summaryrefslogtreecommitdiff
path: root/src/sysctl/sysctl.c
blob: cce91b3d679a72cc2273423f25dda970987a424f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <errno.h>
#include <getopt.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "conf-files.h"
#include "def.h"
#include "fd-util.h"
#include "fileio.h"
#include "hashmap.h"
#include "log.h"
#include "path-util.h"
#include "string-util.h"
#include "strv.h"
#include "sysctl-util.h"
#include "util.h"

static char **arg_prefixes = NULL;

static const char conf_file_dirs[] = CONF_PATHS_NULSTR("sysctl.d");

static int apply_all(OrderedHashmap *sysctl_options) {
        char *property, *value;
        Iterator i;
        int r = 0;

        ORDERED_HASHMAP_FOREACH_KEY(value, property, sysctl_options, i) {
                int k;

                k = sysctl_write(property, value);
                if (k < 0) {
                        /* If the sysctl is not available in the kernel or we are running with reduced privileges and
                         * cannot write it, then log about the issue at LOG_NOTICE level, and proceed without
                         * failing. (EROFS is treated as a permission problem here, since that's how container managers
                         * usually protected their sysctls.) In all other cases log an error and make the tool fail. */

                        if (IN_SET(k, -EPERM, -EACCES, -EROFS, -ENOENT))
                                log_notice_errno(k, "Couldn't write '%s' to '%s', ignoring: %m", value, property);
                        else {
                                log_error_errno(k, "Couldn't write '%s' to '%s': %m", value, property);
                                if (r == 0)
                                        r = k;
                        }
                }
        }

        return r;
}

static bool test_prefix(const char *p) {
        char **i;

        if (strv_isempty(arg_prefixes))
                return true;

        STRV_FOREACH(i, arg_prefixes) {
                const char *t;

                t = path_startswith(*i, "/proc/sys/");
                if (!t)
                        t = *i;
                if (path_startswith(p, t))
                        return true;
        }

        return false;
}

static int parse_file(OrderedHashmap *sysctl_options, const char *path, bool ignore_enoent) {
        _cleanup_fclose_ FILE *f = NULL;
        unsigned c = 0;
        int r;

        assert(path);

        r = search_and_fopen_nulstr(path, "re", NULL, conf_file_dirs, &f);
        if (r < 0) {
                if (ignore_enoent && r == -ENOENT)
                        return 0;

                return log_error_errno(r, "Failed to open file '%s', ignoring: %m", path);
        }

        log_debug("Parsing %s", path);
        for (;;) {
                char l[LINE_MAX], *p, *value, *new_value, *property, *existing;
                void *v;
                int k;

                if (!fgets(l, sizeof(l), f)) {
                        if (feof(f))
                                break;

                        return log_error_errno(errno, "Failed to read file '%s', ignoring: %m", path);
                }

                c++;

                p = strstrip(l);
                if (!*p)
                        continue;

                if (strchr(COMMENTS "\n", *p))
                        continue;

                value = strchr(p, '=');
                if (!value) {
                        log_error("Line is not an assignment at '%s:%u': %s", path, c, value);

                        if (r == 0)
                                r = -EINVAL;
                        continue;
                }

                *value = 0;
                value++;

                p = sysctl_normalize(strstrip(p));
                value = strstrip(value);

                if (!test_prefix(p))
                        continue;

                existing = ordered_hashmap_get2(sysctl_options, p, &v);
                if (existing) {
                        if (streq(value, existing))
                                continue;

                        log_debug("Overwriting earlier assignment of %s at '%s:%u'.", p, path, c);
                        free(ordered_hashmap_remove(sysctl_options, p));
                        free(v);
                }

                property = strdup(p);
                if (!property)
                        return log_oom();

                new_value = strdup(value);
                if (!new_value) {
                        free(property);
                        return log_oom();
                }

                k = ordered_hashmap_put(sysctl_options, property, new_value);
                if (k < 0) {
                        log_error_errno(k, "Failed to add sysctl variable %s to hashmap: %m", property);
                        free(property);
                        free(new_value);
                        return k;
                }
        }

        return r;
}

static void help(void) {
        printf("%s [OPTIONS...] [CONFIGURATION FILE...]\n\n"
               "Applies kernel sysctl settings.\n\n"
               "  -h --help             Show this help\n"
               "     --version          Show package version\n"
               "     --prefix=PATH      Only apply rules with the specified prefix\n"
               , program_invocation_short_name);
}

static int parse_argv(int argc, char *argv[]) {

        enum {
                ARG_VERSION = 0x100,
                ARG_PREFIX
        };

        static const struct option options[] = {
                { "help",      no_argument,       NULL, 'h'           },
                { "version",   no_argument,       NULL, ARG_VERSION   },
                { "prefix",    required_argument, NULL, ARG_PREFIX    },
                {}
        };

        int c;

        assert(argc >= 0);
        assert(argv);

        while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)

                switch (c) {

                case 'h':
                        help();
                        return 0;

                case ARG_VERSION:
                        return version();

                case ARG_PREFIX: {
                        char *p;

                        /* We used to require people to specify absolute paths
                         * in /proc/sys in the past. This is kinda useless, but
                         * we need to keep compatibility. We now support any
                         * sysctl name available. */
                        sysctl_normalize(optarg);

                        if (startswith(optarg, "/proc/sys"))
                                p = strdup(optarg);
                        else
                                p = strappend("/proc/sys/", optarg);
                        if (!p)
                                return log_oom();

                        if (strv_consume(&arg_prefixes, p) < 0)
                                return log_oom();

                        break;
                }

                case '?':
                        return -EINVAL;

                default:
                        assert_not_reached("Unhandled option");
                }

        return 1;
}

int main(int argc, char *argv[]) {
        int r = 0, k;
        OrderedHashmap *sysctl_options;

        r = parse_argv(argc, argv);
        if (r <= 0)
                return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;

        log_set_target(LOG_TARGET_AUTO);
        log_parse_environment();
        log_open();

        umask(0022);

        sysctl_options = ordered_hashmap_new(&string_hash_ops);
        if (!sysctl_options) {
                r = log_oom();
                goto finish;
        }

        r = 0;

        if (argc > optind) {
                int i;

                for (i = optind; i < argc; i++) {
                        k = parse_file(sysctl_options, argv[i], false);
                        if (k < 0 && r == 0)
                                r = k;
                }
        } else {
                _cleanup_strv_free_ char **files = NULL;
                char **f;

                r = conf_files_list_nulstr(&files, ".conf", NULL, conf_file_dirs);
                if (r < 0) {
                        log_error_errno(r, "Failed to enumerate sysctl.d files: %m");
                        goto finish;
                }

                STRV_FOREACH(f, files) {
                        k = parse_file(sysctl_options, *f, true);
                        if (k < 0 && r == 0)
                                r = k;
                }
        }

        k = apply_all(sysctl_options);
        if (k < 0 && r == 0)
                r = k;

finish:
        ordered_hashmap_free_free_free(sysctl_options);
        strv_free(arg_prefixes);

        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}