summaryrefslogtreecommitdiff
path: root/src/shared/virt.c
blob: fc62c72328e381341850d021dbd076fb6d5e73ee (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
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2011 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 <string.h>
#include <errno.h>
#include <unistd.h>

#include "util.h"
#include "virt.h"

/* Returns a short identifier for the various VM implementations */
int detect_vm(const char **id) {

#if defined(__i386__) || defined(__x86_64__)

        /* Both CPUID and DMI are x86 specific interfaces... */

        static const char *const dmi_vendors[] = {
                "/sys/class/dmi/id/sys_vendor",
                "/sys/class/dmi/id/board_vendor",
                "/sys/class/dmi/id/bios_vendor"
        };

        static const char dmi_vendor_table[] =
                "QEMU\0"                  "qemu\0"
                /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
                "VMware\0"                "vmware\0"
                "VMW\0"                   "vmware\0"
                "Microsoft Corporation\0" "microsoft\0"
                "innotek GmbH\0"          "oracle\0"
                "Xen\0"                   "xen\0"
                "Bochs\0"                 "bochs\0";

        static const char cpuid_vendor_table[] =
                "XenVMMXenVMM\0"          "xen\0"
                "KVMKVMKVM\0"             "kvm\0"
                /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
                "VMwareVMware\0"          "vmware\0"
                /* http://msdn.microsoft.com/en-us/library/ff542428.aspx */
                "Microsoft Hv\0"          "microsoft\0";

        uint32_t eax, ecx;
        union {
                uint32_t sig32[3];
                char text[13];
        } sig;
        unsigned i;
        const char *j, *k;
        bool hypervisor;

        /* http://lwn.net/Articles/301888/ */
        zero(sig);

#if defined (__i386__)
#define REG_a "eax"
#define REG_b "ebx"
#elif defined (__amd64__)
#define REG_a "rax"
#define REG_b "rbx"
#endif

        /* First detect whether there is a hypervisor */
        eax = 1;
        __asm__ __volatile__ (
                /* ebx/rbx is being used for PIC! */
                "  push %%"REG_b"         \n\t"
                "  cpuid                  \n\t"
                "  pop %%"REG_b"          \n\t"

                : "=a" (eax), "=c" (ecx)
                : "0" (eax)
        );

        hypervisor = !!(ecx & 0x80000000U);

        if (hypervisor) {

                /* There is a hypervisor, see what it is */
                eax = 0x40000000U;
                __asm__ __volatile__ (
                        /* ebx/rbx is being used for PIC! */
                        "  push %%"REG_b"         \n\t"
                        "  cpuid                  \n\t"
                        "  mov %%ebx, %1          \n\t"
                        "  pop %%"REG_b"          \n\t"

                        : "=a" (eax), "=r" (sig.sig32[0]), "=c" (sig.sig32[1]), "=d" (sig.sig32[2])
                        : "0" (eax)
                );

                NULSTR_FOREACH_PAIR(j, k, cpuid_vendor_table)
                        if (streq(sig.text, j)) {

                                if (id)
                                        *id = k;

                                return 1;
                        }
        }

        for (i = 0; i < ELEMENTSOF(dmi_vendors); i++) {
                char *s;
                int r;
                const char *found = NULL;

                if ((r = read_one_line_file(dmi_vendors[i], &s)) < 0) {
                        if (r != -ENOENT)
                                return r;

                        continue;
                }

                NULSTR_FOREACH_PAIR(j, k, dmi_vendor_table)
                        if (startswith(s, j))
                                found = k;
                free(s);

                if (found) {
                        if (id)
                                *id = found;

                        return 1;
                }
        }

        if (hypervisor) {
                if (id)
                        *id = "other";

                return 1;
        }

#endif
        return 0;
}

int detect_container(const char **id) {
        char *e = NULL;
        int r;

        /* Unfortunately many of these operations require root access
         * in one way or another */

        r = running_in_chroot();
        if (r < 0)
                return r;
        if (r > 0) {

                if (id)
                        *id = "chroot";

                return 1;
        }

        /* /proc/vz exists in container and outside of the container,
         * /proc/bc only outside of the container. */
        if (access("/proc/vz", F_OK) >= 0 &&
            access("/proc/bc", F_OK) < 0) {

                if (id)
                        *id = "openvz";

                return 1;
        }

        r = getenv_for_pid(1, "container", &e);
        if (r <= 0)
                return r;

        /* We only recognize a selected few here, since we want to
         * enforce a redacted namespace */
        if (streq(e, "lxc")) {
                if (id)
                        *id = "lxc";
        } else if (streq(e, "lxc-libvirt")) {
                if (id)
                        *id = "lxc-libvirt";
        } else if (streq(e, "systemd-nspawn")) {
                if (id)
                        *id = "systemd-nspawn";
        } else {
                if (id)
                        *id = "other";
        }

        free(e);

        return r;
}

/* Returns a short identifier for the various VM/container implementations */
Virtualization detect_virtualization(const char **id) {

        static __thread Virtualization cached_virt = _VIRTUALIZATION_INVALID;
        static __thread const char *cached_id = NULL;

        const char *_id;
        int r;
        Virtualization v;

        if (_likely_(cached_virt >= 0)) {

                if (id && cached_virt > 0)
                        *id = cached_id;

                return cached_virt;
        }

        r = detect_container(&_id);
        if (r < 0) {
                v = r;
                goto finish;
        } else if (r > 0) {
                v = VIRTUALIZATION_CONTAINER;
                goto finish;
        }

        r = detect_vm(&_id);
        if (r < 0) {
                v = r;
                goto finish;
        } else if (r > 0) {
                v = VIRTUALIZATION_VM;
                goto finish;
        }

        v = VIRTUALIZATION_NONE;

finish:
        if (v > 0) {
                cached_id = _id;

                if (id)
                        *id = _id;
        }

        if (v >= 0)
                cached_virt = v;

        return v;
}