src/sysctl/sysctl.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <getopt.h>
  22 #include <limits.h>
  23 #include <stdbool.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27
  28 #include "conf-files.h"
  29 #include "def.h"
  30 #include "fd-util.h"
  31 #include "fileio.h"
  32 #include "hashmap.h"
  33 #include "log.h"
  34 #include "path-util.h"
  35 #include "string-util.h"
  36 #include "strv.h"
  37 #include "sysctl-util.h"
  38 #include "util.h"
  39
  40 static char **arg_prefixes = NULL;
  41
  42 static const char conf_file_dirs[] = CONF_PATHS_NULSTR("sysctl.d");
  43
  44 static int apply_all(Hashmap *sysctl_options) {
  45         char *property, *value;
  46         Iterator i;
  47         int r = 0;
  48
  49         HASHMAP_FOREACH_KEY(value, property, sysctl_options, i) {
  50                 int k;
  51
  52                 k = sysctl_write(property, value);
  53                 if (k < 0) {
  54                         log_full_errno(k == -ENOENT ? LOG_INFO : LOG_WARNING, k,
  55                                        "Couldn't write '%s' to '%s', ignoring: %m", value, property);
  56
  57                         if (r == 0 && k != -ENOENT)
  58                                 r = k;
  59                 }
  60         }
  61
  62         return r;
  63 }
  64
  65 static int parse_file(Hashmap *sysctl_options, const char *path, bool ignore_enoent) {
  66         _cleanup_fclose_ FILE *f = NULL;
  67         int r;
  68
  69         assert(path);
  70
  71         r = search_and_fopen_nulstr(path, "re", NULL, conf_file_dirs, &f);
  72         if (r < 0) {
  73                 if (ignore_enoent && r == -ENOENT)
  74                         return 0;
  75
  76                 return log_error_errno(r, "Failed to open file '%s', ignoring: %m", path);
  77         }
  78
  79         log_debug("Parsing %s", path);
  80         while (!feof(f)) {
  81                 char l[LINE_MAX], *p, *value, *new_value, *property, *existing;
  82                 void *v;
  83                 int k;
  84
  85                 if (!fgets(l, sizeof(l), f)) {
  86                         if (feof(f))
  87                                 break;
  88
  89                         return log_error_errno(errno, "Failed to read file '%s', ignoring: %m", path);
  90                 }
  91
  92                 p = strstrip(l);
  93                 if (!*p)
  94                         continue;
  95
  96                 if (strchr(COMMENTS "\n", *p))
  97                         continue;
  98
  99                 value = strchr(p, '=');
 100                 if (!value) {
 101                         log_error("Line is not an assignment in file '%s': %s", path, value);
 102
 103                         if (r == 0)
 104                                 r = -EINVAL;
 105                         continue;
 106                 }
 107
 108                 *value = 0;
 109                 value++;
 110
 111                 p = sysctl_normalize(strstrip(p));
 112                 value = strstrip(value);
 113
 114                 if (!strv_isempty(arg_prefixes)) {
 115                         char **i, *t;
 116                         STRV_FOREACH(i, arg_prefixes) {
 117                                 t = path_startswith(*i, "/proc/sys/");
 118                                 if (t == NULL)
 119                                         t = *i;
 120                                 if (path_startswith(p, t))
 121                                         goto found;
 122                         }
 123                         /* not found */
 124                         continue;
 125                 }
 126
 127 found:
 128                 existing = hashmap_get2(sysctl_options, p, &v);
 129                 if (existing) {
 130                         if (streq(value, existing))
 131                                 continue;
 132
 133                         log_debug("Overwriting earlier assignment of %s in file '%s'.", p, path);
 134                         free(hashmap_remove(sysctl_options, p));
 135                         free(v);
 136                 }
 137
 138                 property = strdup(p);
 139                 if (!property)
 140                         return log_oom();
 141
 142                 new_value = strdup(value);
 143                 if (!new_value) {
 144                         free(property);
 145                         return log_oom();
 146                 }
 147
 148                 k = hashmap_put(sysctl_options, property, new_value);
 149                 if (k < 0) {
 150                         log_error_errno(k, "Failed to add sysctl variable %s to hashmap: %m", property);
