142 lines
3.8 KiB
C
142 lines
3.8 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* renice implementation for busybox
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*
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* Copyright (C) 2005 Manuel Novoa III <mjn3@codepoet.org>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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/* Notes:
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* Setting an absolute priority was obsoleted in SUSv2 and removed
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* in SUSv3. However, the common linux version of renice does
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* absolute and not relative. So we'll continue supporting absolute,
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* although the stdout logging has been removed since both SUSv2 and
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* SUSv3 specify that stdout isn't used.
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*
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* This version is lenient in that it doesn't require any IDs. The
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* options -p, -g, and -u are treated as mode switches for the
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* following IDs (if any). Multiple switches are allowed.
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*/
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//config:config RENICE
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//config: bool "renice (3.8 kb)"
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//config: default y
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//config: help
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//config: Renice alters the scheduling priority of one or more running
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//config: processes.
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//applet:IF_RENICE(APPLET_NOEXEC(renice, renice, BB_DIR_USR_BIN, BB_SUID_DROP, renice))
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//kbuild:lib-$(CONFIG_RENICE) += renice.o
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//usage:#define renice_trivial_usage
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//usage: "[-n] PRIORITY [[-p | -g | -u] ID...]..."
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//usage:#define renice_full_usage "\n\n"
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//usage: "Change scheduling priority of a running process\n"
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//usage: "\n -n Add PRIORITY to current nice value"
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//usage: "\n Without -n, nice value is set to PRIORITY"
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//usage: "\n -p Process ids (default)"
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//usage: "\n -g Process group ids"
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//usage: "\n -u Process user names"
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#include "libbb.h"
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#include <sys/resource.h>
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int renice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int renice_main(int argc UNUSED_PARAM, char **argv)
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{
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static const char Xetpriority_msg[] ALIGN1 = "%cetpriority";
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int retval = EXIT_SUCCESS;
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int which = PRIO_PROCESS; /* Default 'which' value. */
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int use_relative = 0;
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int adjustment, new_priority;
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unsigned who;
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char *arg;
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/* Yes, they are not #defines in glibc 2.4! #if won't work */
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BUILD_BUG_ON(PRIO_PROCESS < CHAR_MIN || PRIO_PROCESS > CHAR_MAX);
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BUILD_BUG_ON(PRIO_PGRP < CHAR_MIN || PRIO_PGRP > CHAR_MAX);
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BUILD_BUG_ON(PRIO_USER < CHAR_MIN || PRIO_USER > CHAR_MAX);
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arg = *++argv;
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/* Check if we are using a relative adjustment. */
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if (arg && arg[0] == '-' && arg[1] == 'n') {
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use_relative = 1;
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if (!arg[2])
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arg = *++argv;
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else
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arg += 2;
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}
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if (!arg) { /* No args? Then show usage. */
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bb_show_usage();
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}
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/* Get the priority adjustment (absolute or relative). */
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adjustment = xatoi_range(arg, INT_MIN/2, INT_MAX/2);
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while ((arg = *++argv) != NULL) {
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/* Check for a mode switch. */
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if (arg[0] == '-' && arg[1]) {
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static const char opts[] ALIGN1 = {
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'p', 'g', 'u', 0, PRIO_PROCESS, PRIO_PGRP, PRIO_USER
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};
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const char *p = strchr(opts, arg[1]);
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if (p) {
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which = p[4];
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if (!arg[2])
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continue;
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arg += 2;
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}
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}
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/* Process an ID arg. */
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if (which == PRIO_USER) {
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struct passwd *p;
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/* NB: use of getpwnam makes it risky to be NOFORK, switch to getpwnam_r? */
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p = getpwnam(arg);
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if (!p) {
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bb_error_msg("unknown user %s", arg);
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goto HAD_ERROR;
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}
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who = p->pw_uid;
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} else {
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who = bb_strtou(arg, NULL, 10);
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if (errno) {
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bb_error_msg("invalid number '%s'", arg);
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goto HAD_ERROR;
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}
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}
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/* Get priority to use, and set it. */
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if (use_relative) {
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int old_priority;
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errno = 0; /* Needed for getpriority error detection. */
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old_priority = getpriority(which, who);
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if (errno) {
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bb_perror_msg(Xetpriority_msg, 'g');
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goto HAD_ERROR;
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}
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new_priority = old_priority + adjustment;
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} else {
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new_priority = adjustment;
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}
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if (setpriority(which, who, new_priority) == 0) {
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continue;
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}
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bb_perror_msg(Xetpriority_msg, 's');
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HAD_ERROR:
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retval = EXIT_FAILURE;
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}
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/* No need to check for errors outputting to stderr since, if it
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* was used, the HAD_ERROR label was reached and retval was set. */
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return retval;
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}
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