taskset: simplify code a bit; tweak --help

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/miscutils/taskset.c b/miscutils/taskset.c
index 68b0fa6eb71d02abcf215c16a3b95f1e975337c0..94a07383ae1ae8cb44f4d2c5284a8c138d03ebce 100644 (file)
--- a/miscutils/taskset.c
+++ b/miscutils/taskset.c
@@ -26,7 +26,7 @@
 //kbuild:lib-$(CONFIG_TASKSET) += taskset.o
 
 //usage:#define taskset_trivial_usage
-//usage:       "[-p] [HEXMASK] [PID | PROG ARGS]"
+//usage:       "[-p] [HEXMASK] PID | PROG ARGS"
 //usage:#define taskset_full_usage "\n\n"
 //usage:       "Set or get CPU affinity\n"
 //usage:     "\n       -p      Operate on an existing PID"
@@ -116,7 +116,7 @@ int taskset_main(int argc UNUSED_PARAM, char **argv)
        pid_t pid = 0;
        unsigned opt_p;
        const char *current_new;
-       char *aff = aff; /* for compiler */
+       char *aff;
 
        /* NB: we mimic util-linux's taskset: -p does not take
         * an argument, i.e., "-pN" is NOT valid, only "-p N"!
@@ -127,29 +127,28 @@ int taskset_main(int argc UNUSED_PARAM, char **argv)
        opt_p = getopt32(argv, "+p");
        argv += optind;
 
+       aff = *argv++;
        if (opt_p) {
-               char *pid_str = *argv++;
+               char *pid_str = aff;
                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...> */
+               /* <aff> <cmd...> */
                if (!*argv)
                        bb_show_usage();
        }
 
        mask_size_in_bytes = SZOF_UL;
-       mask = NULL;
        current_new = "current";
  print_aff:
        mask = get_aff(pid, &mask_size_in_bytes);
        if (opt_p) {
                printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n",
                                pid, current_new, from_mask(mask, mask_size_in_bytes));
-               if (!*argv) {
+               if (*argv == NULL) {
                        /* Either it was just "-p <pid>",
                         * or it was "-p <aff> <pid>" and we came here
                         * for the second time (see goto below) */
@@ -166,8 +165,7 @@ int taskset_main(int argc UNUSED_PARAM, char **argv)
                aff += 2;
 
        if (!ENABLE_FEATURE_TASKSET_FANCY) {
-               /* Do not allow zero mask: */
-               mask[0] = xstrtoul_range(aff, 16, 1, ULONG_MAX);
+               mask[0] = xstrtoul(aff, 16);
        } else {
                unsigned i;
                char *last_char;
@@ -201,8 +199,8 @@ int taskset_main(int argc UNUSED_PARAM, char **argv)
                        /* else:
                         * We can error out here, but we don't.
                         * For one, kernel itself ignores bits in mask[]
-                        * which do not map to any CPUs.
-                        * If mask has one 32-bit long,
+                        * which do not map to any CPUs:
+                        * if mask[] has one 32-bit long element,
                         * but you have only 8 CPUs, all bits beyond first 8
                         * are ignored, silently.
                         * No point in making bits past 31th to be errors.