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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