src/oom/oomd.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <getopt.h>
   4
   5 #include "bus-log-control-api.h"
   6 #include "bus-object.h"
   7 #include "cgroup-util.h"
   8 #include "conf-parser.h"
   9 #include "daemon-util.h"
  10 #include "log.h"
  11 #include "main-func.h"
  12 #include "oomd-manager.h"
  13 #include "oomd-manager-bus.h"
  14 #include "parse-util.h"
  15 #include "pretty-print.c"
  16 #include "psi-util.h"
  17 #include "signal-util.h"
  18
  19 static bool arg_dry_run = false;
  20 static int arg_swap_used_limit = -1;
  21 static int arg_mem_pressure_limit_permyriad = -1;
  22 static usec_t arg_mem_pressure_usec = 0;
  23
  24 static int parse_config(void) {
  25         static const ConfigTableItem items[] = {
  26                 { "OOM", "SwapUsedLimitPercent",             config_parse_percent,   0, &arg_swap_used_limit              },
  27                 { "OOM", "DefaultMemoryPressureLimit",       config_parse_permyriad, 0, &arg_mem_pressure_limit_permyriad },
  28                 { "OOM", "DefaultMemoryPressureDurationSec", config_parse_sec,       0, &arg_mem_pressure_usec            },
  29                 {}
  30         };
  31
  32         return config_parse_many_nulstr(PKGSYSCONFDIR "/oomd.conf",
  33                                         CONF_PATHS_NULSTR("systemd/oomd.conf.d"),
  34                                         "OOM\0",
  35                                         config_item_table_lookup,
  36                                         items,
  37                                         CONFIG_PARSE_WARN,
  38                                         NULL,
  39                                         NULL);
  40 }
  41
  42 static int help(void) {
  43         _cleanup_free_ char *link = NULL;
  44         int r;
  45
  46         r = terminal_urlify_man("systemd-oomd", "1", &link);
  47         if (r < 0)
  48                 return log_oom();
  49
  50         printf("%s [OPTIONS...]\n\n"
  51                "Run the userspace out-of-memory (OOM) killer.\n\n"
  52                "  -h --help                 Show this help\n"
  53                "     --version              Show package version\n"
  54                "     --dry-run              Only print destructive actions instead of doing them\n"
  55                "     --bus-introspect=PATH  Write D-Bus XML introspection data\n"
  56                "\nSee the %s for details.\n",
  57                program_invocation_short_name,
  58                link);
  59
  60         return 0;
  61 }
  62
  63 static int parse_argv(int argc, char *argv[]) {
  64         enum {
  65                 ARG_VERSION = 0x100,
  66                 ARG_DRY_RUN,
  67                 ARG_BUS_INTROSPECT,
  68         };
  69
  70         static const struct option options[] = {
  71                 { "help",           no_argument,       NULL, 'h'                },
  72                 { "version",        no_argument,       NULL, ARG_VERSION        },
  73                 { "dry-run",        no_argument,       NULL, ARG_DRY_RUN        },
  74                 { "bus-introspect", required_argument, NULL, ARG_BUS_INTROSPECT },
  75                 {}
  76         };
  77
  78         int c;
  79
  80         assert(argc >= 0);
  81         assert(argv);
  82
  83         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
  84
  85                 switch (c) {
  86
  87                 case 'h':
  88                         return help();
  89
  90                 case ARG_VERSION:
  91                         return version();
  92
  93                 case ARG_DRY_RUN:
  94                         arg_dry_run = true;
  95                         break;
  96
  97                 case ARG_BUS_INTROSPECT:
  98                         return bus_introspect_implementations(
  99                                         stdout,
 100                                         optarg,
 101                                         BUS_IMPLEMENTATIONS(&manager_object,
 102                                                             &log_control_object));
 103
 104                 case '?':
 105                         return -EINVAL;
 106
 107                 default:
 108                         assert_not_reached("Unknown option code.");
 109                 }
 110
 111         if (optind < argc)
 112                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
 113                                        "This program takes no arguments.");
 114
 115         return 1;
 116 }
 117
 118 static int run(int argc, char *argv[]) {
 119         _cleanup_(notify_on_cleanup) const char *notify_msg = NULL;
 120         _cleanup_(manager_freep) Manager *m = NULL;
 121         _cleanup_free_ char *swap = NULL;
 122         unsigned long long s = 0;
 123         int r;
 124
 125         log_setup_service();
 126
 127         r = parse_argv(argc, argv);
 128         if (r <= 0)
 129                 return r;
 130
 131         r = parse_config();
 132         if (r < 0)
 133                 return r;
 134
 135         /* Do some basic requirement checks for running systemd-oomd. It's not exhaustive as some of the other
 136          * requirements do not have a reliable means to check for in code. */
 137
 138         /* SwapTotal is always available in /proc/meminfo and defaults to 0, even on swap-disabled kernels. */
 139         r = get_proc_field("/proc/meminfo", "SwapTotal", WHITESPACE, &swap);
 140         if (r < 0)
 141                 return log_error_errno(r, "Failed to get SwapTotal from /proc/meminfo: %m");
 142
 143         r = safe_atollu(swap, &s);
 144         if (r < 0 || s == 0)
 145                 log_warning("Swap is currently not detected; memory pressure usage will be degraded");
 146
 147         if (!is_pressure_supported())
 148                 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Pressure Stall Information (PSI) is not supported");
 149
 150         r = cg_all_unified();
 151         if (r < 0)
 152                 return log_error_errno(r, "Failed to determine whether the unified cgroups hierarchy is used: %m");
 153         if (r == 0)
 154                 return log_error_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Requires the unified cgroups hierarchy");
 155
 156         assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGTERM, SIGINT, -1) >= 0);
 157
 158         r = manager_new(&m);
 159         if (r < 0)
 160                 return log_error_errno(r, "Failed to create manager: %m");
 161
 162         r = manager_start(m, arg_dry_run, arg_swap_used_limit, arg_mem_pressure_limit_permyriad, arg_mem_pressure_usec);
 163         if (r < 0)
 164                 return log_error_errno(r, "Failed to start up daemon: %m");
 165
 166         notify_msg = notify_start(NOTIFY_READY, NOTIFY_STOPPING);
 167
 168         log_info("systemd-oomd starting%s!", arg_dry_run ? " in dry run mode" : "");
 169
 170         r = sd_event_loop(m->event);
 171         if (r < 0)
 172                 return log_error_errno(r, "Event loop failed: %m");
 173
 174         return 0;
 175 }
 176
 177 DEFINE_MAIN_FUNCTION(run);