1 /* pthread_mutex_transfer_np. Transfer mutex ownership to another thread.
2 Hurd version.
3 Copyright (C) 2016-2022 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20 #include <pthread.h>
21 #include <stdlib.h>
22 #include <assert.h>
23 #include <pt-internal.h>
24 #include "pt-mutex.h"
25 #include <hurdlock.h>
26
27 int
__pthread_mutex_transfer_np(pthread_mutex_t * mtxp,pthread_t th)28 __pthread_mutex_transfer_np (pthread_mutex_t *mtxp, pthread_t th)
29 {
30 struct __pthread *self = _pthread_self ();
31 struct __pthread *pt = __pthread_getid (th);
32
33 if (pt == NULL)
34 return ESRCH;
35 else if (pt == self)
36 return 0;
37
38 int ret = 0;
39 int flags = mtxp->__flags & GSYNC_SHARED;
40
41 switch (MTX_TYPE (mtxp))
42 {
43 case PT_MTX_NORMAL:
44 break;
45
46 case PT_MTX_RECURSIVE:
47 case PT_MTX_ERRORCHECK:
48 if (!mtx_owned_p (mtxp, self, flags))
49 ret = EPERM;
50 else
51 mtx_set_owner (mtxp, pt, flags);
52
53 break;
54
55 case PT_MTX_NORMAL | PTHREAD_MUTEX_ROBUST:
56 case PT_MTX_RECURSIVE | PTHREAD_MUTEX_ROBUST:
57 case PT_MTX_ERRORCHECK | PTHREAD_MUTEX_ROBUST:
58 /* Note that this can be used to transfer an inconsistent
59 * mutex as well. The new owner will still have the same
60 * flags as the original. */
61 if (mtxp->__owner_id != self->thread
62 || (int) (mtxp->__lock & LLL_OWNER_MASK) != __getpid ())
63 ret = EPERM;
64 else
65 mtxp->__owner_id = pt->thread;
66
67 break;
68
69 default:
70 ret = EINVAL;
71 }
72
73 return ret;
74 }
75
76 weak_alias (__pthread_mutex_transfer_np, pthread_mutex_transfer_np)
77