[1765] | 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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[2725] | 4 | * Copyright (c) 2006 Bernhard Reutner-Fischer
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[1765] | 5 | *
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[2725] | 6 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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[1765] | 7 | */
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| 8 |
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[3621] | 9 | //config:config TASKSET
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| 10 | //config: bool "taskset"
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| 11 | //config: default n # doesn't build on some non-x86 targets (m68k)
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| 12 | //config: help
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| 13 | //config: Retrieve or set a processes's CPU affinity.
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| 14 | //config: This requires sched_{g,s}etaffinity support in your libc.
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| 15 | //config:
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| 16 | //config:config FEATURE_TASKSET_FANCY
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| 17 | //config: bool "Fancy output"
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| 18 | //config: default y
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| 19 | //config: depends on TASKSET
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| 20 | //config: help
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| 21 | //config: Add code for fancy output. This merely silences a compiler-warning
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| 22 | //config: and adds about 135 Bytes. May be needed for machines with alot
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| 23 | //config: of CPUs.
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| 24 |
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| 25 | //applet:IF_TASKSET(APPLET(taskset, BB_DIR_USR_BIN, BB_SUID_DROP))
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| 26 | //kbuild:lib-$(CONFIG_TASKSET) += taskset.o
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| 27 |
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[3232] | 28 | //usage:#define taskset_trivial_usage
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| 29 | //usage: "[-p] [MASK] [PID | PROG ARGS]"
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| 30 | //usage:#define taskset_full_usage "\n\n"
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| 31 | //usage: "Set or get CPU affinity\n"
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| 32 | //usage: "\n -p Operate on an existing PID"
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| 33 | //usage:
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| 34 | //usage:#define taskset_example_usage
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| 35 | //usage: "$ taskset 0x7 ./dgemm_test&\n"
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| 36 | //usage: "$ taskset -p 0x1 $!\n"
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| 37 | //usage: "pid 4790's current affinity mask: 7\n"
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| 38 | //usage: "pid 4790's new affinity mask: 1\n"
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| 39 | //usage: "$ taskset 0x7 /bin/sh -c './taskset -p 0x1 $$'\n"
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| 40 | //usage: "pid 6671's current affinity mask: 1\n"
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| 41 | //usage: "pid 6671's new affinity mask: 1\n"
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| 42 | //usage: "$ taskset -p 1\n"
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| 43 | //usage: "pid 1's current affinity mask: 3\n"
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[3621] | 44 | /*
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| 45 | Not yet implemented:
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| 46 | * -a/--all-tasks (affect all threads)
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| 47 | * -c/--cpu-list (specify CPUs via "1,3,5-7")
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| 48 | */
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[3232] | 49 |
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[1765] | 50 | #include <sched.h>
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| 51 | #include "libbb.h"
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| 52 |
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| 53 | #if ENABLE_FEATURE_TASKSET_FANCY
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| 54 | #define TASKSET_PRINTF_MASK "%s"
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| 55 | /* craft a string from the mask */
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[2725] | 56 | static char *from_cpuset(cpu_set_t *mask)
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[1765] | 57 | {
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| 58 | int i;
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[2725] | 59 | char *ret = NULL;
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| 60 | char *str = xzalloc((CPU_SETSIZE / 4) + 1); /* we will leak it */
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[1765] | 61 |
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| 62 | for (i = CPU_SETSIZE - 4; i >= 0; i -= 4) {
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[2725] | 63 | int val = 0;
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[1765] | 64 | int off;
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| 65 | for (off = 0; off <= 3; ++off)
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[2725] | 66 | if (CPU_ISSET(i + off, mask))
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| 67 | val |= 1 << off;
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[1765] | 68 | if (!ret && val)
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| 69 | ret = str;
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[2725] | 70 | *str++ = bb_hexdigits_upcase[val] | 0x20;
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[1765] | 71 | }
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| 72 | return ret;
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| 73 | }
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| 74 | #else
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[2725] | 75 | #define TASKSET_PRINTF_MASK "%llx"
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| 76 | static unsigned long long from_cpuset(cpu_set_t *mask)
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| 77 | {
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[3621] | 78 | BUILD_BUG_ON(CPU_SETSIZE < 8*sizeof(int));
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[2725] | 79 |
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[3621] | 80 | /* Take the least significant bits. Assume cpu_set_t is
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| 81 | * implemented as an array of unsigned long or unsigned
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| 82 | * int.
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[2725] | 83 | */
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[3621] | 84 | if (CPU_SETSIZE < 8*sizeof(long))
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| 85 | return *(unsigned*)mask;
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| 86 | if (CPU_SETSIZE < 8*sizeof(long long))
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| 87 | return *(unsigned long*)mask;
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| 88 | # if BB_BIG_ENDIAN
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| 89 | if (sizeof(long long) > sizeof(long)) {
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| 90 | /* We can put two long in the long long, but they have to
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| 91 | * be swapped: the least significant word comes first in the
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| 92 | * array */
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| 93 | unsigned long *p = (void*)mask;
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| 94 | return p[0] + ((unsigned long long)p[1] << (8*sizeof(long)));
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| 95 | }
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| 96 | # endif
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| 97 | return *(unsigned long long*)mask;
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[2725] | 98 | }
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| 99 | #endif
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[1765] | 100 |
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| 101 |
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[2725] | 102 | int taskset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 103 | int taskset_main(int argc UNUSED_PARAM, char **argv)
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[1765] | 104 | {
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[2725] | 105 | cpu_set_t mask;
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[1765] | 106 | pid_t pid = 0;
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[2725] | 107 | unsigned opt_p;
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| 108 | const char *current_new;
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| 109 | char *pid_str;
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| 110 | char *aff = aff; /* for compiler */
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[1765] | 111 |
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[2725] | 112 | /* NB: we mimic util-linux's taskset: -p does not take
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| 113 | * an argument, i.e., "-pN" is NOT valid, only "-p N"!
