chrt: -m can be used without any arguments. Closes bug 2989

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

1 files changed, 10 insertions, 8 deletions

diff --git a/miscutils/chrt.c b/miscutils/chrt.c
index 4477d084c..1c6737a3c 100644
--- a/miscutils/chrt.c
+++ b/miscutils/chrt.c
@@ -53,23 +53,25 @@ int chrt_main(int argc UNUSED_PARAM, char **argv)
         const char *current_new;
         int policy = SCHED_RR;
 
-        /* at least 1 arg; only one policy accepted */
-        opt_complementary = "-1:r--fo:f--ro:o--rf";
+        /* only one policy accepted */
+        opt_complementary = "r--fo:f--ro:o--rf";
         opt = getopt32(argv, "+mprfo");
+        if (opt & OPT_m) { /* print min/max and exit */
+                show_min_max(SCHED_FIFO);
+                show_min_max(SCHED_RR);
+                show_min_max(SCHED_OTHER);
+                fflush_stdout_and_exit(EXIT_SUCCESS);
+        }
         if (opt & OPT_r)
                 policy = SCHED_RR;
         if (opt & OPT_f)
                 policy = SCHED_FIFO;
         if (opt & OPT_o)
                 policy = SCHED_OTHER;
-        if (opt & OPT_m) { /* print min/max */
-                show_min_max(SCHED_FIFO);
-                show_min_max(SCHED_RR);
-                show_min_max(SCHED_OTHER);
-                fflush_stdout_and_exit(EXIT_SUCCESS);
-        }
 
         argv += optind;
+        if (!argv[0])
+                bb_show_usage();
         if (opt & OPT_p) {
                 pid_str = *argv++;
                 if (*argv) { /* "-p <priority> <pid> [...]" */