src/shared/virt.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2011 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 <string.h>
  23 #include <errno.h>
  24 #include <unistd.h>
  25
  26 #include "util.h"
  27 #include "virt.h"
  28 #include "fileio.h"
  29
  30 /* Returns a short identifier for the various VM implementations */
  31 int detect_vm(const char **id) {
  32
  33 #if defined(__i386__) || defined(__x86_64__)
  34
  35         /* Both CPUID and DMI are x86 specific interfaces... */
  36
  37         static const char *const dmi_vendors[] = {
  38                 "/sys/class/dmi/id/sys_vendor",
  39                 "/sys/class/dmi/id/board_vendor",
  40                 "/sys/class/dmi/id/bios_vendor"
  41         };
  42
  43         static const char dmi_vendor_table[] =
  44                 "QEMU\0"                  "qemu\0"
  45                 /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
  46                 "VMware\0"                "vmware\0"
  47                 "VMW\0"                   "vmware\0"
  48                 "Microsoft Corporation\0" "microsoft\0"
  49                 "innotek GmbH\0"          "oracle\0"
  50                 "Xen\0"                   "xen\0"
  51                 "Bochs\0"                 "bochs\0";
  52
  53         static const char cpuid_vendor_table[] =
  54                 "XenVMMXenVMM\0"          "xen\0"
  55                 "KVMKVMKVM\0"             "kvm\0"
  56                 /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
  57                 "VMwareVMware\0"          "vmware\0"
  58                 /* http://msdn.microsoft.com/en-us/library/ff542428.aspx */
  59                 "Microsoft Hv\0"          "microsoft\0";
  60
  61         uint32_t eax, ecx;
  62         union {
  63                 uint32_t sig32[3];
  64                 char text[13];
  65         } sig;
  66         unsigned i;
  67         const char *j, *k;
  68         bool hypervisor;
  69
  70         /* http://lwn.net/Articles/301888/ */
  71         zero(sig);
  72
  73 #if defined (__i386__)
  74 #define REG_a "eax"
  75 #define REG_b "ebx"
  76 #elif defined (__amd64__)
  77 #define REG_a "rax"
  78 #define REG_b "rbx"
  79 #endif
  80
  81         /* First detect whether there is a hypervisor */
  82         eax = 1;
  83         __asm__ __volatile__ (
  84                 /* ebx/rbx is being used for PIC! */
  85                 "  push %%"REG_b"         \n\t"
  86                 "  cpuid                  \n\t"
  87                 "  pop %%"REG_b"          \n\t"
  88
  89                 : "=a" (eax), "=c" (ecx)
  90                 : "0" (eax)
  91         );
  92
  93         hypervisor = !!(ecx & 0x80000000U);
  94
  95         if (hypervisor) {
  96
  97                 /* There is a hypervisor, see what it is */
  98                 eax = 0x40000000U;
  99                 __asm__ __volatile__ (
 100                         /* ebx/rbx is being used for PIC! */
 101                         "  push %%"REG_b"         \n\t"
 102                         "  cpuid                  \n\t"
 103                         "  mov %%ebx, %1          \n\t"
 104                         "  pop %%"REG_b"          \n\t"
 105
 106                         : "=a" (eax), "=r" (sig.sig32[0]), "=c" (sig.sig32[1]), "=d" (sig.sig32[2])
 107                         : "0" (eax)
 108                 );
 109
 110                 NULSTR_FOREACH_PAIR(j, k, cpuid_vendor_table)
 111                         if (streq(sig.text, j)) {
 112
 113                                 if (id)
 114                                         *id = k;
 115
 116                                 return 1;
 117                         }
 118         }
 119
 120         for (i = 0; i < ELEMENTSOF(dmi_vendors); i++) {
 121                 char *s;
 122                 int r;
 123                 const char *found = NULL;
 124
 125                 if ((r = read_one_line_file(dmi_vendors[i], &s)) < 0) {
 126                         if (r != -ENOENT)
 127                                 return r;
 128
 129                         continue;
 130                 }
 131
 132                 NULSTR_FOREACH_PAIR(j, k, dmi_vendor_table)
 133                         if (startswith(s, j))
 134                                 found = k;
 135                 free(s);
 136
 137                 if (found) {
 138                         if (id)
 139                                 *id = found;
 140
 141                         return 1;
 142                 }
 143         }
 144
 145         if (hypervisor) {
 146                 if (id)
 147                         *id = "other";
 148
 149                 return 1;
 150         }
 151
 152 #endif
 153         return 0;
 154 }
 155
 156 int detect_container(const char **id) {
 157         char *e = NULL;
 158         int r;
 159
 160         /* Unfortunately many of these operations require root access
 161          * in one way or another */
 162
 163         r = running_in_chroot();
 164         if (r < 0)
 165                 return r;
 166         if (r > 0) {
 167
 168                 if (id)
 169                         *id = "chroot";
 170
 171                 return 1;
 172         }
 173
 174         /* /proc/vz exists in container and outside of the container,
 175          * /proc/bc only outside of the container. */
 176         if (access("/proc/vz", F_OK) >= 0 &&
 177             access("/proc/bc", F_OK) < 0) {
 178
 179                 if (id)
 180                         *id = "openvz";
 181
 182                 return 1;
 183         }
 184
 185         r = getenv_for_pid(1, "container", &e);
 186         if (r <= 0)
 187                 return r;
 188
 189         /* We only recognize a selected few here, since we want to
 190          * enforce a redacted namespace */
 191         if (streq(e, "lxc")) {
 192                 if (id)
 193                         *id = "lxc";
 194         } else if (streq(e, "lxc-libvirt")) {
 195                 if (id)
 196                         *id = "lxc-libvirt";
 197         } else if (streq(e, "systemd-nspawn")) {
 198                 if (id)
 199                         *id = "systemd-nspawn";
 200         } else {
 201                 if (id)
 202                         *id = "other";
 203         }
 204
 205         free(e);
 206
 207         return r;
 208 }
 209
 210 /* Returns a short identifier for the various VM/container implementations */
 211 Virtualization detect_virtualization(const char **id) {
 212
 213         static __thread Virtualization cached_virt = _VIRTUALIZATION_INVALID;
 214         static __thread const char *cached_id = NULL;
 215
 216         const char *_id;
 217         int r;
 218         Virtualization v;
 219
 220         if (_likely_(cached_virt >= 0)) {
 221
 222                 if (id && cached_virt > 0)
 223                         *id = cached_id;
 224
 225                 return cached_virt;
 226         }
 227
 228         r = detect_container(&_id);
 229         if (r < 0) {
 230                 v = r;
 231                 goto finish;
 232         } else if (r > 0) {
 233                 v = VIRTUALIZATION_CONTAINER;
 234                 goto finish;
 235         }
 236
 237         r = detect_vm(&_id);
 238         if (r < 0) {
 239                 v = r;
 240                 goto finish;
 241         } else if (r > 0) {
 242                 v = VIRTUALIZATION_VM;
 243                 goto finish;
 244         }
 245
 246         v = VIRTUALIZATION_NONE;
 247
 248 finish:
 249         if (v > 0) {
 250                 cached_id = _id;
 251
 252                 if (id)
 253                         *id = _id;
 254         }
 255
 256         if (v >= 0)
 257                 cached_virt = v;
 258
 259         return v;
 260 }