1 /* Copyright (C) 2003, 2004, 2006, 2007 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
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 <alloca.h>
20 #include <errno.h>
21 #include <pthreadP.h>
22 #include <sysdep.h>
23 #include <sys/types.h>
24
25
26 size_t __kernel_cpumask_size attribute_hidden;
27
28
29 /* Determine the current affinity. As a side affect we learn
30 about the size of the cpumask_t in the kernel. */
31 extern int __determine_cpumask_size (pid_t tid);
libpthread_hidden_proto(__determine_cpumask_size)32 libpthread_hidden_proto(__determine_cpumask_size)
33 int __determine_cpumask_size (pid_t tid)
34 {
35 INTERNAL_SYSCALL_DECL (err);
36 int res;
37
38 size_t psize = 128;
39 void *p = alloca (psize);
40
41 while (res = INTERNAL_SYSCALL (sched_getaffinity, err, 3, tid, psize, p),
42 INTERNAL_SYSCALL_ERROR_P (res, err)
43 && INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
44 p = extend_alloca (p, psize, 2 * psize);
45
46 if (res == 0 || INTERNAL_SYSCALL_ERROR_P (res, err))
47 return INTERNAL_SYSCALL_ERRNO (res, err);
48
49 __kernel_cpumask_size = res;
50
51 return 0;
52 }
libpthread_hidden_def(__determine_cpumask_size)53 libpthread_hidden_def(__determine_cpumask_size)
54
55 int
56 pthread_setaffinity_np (pthread_t th, size_t cpusetsize,
57 const cpu_set_t *cpuset)
58 {
59 const struct pthread *pd = (const struct pthread *) th;
60
61 INTERNAL_SYSCALL_DECL (err);
62 int res;
63
64 if (__builtin_expect (__kernel_cpumask_size == 0, 0))
65 {
66 res = __determine_cpumask_size (pd->tid);
67 if (res != 0)
68 return res;
69 }
70
71 /* We now know the size of the kernel cpumask_t. Make sure the user
72 does not request to set a bit beyond that. */
73 size_t cnt;
74 for (cnt = __kernel_cpumask_size; cnt < cpusetsize; ++cnt)
75 if (((char *) cpuset)[cnt] != '\0')
76 /* Found a nonzero byte. This means the user request cannot be
77 fulfilled. */
78 return EINVAL;
79
80 res = INTERNAL_SYSCALL (sched_setaffinity, err, 3, pd->tid, cpusetsize,
81 cpuset);
82
83 #ifdef RESET_VGETCPU_CACHE
84 if (!INTERNAL_SYSCALL_ERROR_P (res, err))
85 RESET_VGETCPU_CACHE ();
86 #endif
87
88 return (INTERNAL_SYSCALL_ERROR_P (res, err)
89 ? INTERNAL_SYSCALL_ERRNO (res, err)
90 : 0);
91 }
92