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         _cleanup_free_ char *cpuinfo_contents = NULL;
  33         int r;
  34
  35 #if defined(__i386__) || defined(__x86_64__)
  36
  37         /* Both CPUID and DMI are x86 specific interfaces... */
  38
  39         static const char *const dmi_vendors[] = {
  40                 "/sys/class/dmi/id/sys_vendor",
  41                 "/sys/class/dmi/id/board_vendor",
  42                 "/sys/class/dmi/id/bios_vendor"
  43         };
  44
  45         static const char dmi_vendor_table[] =
  46                 "QEMU\0"                  "qemu\0"
  47                 /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
  48                 "VMware\0"                "vmware\0"
  49                 "VMW\0"                   "vmware\0"
  50                 "Microsoft Corporation\0" "microsoft\0"
  51                 "innotek GmbH\0"          "oracle\0"
  52                 "Xen\0"                   "xen\0"
  53                 "Bochs\0"                 "bochs\0";
  54
  55         static const char cpuid_vendor_table[] =
  56                 "XenVMMXenVMM\0"          "xen\0"
  57                 "KVMKVMKVM\0"             "kvm\0"
  58                 /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
  59                 "VMwareVMware\0"          "vmware\0"
  60                 /* http://msdn.microsoft.com/en-us/library/ff542428.aspx */
  61                 "Microsoft Hv\0"          "microsoft\0";
  62
  63         static __thread int cached_found = -1;
  64         static __thread const char *cached_id = NULL;
  65
  66         uint32_t eax, ecx;
  67         union {
  68                 uint32_t sig32[3];
  69                 char text[13];
  70         } sig = {};
  71         unsigned i;
  72         const char *j, *k;
  73         bool hypervisor;
  74         _cleanup_free_ char *hvtype = NULL;
  75         const char *_id = NULL;
  76
  77         if (_likely_(cached_found >= 0)) {
  78
  79                 if (id)
  80                         *id = cached_id;
  81
  82                 return cached_found;
  83         }
  84
  85         /* Try high-level hypervisor sysfs file first:
  86          *
  87          * https://bugs.freedesktop.org/show_bug.cgi?id=61491 */
  88         r = read_one_line_file("/sys/hypervisor/type", &hvtype);
  89         if (r >= 0) {
  90                 if (streq(hvtype, "xen")) {
  91                         _id = "xen";
  92                         r = 1;
  93                         goto finish;
  94                 }
  95         } else if (r != -ENOENT)
  96                 return r;
  97
  98         /* http://lwn.net/Articles/301888/ */
  99
 100 #if defined (__i386__)
 101 #define REG_a "eax"
 102 #define REG_b "ebx"
 103 #elif defined (__amd64__)
 104 #define REG_a "rax"
 105 #define REG_b "rbx"
 106 #endif
 107
 108         /* First detect whether there is a hypervisor */
 109         eax = 1;
 110         __asm__ __volatile__ (
 111                 /* ebx/rbx is being used for PIC! */
 112                 "  push %%"REG_b"         \n\t"
 113                 "  cpuid                  \n\t"
 114                 "  pop %%"REG_b"          \n\t"
 115
 116                 : "=a" (eax), "=c" (ecx)
 117                 : "0" (eax)
 118         );
 119
 120         hypervisor = !!(ecx & 0x80000000U);
 121
 122         if (hypervisor) {
 123
 124                 /* There is a hypervisor, see what it is */
 125                 eax = 0x40000000U;
 126                 __asm__ __volatile__ (
 127                         /* ebx/rbx is being used for PIC! */
 128                         "  push %%"REG_b"         \n\t"
 129                         "  cpuid                  \n\t"
 130                         "  mov %%ebx, %1          \n\t"
 131                         "  pop %%"REG_b"          \n\t"
 132
 133                         : "=a" (eax), "=r" (sig.sig32[0]), "=c" (sig.sig32[1]), "=d" (sig.sig32[2])
 134                         : "0" (eax)
 135                 );
 136
 137                 NULSTR_FOREACH_PAIR(j, k, cpuid_vendor_table)
 138                         if (streq(sig.text, j)) {
