224 lines
5.4 KiB
C
224 lines
5.4 KiB
C
/*
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* chrt.c - chrt
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* Command-line utility for manipulating a task's real-time attributes
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*
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* Robert Love <rml@tech9.net>
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* 27-Apr-2002: initial version
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, v2, as
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* published by the Free Software Foundation
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* Copyright (C) 2004 Robert Love
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*/
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <stdlib.h>
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#include <sched.h>
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#include <unistd.h>
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#include <getopt.h>
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#include <errno.h>
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static void show_usage(const char *cmd)
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{
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fprintf(stderr, "chrt version " VERSION "\n");
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fprintf(stderr, "usage: %s [options] [prio] [pid | cmd [args...]]\n",
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cmd);
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fprintf(stderr, "manipulate real-time attributes of a process\n");
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fprintf(stderr, " -f, --fifo "
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"set policy to SCHED_FF\n");
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fprintf(stderr, " -p, --pid "
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"operate on existing given pid\n");
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fprintf(stderr, " -m, --max "
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"show min and max valid priorities\n");
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fprintf(stderr, " -o, --other "
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"set policy to SCHED_OTHER\n");
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fprintf(stderr, " -r, --rr "
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"set policy to SCHED_RR (default)\n");
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fprintf(stderr, " -h, --help "
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"display this help\n");
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fprintf(stderr, " -v, --verbose "
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"display status information\n");
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fprintf(stderr, " -V, --version "
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"output version information\n\n");
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fprintf(stderr, "You must give a priority if changing policy.\n\n");
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fprintf(stderr, "Report bugs and send patches to <rml@tech9.net>\n");
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}
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static void show_rt_info(const char *what, pid_t pid)
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{
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struct sched_param sp;
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int policy;
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/* don't display "pid 0" as that is confusing */
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if (!pid)
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pid = getpid();
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policy = sched_getscheduler(pid);
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if (policy == -1) {
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perror("sched_getscheduler");
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fprintf(stderr, "failed to get pid %d's policy\n", pid);
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exit(1);
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}
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printf("pid %d's %s scheduling policy: ", pid, what);
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switch (policy) {
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case SCHED_OTHER:
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printf("SCHED_OTHER\n");
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break;
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case SCHED_FIFO:
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printf("SCHED_FIFO\n");
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break;
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case SCHED_RR:
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printf("SCHED_RR\n");
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break;
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default:
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printf("unknown\n");
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}
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if (sched_getparam(pid, &sp)) {
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perror("sched_getparam");
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fprintf(stderr, "failed to get pid %d's attributes\n", pid);
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exit(1);
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}
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printf("pid %d's %s scheduling priority: %d\n",
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pid, what, sp.sched_priority);
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}
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static void show_min_max(void)
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{
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int max, min;
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max = sched_get_priority_max(SCHED_FIFO);
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min = sched_get_priority_min(SCHED_FIFO);
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if (max >= 0 && min >= 0)
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printf("SCHED_FIFO min/max priority\t: %d/%d\n", min, max);
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else
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printf("SCHED_FIFO not supported?\n");
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max = sched_get_priority_max(SCHED_RR);
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min = sched_get_priority_min(SCHED_RR);
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if (max >= 0 && min >= 0)
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printf("SCHED_RR min/max priority\t: %d/%d\n", min, max);
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else
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printf("SCHED_RR not supported?\n");
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max = sched_get_priority_max(SCHED_OTHER);
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min = sched_get_priority_min(SCHED_OTHER);
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if (max >= 0 && min >= 0)
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printf("SCHED_OTHER min/max priority\t: %d/%d\n", min, max);
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else
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printf("SCHED_OTHER not supported?\n");
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}
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int main(int argc, char *argv[])
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{
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int i, policy = SCHED_RR, priority = 0, verbose = 0;
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struct sched_param sp;
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pid_t pid = 0;
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struct option longopts[] = {
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{ "fifo", 0, NULL, 'f' },
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{ "pid", 0, NULL, 'p' },
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{ "help", 0, NULL, 'h' },
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{ "max", 0, NULL, 'm' },
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{ "other", 0, NULL, 'o' },
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{ "rr", 0, NULL, 'r' },
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{ "verbose", 0, NULL, 'v' },
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{ "version", 0, NULL, 'V' },
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{ NULL, 0, NULL, 0 }
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};
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while((i = getopt_long(argc, argv, "+fphmorvV", longopts, NULL)) != -1)
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{
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int ret = 1;
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switch (i) {
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case 'f':
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policy = SCHED_FIFO;
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break;
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case 'm':
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show_min_max();
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return 0;
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case 'o':
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policy = SCHED_OTHER;
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break;
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case 'p':
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errno = 0;
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pid = strtol(argv[argc - 1], NULL, 10);
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if (errno) {
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perror("strtol");
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fprintf(stderr, "failed to parse pid!\n");
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return 1;
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}
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break;
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case 'r':
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policy = SCHED_RR;
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break;
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case 'v':
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verbose = 1;
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break;
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case 'V':
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printf("chrt version " VERSION "\n");
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return 0;
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case 'h':
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ret = 0;
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default:
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show_usage(argv[0]);
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return ret;
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}
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}
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if ((pid && argc - optind < 1) || (!pid && argc - optind < 2)) {
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show_usage(argv[0]);
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return 1;
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}
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if (pid && (verbose || argc - optind == 1)) {
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show_rt_info("current", pid);
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if (argc - optind == 1)
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return 0;
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}
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errno = 0;
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priority = strtol(argv[optind], NULL, 10);
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if (errno) {
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perror("strtol");
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fprintf(stderr, "failed to parse priority!\n");
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return 1;
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}
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sp.sched_priority = priority;
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if (sched_setscheduler(pid, policy, &sp) == -1) {
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perror("sched_setscheduler");
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fprintf(stderr, "failed to set pid %d's policy\n", pid);
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return 1;
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}
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if (verbose)
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show_rt_info("new", pid);
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if (!pid) {
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argv += optind + 1;
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execvp(argv[0], argv);
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perror("execvp");
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fprintf(stderr, "failed to execute %s\n", argv[0]);
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return 1;
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}
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return 0;
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}
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