sys-utils/choom.c

   1 /*
   2  * choom - Change OOM score setting
   3  *
   4  * Copyright (C) 2018 Karel Zak <kzak@redhat.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it would be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <getopt.h>
  25 #include <errno.h>
  26
  27 #include <linux/oom.h>
  28
  29 #include "nls.h"
  30 #include "c.h"
  31 #include "path.h"
  32 #include "strutils.h"
  33 #include "closestream.h"
  34
  35 static void __attribute__((__noreturn__)) usage(void)
  36 {
  37         FILE *out = stdout;
  38         fputs(USAGE_HEADER, out);
  39         fprintf(out,
  40               _(" %1$s [options] -p pid\n"
  41                 " %1$s [options] -n number -p pid\n"
  42                 " %1$s [options] -n number command [args...]]\n"),
  43                 program_invocation_short_name);
  44
  45         fputs(USAGE_SEPARATOR, out);
  46         fputs(_("Display and adjust OOM-killer score.\n"), out);
  47
  48         fputs(USAGE_OPTIONS, out);
  49         fputs(_(" -n, --adjust <num>     specify the adjust score value\n"), out);
  50         fputs(_(" -p, --pid <num>        process ID\n"), out);
  51         fputs(USAGE_SEPARATOR, out);
  52         printf(USAGE_HELP_OPTIONS(24));
  53         printf(USAGE_MAN_TAIL("choom(1)"));
  54         exit(EXIT_SUCCESS);
  55 }
  56
  57 static int get_score(const pid_t pid)
  58 {
  59         return path_read_s32("/proc/%d/oom_score", (int) pid);
  60 }
  61
  62 static int get_score_adj(const pid_t pid)
  63 {
  64         return path_read_s32("/proc/%d/oom_score_adj", (int) pid);
  65 }
  66
  67 static int set_score_adj(const pid_t pid, int adj)
  68 {
  69         char buf[sizeof(stringify_value(OOM_SCORE_ADJ_MIN))];
  70
  71         snprintf(buf, sizeof(buf), "%d", adj);
  72
  73         if (path_write_str(buf, "/proc/%d/oom_score_adj", (int) pid) < 0)
  74                 return -1;
  75         return 0;
  76 }
  77
  78 int main(int argc, char **argv)
  79 {
  80         pid_t pid = 0;
  81         int c, adj = 0, has_adj = 0;
  82
  83         static const struct option longopts[] = {
  84                 { "adjust",  required_argument, NULL, 'n' },
  85                 { "pid",     required_argument, NULL, 'p' },
  86                 { "help",    no_argument,       NULL, 'h' },
  87                 { "version", no_argument,       NULL, 'V' },
  88                 { NULL,      0,                 NULL,  0  }
  89         };
  90
  91         setlocale(LC_ALL, "");
  92         bindtextdomain(PACKAGE, LOCALEDIR);
  93         textdomain(PACKAGE);
  94         atexit(close_stdout);
  95
  96         while ((c = getopt_long(argc, argv, "hn:p:V", longopts, NULL)) != -1) {
  97                 switch (c) {
  98                 case 'p':
  99                         pid = strtos32_or_err(optarg, _("invalid PID argument"));
 100                         break;
 101                 case 'n':
 102                         adj = strtos32_or_err(optarg, _("invalid adjust argument"));
 103                         has_adj = 1;
 104                         break;
 105                 case 'V':
 106                         printf(UTIL_LINUX_VERSION);
 107                         return EXIT_SUCCESS;
 108                 case 'h':
 109                         usage();
 110                 default:
 111                         errtryhelp(EXIT_FAILURE);
 112                 }
 113         }
 114
 115         if (optind < argc && pid) {
 116                 warnx(_("invalid argument: %s"), argv[optind]);
 117                 errtryhelp(EXIT_FAILURE);
 118         }
 119         if (!pid && argc - optind < 1) {
 120                 warnx(_("no PID or COMMAND specified"));
 121                 errtryhelp(EXIT_FAILURE);
 122         }
 123         if (optind < argc && !has_adj) {
 124                 warnx(_("no OOM score adjust value specified"));
 125                 errtryhelp(EXIT_FAILURE);
 126         }
 127
 128         /* Show */
 129         if (!has_adj) {
 130                 printf(_("pid %d's current OOM score: %d\n"), pid, get_score(pid));
 131                 printf(_("pid %d's current OOM score adjust value: %d\n"), pid, get_score_adj(pid));
 132
 133         /* Change */
 134         } else if (pid) {
 135                 int old = get_score_adj(pid);
 136
 137                 if (set_score_adj(pid, adj))
 138                         err(EXIT_FAILURE, _("failed to set score adjust value"));
 139
 140                 printf(_("pid %d's OOM score adjust value changed from %d to %d\n"), pid, old, adj);
 141
 142         /* Start new process */
 143         } else {
 144                 argv += optind;
 145                 execvp(argv[0], argv);
 146                 errexec(argv[0]);
 147         }
 148
 149         return EXIT_SUCCESS;
 150 }