/* vi: set sw=4 ts=4: */ /* * taskset - retrieve or set a processes' CPU affinity * Copyright (c) 2006 Bernhard Reutner-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" /* craft a string from the mask */ static char *from_cpuset(cpu_set_t *mask) { int i; char *ret = NULL; char *str = xzalloc((CPU_SETSIZE / 4) + 1); /* we will leak it */ for (i = CPU_SETSIZE - 4; i >= 0; i -= 4) { int 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++ = bb_hexdigits_upcase[val] | 0x20; } return ret; } #else #define TASKSET_PRINTF_MASK "%llx" static unsigned long long from_cpuset(cpu_set_t *mask) { struct BUG_CPU_SETSIZE_is_too_small { char BUG_CPU_SETSIZE_is_too_small[ CPU_SETSIZE < sizeof(int) ? -1 : 1]; }; char *p = (void*)mask; /* Take the least significant bits. Careful! * Consider both CPU_SETSIZE=4 and CPU_SETSIZE=1024 cases */ #if BB_BIG_ENDIAN /* For big endian, it means LAST bits */ if (CPU_SETSIZE < sizeof(long)) p += CPU_SETSIZE - sizeof(int); else if (CPU_SETSIZE < sizeof(long long)) p += CPU_SETSIZE - sizeof(long); else p += CPU_SETSIZE - sizeof(long long); #endif if (CPU_SETSIZE < sizeof(long)) return *(unsigned*)p; if (CPU_SETSIZE < sizeof(long long)) return *(unsigned long*)p; return *(unsigned long long*)p; } #endif int taskset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; int taskset_main(int argc UNUSED_PARAM, 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); }