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139 lines
3.3 KiB
C
139 lines
3.3 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 the GPL v2 or later, see the file LICENSE in this tarball.
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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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#include "busybox.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <limits.h>
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#include <errno.h>
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#include <unistd.h>
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#include <sys/resource.h>
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#if (PRIO_PROCESS < CHAR_MIN) || (PRIO_PROCESS > CHAR_MAX)
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#error Assumption violated : PRIO_PROCESS value
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#endif
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#if (PRIO_PGRP < CHAR_MIN) || (PRIO_PGRP > CHAR_MAX)
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#error Assumption violated : PRIO_PGRP value
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#endif
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#if (PRIO_USER < CHAR_MIN) || (PRIO_USER > CHAR_MAX)
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#error Assumption violated : PRIO_USER value
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#endif
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static inline int int_add_no_wrap(int a, int b)
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{
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int s = a + b;
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if (b < 0) {
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if (s > a) s = INT_MIN;
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} else {
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if (s < a) s = INT_MAX;
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}
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return s;
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}
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int renice_main(int argc, char **argv)
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{
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static const char Xetpriority_msg[] = "%d : %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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id_t who;
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++argv;
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/* Check if we are using a relative adjustment. */
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if (argv[0] && (argv[0][0] == '-') && (argv[0][1] == 'n') && !argv[0][2]) {
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use_relative = 1;
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++argv;
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}
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if (!*argv) { /* 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 = bb_xgetlarg(*argv, 10, INT_MIN, INT_MAX);
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while (*++argv) {
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/* Check for a mode switch. */
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if ((argv[0][0] == '-') && argv[0][1] && !argv[0][2]) {
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static const char opts[]
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= { 'p', 'g', 'u', 0, PRIO_PROCESS, PRIO_PGRP, PRIO_USER };
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const char *p;
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if ((p = strchr(opts, argv[0][1]))) {
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which = p[4];
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continue;
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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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if (!(p = getpwnam(*argv))) {
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bb_error_msg("unknown user: %s", *argv);
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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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char *e;
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errno = 0;
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who = strtoul(*argv, &e, 10);
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if (*e || (*argv == e) || errno) {
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bb_error_msg("bad value: %s", *argv);
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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, who, 'g');
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goto HAD_ERROR;
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}
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new_priority = int_add_no_wrap(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, who, '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 outputing 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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