1 /* Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
17
18 #include <sys/syscall.h>
19
20 #if defined __NR_sched_setaffinity && defined __USE_GNU
21 # include <sched.h>
22 # include <sys/types.h>
23 # include <string.h>
24 # include <unistd.h>
25 # include <alloca.h>
26 # define __NR___syscall_sched_setaffinity __NR_sched_setaffinity
27 static __always_inline _syscall3(int, __syscall_sched_setaffinity, __kernel_pid_t, pid,
28 size_t, cpusetsize, const cpu_set_t *, cpuset)
29
30 static size_t __kernel_cpumask_size;
31
sched_setaffinity(pid_t pid,size_t cpusetsize,const cpu_set_t * cpuset)32 int sched_setaffinity(pid_t pid, size_t cpusetsize, const cpu_set_t *cpuset)
33 {
34 size_t cnt;
35 if (unlikely (__kernel_cpumask_size == 0)) {
36 INTERNAL_SYSCALL_DECL (err);
37 int res;
38 size_t psize = 128;
39 void *p = alloca (psize);
40
41 while (res = INTERNAL_SYSCALL (sched_getaffinity, err, 3, getpid (),
42 psize, p),
43 INTERNAL_SYSCALL_ERROR_P (res, err)
44 && INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
45 p = extend_alloca (p, psize, 2 * psize);
46
47 if (res == 0 || INTERNAL_SYSCALL_ERROR_P (res, err)) {
48 __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
49 return -1;
50 }
51
52 __kernel_cpumask_size = res;
53 }
54
55 /* We now know the size of the kernel cpumask_t. Make sure the user
56 does not request to set a bit beyond that. */
57 for (cnt = __kernel_cpumask_size; cnt < cpusetsize; ++cnt)
58 if (((char *) cpuset)[cnt] != '\0') {
59 /* Found a nonzero byte. This means the user request cannot be
60 fulfilled. */
61 __set_errno (EINVAL);
62 return -1;
63 }
64
65 return __syscall_sched_setaffinity(pid, cpusetsize, cpuset);
66 }
67 #endif
68