Add 'nice' and replace 'renice' with a new implementation.

1 files changed, 115 insertions, 17 deletions

diff --git a/procps/renice.c b/procps/renice.c
index a6f0820df..d4ce66d2e 100644
--- a/procps/renice.c
+++ b/procps/renice.c
@@ -1,8 +1,8 @@
+/* vi: set sw=4 ts=4: */
 /*
- * Mini renice implementation for busybox
+ * renice implementation for busybox
  *
- *
- * Copyright (C) 2000 Dave 'Kill a Cop' Cinege <dcinege@psychosis.com>
+ * Copyright (C) 2005  Manuel Novoa III  <mjn3@codepoet.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -20,35 +20,133 @@
  *
  */
 
+/* Notes:
+ *   Setting an absolute priority was obsoleted in SUSv2 and removed
+ *   in SUSv3.  However, the common linux version of renice does
+ *   absolute and not relative.  So we'll continue supporting absolute,
+ *   although the stdout logging has been removed since both SUSv2 and
+ *   SUSv3 specify that stdout isn't used.
+ *
+ *   This version is lenient in that it doesn't require any IDs.  The
+ *   options -p, -g, and -u are treated as mode switches for the
+ *   following IDs (if any).  Multiple switches are allowed.
+ */
+
 #include <stdio.h>
-#include <errno.h>
 #include <stdlib.h>
+#include <string.h>
+#include <limits.h>
+#include <errno.h>
+#include <unistd.h>
 #include <sys/time.h>
 #include <sys/resource.h>
 #include "busybox.h"
 
+#if (PRIO_PROCESS < CHAR_MIN) || (PRIO_PROCESS > CHAR_MAX)
+#error Assumption violated : PRIO_PROCESS value
+#endif
+#if (PRIO_PGRP < CHAR_MIN) || (PRIO_PGRP > CHAR_MAX)
+#error Assumption violated : PRIO_PGRP value
+#endif
+#if (PRIO_USER < CHAR_MIN) || (PRIO_USER > CHAR_MAX)
+#error Assumption violated : PRIO_USER value
+#endif
+
+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;
+	}
 
-extern int renice_main(int argc, char **argv)
+	return s;
+}
+
+int renice_main(int argc, char **argv)
 {
-	int prio, status = EXIT_SUCCESS;
+	static const char Xetpriority_msg[] = "%d : %cetpriority";
+
+	int retval = EXIT_SUCCESS;
+	int which = PRIO_PROCESS;	/* Default 'which' value. */
+	int use_relative = 0;
+	int adjustment, new_priority;
+	id_t who;
 
-	if (argc < 3)	bb_show_usage();
+	++argv;
 
-	prio = atoi(*++argv);
-	if (prio > 20)		prio = 20;
-	if (prio < -20)		prio = -20;
+	/* Check if we are using a relative adjustment. */
+	if (argv[0] && (argv[0][0] == '-') && (argv[0][1] == 'n') && !argv[0][2]) {
+		use_relative = 1;
+		++argv;
+	}
+
+	if (!*argv) {				/* No args?  Then show usage. */
+		bb_show_usage();
+	}
+
+	/* Get the priority adjustment (absolute or relative). */
+	adjustment = bb_xgetlarg(*argv, 10, INT_MIN, INT_MAX);
 
 	while (*++argv) {
-		int ps = atoi(*argv);
-		int oldp = getpriority(PRIO_PROCESS, ps);
+		/* Check for a mode switch. */
+		if ((argv[0][0] == '-') && argv[0][1] && !argv[0][2]) {
+			static const char opts[]
+				= { 'p', 'g', 'u', 0, PRIO_PROCESS, PRIO_PGRP, PRIO_USER };
+			const char *p;
+			if ((p = strchr(opts, argv[0][1]))) {
+				which = p[4];
+				continue;
+			}
+		}
 
-		if (setpriority(PRIO_PROCESS, ps, prio) == 0) {
-			printf("%d: old priority %d, new priority %d\n", ps, oldp, prio );
+		/* Process an ID arg. */
+		if (which == PRIO_USER) {
+			struct passwd *p;
+			if (!(p = getpwnam(*argv))) {
+				bb_error_msg("unknown user: %s", *argv);
+				goto HAD_ERROR;
+			}
+			who = p->pw_uid;
 		} else {
-			bb_perror_msg("%d: setpriority", ps);
-			status = EXIT_FAILURE;
+			char *e;
+			errno = 0;
+			who = strtoul(*argv, &e, 10);
+			if (*e || (*argv == e) || errno) {
+				bb_error_msg("bad value: %s", *argv);
+				goto HAD_ERROR;
+			}
 		}
+
+		/* Get priority to use, and set it. */
+		if (use_relative) {
+			int old_priority;
+
+			errno = 0;	 /* Needed for getpriority error detection. */
+			old_priority = getpriority(which, who);
+			if (errno) {
+				bb_perror_msg(Xetpriority_msg, who, 'g');
+				goto HAD_ERROR;
+			}
+
+			new_priority = int_add_no_wrap(old_priority, adjustment);
+		} else {
+			new_priority = adjustment;
+		}
+
+		if (setpriority(which, who, new_priority) == 0) {
+			continue;
+		}
+
+		bb_perror_msg(Xetpriority_msg, who, 's');
+	HAD_ERROR:
+		retval = EXIT_FAILURE;
 	}
 
-	return status;
+	/* No need to check for errors outputing to stderr since, if it
+	 * was used, the HAD_ERROR label was reached and retval was set. */
+
+	return retval;
 }