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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 <sched.h>
#include "libbb.h"
#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
int taskset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int taskset_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
cpu_set_t mask;
pid_t pid = 0;
unsigned opt_p;
const char *current_new;
char *pid_str;
char *aff = aff; /* for compiler */
/* NB: we mimic util-linux's taskset: -p does not take
* an argument, i.e., "-pN" is NOT valid, only "-p N"!
* Indeed, util-linux-2.13-pre7 uses:
* getopt_long(argc, argv, "+pchV", ...), not "...p:..." */
opt_complementary = "-1"; /* at least 1 arg */
opt_p = getopt32(argv, "+p");
argv += optind;
if (opt_p) {
pid_str = *argv++;
if (*argv) { /* "-p <aff> <pid> ...rest.is.ignored..." */
aff = pid_str;
pid_str = *argv; /* NB: *argv != NULL in this case */
}
/* else it was just "-p <pid>", and *argv == NULL */
pid = xatoul_range(pid_str, 1, ((unsigned)(pid_t)ULONG_MAX) >> 1);
} else {
aff = *argv++; /* <aff> <cmd...> */
if (!*argv)
bb_show_usage();
}
current_new = "current\0new";
if (opt_p) {
print_aff:
if (sched_getaffinity(pid, sizeof(mask), &mask) < 0)
bb_perror_msg_and_die("can't %cet pid %d's affinity", 'g', pid);
printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n",
pid, current_new, from_cpuset(mask));
if (!*argv) {
/* Either it was just "-p <pid>",
* or it was "-p <aff> <pid>" and we came here
* for the second time (see goto below) */
return EXIT_SUCCESS;
}
*argv = NULL;
current_new += 8; /* "new" */
}
{ /* Affinity was specified, translate it into cpu_set_t */
unsigned i;
/* Do not allow zero mask: */
unsigned long long m = xstrtoull_range(aff, 0, 1, ULLONG_MAX);
enum { CNT_BIT = CPU_SETSIZE < sizeof(m)*8 ? CPU_SETSIZE : sizeof(m)*8 };
CPU_ZERO(&mask);
for (i = 0; i < CNT_BIT; i++) {
unsigned long long bit = (1ULL << i);
if (bit & m)
CPU_SET(i, &mask);
}
}
/* Set pid's or our own (pid==0) affinity */
if (sched_setaffinity(pid, sizeof(mask), &mask))
bb_perror_msg_and_die("can't %cet pid %d's affinity", 's', pid);
if (!*argv) /* "-p <aff> <pid> [...ignored...]" */
goto print_aff; /* print new affinity and exit */
BB_EXECVP(*argv, argv);
bb_simple_perror_msg_and_die(*argv);
}
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