opnsense-src/lib/libc/gen/sched_setaffinity.c
Dmitry Chagin 72bc1e6806 cpuset: Byte swap cpuset for compat32 on big endian architectures
Summary:
BITSET uses long as its basic underlying type, which is dependent on the
compile type, meaning on 32-bit builds the basic type is 32 bits, but on
64-bit builds it's 64 bits.  On little endian architectures this doesn't
matter, because the LSB is always at the low bit, so the words get
effectively concatenated moving between 32-bit and 64-bit, but on
big-endian architectures it throws a wrench in, as setting bit 0 in
32-bit mode is equivalent to setting bit 32 in 64-bit mode.  To
demonstrate:

32-bit mode:

BIT_SET(foo, 0):        0x00000001

64-bit sees: 0x0000000100000000

cpuset is the only system interface that uses bitsets, so solve this
by swapping the integer sub-components at the copyin/copyout points.

Reviewed by:    kib
Sponsored by:   Juniper Networks, Inc.
Differential Revision:  https://reviews.freebsd.org/D35225

(cherry picked from commit 47a57144af)

Fix the build after 47a57144

(cherry picked from commit 89737eb829)

cpuset: Fix the KASAN and KMSAN builds

Rename the "copyin" and "copyout" fields of struct cpuset_copy_cb to
something less generic, since sanitizers define interceptors for
copyin() and copyout() using #define.

Reported by:    syzbot+2db5d644097fc698fb6f@syzkaller.appspotmail.com
Fixes:  47a57144af ("cpuset: Byte swap cpuset for compat32 on big endian architectures")
Sponsored by:   The FreeBSD Foundation

(cherry picked from commit 4a3e51335e)

Use Linux semantics for the thread affinity syscalls.

Linux has more tolerant checks of the user supplied cpuset_t's.

Minimum cpuset_t size that the Linux kernel permits in case of
getaffinity() is the maximum CPU id, present in the system / NBBY,
the maximum size is not limited.
For setaffinity(), Linux does not limit the size of the user-provided
cpuset_t, internally using only the meaningful part of the set, where
the upper bound is the maximum CPU id, present in the system, no larger
than the size of the kernel cpuset_t.
Unlike FreeBSD, Linux ignores high bits if set in the setaffinity(),
so clear it in the sched_setaffinity() and Linuxulator itself.

Reviewed by:            Pau Amma (man pages)
In collaboration with:  jhb
Differential revision:  https://reviews.freebsd.org/D34849
MFC after:              2 weeks

(cherry picked from commit f35093f8d6)
2022-06-17 22:35:14 +03:00

67 lines
2.3 KiB
C

/*-
* Copyright (c) 2021 The FreeBSD Foundation
*
* This software were developed by Konstantin Belousov <kib@FreeBSD.org>
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/sysctl.h>
#include <errno.h>
#include <sched.h>
#include <string.h>
int
sched_setaffinity(pid_t pid, size_t cpusetsz, const cpuset_t *cpuset)
{
static int mp_maxid;
cpuset_t c;
int error, lbs, cpu;
size_t len, sz;
sz = cpusetsz > sizeof(cpuset_t) ? sizeof(cpuset_t) : cpusetsz;
memset(&c, 0, sizeof(c));
memcpy(&c, cpuset, sz);
/* Linux ignores high bits */
if (mp_maxid == 0) {
len = sizeof(mp_maxid);
error = sysctlbyname("kern.smp.maxid", &mp_maxid, &len,
NULL, 0);
if (error == -1)
return (error);
}
lbs = CPU_FLS(&c) - 1;
if (lbs > mp_maxid) {
CPU_FOREACH_ISSET(cpu, &c)
if (cpu > mp_maxid)
CPU_CLR(cpu, &c);
}
error = cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_PID,
pid == 0 ? -1 : pid, sizeof(cpuset_t), &c);
if (error == -1 && errno == EDEADLK)
errno = EINVAL;
return (error);
}