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;
 }