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    Contents of /tags/mkinitrd-6_1_12/busybox/miscutils/chrt.c

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    Revision 939 - (show annotations) (download)
    Tue Nov 17 21:24:51 2009 UTC (14 years, 6 months ago) by niro
    File MIME type: text/plain
    File size: 3243 byte(s) 
    tagged 'mkinitrd-6_1_12'
    1 /* vi: set sw=4 ts=4: */
    2 /*
    3 * chrt - manipulate real-time attributes of a process
    4 * Copyright (c) 2006-2007 Bernhard Reutner-Fischer
    5 *
    6 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
    7 */
    8
    9 #include <sched.h>
    10 #include "libbb.h"
    11 #ifndef _POSIX_PRIORITY_SCHEDULING
    12 #warning your system may be foobared
    13 #endif
    14 static const struct {
    15 int policy;
    16 char name[12];
    17 } policies[] = {
    18 {SCHED_OTHER, "SCHED_OTHER"},
    19 {SCHED_FIFO, "SCHED_FIFO"},
    20 {SCHED_RR, "SCHED_RR"}
    21 };
    22
    23 static void show_min_max(int pol)
    24 {
    25 const char *fmt = "%s min/max priority\t: %d/%d\n\0%s not supported?\n";
    26 int max, min;
    27 max = sched_get_priority_max(pol);
    28 min = sched_get_priority_min(pol);
    29 if (max >= 0 && min >= 0)
    30 printf(fmt, policies[pol].name, min, max);
    31 else {
    32 fmt += 29;
    33 printf(fmt, policies[pol].name);
    34 }
    35 }
    36
    37 #define OPT_m (1<<0)
    38 #define OPT_p (1<<1)
    39 #define OPT_r (1<<2)
    40 #define OPT_f (1<<3)
    41 #define OPT_o (1<<4)
    42
    43 int chrt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
    44 int chrt_main(int argc UNUSED_PARAM, char **argv)
    45 {
    46 pid_t pid = 0;
    47 unsigned opt;
    48 struct sched_param sp;
    49 char *pid_str;
    50 char *priority = priority; /* for compiler */
    51 const char *current_new;
    52 int policy = SCHED_RR;
    53
    54 /* at least 1 arg; only one policy accepted */
    55 opt_complementary = "-1:r--fo:f--ro:r--fo";
    56 opt = getopt32(argv, "+mprfo");
    57 if (opt & OPT_r)
    58 policy = SCHED_RR;
    59 if (opt & OPT_f)
    60 policy = SCHED_FIFO;
    61 if (opt & OPT_o)
    62 policy = SCHED_OTHER;
    63 if (opt & OPT_m) { /* print min/max */
    64 show_min_max(SCHED_FIFO);
    65 show_min_max(SCHED_RR);
    66 show_min_max(SCHED_OTHER);
    67 fflush_stdout_and_exit(EXIT_SUCCESS);
    68 }
    69
    70 argv += optind;
    71 if (opt & OPT_p) {
    72 pid_str = *argv++;
    73 if (*argv) { /* "-p <priority> <pid> [...]" */
    74 priority = pid_str;
    75 pid_str = *argv;
    76 }
    77 /* else "-p <pid>", and *argv == NULL */
    78 pid = xatoul_range(pid_str, 1, ((unsigned)(pid_t)ULONG_MAX) >> 1);
    79 } else {
    80 priority = *argv++;
    81 if (!*argv)
    82 bb_show_usage();
    83 }
    84
    85 current_new = "current\0new";
    86 if (opt & OPT_p) {
    87 int pol;
    88 print_rt_info:
    89 pol = sched_getscheduler(pid);
    90 if (pol < 0)
    91 bb_perror_msg_and_die("can't %cet pid %d's policy", 'g', pid);
    92 printf("pid %d's %s scheduling policy: %s\n",
    93 pid, current_new, policies[pol].name);
    94 if (sched_getparam(pid, &sp))
    95 bb_perror_msg_and_die("can't get pid %d's attributes", pid);
    96 printf("pid %d's %s scheduling priority: %d\n",
    97 pid, current_new, sp.sched_priority);
    98 if (!*argv) {
    99 /* Either it was just "-p <pid>",
    100 * or it was "-p <priority> <pid>" and we came here
    101 * for the second time (see goto below) */
    102 return EXIT_SUCCESS;
    103 }
    104 *argv = NULL;
    105 current_new += 8;
    106 }
    107
    108 /* from the manpage of sched_getscheduler:
    109 [...] sched_priority can have a value in the range 0 to 99.
    110 [...] SCHED_OTHER or SCHED_BATCH must be assigned static priority 0.
    111 [...] SCHED_FIFO or SCHED_RR can have static priority in 1..99 range.
    112 */
    113 sp.sched_priority = xstrtou_range(priority, 0, policy != SCHED_OTHER ? 1 : 0, 99);
    114
    115 if (sched_setscheduler(pid, policy, &sp) < 0)
    116 bb_perror_msg_and_die("can't %cet pid %d's policy", 's', pid);
    117
    118 if (!*argv) /* "-p <priority> <pid> [...]" */
    119 goto print_rt_info;
    120
    121 BB_EXECVP(*argv, argv);
    122 bb_simple_perror_msg_and_die(*argv);
    123 }