xref: /freebsd/lib/libc/gen/sched_setaffinity.c (revision 031beb4e239bfce798af17f5fe8dba8bcaf13d99)
1 /*-
2  * Copyright (c) 2021 The FreeBSD Foundation
3  *
4  * This software were developed by Konstantin Belousov <kib@FreeBSD.org>
5  * under sponsorship from the FreeBSD Foundation.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #define	_WANT_P_OSREL
30 #include <sys/param.h>
31 #include <sys/sysctl.h>
32 #include <errno.h>
33 #include <sched.h>
34 #include <string.h>
35 
36 #include "libc_private.h"
37 
38 int
39 sched_setaffinity(pid_t pid, size_t cpusetsz, const cpuset_t *cpuset)
40 {
41 	static int mp_maxid;
42 	cpuwhich_t which;
43 	cpuset_t c;
44 	int error, lbs, cpu;
45 	size_t len, sz;
46 
47 	if (__getosreldate() < P_OSREL_TIDPID) {
48 		if (pid == 0 || pid > _PID_MAX)
49 			which = CPU_WHICH_TID;
50 		else
51 			which = CPU_WHICH_PID;
52 	} else
53 		which = CPU_WHICH_TIDPID;
54 
55 	sz = cpusetsz > sizeof(cpuset_t) ? sizeof(cpuset_t) : cpusetsz;
56 	memset(&c, 0, sizeof(c));
57 	memcpy(&c, cpuset, sz);
58 
59 	/* Linux ignores high bits */
60 	if (mp_maxid == 0) {
61 		len = sizeof(mp_maxid);
62 		error = sysctlbyname("kern.smp.maxid", &mp_maxid, &len,
63 		    NULL, 0);
64 		if (error == -1)
65 			return (error);
66 	}
67 	lbs = CPU_FLS(&c) - 1;
68 	if (lbs > mp_maxid) {
69 		CPU_FOREACH_ISSET(cpu, &c)
70 			if (cpu > mp_maxid)
71 				CPU_CLR(cpu, &c);
72 	}
73 	error = cpuset_setaffinity(CPU_LEVEL_WHICH, which,
74 	    pid == 0 ? -1 : pid, sizeof(cpuset_t), &c);
75 	if (error == -1 && errno == EDEADLK)
76 		errno = EINVAL;
77 
78 	return (error);
79 }
80