src/sysctl/sysctl.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <stdlib.h>
  23 #include <stdbool.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <stdio.h>
  27 #include <limits.h>
  28 #include <getopt.h>
  29
  30 #include "log.h"
  31 #include "strv.h"
  32 #include "util.h"
  33 #include "hashmap.h"
  34 #include "path-util.h"
  35 #include "conf-files.h"
  36 #include "fileio.h"
  37 #include "build.h"
  38
  39 static char **arg_prefixes = NULL;
  40
  41 static const char conf_file_dirs[] =
  42         "/etc/sysctl.d\0"
  43         "/run/sysctl.d\0"
  44         "/usr/local/lib/sysctl.d\0"
  45         "/usr/lib/sysctl.d\0"
  46 #ifdef HAVE_SPLIT_USR
  47         "/lib/sysctl.d\0"
  48 #endif
  49         ;
  50
  51 static char *normalize_sysctl(char *s) {
  52         char *n;
  53
  54         for (n = s; *n; n++)
  55                 if (*n == '.')
  56                         *n = '/';
  57
  58         return s;
  59 }
  60
  61 static int apply_sysctl(const char *property, const char *value) {
  62         _cleanup_free_ char *p = NULL;
  63         char *n;
  64         int r = 0, k;
  65
  66         log_debug("Setting '%s' to '%s'", property, value);
  67
  68         p = new(char, strlen("/proc/sys/") + strlen(property) + 1);
  69         if (!p)
  70                 return log_oom();
  71
  72         n = stpcpy(p, "/proc/sys/");
  73         strcpy(n, property);
  74
  75         if (!strv_isempty(arg_prefixes)) {
  76                 char **i;
  77                 bool good = false;
  78
  79                 STRV_FOREACH(i, arg_prefixes)
  80                         if (path_startswith(p, *i)) {
  81                                 good = true;
  82                                 break;
  83                         }
  84
  85                 if (!good) {
  86                         log_debug("Skipping %s", p);
  87                         return 0;
  88                 }
  89         }
  90
  91         k = write_string_file(p, value);
  92         if (k < 0) {
  93                 log_full(k == -ENOENT ? LOG_DEBUG : LOG_WARNING,
  94                          "Failed to write '%s' to '%s': %s", value, p, strerror(-k));
  95
  96                 if (k != -ENOENT && r == 0)
  97                         r = k;
  98         }
  99
 100         return r;
 101 }
 102
 103 static int apply_all(Hashmap *sysctl_options) {
 104         int r = 0;
 105         char *property, *value;
 106         Iterator i;
 107
 108         assert(sysctl_options);
 109
 110         HASHMAP_FOREACH_KEY(value, property, sysctl_options, i) {
 111                 int k;
 112
 113                 k = apply_sysctl(property, value);
 114                 if (k < 0 && r == 0)
 115                         r = k;
 116         }
 117         return r;
 118 }
 119
 120 static int parse_file(Hashmap *sysctl_options, const char *path, bool ignore_enoent) {
 121         _cleanup_fclose_ FILE *f = NULL;
 122         int r;
 123
 124         assert(path);
 125
 126         r = search_and_fopen_nulstr(path, "re", NULL, conf_file_dirs, &f);
 127         if (r < 0) {
 128                 if (ignore_enoent && r == -ENOENT)
 129                         return 0;
 130
 131                 log_error("Failed to open file '%s', ignoring: %s", path, strerror(-r));
 132                 return r;
 133         }
 134
 135         log_debug("parse: %s", path);
 136         while (!feof(f)) {
 137                 char l[LINE_MAX], *p, *value, *new_value, *property, *existing;
 138                 void *v;
 139                 int k;
 140
 141                 if (!fgets(l, sizeof(l), f)) {
 142                         if (feof(f))
 143                                 break;
 144
 145                         log_error("Failed to read file '%s', ignoring: %m", path);
 146                         return -errno;
 147                 }
 148
 149                 p = strstrip(l);
 150                 if (!*p)
 151                         continue;
 152
 153                 if (strchr(COMMENTS "\n", *p))
 154                         continue;
 155
 156                 value = strchr(p, '=');
 157                 if (!value) {
 158                         log_error("Line is not an assignment in file '%s': %s", path, value);
 159
 160                         if (r == 0)
 161                                 r = -EINVAL;
 162                         continue;
 163                 }
 164
 165                 *value = 0;
 166                 value++;
 167
 168                 p = normalize_sysctl(strstrip(p));
 169                 value = strstrip(value);
 170
 171                 existing = hashmap_get2(sysctl_options, p, &v);
 172                 if (existing) {
 173                         if (streq(value, existing))
 174                                 continue;
 175
 176                         log_info("Overwriting earlier assignment of %s in file '%s'.", p, path);
