1 /* vi: set sw=4 ts=4: */
3 * renice implementation for busybox
5 * Copyright (C) 2005 Manuel Novoa III <mjn3@codepoet.org>
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
10 * Setting an absolute priority was obsoleted in SUSv2 and removed
11 * in SUSv3. However, the common linux version of renice does
12 * absolute and not relative. So we'll continue supporting absolute,
13 * although the stdout logging has been removed since both SUSv2 and
14 * SUSv3 specify that stdout isn't used.
16 * This version is lenient in that it doesn't require any IDs. The
17 * options -p, -g, and -u are treated as mode switches for the
18 * following IDs (if any). Multiple switches are allowed.
20 //config:config RENICE
21 //config: bool "renice (3.8 kb)"
24 //config: Renice alters the scheduling priority of one or more running
27 //applet:IF_RENICE(APPLET_NOEXEC(renice, renice, BB_DIR_USR_BIN, BB_SUID_DROP, renice))
29 //kbuild:lib-$(CONFIG_RENICE) += renice.o
31 //usage:#define renice_trivial_usage
32 //usage: "[-n] PRIORITY [[-p | -g | -u] ID...]..."
33 //usage:#define renice_full_usage "\n\n"
34 //usage: "Change scheduling priority of a running process\n"
35 //usage: "\n -n Add PRIORITY to current nice value"
36 //usage: "\n Without -n, nice value is set to PRIORITY"
37 //usage: "\n -p Process ids (default)"
38 //usage: "\n -g Process group ids"
39 //usage: "\n -u Process user names"
42 #include <sys/resource.h>
44 int renice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
45 int renice_main(int argc UNUSED_PARAM, char **argv)
47 static const char Xetpriority_msg[] ALIGN1 = "%cetpriority";
49 int retval = EXIT_SUCCESS;
50 int which = PRIO_PROCESS; /* Default 'which' value. */
52 int adjustment, new_priority;
56 /* Yes, they are not #defines in glibc 2.4! #if won't work */
57 BUILD_BUG_ON(PRIO_PROCESS < CHAR_MIN || PRIO_PROCESS > CHAR_MAX);
58 BUILD_BUG_ON(PRIO_PGRP < CHAR_MIN || PRIO_PGRP > CHAR_MAX);
59 BUILD_BUG_ON(PRIO_USER < CHAR_MIN || PRIO_USER > CHAR_MAX);
63 /* Check if we are using a relative adjustment. */
64 if (arg && arg[0] == '-' && arg[1] == 'n') {
72 if (!arg) { /* No args? Then show usage. */
76 /* Get the priority adjustment (absolute or relative). */
77 adjustment = xatoi_range(arg, INT_MIN/2, INT_MAX/2);
79 while ((arg = *++argv) != NULL) {
80 /* Check for a mode switch. */
81 if (arg[0] == '-' && arg[1]) {
82 static const char opts[] ALIGN1 = {
83 'p', 'g', 'u', 0, PRIO_PROCESS, PRIO_PGRP, PRIO_USER
85 const char *p = strchr(opts, arg[1]);
94 /* Process an ID arg. */
95 if (which == PRIO_USER) {
97 /* NB: use of getpwnam makes it risky to be NOFORK, switch to getpwnam_r? */
100 bb_error_msg("unknown user %s", arg);
105 who = bb_strtou(arg, NULL, 10);
107 bb_error_msg("invalid number '%s'", arg);
112 /* Get priority to use, and set it. */
116 errno = 0; /* Needed for getpriority error detection. */
117 old_priority = getpriority(which, who);
119 bb_perror_msg(Xetpriority_msg, 'g');
123 new_priority = old_priority + adjustment;
125 new_priority = adjustment;
128 if (setpriority(which, who, new_priority) == 0) {
132 bb_perror_msg(Xetpriority_msg, 's');
134 retval = EXIT_FAILURE;
137 /* No need to check for errors outputting to stderr since, if it
138 * was used, the HAD_ERROR label was reached and retval was set. */