error_t
hurd_thread_cancel (thread_t thread)
{
struct hurd_sigstate *ss = _hurd_thread_sigstate (thread);
struct machine_thread_all_state state;
int state_change;
error_t err;
if (! ss)
return EINVAL;
if (ss == _hurd_self_sigstate ())
{
/* We are cancelling ourselves, so it is easy to succeed
quickly. Since this function is not a cancellation point, we
just leave the flag set pending the next cancellation point
(hurd_check_cancel or RPC) and return success. */
ss->cancel = 1;
return 0;
}
assert (! __spin_lock_locked (&ss->critical_section_lock));
__spin_lock (&ss->critical_section_lock);
__spin_lock (&ss->lock);
err = __thread_suspend (thread);
__spin_unlock (&ss->lock);
if (! err)
{
/* Set the flag telling the thread its operation is being cancelled. */
ss->cancel = 1;
/* Interrupt any interruptible RPC now in progress. */
state.set = 0;
_hurdsig_abort_rpcs (ss, 0, 0, &state, &state_change, NULL, 0, 0);
if (state_change)
err = __thread_set_state (thread, MACHINE_THREAD_STATE_FLAVOR,
(natural_t *) &state.basic,
MACHINE_THREAD_STATE_COUNT);
if (ss->cancel_hook)
/* The code being cancelled has a special wakeup function.
Calling this should make the thread wake up and check the
cancellation flag. */
(*ss->cancel_hook) ();
__thread_resume (thread);
}
_hurd_critical_section_unlock (ss);
return err;
}
static void
abort_all_rpcs (int signo, struct machine_thread_all_state *state, int live)
{
/* We can just loop over the sigstates. Any thread doing something
interruptible must have one. We needn't bother locking because all
other threads are stopped. */
struct hurd_sigstate *ss;
size_t nthreads;
mach_port_t *reply_ports;
/* First loop over the sigstates to count them.
We need to know how big a vector we will need for REPLY_PORTS. */
nthreads = 0;
for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)
++nthreads;
reply_ports = alloca (nthreads * sizeof *reply_ports);
nthreads = 0;
for (ss = _hurd_sigstates; ss != NULL; ss = ss->next, ++nthreads)
if (ss->thread == _hurd_msgport_thread)
reply_ports[nthreads] = MACH_PORT_NULL;
else
{
int state_changed;
state->set = 0; /* Reset scratch area. */
/* Abort any operation in progress with interrupt_operation.
Record the reply port the thread is waiting on.
We will wait for all the replies below. */
reply_ports[nthreads] = _hurdsig_abort_rpcs (ss, signo, 1,
state, &state_changed,
NULL);
if (live)
{
if (reply_ports[nthreads] != MACH_PORT_NULL)
{
/* We will wait for the reply to this RPC below, so the
thread must issue a new RPC rather than waiting for the
reply to the one it sent. */
state->basic.SYSRETURN = EINTR;
state_changed = 1;
}
if (state_changed)
/* Aborting the RPC needed to change this thread's state,
and it might ever run again. So write back its state. */
__thread_set_state (ss->thread, MACHINE_THREAD_STATE_FLAVOR,
(natural_t *) &state->basic,
MACHINE_THREAD_STATE_COUNT);
}
}
/* Wait for replies from all the successfully interrupted RPCs. */
while (nthreads-- > 0)
if (reply_ports[nthreads] != MACH_PORT_NULL)
{
error_t err;
mach_msg_header_t head;
err = __mach_msg (&head, MACH_RCV_MSG|MACH_RCV_TIMEOUT, 0, sizeof head,
reply_ports[nthreads],
_hurd_interrupted_rpc_timeout, MACH_PORT_NULL);
switch (err)
{
case MACH_RCV_TIMED_OUT:
case MACH_RCV_TOO_LARGE:
break;
default:
assert_perror (err);
}
}
}