 151                         free(property);
 152                         free(new_value);
 153                         return k;
 154                 }
 155         }
 156
 157         return r;
 158 }
 159
 160 static void help(void) {
 161         printf("%s [OPTIONS...] [CONFIGURATION FILE...]\n\n"
 162                "Applies kernel sysctl settings.\n\n"
 163                "  -h --help             Show this help\n"
 164                "     --version          Show package version\n"
 165                "     --prefix=PATH      Only apply rules with the specified prefix\n"
 166                , program_invocation_short_name);
 167 }
 168
 169 static int parse_argv(int argc, char *argv[]) {
 170
 171         enum {
 172                 ARG_VERSION = 0x100,
 173                 ARG_PREFIX
 174         };
 175
 176         static const struct option options[] = {
 177                 { "help",      no_argument,       NULL, 'h'           },
 178                 { "version",   no_argument,       NULL, ARG_VERSION   },
 179                 { "prefix",    required_argument, NULL, ARG_PREFIX    },
 180                 {}
 181         };
 182
 183         int c;
 184
 185         assert(argc >= 0);
 186         assert(argv);
 187
 188         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
 189
 190                 switch (c) {
 191
 192                 case 'h':
 193                         help();
 194                         return 0;
 195
 196                 case ARG_VERSION:
 197                         return version();
 198
 199                 case ARG_PREFIX: {
 200                         char *p;
 201
 202                         /* We used to require people to specify absolute paths
 203                          * in /proc/sys in the past. This is kinda useless, but
 204                          * we need to keep compatibility. We now support any
 205                          * sysctl name available. */
 206                         sysctl_normalize(optarg);
 207
 208                         if (startswith(optarg, "/proc/sys"))
 209                                 p = strdup(optarg);
 210                         else
 211                                 p = strappend("/proc/sys/", optarg);
 212                         if (!p)
 213                                 return log_oom();
 214
 215                         if (strv_consume(&arg_prefixes, p) < 0)
 216                                 return log_oom();
 217
 218                         break;
 219                 }
 220
 221                 case '?':
 222                         return -EINVAL;
 223
 224                 default:
 225                         assert_not_reached("Unhandled option");
 226                 }
 227
 228         return 1;
 229 }
 230
 231 int main(int argc, char *argv[]) {
 232         int r = 0, k;
 233         Hashmap *sysctl_options;
 234
 235         r = parse_argv(argc, argv);
 236         if (r <= 0)
 237                 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 238
 239         log_set_target(LOG_TARGET_AUTO);
 240         log_parse_environment();
 241         log_open();
 242
 243         umask(0022);
 244
 245         sysctl_options = hashmap_new(&string_hash_ops);
 246         if (!sysctl_options) {
 247                 r = log_oom();
 248                 goto finish;
 249         }
 250
 251         r = 0;
 252
 253         if (argc > optind) {
 254                 int i;
 255
 256                 for (i = optind; i < argc; i++) {
 257                         k = parse_file(sysctl_options, argv[i], false);
 258                         if (k < 0 && r == 0)
 259                                 r = k;
 260                 }
 261         } else {
 262                 _cleanup_strv_free_ char **files = NULL;
 263                 char **f;
 264
 265                 r = conf_files_list_nulstr(&files, ".conf", NULL, conf_file_dirs);
 266                 if (r < 0) {
 267                         log_error_errno(r, "Failed to enumerate sysctl.d files: %m");
 268                         goto finish;
 269                 }
 270
 271                 STRV_FOREACH(f, files) {
 272                         k = parse_file(sysctl_options, *f, true);
 273                         if (k < 0 && r == 0)
 274                                 r = k;
 275                 }
 276         }
 277
 278         k = apply_all(sysctl_options);
 279         if (k < 0 && r == 0)
 280                 r = k;
 281
 282 finish:
 283         hashmap_free_free_free(sysctl_options);
 284         strv_free(arg_prefixes);
 285
 286         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 287 }