 177                         free(hashmap_remove(sysctl_options, p));
 178                         free(v);
 179                 }
 180
 181                 property = strdup(p);
 182                 if (!property)
 183                         return log_oom();
 184
 185                 new_value = strdup(value);
 186                 if (!new_value) {
 187                         free(property);
 188                         return log_oom();
 189                 }
 190
 191                 k = hashmap_put(sysctl_options, property, new_value);
 192                 if (k < 0) {
 193                         log_error("Failed to add sysctl variable %s to hashmap: %s", property, strerror(-k));
 194                         free(property);
 195                         free(new_value);
 196                         return k;
 197                 }
 198         }
 199
 200         return r;
 201 }
 202
 203 static int help(void) {
 204
 205         printf("%s [OPTIONS...] [CONFIGURATION FILE...]\n\n"
 206                "Applies kernel sysctl settings.\n\n"
 207                "  -h --help             Show this help\n"
 208                "     --version          Show package version\n"
 209                "     --prefix=PATH      Only apply rules that apply to paths with the specified prefix\n",
 210                program_invocation_short_name);
 211
 212         return 0;
 213 }
 214
 215 static int parse_argv(int argc, char *argv[]) {
 216
 217         enum {
 218                 ARG_VERSION = 0x100,
 219                 ARG_PREFIX
 220         };
 221
 222         static const struct option options[] = {
 223                 { "help",      no_argument,       NULL, 'h'           },
 224                 { "version",   no_argument,       NULL, ARG_VERSION   },
 225                 { "prefix",    required_argument, NULL, ARG_PREFIX    },
 226                 {}
 227         };
 228
 229         int c;
 230
 231         assert(argc >= 0);
 232         assert(argv);
 233
 234         while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
 235
 236                 switch (c) {
 237
 238                 case 'h':
 239                         return help();
 240
 241                 case ARG_VERSION:
 242                         puts(PACKAGE_STRING);
 243                         puts(SYSTEMD_FEATURES);
 244                         return 0;
 245
 246                 case ARG_PREFIX: {
 247                         char *p;
 248
 249                         for (p = optarg; *p; p++)
 250                                 if (*p == '.')
 251                                         *p = '/';
 252
 253                         if (strv_extend(&arg_prefixes, optarg) < 0)
 254                                 return log_oom();
 255
 256                         break;
 257                 }
 258
 259                 case '?':
 260                         return -EINVAL;
 261
 262                 default:
 263                         assert_not_reached("Unhandled option");
 264                 }
 265         }
 266
 267         return 1;
 268 }
 269
 270 int main(int argc, char *argv[]) {
 271         int r = 0, k;
 272         Hashmap *sysctl_options;
 273
 274         r = parse_argv(argc, argv);
 275         if (r <= 0)
 276                 return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 277
 278         log_set_target(LOG_TARGET_AUTO);
 279         log_parse_environment();
 280         log_open();
 281
 282         umask(0022);
 283
 284         sysctl_options = hashmap_new(string_hash_func, string_compare_func);
 285         if (!sysctl_options) {
 286                 r = log_oom();
 287                 goto finish;
 288         }
 289
 290         r = 0;
 291
 292         if (argc > optind) {
 293                 int i;
 294
 295                 for (i = optind; i < argc; i++) {
 296                         k = parse_file(sysctl_options, argv[i], false);
 297                         if (k < 0 && r == 0)
 298                                 r = k;
 299                 }
 300         } else {
 301                 _cleanup_strv_free_ char **files = NULL;
 302                 char **f;
 303
 304                 r = conf_files_list_nulstr(&files, ".conf", NULL, conf_file_dirs);
 305                 if (r < 0) {
 306                         log_error("Failed to enumerate sysctl.d files: %s", strerror(-r));
 307                         goto finish;
 308                 }
 309
 310                 STRV_FOREACH(f, files) {
 311                         k = parse_file(sysctl_options, *f, true);
 312                         if (k < 0 && r == 0)
 313                                 r = k;
 314                 }
 315         }
 316
 317         k = apply_all(sysctl_options);
 318         if (k < 0 && r == 0)
 319                 r = k;
 320
 321 finish:
 322         hashmap_free_free_free(sysctl_options);
 323         strv_free(arg_prefixes);
 324
 325         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 326 }