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