| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * chrt - manipulate real-time attributes of a process
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| 4 | * Copyright (c) 2006-2007 Bernhard Fischer
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| 5 | *
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| 6 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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| 7 | */
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| 8 |
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| 9 | #include <sched.h>
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| 10 | #include <getopt.h> /* optind */
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| 11 | #include "libbb.h"
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| 12 | #ifndef _POSIX_PRIORITY_SCHEDULING
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| 13 | #warning your system may be foobared
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| 14 | #endif
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| 15 | static const struct {
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| 16 | const int policy;
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| 17 | const char const name[12];
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| 18 | } policies[] = {
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| 19 | {SCHED_OTHER, "SCHED_OTHER"},
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| 20 | {SCHED_FIFO, "SCHED_FIFO"},
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| 21 | {SCHED_RR, "SCHED_RR"}
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| 22 | };
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| 23 |
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| 24 | static void show_min_max(int pol)
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| 25 | {
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| 26 | const char *fmt = "%s min/max priority\t: %d/%d\n\0%s not supported?\n";
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| 27 | int max, min;
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| 28 | max = sched_get_priority_max(pol);
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| 29 | min = sched_get_priority_min(pol);
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| 30 | if (max >= 0 && min >= 0)
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| 31 | printf(fmt, policies[pol].name, min, max);
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| 32 | else {
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| 33 | fmt += 29;
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| 34 | printf(fmt, policies[pol].name);
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| 35 | }
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| 36 | }
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| 37 |
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| 38 | #define OPT_m (1<<0)
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| 39 | #define OPT_p (1<<1)
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| 40 | #define OPT_r (1<<2)
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| 41 | #define OPT_f (1<<3)
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| 42 | #define OPT_o (1<<4)
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| 43 |
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| 44 | int chrt_main(int argc, char** argv);
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| 45 | int chrt_main(int argc, char** argv)
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| 46 | {
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| 47 | pid_t pid = 0;
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| 48 | unsigned opt;
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| 49 | struct sched_param sp;
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| 50 | char *p_opt = NULL, *priority = NULL;
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| 51 | const char *state = "current\0new";
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| 52 | int prio = 0, policy = SCHED_RR;
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| 53 |
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| 54 | opt_complementary = "r--fo:f--ro:r--fo"; /* only one policy accepted */
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| 55 | opt = getopt32(argv, "+mp:rfo", &p_opt);
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| 56 | if (opt & OPT_r)
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| 57 | policy = SCHED_RR;
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| 58 | if (opt & OPT_f)
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| 59 | policy = SCHED_FIFO;
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| 60 | if (opt & OPT_o)
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| 61 | policy = SCHED_OTHER;
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| 62 |
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| 63 | if (opt & OPT_m) { /* print min/max */
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| 64 | show_min_max(SCHED_FIFO);
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| 65 | show_min_max(SCHED_RR);
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| 66 | show_min_max(SCHED_OTHER);
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| 67 | fflush_stdout_and_exit(EXIT_SUCCESS);
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| 68 | }
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| 69 | if (opt & OPT_p) {
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| 70 | if (argc == optind+1) { /* -p <priority> <pid> */
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| 71 | priority = p_opt;
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| 72 | p_opt = argv[optind];
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| 73 | }
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| 74 | argv += optind; /* me -p <arg> */
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| 75 | pid = xatoul_range(p_opt, 1, ULONG_MAX); /* -p <pid> */
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| 76 | } else {
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| 77 | argv += optind; /* me -p <arg> */
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| 78 | priority = *argv;
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| 79 | }
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| 80 | if (priority) {
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| 81 | /* from the manpage of sched_getscheduler:
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| 82 | [...] sched_priority can have a value
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| 83 | in the range 0 to 99.
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| 84 | [...] SCHED_OTHER or SCHED_BATCH must be assigned
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| 85 | the static priority 0. [...] SCHED_FIFO or
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| 86 | SCHED_RR can have a static priority in the range 1 to 99.
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| 87 | */
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| 88 | prio = xstrtol_range(priority, 0, policy == SCHED_OTHER
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| 89 | ? 0 : 1, 99);
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| 90 | }
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| 91 |
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| 92 | if (opt & OPT_p) {
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| 93 | int pol = 0;
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| 94 | print_rt_info:
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| 95 | pol = sched_getscheduler(pid);
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| 96 | if (pol < 0)
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| 97 | bb_perror_msg_and_die("failed to %cet pid %d's policy", 'g', pid);
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| 98 | printf("pid %d's %s scheduling policy: %s\n",
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| 99 | pid, state, policies[pol].name);
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| 100 | if (sched_getparam(pid, &sp))
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| 101 | bb_perror_msg_and_die("failed to get pid %d's attributes", pid);
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| 102 | printf("pid %d's %s scheduling priority: %d\n",
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| 103 | pid, state, sp.sched_priority);
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| 104 | if (!*argv) /* no new prio given or we did print already, done. */
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| 105 | return EXIT_SUCCESS;
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| 106 | }
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| 107 |
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| 108 | sp.sched_priority = prio;
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| 109 | if (sched_setscheduler(pid, policy, &sp) < 0)
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| 110 | bb_perror_msg_and_die("failed to %cet pid %d's policy", 's', pid);
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| 111 | if (opt & OPT_p) {
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| 112 | state += 8;
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| 113 | ++argv;
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| 114 | goto print_rt_info;
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| 115 | }
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| 116 | ++argv;
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| 117 | BB_EXECVP(*argv, argv);
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| 118 | bb_perror_msg_and_die("%s", *argv);
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| 119 | }
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| 120 | #undef OPT_p
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| 121 | #undef OPT_r
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| 122 | #undef OPT_f
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| 123 | #undef OPT_o
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| 124 | #undef OPT_m
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