1 /*
2 * Copyright (c) 2002-2004 Roland McGrath <roland@redhat.com>
3 * Copyright (c) 2009-2016 Dmitry V. Levin <ldv@altlinux.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "defs.h"
30 #include <sched.h>
31
32 static unsigned int
get_cpuset_size(void)33 get_cpuset_size(void)
34 {
35 static unsigned int cpuset_size;
36
37 if (!cpuset_size) {
38 /*
39 * If the cpuset size passed to sched_getaffinity is less
40 * than necessary to store the bitmask, the kernel does not
41 * look at the mask pointer and fails with EINVAL.
42 *
43 * If the cpuset size is large enough, the kernel fails with
44 * EFAULT on inaccessible mask pointers.
45 *
46 * This undocumented kernel feature can be used to probe
47 * the kernel and find out the minimal valid cpuset size
48 * without allocating any memory for the CPU affinity mask.
49 */
50 cpuset_size = 128;
51 while (cpuset_size &&
52 sched_getaffinity(0, cpuset_size, NULL) == -1 &&
53 EINVAL == errno) {
54 cpuset_size <<= 1;
55 }
56 if (!cpuset_size)
57 cpuset_size = 128;
58 }
59
60 return cpuset_size;
61 }
62
63 static void
print_affinitylist(struct tcb * const tcp,const kernel_ulong_t addr,const unsigned int len)64 print_affinitylist(struct tcb *const tcp, const kernel_ulong_t addr,
65 const unsigned int len)
66 {
67 const unsigned int max_size = get_cpuset_size();
68 const unsigned int umove_size = len < max_size ? len : max_size;
69 const unsigned int size =
70 (umove_size + current_wordsize - 1) & -current_wordsize;
71 const unsigned int ncpu = size * 8;
72 void *cpu;
73
74 if (!verbose(tcp) || (exiting(tcp) && syserror(tcp)) ||
75 !addr || !len || !(cpu = calloc(size, 1))) {
76 printaddr(addr);
77 return;
78 }
79
80 if (!umoven_or_printaddr(tcp, addr, umove_size, cpu)) {
81 int i = 0;
82 const char *sep = "";
83
84 tprints("[");
85 for (;; i++) {
86 i = next_set_bit(cpu, i, ncpu);
87 if (i < 0)
88 break;
89 tprintf("%s%d", sep, i);
90 sep = ", ";
91 }
92 if (size < len)
93 tprintf("%s...", sep);
94 tprints("]");
95 }
96
97 free(cpu);
98 }
99
SYS_FUNC(sched_setaffinity)100 SYS_FUNC(sched_setaffinity)
101 {
102 const int pid = tcp->u_arg[0];
103 const unsigned int len = tcp->u_arg[1];
104
105 tprintf("%d, %u, ", pid, len);
106 print_affinitylist(tcp, tcp->u_arg[2], len);
107
108 return RVAL_DECODED;
109 }
110
SYS_FUNC(sched_getaffinity)111 SYS_FUNC(sched_getaffinity)
112 {
113 const int pid = tcp->u_arg[0];
114 const unsigned int len = tcp->u_arg[1];
115
116 if (entering(tcp)) {
117 tprintf("%d, %u, ", pid, len);
118 } else {
119 print_affinitylist(tcp, tcp->u_arg[2], tcp->u_rval);
120 }
121 return 0;
122 }
123