summaryrefslogtreecommitdiff
path: root/src/core/condition.c
blob: 658e8d6a4c000e47d9f6b769d9d3ec559ec6c44f (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
/*-*- 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 <systemd/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"

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

        if (streq(c->parameter, "selinux"))
                return use_selinux() == !c->negate;
        if (streq(c->parameter, "apparmor"))
                return use_apparmor() == !c->negate;
        if (streq(c->parameter, "ima"))
                return use_ima() == !c->negate;
        if (streq(c->parameter, "smack"))
                return use_smack() == !c->negate;
        return c->negate;
}

static bool condition_test_capability(Condition *c) {
        cap_value_t value;
        FILE *f;
        char line[LINE_MAX];
        unsigned long long capabilities = (unsigned long long) -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 c->negate;

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

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

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

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

        fclose(f);

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

static bool 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_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) {
                bool b;

                b = condition_test(c);
                if (unit)
                        log_debug_unit(unit,
                                       "%s=%s%s%s %s for %s.",
                                       condition_type_to_string(c->type),
                                       c->trigger ? "|" : "",
                                       c->negate ? "!" : "",
                                       c->parameter,
                                       b ? "succeeded" : "failed",
                                       unit);
                c->state = b ? 1 : -1;

                if (!c->trigger && !b)
                        return false;

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

        return triggered != 0;
}