busybox/miscutils/taskset.c

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/* vi: set sw=4 ts=4: */
/*
* taskset - retrieve or set a processes's 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 <unistd.h>
#include <getopt.h> /* optind */
int taskset_main(int argc, char** argv)
{
cpu_set_t mask, new_mask;
pid_t pid = 0;
unsigned long ul;
const char *state = "current\0new";
char *p_opt = NULL, *aff = NULL;
ul = bb_getopt_ulflags(argc, argv, "+p:", &p_opt);
#define TASKSET_OPT_p (1)
if (ul & TASKSET_OPT_p) {
if (argc == optind+1) { /* -p <aff> <pid> */
aff = p_opt;
p_opt = argv[optind];
}
argv += optind; /* me -p <arg> */
pid = bb_xgetularg10_bnd(p_opt, 1, ULONG_MAX); /* -p <pid> */
} else
aff = *++argv; /* <aff> <cmd...> */
if (aff) {
/* to_cpuset(bb_xgetularg_bnd(aff, 16, 1, ULONG_MAX), &new_mask); */
unsigned i = 0;
unsigned long l = bb_xgetularg_bnd(aff, 16, 1, ULONG_MAX);
CPU_ZERO(&new_mask);
while (i < CPU_SETSIZE && l >= (1<<i)) {
if ((1<<i) & l)
CPU_SET(i, &new_mask);
++i;
}
}
if (ul & TASKSET_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);
bb_printf("pid %d's %s affinity mask: %x\n", /* %x .. perhaps _FANCY */
pid, state, 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 (ul & TASKSET_OPT_p) {
state += 8;
++argv;
goto print_aff;
}
++argv;
execvp(*argv, argv);
bb_perror_msg_and_die("%s", *argv);
}