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 "nls.h"
  28 #include "c.h"
  29 #include "path.h"
  30 #include "strutils.h"
  31 #include "closestream.h"
  32
  33 static void __attribute__((__noreturn__)) usage(void)
  34 {
  35         FILE *out = stdout;
  36         fputs(USAGE_HEADER, out);
  37         fprintf(out,
  38               _(" %1$s [options] -p pid\n"
  39                 " %1$s [options] -n number -p pid\n"
  40                 " %1$s [options] -n number command [args...]]\n"),
  41                 program_invocation_short_name);
  42
  43         fputs(USAGE_SEPARATOR, out);
  44         fputs(_("Display and adjust OOM-killer score.\n"), out);
  45
  46         fputs(USAGE_OPTIONS, out);
  47         fputs(_(" -n, --adjust <num>     specify the adjust score value\n"), out);
  48         fputs(_(" -p, --pid <num>        process ID\n"), out);
  49         fputs(USAGE_SEPARATOR, out);
  50         printf(USAGE_HELP_OPTIONS(24));
  51         printf(USAGE_MAN_TAIL("choom(1)"));
  52         exit(EXIT_SUCCESS);
  53 }
  54
  55 static int get_score(struct path_cxt *pc)
  56 {
  57         int ret;
  58
  59         if (ul_path_read_s32(pc, &ret, "oom_score") != 0)
  60                 err(EXIT_FAILURE, _("failed to read OOM score value"));
  61
  62         return ret;
  63 }
  64
  65 static int get_score_adj(struct path_cxt *pc)
  66 {
  67         int ret;
  68
  69         if (ul_path_read_s32(pc, &ret, "oom_score_adj") != 0)
  70                 err(EXIT_FAILURE, _("failed to read OOM score adjust value"));
  71
  72         return ret;
  73 }
  74
  75 static int set_score_adj(struct path_cxt *pc, int adj)
  76 {
  77         return ul_path_write_s64(pc, adj, "oom_score_adj");
  78 }
  79
  80 int main(int argc, char **argv)
  81 {
  82         pid_t pid = 0;
  83         int c, adj = 0, has_adj = 0;
  84         struct path_cxt *pc = NULL;
  85
  86         static const struct option longopts[] = {
  87                 { "adjust",  required_argument, NULL, 'n' },
  88                 { "pid",     required_argument, NULL, 'p' },
  89                 { "help",    no_argument,       NULL, 'h' },
  90                 { "version", no_argument,       NULL, 'V' },
  91                 { NULL,      0,                 NULL,  0  }
  92         };
  93
  94         setlocale(LC_ALL, "");
  95         bindtextdomain(PACKAGE, LOCALEDIR);
  96         textdomain(PACKAGE);
  97         close_stdout_atexit();
  98
  99         while ((c = getopt_long(argc, argv, "hn:p:V", longopts, NULL)) != -1) {
 100                 switch (c) {
 101                 case 'p':
 102                         pid = strtos32_or_err(optarg, _("invalid PID argument"));
 103                         break;
 104                 case 'n':
 105                         adj = strtos32_or_err(optarg, _("invalid adjust argument"));
 106                         has_adj = 1;
 107                         break;
 108
 109                 case 'V':
 110                         print_version(EXIT_SUCCESS);
 111                 case 'h':
 112                         usage();
 113                 default:
 114                         errtryhelp(EXIT_FAILURE);
 115                 }
 116         }
 117
 118         if (optind < argc && pid) {
 119                 warnx(_("invalid argument: %s"), argv[optind]);
 120                 errtryhelp(EXIT_FAILURE);
 121         }
 122         if (!pid && argc - optind < 1) {
 123                 warnx(_("no PID or COMMAND specified"));
 124                 errtryhelp(EXIT_FAILURE);
 125         }
 126         if (optind < argc && !has_adj) {
 127                 warnx(_("no OOM score adjust value specified"));
 128                 errtryhelp(EXIT_FAILURE);
 129         }
 130
 131         pc = ul_new_path("/proc/%d", (int) (pid ? pid : getpid()));
 132
 133         /* Show */
 134         if (!has_adj) {
 135                 printf(_("pid %d's current OOM score: %d\n"), pid, get_score(pc));
 136                 printf(_("pid %d's current OOM score adjust value: %d\n"), pid, get_score_adj(pc));
 137
 138         /* Change */
 139         } else if (pid) {
 140                 int old = get_score_adj(pc);
 141
 142                 if (set_score_adj(pc, adj))
 143                         err(EXIT_FAILURE, _("failed to set score adjust value"));
 144
 145                 printf(_("pid %d's OOM score adjust value changed from %d to %d\n"), pid, old, adj);
 146
 147         /* Start new process */
 148         } else {
 149                 if (set_score_adj(pc, adj))
 150                         err(EXIT_FAILURE, _("failed to set score adjust value"));
 151                 ul_unref_path(pc);
 152                 argv += optind;
 153                 execvp(argv[0], argv);
 154                 errexec(argv[0]);
 155         }
 156
 157         ul_unref_path(pc);
 158         return EXIT_SUCCESS;
 159 }