1 | /* Thread cancellation support. |
2 | Copyright (C) 1995-2022 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <https://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <hurd/signal.h> |
20 | #include <hurd/interrupt.h> |
21 | #include <assert.h> |
22 | #include <thread_state.h> |
23 | |
24 | |
25 | /* See hurdsig.c. */ |
26 | extern mach_port_t _hurdsig_abort_rpcs (struct hurd_sigstate *ss, |
27 | int signo, int sigthread, |
28 | struct machine_thread_all_state *, |
29 | int *state_change, |
30 | mach_port_t *reply_port, |
31 | mach_msg_type_name_t reply_port_type, |
32 | int untraced); |
33 | |
34 | error_t |
35 | hurd_thread_cancel (thread_t thread) |
36 | { |
37 | struct hurd_sigstate *ss = _hurd_thread_sigstate (thread); |
38 | struct machine_thread_all_state state; |
39 | int state_change; |
40 | error_t err; |
41 | |
42 | if (! ss) |
43 | return EINVAL; |
44 | if (ss == _hurd_self_sigstate ()) |
45 | { |
46 | /* We are cancelling ourselves, so it is easy to succeed |
47 | quickly. Since this function is not a cancellation point, we |
48 | just leave the flag set pending the next cancellation point |
49 | (hurd_check_cancel or RPC) and return success. */ |
50 | ss->cancel = 1; |
51 | return 0; |
52 | } |
53 | |
54 | assert (! __spin_lock_locked (&ss->critical_section_lock)); |
55 | __spin_lock (&ss->critical_section_lock); |
56 | __spin_lock (&ss->lock); |
57 | err = __thread_suspend (thread); |
58 | __spin_unlock (&ss->lock); |
59 | |
60 | if (! err) |
61 | { |
62 | /* Set the flag telling the thread its operation is being cancelled. */ |
63 | ss->cancel = 1; |
64 | |
65 | /* Interrupt any interruptible RPC now in progress. */ |
66 | state.set = 0; |
67 | _hurdsig_abort_rpcs (ss, 0, 0, &state, &state_change, NULL, 0, 0); |
68 | if (state_change) |
69 | err = __thread_set_state (thread, MACHINE_THREAD_STATE_FLAVOR, |
70 | (natural_t *) &state.basic, |
71 | MACHINE_THREAD_STATE_COUNT); |
72 | |
73 | if (ss->cancel_hook) |
74 | /* The code being cancelled has a special wakeup function. |
75 | Calling this should make the thread wake up and check the |
76 | cancellation flag. */ |
77 | (*ss->cancel_hook) (); |
78 | |
79 | __thread_resume (thread); |
80 | } |
81 | |
82 | _hurd_critical_section_unlock (our_lock: ss); |
83 | return err; |
84 | } |
85 | |
86 | |
87 | int |
88 | hurd_check_cancel (void) |
89 | { |
90 | struct hurd_sigstate *ss = _hurd_self_sigstate (); |
91 | int cancel; |
92 | |
93 | __spin_lock (&ss->lock); |
94 | assert (! __spin_lock_locked (&ss->critical_section_lock)); |
95 | cancel = ss->cancel; |
96 | ss->cancel = 0; |
97 | __spin_unlock (&ss->lock); |
98 | |
99 | return cancel; |
100 | } |
101 | |