1/* vi: set sw=4 ts=4: */
2/*
3 * taskset - retrieve or set a processes' CPU affinity
4 * Copyright (c) 2006 Bernhard Fischer
5 *
6 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
7 */
8
9#include <sched.h>
10#include <getopt.h> /* optind */
11#include "libbb.h"
12
13#if ENABLE_FEATURE_TASKSET_FANCY
14#define TASKSET_PRINTF_MASK "%s"
15#define from_cpuset(x) __from_cpuset(&x)
16/* craft a string from the mask */
17static char *__from_cpuset(cpu_set_t *mask)
18{
19	int i;
20	char *ret = 0, *str = xzalloc(9);
21
22	for (i = CPU_SETSIZE - 4; i >= 0; i -= 4) {
23		char val = 0;
24		int off;
25		for (off = 0; off <= 3; ++off)
26			if (CPU_ISSET(i+off, mask))
27				val |= 1<<off;
28
29		if (!ret && val)
30			ret = str;
31		*str++ = (val-'0'<=9) ? (val+48) : (val+87);
32	}
33	return ret;
34}
35#else
36#define TASKSET_PRINTF_MASK "%x"
37/* (void*) cast is for battling gcc: */
38/* "dereferencing type-punned pointer will break strict-aliasing rules" */
39#define from_cpuset(mask) (*(unsigned*)(void*)&(mask))
40#endif
41
42#define OPT_p 1
43
44int taskset_main(int argc, char** argv);
45int taskset_main(int argc, char** argv)
46{
47	cpu_set_t mask, new_mask;
48	pid_t pid = 0;
49	unsigned opt;
50	const char *state = "current\0new";
51	char *p_opt = NULL, *aff = NULL;
52
53	opt = getopt32(argv, "+p:", &p_opt);
54
55	if (opt & OPT_p) {
56		if (argc == optind+1) { /* -p <aff> <pid> */
57			aff = p_opt;
58			p_opt = argv[optind];
59		}
60		argv += optind; /* me -p <arg> */
61		pid = xatoul_range(p_opt, 1, ULONG_MAX); /* -p <pid> */
62	} else
63		aff = *++argv; /* <aff> <cmd...> */
64	if (aff) {
65		unsigned i = 0;
66		unsigned long l = xstrtol_range(aff, 0, 1, LONG_MAX);
67
68		CPU_ZERO(&new_mask);
69		while (i < CPU_SETSIZE && l >= (1<<i)) {
70			if ((1<<i) & l)
71				CPU_SET(i, &new_mask);
72			++i;
73		}
74	}
75
76	if (opt & OPT_p) {
77 print_aff:
78		if (sched_getaffinity(pid, sizeof(mask), &mask) < 0)
79			bb_perror_msg_and_die("failed to %cet pid %d's affinity", 'g', pid);
80		printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n",
81				pid, state, from_cpuset(mask));
82		if (!*argv) /* no new affinity given or we did print already, done. */
83			return EXIT_SUCCESS;
84	}
85
86	if (sched_setaffinity(pid, sizeof(new_mask), &new_mask))
87		bb_perror_msg_and_die("failed to %cet pid %d's affinity", 's', pid);
88	if (opt & OPT_p) {
89		state += 8;
90		++argv;
91		goto print_aff;
92	}
93	++argv;
94	BB_EXECVP(*argv, argv);
95	bb_perror_msg_and_die("%s", *argv);
96}
97#undef OPT_p
98#undef TASKSET_PRINTF_MASK
99#undef from_cpuset
100