(GET_NICE_VALUE): Renamed from GET_PRIORITY.

All uses changed.
(NZERO): New macro, if system doesn't define it already.
(usage): Distinguish priorities from nice values.
Don't assume NZERO is 20.
(main): Use bool instead of int where appropriate.
If user specifies an adjustment out of range, always truncate it
to an inrange value instead of sometimes giving an error message
and sometimes not.
Do not assume that -1 is an error return from "nice" or
"getpriority", as it might be the current nice value minus NZERO.
If nice/setpriority fails with errno == EPERM, go ahead and run
the command anyway; POSIX requires this.

1 files changed, 42 insertions, 50 deletions

diff --git a/src/nice.c b/src/nice.c
index 9acd907a9..83e7fd9b4 100644
--- a/src/nice.c
+++ b/src/nice.c
@@ -44,9 +44,13 @@
 #define AUTHORS "David MacKenzie"
 
 #ifdef NICE_PRIORITY
-# define GET_PRIORITY() nice (0)
+# define GET_NICE_VALUE() nice (0)
 #else
-# define GET_PRIORITY() getpriority (PRIO_PROCESS, 0)
+# define GET_NICE_VALUE() getpriority (PRIO_PROCESS, 0)
+#endif
+
+#ifndef NZERO
+# define NZERO 20
 #endif
 
 /* The name this program was run with. */
@@ -67,13 +71,14 @@ usage (int status)
   else
     {
       printf (_("Usage: %s [OPTION] [COMMAND [ARG]...]\n"), program_name);
-      fputs (_("\
-Run COMMAND with an adjusted scheduling priority.\n\
-With no COMMAND, print the current scheduling priority.  ADJUST is 10\n\
-by default.  Range goes from -20 (highest priority) to 19 (lowest).\n\
+      printf (_("\
+Run COMMAND with an adjusted nice value, which affects the scheduling priority.\n\
+With no COMMAND, print the current nice value.  Nice values range from\n\
+%d (most favorable scheduling) to %d (least favorable).\n\
 \n\
-  -n, --adjustment=ADJUST   increment priority by ADJUST first\n\
-"), stdout);
+  -n, --adjustment=N   add integer N to the nice value (default 10)\n\
+"),
+	      - NZERO, NZERO - 1);
       fputs (HELP_OPTION_DESCRIPTION, stdout);
       fputs (VERSION_OPTION_DESCRIPTION, stdout);
       printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
@@ -84,10 +89,10 @@ by default.  Range goes from -20 (highest priority) to 19 (lowest).\n\
 int
 main (int argc, char **argv)
 {
-  int current_priority;
-  long int adjustment = 0;
-  int minusflag = 0;
-  int adjustment_given = 0;
+  int current_nice_value;
+  int adjustment = 10;
+  char const *adjustment_given = NULL;
+  bool ok;
   int i;
 
   initialize_main (&argc, &argv);
@@ -106,27 +111,10 @@ main (int argc, char **argv)
     {
       char *s = argv[i];
 
-      if (s[0] == '-' && s[1] == '-' && ISDIGIT (s[2])
+      if (s[0] == '-' && ISDIGIT (s[1 + (s[1] == '-' || s[1] == '+')])
 	  && posix2_version () < 200112)
 	{
-	  if (xstrtol (&s[2], NULL, 10, &adjustment, "") != LONGINT_OK)
-	    error (EXIT_FAIL, 0, _("invalid option `%s'"), s);
-
-	  minusflag = 1;
-	  adjustment_given = 1;
-	  ++i;
-	}
-      else if (s[0] == '-'
-	       && (ISDIGIT (s[1]) || (s[1] == '+' && ISDIGIT (s[2])))
-	       && posix2_version () < 200112)
-	{
-	  if (s[1] == '+')
-	    ++s;
-	  if (xstrtol (&s[1], NULL, 10, &adjustment, "") != LONGINT_OK)
-	    error (EXIT_FAIL, 0, _("invalid option `%s'"), s);
-
-	  minusflag = 0;
-	  adjustment_given = 1;
+	  adjustment_given = s + 1;
 	  ++i;
 	}
       else
@@ -146,12 +134,7 @@ main (int argc, char **argv)
 		  usage (EXIT_FAIL);
 
 		case 'n':
-		  if (xstrtol (optarg, NULL, 10, &adjustment, "")
-		      != LONGINT_OK)
-		    error (EXIT_FAIL, 0, _("invalid priority `%s'"), optarg);
-
-		  minusflag = 0;
-		  adjustment_given = 1;
+		  adjustment_given = optarg;
 		  break;
 		}
 	    }
@@ -163,10 +146,17 @@ main (int argc, char **argv)
 	}
     }
 
-  if (minusflag)
-    adjustment = -adjustment;
-  if (!adjustment_given)
-    adjustment = 10;
+  if (adjustment_given)
+    {
+      /* If the requested adjustment is outside the valid range,
+	 silently bring it to just within range; this mimics what
+	 "setpriority" and "nice" do.  */
+      enum { MIN_ADJUSTMENT = 1 - 2 * NZERO, MAX_ADJUSTMENT = 2 * NZERO - 1 };
+      long int tmp;
+      if (LONGINT_OVERFLOW < xstrtol (adjustment_given, NULL, 10, &tmp, ""))
+	error (EXIT_FAIL, 0, _("invalid adjustment `%s'"), adjustment_given);
+      adjustment = MAX (MIN_ADJUSTMENT, MIN (tmp, MAX_ADJUSTMENT));
+    }
 
   if (i == argc)
     {
@@ -175,25 +165,27 @@ main (int argc, char **argv)
 	  error (0, 0, _("a command must be given with an adjustment"));
 	  usage (EXIT_FAIL);
 	}
-      /* No command given; print the priority. */
+      /* No command given; print the nice value.  */
       errno = 0;
-      current_priority = GET_PRIORITY ();
-      if (current_priority == -1 && errno != 0)
+      current_nice_value = GET_NICE_VALUE ();
+      if (current_nice_value == -1 && errno != 0)
 	error (EXIT_FAIL, errno, _("cannot get priority"));
-      printf ("%d\n", current_priority);
+      printf ("%d\n", current_nice_value);
       exit (EXIT_SUCCESS);
     }
 
 #ifndef NICE_PRIORITY
   errno = 0;
-  current_priority = GET_PRIORITY ();
-  if (current_priority == -1 && errno != 0)
+  current_nice_value = GET_NICE_VALUE ();
+  if (current_nice_value == -1 && errno != 0)
     error (EXIT_FAIL, errno, _("cannot get priority"));
-  if (setpriority (PRIO_PROCESS, 0, current_priority + adjustment))
+  ok = (setpriority (PRIO_PROCESS, 0, current_nice_value + adjustment) == 0);
 #else
-  if (nice (adjustment) == -1)
+  errno = 0;
+  ok = (nice (adjustment) != -1 || errno == 0);
 #endif
-    error (EXIT_FAIL, errno, _("cannot set priority"));
+  if (!ok)
+    error (errno == EPERM ? 0 : EXIT_FAIL, errno, _("cannot set priority"));
 
   execvp (argv[i], &argv[i]);