/* vi: set sw=4 ts=4: */
/*
* chrt - manipulate real-time attributes of a process
- * Copyright (c) 2006-2007 Bernhard Fischer
+ * Copyright (c) 2006-2007 Bernhard Reutner-Fischer
*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
+//usage:#define chrt_trivial_usage
+//usage: "[-prfom] [PRIO] [PID | PROG ARGS]"
+//usage:#define chrt_full_usage "\n\n"
+//usage: "Change scheduling priority and class for a process\n"
+//usage: "\n -p Operate on PID"
+//usage: "\n -r Set SCHED_RR class"
+//usage: "\n -f Set SCHED_FIFO class"
+//usage: "\n -o Set SCHED_OTHER class"
+//usage: "\n -m Show min/max priorities"
+//usage:
+//usage:#define chrt_example_usage
+//usage: "$ chrt -r 4 sleep 900; x=$!\n"
+//usage: "$ chrt -f -p 3 $x\n"
+//usage: "You need CAP_SYS_NICE privileges to set scheduling attributes of a process"
+
#include <sched.h>
-#include <getopt.h> /* optind */
#include "libbb.h"
-#ifndef _POSIX_PRIORITY_SCHEDULING
-#warning your system may be foobared
-#endif
+
static const struct {
- const int policy;
- const char const name[12];
+ int policy;
+ char name[sizeof("SCHED_OTHER")];
} policies[] = {
{SCHED_OTHER, "SCHED_OTHER"},
{SCHED_FIFO, "SCHED_FIFO"},
{SCHED_RR, "SCHED_RR"}
};
+//TODO: add
+// -b, SCHED_BATCH
+// -i, SCHED_IDLE
+
static void show_min_max(int pol)
{
- const char *fmt = "%s min/max priority\t: %d/%d\n\0%s not supported?\n";
+ const char *fmt = "%s min/max priority\t: %u/%u\n";
int max, min;
+
max = sched_get_priority_max(pol);
min = sched_get_priority_min(pol);
- if (max >= 0 && min >= 0)
- printf(fmt, policies[pol].name, min, max);
- else {
- fmt += 29;
- printf(fmt, policies[pol].name);
- }
+ if ((max|min) < 0)
+ fmt = "%s not supported\n";
+ printf(fmt, policies[pol].name, min, max);
}
#define OPT_m (1<<0)
#define OPT_o (1<<4)
int chrt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int chrt_main(int argc, char **argv)
+int chrt_main(int argc UNUSED_PARAM, char **argv)
{
pid_t pid = 0;
unsigned opt;
struct sched_param sp;
- char *p_opt = NULL, *priority = NULL;
- const char *state = "current\0new";
- int prio = 0, policy = SCHED_RR;
+ char *pid_str;
+ char *priority = priority; /* for compiler */
+ const char *current_new;
+ int policy = SCHED_RR;
- opt_complementary = "r--fo:f--ro:r--fo"; /* only one policy accepted */
- opt = getopt32(argv, "+mp:rfo", &p_opt);
+ /* only one policy accepted */
+ opt_complementary = "r--fo:f--ro:o--rf";
+ opt = getopt32(argv, "+mprfo");
+ if (opt & OPT_m) { /* print min/max and exit */
+ show_min_max(SCHED_FIFO);
+ show_min_max(SCHED_RR);
+ show_min_max(SCHED_OTHER);
+ fflush_stdout_and_exit(EXIT_SUCCESS);
+ }
if (opt & OPT_r)
policy = SCHED_RR;
if (opt & OPT_f)
if (opt & OPT_o)
policy = SCHED_OTHER;
- if (opt & OPT_m) { /* print min/max */
- show_min_max(SCHED_FIFO);
- show_min_max(SCHED_RR);
- show_min_max(SCHED_OTHER);
- fflush_stdout_and_exit(EXIT_SUCCESS);
- }
+ argv += optind;
+ if (!argv[0])
+ bb_show_usage();
if (opt & OPT_p) {
- if (argc == optind+1) { /* -p <priority> <pid> */
- priority = p_opt;
- p_opt = argv[optind];
+ pid_str = *argv++;
+ if (*argv) { /* "-p <priority> <pid> [...]" */
+ priority = pid_str;
+ pid_str = *argv;
}
- argv += optind; /* me -p <arg> */
- pid = xatoul_range(p_opt, 1, ULONG_MAX); /* -p <pid> */
+ /* else "-p <pid>", and *argv == NULL */
+ pid = xatoul_range(pid_str, 1, ((unsigned)(pid_t)ULONG_MAX) >> 1);
} else {
- argv += optind; /* me -p <arg> */
- priority = *argv;
- }
- if (priority) {
- /* from the manpage of sched_getscheduler:
- [...] sched_priority can have a value
- in the range 0 to 99.
- [...] SCHED_OTHER or SCHED_BATCH must be assigned
- the static priority 0. [...] SCHED_FIFO or
- SCHED_RR can have a static priority in the range 1 to 99.
- */
- prio = xstrtol_range(priority, 0, policy == SCHED_OTHER
- ? 0 : 1, 99);
+ priority = *argv++;
+ if (!*argv)
+ bb_show_usage();
}
+ current_new = "current\0new";
if (opt & OPT_p) {
- int pol = 0;
-print_rt_info:
+ int pol;
+ print_rt_info:
pol = sched_getscheduler(pid);
if (pol < 0)
- bb_perror_msg_and_die("failed to %cet pid %d's policy", 'g', pid);
+ bb_perror_msg_and_die("can't %cet pid %d's policy", 'g', (int)pid);
printf("pid %d's %s scheduling policy: %s\n",
- pid, state, policies[pol].name);
+ pid, current_new, policies[pol].name);
if (sched_getparam(pid, &sp))
- bb_perror_msg_and_die("failed to get pid %d's attributes", pid);
+ bb_perror_msg_and_die("can't get pid %d's attributes", (int)pid);
printf("pid %d's %s scheduling priority: %d\n",
- pid, state, sp.sched_priority);
- if (!*argv) /* no new prio given or we did print already, done. */
+ (int)pid, current_new, sp.sched_priority);
+ if (!*argv) {
+ /* Either it was just "-p <pid>",
+ * or it was "-p <priority> <pid>" and we came here
+ * for the second time (see goto below) */
return EXIT_SUCCESS;
+ }
+ *argv = NULL;
+ current_new += 8;
}
- sp.sched_priority = prio;
+ /* from the manpage of sched_getscheduler:
+ [...] sched_priority can have a value in the range 0 to 99.
+ [...] SCHED_OTHER or SCHED_BATCH must be assigned static priority 0.
+ [...] SCHED_FIFO or SCHED_RR can have static priority in 1..99 range.
+ */
+ sp.sched_priority = xstrtou_range(priority, 0, policy != SCHED_OTHER ? 1 : 0, 99);
+
if (sched_setscheduler(pid, policy, &sp) < 0)
- bb_perror_msg_and_die("failed to %cet pid %d's policy", 's', pid);
- if (opt & OPT_p) {
- state += 8;
- ++argv;
+ bb_perror_msg_and_die("can't %cet pid %d's policy", 's', (int)pid);
+
+ if (!argv[0]) /* "-p <priority> <pid> [...]" */
goto print_rt_info;
- }
- ++argv;
- BB_EXECVP(*argv, argv);
- bb_simple_perror_msg_and_die(*argv);
+
+ BB_EXECVP_or_die(argv);
}
-#undef OPT_p
-#undef OPT_r
-#undef OPT_f
-#undef OPT_o
-#undef OPT_m
projects / oweals / busybox.git / blobdiff