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