dubious...
# we should make it possible to control the namespace sharing more, hmm.
# TODO maybe the describe should contain the net namespace number? and we can store our own as well?
# then we can automatically do it right
base_task = Task(process, fd_table, address_space, pidns)
remote_syscall_fd = base_task.make_fd_handle(
near.FileDescriptor(describe_struct.syscall_fd))
base_task.sysif = SyscallConnection(
logger.getChild(str(process)),
access_syscall_sock,
access_syscall_sock,
remote_syscall_fd,
remote_syscall_fd,
)
allocator = memory.AllocatorClient.make_allocator(base_task)
base_task.sigmask = Sigset(
{SIG(bit)
for bit in rsyscall.struct.bits(describe_struct.sigmask)})
ram = RAM(
base_task,
SocketMemoryTransport(
access_data_sock,
base_task.make_fd_handle(
near.FileDescriptor(describe_struct.data_fd))), allocator)
# TODO I think I can maybe elide creating this epollcenter and instead inherit it or share it, maybe?
# I guess I need to write out the set too in describe
epoller = await Epoller.make_root(ram, base_task)
child_monitor = await ChildProcessMonitor.make(ram, base_task, epoller)
connection = make_connection(
base_task, ram,
base_task.make_fd_handle(
near.FileDescriptor(describe_struct.connecting_fd)))
new_thread = Thread(
task=base_task,
ram=ram,
connection=connection,
loader=NativeLoader.make_from_symbols(base_task,
describe_struct.symbols),
epoller=epoller,
child_monitor=child_monitor,
environ=Environment.make_from_environ(base_task, ram, environ),
stdin=base_task.make_fd_handle(near.FileDescriptor(0)),
stdout=base_task.make_fd_handle(near.FileDescriptor(1)),
stderr=base_task.make_fd_handle(near.FileDescriptor(2)),
)
#### TODO set up futex I guess
remote_futex_memfd = near.FileDescriptor(describe_struct.futex_memfd)
return argv, new_thread
def from_bytes(cls: t.Type[T], data: bytes) -> T:
struct = ffi.cast('struct signalfd_siginfo const*',
ffi.from_buffer(data))
return cls(signo=SIG(struct.ssi_signo), )
def make(code: CLD, pid: int, uid: int, status: int) -> ChildState:
if code is CLD.EXITED:
return ChildState(code, pid, uid, status, None)
else:
return ChildState(code, pid, uid, None, SIG(status))