 139                                 _id = k;
 140                                 r = 1;
 141                                 goto finish;
 142                         }
 143         }
 144
 145         for (i = 0; i < ELEMENTSOF(dmi_vendors); i++) {
 146                 _cleanup_free_ char *s = NULL;
 147
 148                 r = read_one_line_file(dmi_vendors[i], &s);
 149                 if (r < 0) {
 150                         if (r != -ENOENT)
 151                                 return r;
 152
 153                         continue;
 154                 }
 155
 156                 NULSTR_FOREACH_PAIR(j, k, dmi_vendor_table)
 157                         if (startswith(s, j)) {
 158                                 _id = k;
 159                                 r = 1;
 160                                 goto finish;
 161                         }
 162         }
 163
 164         if (hypervisor || hvtype) {
 165                 _id = "other";
 166                 r = 1;
 167                 goto finish;
 168         }
 169
 170 #endif
 171
 172         /* Detect User-Mode Linux by reading /proc/cpuinfo */
 173         r = read_full_file("/proc/cpuinfo", &cpuinfo_contents, NULL);
 174         if (r < 0)
 175                 return r;
 176         if (strstr(cpuinfo_contents, "\nvendor_id\t: User Mode Linux\n")) {
 177                 _id = "uml";
 178                 r = 1;
 179                 goto finish;
 180         }
 181
 182         r = 0;
 183
 184 finish:
 185         cached_found = r;
 186
 187         cached_id = _id;
 188         if (id)
 189                 *id = _id;
 190
 191         return r;
 192 }
 193
 194 int detect_container(const char **id) {
 195
 196         static __thread int cached_found = -1;
 197         static __thread const char *cached_id = NULL;
 198
 199         _cleanup_free_ char *e = NULL;
 200         const char *_id = NULL;
 201         int r;
 202
 203         if (_likely_(cached_found >= 0)) {
 204
 205                 if (id)
 206                         *id = cached_id;
 207
 208                 return cached_found;
 209         }
 210
 211         /* Unfortunately many of these operations require root access
 212          * in one way or another */
 213
 214         r = running_in_chroot();
 215         if (r < 0)
 216                 return r;
 217         if (r > 0) {
 218                 _id = "chroot";
 219                 goto finish;
 220         }
 221
 222         /* /proc/vz exists in container and outside of the container,
 223          * /proc/bc only outside of the container. */
 224         if (access("/proc/vz", F_OK) >= 0 &&
 225             access("/proc/bc", F_OK) < 0) {
 226                 _id = "openvz";
 227                 r = 1;
 228                 goto finish;
 229         }
 230
 231         r = getenv_for_pid(1, "container", &e);
 232         if (r < 0)
 233                 return r;
 234         if (r == 0)
 235                 goto finish;
 236
 237         /* We only recognize a selected few here, since we want to
 238          * enforce a redacted namespace */
 239         if (streq(e, "lxc"))
 240                 _id ="lxc";
 241         else if (streq(e, "lxc-libvirt"))
 242                 _id = "lxc-libvirt";
 243         else if (streq(e, "systemd-nspawn"))
 244                 _id = "systemd-nspawn";
 245         else
 246                 _id = "other";
 247
 248 finish:
 249         cached_found = r;
 250
 251         cached_id = _id;
 252         if (id)
 253                 *id = _id;
 254
 255         return r;
 256 }
 257
 258 /* Returns a short identifier for the various VM/container implementations */
 259 Virtualization detect_virtualization(const char **id) {
 260         int r;
 261
 262         r = detect_container(id);
 263         if (r < 0)
 264                 return r;
 265         if (r > 0)
 266                 return VIRTUALIZATION_CONTAINER;
 267
 268         r = detect_vm(id);
 269         if (r < 0)
 270                 return r;
 271         if (r > 0)
 272                 return VIRTUALIZATION_VM;
 273
 274         return VIRTUALIZATION_NONE;
 275 }