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| 114 | * Indeed, util-linux-2.13-pre7 uses:
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| 115 | * getopt_long(argc, argv, "+pchV", ...), not "...p:..." */
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[1765] | 116 |
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[2725] | 117 | opt_complementary = "-1"; /* at least 1 arg */
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| 118 | opt_p = getopt32(argv, "+p");
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| 119 | argv += optind;
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[1765] | 120 |
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[2725] | 121 | if (opt_p) {
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| 122 | pid_str = *argv++;
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| 123 | if (*argv) { /* "-p <aff> <pid> ...rest.is.ignored..." */
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| 124 | aff = pid_str;
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| 125 | pid_str = *argv; /* NB: *argv != NULL in this case */
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[1765] | 126 | }
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[2725] | 127 | /* else it was just "-p <pid>", and *argv == NULL */
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| 128 | pid = xatoul_range(pid_str, 1, ((unsigned)(pid_t)ULONG_MAX) >> 1);
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| 129 | } else {
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| 130 | aff = *argv++; /* <aff> <cmd...> */
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| 131 | if (!*argv)
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| 132 | bb_show_usage();
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[1765] | 133 | }
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| 134 |
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[2725] | 135 | current_new = "current\0new";
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| 136 | if (opt_p) {
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[1765] | 137 | print_aff:
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| 138 | if (sched_getaffinity(pid, sizeof(mask), &mask) < 0)
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[2725] | 139 | bb_perror_msg_and_die("can't %cet pid %d's affinity", 'g', pid);
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[1765] | 140 | printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n",
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[2725] | 141 | pid, current_new, from_cpuset(&mask));
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| 142 | if (!*argv) {
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| 143 | /* Either it was just "-p <pid>",
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| 144 | * or it was "-p <aff> <pid>" and we came here
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| 145 | * for the second time (see goto below) */
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[1765] | 146 | return EXIT_SUCCESS;
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[2725] | 147 | }
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| 148 | *argv = NULL;
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| 149 | current_new += 8; /* "new" */
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[1765] | 150 | }
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| 151 |
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[3621] | 152 | /* Affinity was specified, translate it into cpu_set_t */
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| 153 | CPU_ZERO(&mask);
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| 154 | if (!ENABLE_FEATURE_TASKSET_FANCY) {
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[2725] | 155 | unsigned i;
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[3621] | 156 | unsigned long long m;
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| 157 |
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[2725] | 158 | /* Do not allow zero mask: */
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[3621] | 159 | m = xstrtoull_range(aff, 0, 1, ULLONG_MAX);
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| 160 | i = 0;
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| 161 | do {
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| 162 | if (m & 1)
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| 163 | CPU_SET(i, &mask);
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| 164 | i++;
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| 165 | m >>= 1;
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| 166 | } while (m != 0);
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| 167 | } else {
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| 168 | unsigned i;
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| 169 | char *last_byte;
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| 170 | char *bin;
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| 171 | uint8_t bit_in_byte;
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[2725] | 172 |
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[3621] | 173 | /* Cheap way to get "long enough" buffer */
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| 174 | bin = xstrdup(aff);
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| 175 |
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| 176 | if (aff[0] != '0' || (aff[1]|0x20) != 'x') {
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| 177 | /* TODO: decimal/octal masks are still limited to 2^64 */
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| 178 | unsigned long long m = xstrtoull_range(aff, 0, 1, ULLONG_MAX);
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| 179 | bin += strlen(bin);
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| 180 | last_byte = bin - 1;
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| 181 | while (m) {
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| 182 | *--bin = m & 0xff;
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| 183 | m >>= 8;
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| 184 | }
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| 185 | } else {
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| 186 | /* aff is "0x.....", we accept very long masks in this form */
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| 187 | last_byte = hex2bin(bin, aff + 2, INT_MAX);
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| 188 | if (!last_byte) {
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| 189 | bad_aff:
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| 190 | bb_error_msg_and_die("bad affinity '%s'", aff);
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| 191 | }
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| 192 | last_byte--; /* now points to the last byte */
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| 193 | }
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| 194 |
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| 195 | i = 0;
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| 196 | bit_in_byte = 1;
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| 197 | while (last_byte >= bin) {
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| 198 | if (bit_in_byte & *last_byte) {
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| 199 | if (i >= CPU_SETSIZE)
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| 200 | goto bad_aff;
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[2725] | 201 | CPU_SET(i, &mask);
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[3621] | 202 | //bb_error_msg("bit %d set", i);
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| 203 | }
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| 204 | i++;
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| 205 | /* bit_in_byte is uint8_t! & 0xff is implied */
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| 206 | bit_in_byte = (bit_in_byte << 1);
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| 207 | if (!bit_in_byte) {
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| 208 | bit_in_byte = 1;
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| 209 | last_byte--;
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| 210 | }
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[2725] | 211 | }
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[1765] | 212 | }
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[2725] | 213 |
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| 214 | /* Set pid's or our own (pid==0) affinity */
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| 215 | if (sched_setaffinity(pid, sizeof(mask), &mask))
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| 216 | bb_perror_msg_and_die("can't %cet pid %d's affinity", 's', pid);
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| 217 |
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| 218 | if (!argv[0]) /* "-p <aff> <pid> [...ignored...]" */
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| 219 | goto print_aff; /* print new affinity and exit */
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| 220 |
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| 221 | BB_EXECVP_or_die(argv);
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[1765] | 222 | }
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