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/* vi: set sw=4 ts=4: */
/*
* renice implementation for busybox
*
* Copyright (C) 2005 Manuel Novoa III <mjn3@codepoet.org>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
/* 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.
*/
//config:config RENICE
//config: bool "renice (4.2 kb)"
//config: default y
//config: help
//config: Renice alters the scheduling priority of one or more running
//config: processes.
//applet:IF_RENICE(APPLET_NOEXEC(renice, renice, BB_DIR_USR_BIN, BB_SUID_DROP, renice))
//kbuild:lib-$(CONFIG_RENICE) += renice.o
//usage:#define renice_trivial_usage
//usage: "[-n] PRIORITY [[-p | -g | -u] ID...]..."
//usage:#define renice_full_usage "\n\n"
//usage: "Change scheduling priority of a running process\n"
//usage: "\n -n Add PRIORITY to current nice value"
//usage: "\n Without -n, nice value is set to PRIORITY"
//usage: "\n -p Process ids (default)"
//usage: "\n -g Process group ids"
//usage: "\n -u Process user names"
#include "libbb.h"
int renice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int renice_main(int argc UNUSED_PARAM, char **argv)
{
static const char Xetpriority_msg[] ALIGN1 = "%cetpriority";
int retval = EXIT_SUCCESS;
int which = PRIO_PROCESS; /* Default 'which' value. */
int use_relative = 0;
int adjustment, new_priority;
unsigned who;
char *arg;
/* Yes, they are not #defines in glibc 2.4! #if won't work */
BUILD_BUG_ON(PRIO_PROCESS < CHAR_MIN || PRIO_PROCESS > CHAR_MAX);
BUILD_BUG_ON(PRIO_PGRP < CHAR_MIN || PRIO_PGRP > CHAR_MAX);
BUILD_BUG_ON(PRIO_USER < CHAR_MIN || PRIO_USER > CHAR_MAX);
arg = *++argv;
/* Check if we are using a relative adjustment. */
if (arg && arg[0] == '-' && arg[1] == 'n') {
use_relative = 1;
if (!arg[2])
arg = *++argv;
else
arg += 2;
}
if (!arg) { /* No args? Then show usage. */
bb_show_usage();
}
/* Get the priority adjustment (absolute or relative). */
adjustment = xatoi_range(arg, INT_MIN/2, INT_MAX/2);
while ((arg = *++argv) != NULL) {
/* Check for a mode switch. */
if (arg[0] == '-' && arg[1]) {
static const char opts[] ALIGN1 = {
'p', 'g', 'u', 0, PRIO_PROCESS, PRIO_PGRP, PRIO_USER
};
const char *p = strchr(opts, arg[1]);
if (p) {
which = p[4];
if (!arg[2])
continue;
arg += 2;
}
}
/* Process an ID arg. */
if (which == PRIO_USER) {
struct passwd *p;
/* NB: use of getpwnam makes it risky to be NOFORK, switch to getpwnam_r? */
p = getpwnam(arg);
if (!p) {
bb_error_msg("unknown user %s", arg);
goto HAD_ERROR;
}
who = p->pw_uid;
} else {
who = bb_strtou(arg, NULL, 10);
if (errno) {
bb_error_msg("invalid number '%s'", arg);
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, 'g');
goto HAD_ERROR;
}
new_priority = old_priority + adjustment;
} else {
new_priority = adjustment;
}
if (setpriority(which, who, new_priority) == 0) {
continue;
}
bb_perror_msg(Xetpriority_msg, 's');
HAD_ERROR:
retval = EXIT_FAILURE;
}
/* No need to check for errors outputting to stderr since, if it
* was used, the HAD_ERROR label was reached and retval was set. */
return retval;
}
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