diff options
Diffstat (limited to 'release/src/router/busybox/miscutils/taskset.c')
| -rw-r--r-- | release/src/router/busybox/miscutils/taskset.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/release/src/router/busybox/miscutils/taskset.c b/release/src/router/busybox/miscutils/taskset.c new file mode 100644 index 00000000..a0bbf0aa --- /dev/null +++ b/release/src/router/busybox/miscutils/taskset.c @@ -0,0 +1,137 @@ +/* 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); +} |