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/*
* Copyright (c) 2002-2004 Roland McGrath <roland@redhat.com>
* Copyright (c) 2009-2018 Dmitry V. Levin <ldv@strace.io>
* Copyright (c) 2014-2022 The strace developers.
* All rights reserved.
*
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#include "defs.h"
#include <sched.h>
static unsigned int
get_cpuset_size(void)
{
static unsigned int cpuset_size;
if (!cpuset_size) {
/*
* If the cpuset size passed to sched_getaffinity is less
* than necessary to store the bitmask, the kernel does not
* look at the mask pointer and fails with EINVAL.
*
* If the cpuset size is large enough, the kernel fails with
* EFAULT on inaccessible mask pointers.
*
* This undocumented kernel feature can be used to probe
* the kernel and find out the minimal valid cpuset size
* without allocating any memory for the CPU affinity mask.
*/
cpuset_size = 128;
while (cpuset_size &&
sched_getaffinity(0, cpuset_size, NULL) == -1 &&
EINVAL == errno) {
cpuset_size <<= 1;
}
if (!cpuset_size)
cpuset_size = 128;
}
return cpuset_size;
}
void
print_affinitylist(struct tcb *const tcp, const kernel_ulong_t addr,
const unsigned int len)
{
const unsigned int max_size = get_cpuset_size();
const unsigned int umove_size = MIN(len, max_size);
const unsigned int size = ROUNDUP(umove_size, current_wordsize);
const unsigned int ncpu = size * 8;
void *cpu;
if (!verbose(tcp) || (exiting(tcp) && syserror(tcp)) ||
!addr) {
printaddr(addr);
return;
}
if (!len) {
tprint_array_begin();
tprint_array_end();
return;
}
if (!(cpu = calloc(size, 1))) {
printaddr(addr);
return;
}
if (!umoven_or_printaddr(tcp, addr, umove_size, cpu)) {
bool printed = false;
tprint_bitset_begin();
for (int i = 0;; i++) {
i = next_set_bit(cpu, i, ncpu);
if (i < 0)
break;
if (printed)
tprint_bitset_next();
else
printed = true;
PRINT_VAL_D(i);
}
if (size < len) {
if (printed)
tprint_bitset_next();
tprint_more_data_follows();
}
tprint_bitset_end();
}
free(cpu);
}
SYS_FUNC(sched_setaffinity)
{
/* pid */
const int pid = tcp->u_arg[0];
printpid(tcp, pid, PT_TGID);
tprint_arg_next();
/* cpusetsize */
const unsigned int len = tcp->u_arg[1];
PRINT_VAL_U(len);
tprint_arg_next();
/* mask */
print_affinitylist(tcp, tcp->u_arg[2], len);
return RVAL_DECODED;
}
SYS_FUNC(sched_getaffinity)
{
if (entering(tcp)) {
/* pid */
const int pid = tcp->u_arg[0];
printpid(tcp, pid, PT_TGID);
tprint_arg_next();
/* cpusetsize */
const unsigned int len = tcp->u_arg[1];
PRINT_VAL_U(len);
tprint_arg_next();
} else {
/* mask */
print_affinitylist(tcp, tcp->u_arg[2], tcp->u_rval);
}
return 0;
}
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