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/* vi: set sw=4 ts=4: */
/*
* taskset - retrieve or set a processes' CPU affinity
* Copyright (c) 2006 Bernhard Fischer
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "busybox.h"
#include <sched.h>
#include <getopt.h> /* optind */
#if ENABLE_FEATURE_TASKSET_FANCY
#define TASKSET_PRINTF_MASK "%s"
#define from_cpuset(x) __from_cpuset(&x)
/* craft a string from the mask */
static char *__from_cpuset(cpu_set_t *mask)
{
int i;
char *ret = 0, *str = xzalloc(9);
for (i = CPU_SETSIZE - 4; i >= 0; i -= 4) {
char val = 0;
int off;
for (off = 0; off <= 3; ++off)
if (CPU_ISSET(i+off, mask))
val |= 1<<off;
if (!ret && val)
ret = str;
*str++ = (val-'0'<=9) ? (val+48) : (val+87);
}
return ret;
}
#else
#define TASKSET_PRINTF_MASK "%x"
/* (void*) cast is for battling gcc: */
/* "dereferencing type-punned pointer will break strict-aliasing rules" */
#define from_cpuset(mask) (*(unsigned*)(void*)&(mask))
#endif
#define OPT_p 1
int taskset_main(int argc, char** argv);
int taskset_main(int argc, char** argv)
{
cpu_set_t mask, new_mask;
pid_t pid = 0;
unsigned opt;
const char *state = "current\0new";
char *p_opt = NULL, *aff = NULL;
opt = getopt32(argc, argv, "+p:", &p_opt);
if (opt & OPT_p) {
if (argc == optind+1) { /* -p <aff> <pid> */
aff = p_opt;
p_opt = argv[optind];
}
argv += optind; /* me -p <arg> */
pid = xatoul_range(p_opt, 1, ULONG_MAX); /* -p <pid> */
} else
aff = *++argv; /* <aff> <cmd...> */
if (aff) {
unsigned i = 0;
unsigned long l = xstrtol_range(aff, 0, 1, LONG_MAX);
CPU_ZERO(&new_mask);
while (i < CPU_SETSIZE && l >= (1<<i)) {
if ((1<<i) & l)
CPU_SET(i, &new_mask);
++i;
}
}
if (opt & OPT_p) {
print_aff:
if (sched_getaffinity(pid, sizeof(mask), &mask) < 0)
bb_perror_msg_and_die("failed to %cet pid %d's affinity", 'g', pid);
printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n",
pid, state, from_cpuset(mask));
if (!*argv) /* no new affinity given or we did print already, done. */
return EXIT_SUCCESS;
}
if (sched_setaffinity(pid, sizeof(new_mask), &new_mask))
bb_perror_msg_and_die("failed to %cet pid %d's affinity", 's', pid);
if (opt & OPT_p) {
state += 8;
++argv;
goto print_aff;
}
++argv;
execvp(*argv, argv);
bb_perror_msg_and_die("%s", *argv);
}
#undef OPT_p
#undef TASKSET_PRINTF_MASK
#undef from_cpuset
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