summaryrefslogtreecommitdiff
path: root/src/core/condition.c
blob: 32135ec5b2b83242a5a9c918c40b8356b2ca0128 (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
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  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 <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/capability.h>
#include <sys/statvfs.h>
#include <fnmatch.h>

#include "sd-id128.h"
#include "util.h"
#include "condition.h"
#include "virt.h"
#include "path-util.h"
#include "fileio.h"
#include "unit.h"
#include "smack-util.h"
#include "apparmor-util.h"
#include "ima-util.h"
#include "selinux-util.h"
#include "audit.h"

static int condition_test_security(Condition *c) {
        assert(c);
        assert(c->parameter);
        assert(c->type == CONDITION_SECURITY);

        if (streq(c->parameter, "selinux"))
                return mac_selinux_use() == !c->negate;
        if (streq(c->parameter, "smack"))
                return mac_smack_use() == !c->negate;
        if (streq(c->parameter, "apparmor"))
                return mac_apparmor_use() == !c->negate;
        if (streq(c->parameter, "audit"))
                return use_audit() == !c->negate;
        if (streq(c->parameter, "ima"))
                return use_ima() == !c->negate;

        return c->negate;
}

static int condition_test_capability(Condition *c) {
        _cleanup_fclose_ FILE *f = NULL;
        cap_value_t value;
        char line[LINE_MAX];
        unsigned long long capabilities = -1;

        assert(c);
        assert(c->parameter);
        assert(c->type == CONDITION_CAPABILITY);

        /* If it's an invalid capability, we don't have it */

        if (cap_from_name(c->parameter, &value) < 0)
                return -EINVAL;

        /* If it's a valid capability we default to assume
         * that we have it */

        f = fopen("/proc/self/status", "re");
        if (!f)
                return -errno;

        while (fgets(line, sizeof(line), f)) {
                truncate_nl(line);

                if (startswith(line, "CapBnd:")) {
                        (void) sscanf(line+7, "%llx", &capabilities);
                        break;
                }
        }

        return !!(capabilities & (1ULL << value)) == !c->negate;
}

static bool condition_test_needs_update(Condition *c) {
        const char *p;
        struct stat usr, other;

        assert(c);
        assert(c->parameter);
        assert(c->type == CONDITION_NEEDS_UPDATE);

        /* If the file system is read-only we shouldn't suggest an update */
        if (path_is_read_only_fs(c->parameter) > 0)
                return c->negate;

        /* Any other failure means we should allow the condition to be true,
         * so that we rather invoke too many update tools then too
         * few. */

        if (!path_is_absolute(c->parameter))
                return !c->negate;

        p = strappenda(c->parameter, "/.updated");
        if (lstat(p, &other) < 0)
                return !c->negate;

        if (lstat("/usr/", &usr) < 0)
                return !c->negate;

        return (usr.st_mtim.tv_sec > other.st_mtim.tv_sec ||
                (usr.st_mtim.tv_sec == other.st_mtim.tv_sec && usr.st_mtim.tv_nsec > other.st_mtim.tv_nsec)) == !c->negate;
}

static bool condition_test_first_boot(Condition *c) {
        int r;

        assert(c);
        assert(c->parameter);
        assert(c->type == CONDITION_FIRST_BOOT);

        r = parse_boolean(c->parameter);
        if (r < 0)
                return r;

        return ((access("/run/systemd/first-boot", F_OK) >= 0) == !!r) == !c->negate;
}

static int condition_test(Condition *c) {
        assert(c);

        switch(c->type) {

        case CONDITION_PATH_EXISTS:
                return (access(c->parameter, F_OK) >= 0) == !c->negate;

        case CONDITION_PATH_EXISTS_GLOB:
                return (glob_exists(c->parameter) > 0) == !c->negate;

        case CONDITION_PATH_IS_DIRECTORY: {
                struct stat st;

                if (stat(c->parameter, &st) < 0)
                        return c->negate;
                return S_ISDIR(st.st_mode) == !c->negate;
        }

        case CONDITION_PATH_IS_SYMBOLIC_LINK: {
                struct stat st;

                if (lstat(c->parameter, &st) < 0)
                        return c->negate;
                return S_ISLNK(st.st_mode) == !c->negate;
        }

        case CONDITION_PATH_IS_MOUNT_POINT:
                return (path_is_mount_point(c->parameter, true) > 0) == !c->negate;

        case CONDITION_PATH_IS_READ_WRITE:
                return (path_is_read_only_fs(c->parameter) > 0) == c->negate;

        case CONDITION_DIRECTORY_NOT_EMPTY: {
                int k;

                k = dir_is_empty(c->parameter);
                return !(k == -ENOENT || k > 0) == !c->negate;
        }

        case CONDITION_FILE_NOT_EMPTY: {
                struct stat st;

                if (stat(c->parameter, &st) < 0)
                        return c->negate;

                return (S_ISREG(st.st_mode) && st.st_size > 0) == !c->negate;
        }

        case CONDITION_FILE_IS_EXECUTABLE: {
                struct stat st;

                if (stat(c->parameter, &st) < 0)
                        return c->negate;

                return (S_ISREG(st.st_mode) && (st.st_mode & 0111)) == !c->negate;
        }

        case CONDITION_KERNEL_COMMAND_LINE:
                return condition_test_kernel_command_line(c);

        case CONDITION_VIRTUALIZATION:
                return condition_test_virtualization(c);

        case CONDITION_SECURITY:
                return condition_test_security(c);

        case CONDITION_CAPABILITY:
                return condition_test_capability(c);

        case CONDITION_HOST:
                return condition_test_host(c);

        case CONDITION_AC_POWER:
                return condition_test_ac_power(c);

        case CONDITION_ARCHITECTURE:
                return condition_test_architecture(c);

        case CONDITION_NEEDS_UPDATE:
                return condition_test_needs_update(c);

        case CONDITION_FIRST_BOOT:
                return condition_test_first_boot(c);

        case CONDITION_NULL:
                return !c->negate;

        default:
                assert_not_reached("Invalid condition type.");
        }
}

bool condition_test_list(const char *unit, Condition *first) {
        Condition *c;
        int triggered = -1;

        /* If the condition list is empty, then it is true */
        if (!first)
                return true;

        /* Otherwise, if all of the non-trigger conditions apply and
         * if any of the trigger conditions apply (unless there are
         * none) we return true */
        LIST_FOREACH(conditions, c, first) {
                int r;

                r = condition_test(c);
                if (r < 0)
                        log_warning_unit(unit,
                                         "Couldn't determine result for %s=%s%s%s for %s, assuming failed: %s",
                                         condition_type_to_string(c->type),
                                         c->trigger ? "|" : "",
                                         c->negate ? "!" : "",
                                         c->parameter,
                                         unit,
                                         strerror(-r));
                else
                        log_debug_unit(unit,
                                       "%s=%s%s%s %s for %s.",
                                       condition_type_to_string(c->type),
                                       c->trigger ? "|" : "",
                                       c->negate ? "!" : "",
                                       c->parameter,
                                       r > 0 ? "succeeded" : "failed",
                                       unit);

                c->state = r > 0 ? CONDITION_STATE_SUCCEEDED : CONDITION_STATE_FAILED;

                if (!c->trigger && r <= 0)
                        return false;

                if (c->trigger && triggered <= 0)
                        triggered = r > 0;
        }

        return triggered != 0;
}