| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Copyright (C) 2002-2015 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. |
| 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 <errno.h> |
| 20 | #include <stdlib.h> |
| 21 | #include <atomic.h> |
| 22 | #include "pthreadP.h" |
| 23 | |
| 24 | |
| 25 | static void |
| 26 | cleanup (void *arg) |
| 27 | { |
| 28 | *(void **) arg = NULL; |
| 29 | } |
| 30 | |
| 31 | |
| 32 | int |
| 33 | pthread_timedjoin_np (pthread_t threadid, void **thread_return, |
| 34 | const struct timespec *abstime) |
| 35 | { |
| 36 | struct pthread *self; |
| 37 | struct pthread *pd = (struct pthread *) threadid; |
| 38 | int result; |
| 39 | |
| 40 | /* Make sure the descriptor is valid. */ |
| 41 | if (INVALID_NOT_TERMINATED_TD_P (pd)) |
| 42 | /* Not a valid thread handle. */ |
| 43 | return ESRCH; |
| 44 | |
| 45 | /* Is the thread joinable?. */ |
| 46 | if (IS_DETACHED (pd)) |
| 47 | /* We cannot wait for the thread. */ |
| 48 | return EINVAL; |
| 49 | |
| 50 | self = THREAD_SELF; |
| 51 | if (pd == self || self->joinid == pd) |
| 52 | /* This is a deadlock situation. The threads are waiting for each |
| 53 | other to finish. Note that this is a "may" error. To be 100% |
| 54 | sure we catch this error we would have to lock the data |
| 55 | structures but it is not necessary. In the unlikely case that |
| 56 | two threads are really caught in this situation they will |
| 57 | deadlock. It is the programmer's problem to figure this |
| 58 | out. */ |
| 59 | return EDEADLK; |
| 60 | |
| 61 | /* Wait for the thread to finish. If it is already locked something |
| 62 | is wrong. There can only be one waiter. */ |
| 63 | if (__builtin_expect (atomic_compare_and_exchange_bool_acq (&pd->joinid, |
| 64 | self, NULL), 0)) |
| 65 | /* There is already somebody waiting for the thread. */ |
| 66 | return EINVAL; |
| 67 | |
| 68 | |
| 69 | /* During the wait we change to asynchronous cancellation. If we |
| 70 | are cancelled the thread we are waiting for must be marked as |
| 71 | un-wait-ed for again. */ |
| 72 | pthread_cleanup_push (cleanup, &pd->joinid); |
| 73 | |
| 74 | /* Switch to asynchronous cancellation. */ |
| 75 | int oldtype = CANCEL_ASYNC (); |
| 76 | |
| 77 | |
| 78 | /* Wait for the child. */ |
| 79 | result = lll_timedwait_tid (pd->tid, abstime); |
| 80 | |
| 81 | |
| 82 | /* Restore cancellation mode. */ |
| 83 | CANCEL_RESET (oldtype); |
| 84 | |
| 85 | /* Remove the handler. */ |
| 86 | pthread_cleanup_pop (0); |
| 87 | |
| 88 | |
| 89 | /* We might have timed out. */ |
| 90 | if (result == 0) |
| 91 | { |
| 92 | /* Store the return value if the caller is interested. */ |
| 93 | if (thread_return != NULL) |
| 94 | *thread_return = pd->result; |
| 95 | |
| 96 | |
| 97 | /* Free the TCB. */ |
| 98 | __free_tcb (pd); |
| 99 | } |
| 100 | else |
| 101 | pd->joinid = NULL; |
| 102 | |
| 103 | return result; |
| 104 | } |