start_stop_daemon: add -N <nice> compat

[re]nice: add support for -nNNN w/o spaces, -NNN (nice only),
          simplified code

1 files changed, 13 insertions, 31 deletions

diff --git a/coreutils/nice.c b/coreutils/nice.c
index a347001e3..dbd90648d 100644
--- a/coreutils/nice.c
+++ b/coreutils/nice.c
@@ -7,39 +7,14 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <limits.h>
-#include <errno.h>
-#include <unistd.h>
 #include <sys/resource.h>
 #include "busybox.h"
 
-static inline int int_add_no_wrap(int a, int b)
-{
-        int s = a + b;
-
-        if (b < 0) {
-                if (s > a) s = INT_MIN;
-        } else {
-                if (s < a) s = INT_MAX;
-        }
-
-        return s;
-}
-
 int nice_main(int argc, char **argv)
 {
-        static const char Xetpriority_msg[] = "cannot %cet priority";
-
         int old_priority, adjustment;
 
-        errno = 0;                       /* Needed for getpriority error detection. */
         old_priority = getpriority(PRIO_PROCESS, 0);
-        if (errno) {
-                bb_perror_msg_and_die(Xetpriority_msg, 'g');
-        }
 
         if (!*++argv) { /* No args, so (GNU) output current nice value. */
                 bb_printf("%d\n", old_priority);
@@ -48,19 +23,26 @@ int nice_main(int argc, char **argv)
 
         adjustment = 10;                        /* Set default adjustment. */
 
-        if ((argv[0][0] == '-') && (argv[0][1] == 'n') && !argv[0][2]) { /* "-n" */
+        if (argv[0][0] == '-') {
+                if (argv[0][1] == 'n') { /* -n */
+                        if (argv[0][2]) { /* -nNNNN (w/o space) */
+                                argv[0] += 2; argv--; argc++;
+                        }
+                } else { /* -NNN (NNN may be negative) == -n NNN */
+                        argv[0] += 1; argv--; argc++;
+                }
                 if (argc < 4) {                 /* Missing priority and/or utility! */
                         bb_show_usage();
                 }
-                adjustment = xatoi(argv[1]);
+                adjustment = xatoi_range(argv[1], INT_MIN/2, INT_MAX/2);
                 argv += 2;
         }
 
-        {  /* Set our priority.  Handle integer wrapping for old + adjust. */
-                int new_priority = int_add_no_wrap(old_priority, adjustment);
+        {  /* Set our priority. */
+                int prio = old_priority + adjustment;
 
-                if (setpriority(PRIO_PROCESS, 0, new_priority) < 0) {
-                        bb_perror_msg_and_die(Xetpriority_msg, 's');
+                if (setpriority(PRIO_PROCESS, 0, prio) < 0) {
+                        bb_perror_msg_and_die("setpriority(%d)", prio);
                 }
         }