1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * ionice implementation for busybox based on linux-utils-ng 2.14
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4 | *
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5 | * Copyright (C) 2008 by <u173034@informatik.uni-oldenburg.de>
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6 | *
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7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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8 | */
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9 |
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10 | //usage:#define ionice_trivial_usage
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11 | //usage: "[-c 1-3] [-n 0-7] [-p PID] [PROG]"
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12 | //usage:#define ionice_full_usage "\n\n"
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13 | //usage: "Change I/O priority and class\n"
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14 | //usage: "\n -c Class. 1:realtime 2:best-effort 3:idle"
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15 | //usage: "\n -n Priority"
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16 |
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17 | #include <sys/syscall.h>
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18 | #include <asm/unistd.h>
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19 | #include "libbb.h"
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20 |
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21 | static int ioprio_set(int which, int who, int ioprio)
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22 | {
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23 | return syscall(SYS_ioprio_set, which, who, ioprio);
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24 | }
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25 |
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26 | static int ioprio_get(int which, int who)
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27 | {
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28 | return syscall(SYS_ioprio_get, which, who);
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29 | }
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30 |
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31 | enum {
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32 | IOPRIO_WHO_PROCESS = 1,
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33 | IOPRIO_WHO_PGRP,
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34 | IOPRIO_WHO_USER
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35 | };
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36 |
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37 | enum {
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38 | IOPRIO_CLASS_NONE,
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39 | IOPRIO_CLASS_RT,
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40 | IOPRIO_CLASS_BE,
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41 | IOPRIO_CLASS_IDLE
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42 | };
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43 |
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44 | static const char to_prio[] = "none\0realtime\0best-effort\0idle";
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45 |
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46 | #define IOPRIO_CLASS_SHIFT 13
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47 |
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48 | int ionice_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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49 | int ionice_main(int argc UNUSED_PARAM, char **argv)
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50 | {
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51 | /* Defaults */
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52 | int ioclass = 0;
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53 | int pri = 0;
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54 | int pid = 0; /* affect own porcess */
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55 | int opt;
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56 | enum {
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57 | OPT_n = 1,
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58 | OPT_c = 2,
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59 | OPT_p = 4,
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60 | };
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61 |
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62 | /* Numeric params */
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63 | opt_complementary = "n+:c+:p+";
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64 | /* '+': stop at first non-option */
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65 | opt = getopt32(argv, "+n:c:p:", &pri, &ioclass, &pid);
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66 | argv += optind;
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67 |
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68 | if (opt & OPT_c) {
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69 | if (ioclass > 3)
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70 | bb_error_msg_and_die("bad class %d", ioclass);
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71 | // Do we need this (compat?)?
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72 | // if (ioclass == IOPRIO_CLASS_NONE)
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73 | // ioclass = IOPRIO_CLASS_BE;
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74 | // if (ioclass == IOPRIO_CLASS_IDLE) {
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75 | // //if (opt & OPT_n)
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76 | // // bb_error_msg("ignoring priority for idle class");
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77 | // pri = 7;
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78 | // }
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79 | }
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80 |
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81 | if (!(opt & (OPT_n|OPT_c))) {
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82 | if (!(opt & OPT_p) && *argv)
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83 | pid = xatoi_positive(*argv);
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84 |
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85 | pri = ioprio_get(IOPRIO_WHO_PROCESS, pid);
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86 | if (pri == -1)
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87 | bb_perror_msg_and_die("ioprio_%cet", 'g');
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88 |
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89 | ioclass = (pri >> IOPRIO_CLASS_SHIFT) & 0x3;
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90 | pri &= 0xff;
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91 | printf((ioclass == IOPRIO_CLASS_IDLE) ? "%s\n" : "%s: prio %d\n",
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92 | nth_string(to_prio, ioclass), pri);
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93 | } else {
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94 | //printf("pri=%d class=%d val=%x\n",
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95 | //pri, ioclass, pri | (ioclass << IOPRIO_CLASS_SHIFT));
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96 | pri |= (ioclass << IOPRIO_CLASS_SHIFT);
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97 | if (ioprio_set(IOPRIO_WHO_PROCESS, pid, pri) == -1)
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98 | bb_perror_msg_and_die("ioprio_%cet", 's');
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99 | if (argv[0]) {
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100 | BB_EXECVP_or_die(argv);
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101 | }
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102 | }
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103 |
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104 | return EXIT_SUCCESS;
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105 | }
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