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