| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Thread cancellation support. |
| 2 | Copyright (C) 1995-2015 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 | <http://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 (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 | } |