src/basic/virt.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2011 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <stdint.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25
  26 #include "alloc-util.h"
  27 #include "dirent-util.h"
  28 #include "fd-util.h"
  29 #include "fileio.h"
  30 #include "macro.h"
  31 #include "process-util.h"
  32 #include "stat-util.h"
  33 #include "string-table.h"
  34 #include "string-util.h"
  35 #include "virt.h"
  36
  37 static int detect_vm_cpuid(void) {
  38
  39         /* CPUID is an x86 specific interface. */
  40 #if defined(__i386__) || defined(__x86_64__)
  41
  42         static const struct {
  43                 const char *cpuid;
  44                 int id;
  45         } cpuid_vendor_table[] = {
  46                 { "XenVMMXenVMM", VIRTUALIZATION_XEN       },
  47                 { "KVMKVMKVM",    VIRTUALIZATION_KVM       },
  48                 /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
  49                 { "VMwareVMware", VIRTUALIZATION_VMWARE    },
  50                 /* http://msdn.microsoft.com/en-us/library/ff542428.aspx */
  51                 { "Microsoft Hv", VIRTUALIZATION_MICROSOFT },
  52                 /* https://wiki.freebsd.org/bhyve */
  53                 { "bhyve bhyve ", VIRTUALIZATION_BHYVE     },
  54         };
  55
  56         uint32_t eax, ecx;
  57         bool hypervisor;
  58
  59         /* http://lwn.net/Articles/301888/ */
  60
  61 #if defined (__i386__)
  62 #define REG_a "eax"
  63 #define REG_b "ebx"
  64 #elif defined (__amd64__)
  65 #define REG_a "rax"
  66 #define REG_b "rbx"
  67 #endif
  68
  69         /* First detect whether there is a hypervisor */
  70         eax = 1;
  71         __asm__ __volatile__ (
  72                 /* ebx/rbx is being used for PIC! */
  73                 "  push %%"REG_b"         \n\t"
  74                 "  cpuid                  \n\t"
  75                 "  pop %%"REG_b"          \n\t"
  76
  77                 : "=a" (eax), "=c" (ecx)
  78                 : "0" (eax)
  79         );
  80
  81         hypervisor = !!(ecx & 0x80000000U);
  82
  83         if (hypervisor) {
  84                 union {
  85                         uint32_t sig32[3];
  86                         char text[13];
  87                 } sig = {};
  88                 unsigned j;
  89
  90                 /* There is a hypervisor, see what it is */
  91                 eax = 0x40000000U;
  92                 __asm__ __volatile__ (
  93                         /* ebx/rbx is being used for PIC! */
  94                         "  push %%"REG_b"         \n\t"
  95                         "  cpuid                  \n\t"
  96                         "  mov %%ebx, %1          \n\t"
  97                         "  pop %%"REG_b"          \n\t"
  98
  99                         : "=a" (eax), "=r" (sig.sig32[0]), "=c" (sig.sig32[1]), "=d" (sig.sig32[2])
 100                         : "0" (eax)
 101                 );
 102
 103                 log_debug("Virtualization found, CPUID=%s", sig.text);
 104
 105                 for (j = 0; j < ELEMENTSOF(cpuid_vendor_table); j ++)
 106                         if (streq(sig.text, cpuid_vendor_table[j].cpuid))
 107                                 return cpuid_vendor_table[j].id;
 108
 109                 return VIRTUALIZATION_VM_OTHER;
 110         }
 111 #endif
 112         log_debug("No virtualization found in CPUID");
 113
 114         return VIRTUALIZATION_NONE;
 115 }
 116
 117 static int detect_vm_device_tree(void) {
 118 #if defined(__arm__) || defined(__aarch64__) || defined(__powerpc__) || defined(__powerpc64__)
 119         _cleanup_free_ char *hvtype = NULL;
 120         int r;
 121
 122         r = read_one_line_file("/proc/device-tree/hypervisor/compatible", &hvtype);
 123         if (r == -ENOENT) {
 124                 _cleanup_closedir_ DIR *dir = NULL;
 125                 struct dirent *dent;
 126
 127                 dir = opendir("/proc/device-tree");
 128                 if (!dir) {
 129                         if (errno == ENOENT) {
 130                                 log_debug_errno(errno, "/proc/device-tree: %m");
 131                                 return VIRTUALIZATION_NONE;
 132                         }
 133                         return -errno;
 134                 }
 135
 136                 FOREACH_DIRENT(dent, dir, return -errno)
 137                         if (strstr(dent->d_name, "fw-cfg")) {
 138                                 log_debug("Virtualization QEMU: \"fw-cfg\" present in /proc/device-tree/%s", dent->d_name);
 139                                 return VIRTUALIZATION_QEMU;
 140                         }
 141
 142                 log_debug("No virtualization found in /proc/device-tree/*");
 143                 return VIRTUALIZATION_NONE;
