| 1 | /* Internal definitions for pthreads library. |
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| 2 | Copyright (C) 2016-2024 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #ifndef _PT_MUTEX_H |
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| 20 | #define _PT_MUTEX_H 1 |
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| 21 | |
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| 22 | /* Special ID used to signal an unrecoverable robust mutex. */ |
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| 23 | #define NOTRECOVERABLE_ID (1U << 31) |
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| 24 | |
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| 25 | /* Common path for robust mutexes. Assumes the variable 'ret' |
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| 26 | * is bound in the function this is called from. */ |
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| 27 | #define ROBUST_LOCK(self, mtxp, cb, ...) \ |
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| 28 | if (mtxp->__owner_id == NOTRECOVERABLE_ID) \ |
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| 29 | return ENOTRECOVERABLE; \ |
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| 30 | else if (mtxp->__owner_id == self->thread \ |
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| 31 | && __getpid () == (int)(mtxp->__lock & LLL_OWNER_MASK)) \ |
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| 32 | { \ |
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| 33 | if (mtxp->__type == PT_MTX_RECURSIVE) \ |
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| 34 | { \ |
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| 35 | if (__glibc_unlikely (mtxp->__cnt + 1 == 0)) \ |
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| 36 | return EAGAIN; \ |
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| 37 | \ |
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| 38 | ++mtxp->__cnt; \ |
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| 39 | return 0; \ |
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| 40 | } \ |
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| 41 | else if (mtxp->__type == PT_MTX_ERRORCHECK) \ |
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| 42 | return EDEADLK; \ |
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| 43 | } \ |
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| 44 | \ |
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| 45 | ret = cb (mtxp->__lock, ##__VA_ARGS__); \ |
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| 46 | if (ret == 0 || ret == EOWNERDEAD) \ |
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| 47 | { \ |
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| 48 | if (mtxp->__owner_id == ENOTRECOVERABLE) \ |
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| 49 | ret = ENOTRECOVERABLE; \ |
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| 50 | else \ |
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| 51 | { \ |
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| 52 | mtxp->__owner_id = self->thread; \ |
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| 53 | mtxp->__cnt = 1; \ |
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| 54 | if (ret == EOWNERDEAD) \ |
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| 55 | { \ |
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| 56 | mtxp->__lock = mtxp->__lock | LLL_DEAD_OWNER; \ |
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| 57 | atomic_write_barrier (); \ |
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| 58 | } \ |
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| 59 | } \ |
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| 60 | } \ |
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| 61 | (void)0 |
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| 62 | |
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| 63 | /* Check that a thread owns the mutex. For non-robust, task-shared |
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| 64 | * objects, we have to check the thread *and* process-id. */ |
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| 65 | #define mtx_owned_p(mtx, pt, flags) \ |
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| 66 | ((mtx)->__owner_id == (pt)->thread \ |
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| 67 | && (((flags) & GSYNC_SHARED) == 0 \ |
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| 68 | || (mtx)->__shpid == __getpid ())) |
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| 69 | |
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| 70 | /* Record a thread as the owner of the mutex. */ |
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| 71 | #define mtx_set_owner(mtx, pt, flags) \ |
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| 72 | (void) \ |
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| 73 | ({ \ |
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| 74 | (mtx)->__owner_id = (pt)->thread; \ |
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| 75 | if ((flags) & GSYNC_SHARED) \ |
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| 76 | (mtx)->__shpid = __getpid (); \ |
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| 77 | }) |
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| 78 | |
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| 79 | /* Redefined mutex types. The +1 is for binary compatibility. */ |
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| 80 | #define PT_MTX_NORMAL __PTHREAD_MUTEX_TIMED |
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| 81 | #define PT_MTX_RECURSIVE (__PTHREAD_MUTEX_RECURSIVE + 1) |
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| 82 | #define PT_MTX_ERRORCHECK (__PTHREAD_MUTEX_ERRORCHECK + 1) |
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| 83 | |
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| 84 | /* Mutex type, including robustness. */ |
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| 85 | #define MTX_TYPE(mtxp) \ |
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| 86 | ((mtxp)->__type | ((mtxp)->__flags & PTHREAD_MUTEX_ROBUST)) |
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| 87 | |
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| 88 | extern int __getpid (void) __attribute__ ((const)); |
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| 89 | |
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| 90 | #endif /* pt-mutex.h */ |
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| 91 | |
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