| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame^] | 1 | /* Copyright (C) 2002, 2003, 2005 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, write to the Free |
| 17 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 18 | 02111-1307 USA. */ |
| 19 | |
| 20 | #include <errno.h> |
| 21 | #include <stdlib.h> |
| 22 | |
| 23 | #include <atomic.h> |
| 24 | #include "pthreadP.h" |
| 25 | |
| 26 | |
| 27 | int |
| 28 | pthread_tryjoin_np ( |
| 29 | pthread_t threadid, |
| 30 | void **thread_return) |
| 31 | { |
| 32 | struct pthread *self; |
| 33 | struct pthread *pd = (struct pthread *) threadid; |
| 34 | |
| 35 | /* Make sure the descriptor is valid. */ |
| 36 | if (DEBUGGING_P && __find_in_stack_list (pd) == NULL) |
| 37 | /* Not a valid thread handle. */ |
| 38 | return ESRCH; |
| 39 | |
| 40 | /* Is the thread joinable?. */ |
| 41 | if (IS_DETACHED (pd)) |
| 42 | /* We cannot wait for the thread. */ |
| 43 | return EINVAL; |
| 44 | |
| 45 | self = THREAD_SELF; |
| 46 | if (pd == self || self->joinid == pd) |
| 47 | /* This is a deadlock situation. The threads are waiting for each |
| 48 | other to finish. Note that this is a "may" error. To be 100% |
| 49 | sure we catch this error we would have to lock the data |
| 50 | structures but it is not necessary. In the unlikely case that |
| 51 | two threads are really caught in this situation they will |
| 52 | deadlock. It is the programmer's problem to figure this |
| 53 | out. */ |
| 54 | return EDEADLK; |
| 55 | |
| 56 | /* Return right away if the thread hasn't terminated yet. */ |
| 57 | if (pd->tid != 0) |
| 58 | return EBUSY; |
| 59 | |
| 60 | /* Wait for the thread to finish. If it is already locked something |
| 61 | is wrong. There can only be one waiter. */ |
| 62 | if (atomic_compare_and_exchange_bool_acq (&pd->joinid, self, NULL)) |
| 63 | /* There is already somebody waiting for the thread. */ |
| 64 | return EINVAL; |
| 65 | |
| 66 | /* Store the return value if the caller is interested. */ |
| 67 | if (thread_return != NULL) |
| 68 | *thread_return = pd->result; |
| 69 | |
| 70 | |
| 71 | /* Free the TCB. */ |
| 72 | __free_tcb (pd); |
| 73 | |
| 74 | return 0; |
| 75 | } |