 144         } else if (r < 0)
 145                 return r;
 146
 147         log_debug("Virtualization %s found in /proc/device-tree/hypervisor/compatible", hvtype);
 148         if (streq(hvtype, "linux,kvm"))
 149                 return VIRTUALIZATION_KVM;
 150         else if (strstr(hvtype, "xen"))
 151                 return VIRTUALIZATION_XEN;
 152         else
 153                 return VIRTUALIZATION_VM_OTHER;
 154 #else
 155         log_debug("This platform does not support /proc/device-tree");
 156         return VIRTUALIZATION_NONE;
 157 #endif
 158 }
 159
 160 static int detect_vm_dmi(void) {
 161 #if defined(__i386__) || defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)
 162
 163         static const char *const dmi_vendors[] = {
 164                 "/sys/class/dmi/id/product_name", /* Test this before sys_vendor to detect KVM over QEMU */
 165                 "/sys/class/dmi/id/sys_vendor",
 166                 "/sys/class/dmi/id/board_vendor",
 167                 "/sys/class/dmi/id/bios_vendor"
 168         };
 169
 170         static const struct {
 171                 const char *vendor;
 172                 int id;
 173         } dmi_vendor_table[] = {
 174                 { "KVM",           VIRTUALIZATION_KVM       },
 175                 { "QEMU",          VIRTUALIZATION_QEMU      },
 176                 /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
 177                 { "VMware",        VIRTUALIZATION_VMWARE    },
 178                 { "VMW",           VIRTUALIZATION_VMWARE    },
 179                 { "innotek GmbH",  VIRTUALIZATION_ORACLE    },
 180                 { "Xen",           VIRTUALIZATION_XEN       },
 181                 { "Bochs",         VIRTUALIZATION_BOCHS     },
 182                 { "Parallels",     VIRTUALIZATION_PARALLELS },
 183                 /* https://wiki.freebsd.org/bhyve */
 184                 { "BHYVE",         VIRTUALIZATION_BHYVE     },
 185         };
 186         unsigned i;
 187         int r;
 188
 189         for (i = 0; i < ELEMENTSOF(dmi_vendors); i++) {
 190                 _cleanup_free_ char *s = NULL;
 191                 unsigned j;
 192
 193                 r = read_one_line_file(dmi_vendors[i], &s);
 194                 if (r < 0) {
 195                         if (r == -ENOENT)
 196                                 continue;
 197
 198                         return r;
 199                 }
 200
 201
 202
 203                 for (j = 0; j < ELEMENTSOF(dmi_vendor_table); j++)
 204                         if (startswith(s, dmi_vendor_table[j].vendor)) {
 205                                 log_debug("Virtualization %s found in DMI (%s)", s, dmi_vendors[i]);
 206                                 return dmi_vendor_table[j].id;
 207                         }
 208         }
 209 #endif
 210
 211         log_debug("No virtualization found in DMI");
 212
 213         return VIRTUALIZATION_NONE;
 214 }
 215
 216 static int detect_vm_xen(void) {
 217         /* Check for Dom0 will be executed later in detect_vm_xen_dom0
 218            Thats why we dont check the content of /proc/xen/capabilities here. */
 219         if (access("/proc/xen/capabilities", F_OK) < 0) {
 220                 log_debug("Virtualization XEN not found, /proc/xen/capabilities does not exist");
 221                 return VIRTUALIZATION_NONE;
 222         }
 223
 224         log_debug("Virtualization XEN found (/proc/xen/capabilities exists)");
 225         return  VIRTUALIZATION_XEN;
 226
 227 }
 228
 229 static bool detect_vm_xen_dom0(void) {
 230         _cleanup_free_ char *domcap = NULL;
 231         char *cap, *i;
 232         int r;
 233
 234         r = read_one_line_file("/proc/xen/capabilities", &domcap);
 235         if (r == -ENOENT) {
 236                 log_debug("Virtualization XEN not found, /proc/xen/capabilities does not exist");
 237                 return false;
 238         }
 239         if (r < 0)
 240                 return r;
 241
 242         i = domcap;
 243         while ((cap = strsep(&i, ",")))
 244                 if (streq(cap, "control_d"))
 245                         break;
 246         if (!cap) {
 247                 log_debug("Virtualization XEN DomU found (/proc/xen/capabilites)");
 248                 return false;
 249         }
 250
 251         log_debug("Virtualization XEN Dom0 ignored (/proc/xen/capabilities)");
 252         return true;
 253 }
 254
 255 static int detect_vm_hypervisor(void) {
 256         _cleanup_free_ char *hvtype = NULL;
 257         int r;
 258
 259         r = read_one_line_file("/sys/hypervisor/type", &hvtype);
 260         if (r == -ENOENT)
 261                 return VIRTUALIZATION_NONE;
 262         if (r < 0)
 263                 return r;
 264
 265         log_debug("Virtualization %s found in /sys/hypervisor/type", hvtype);
 266
 267         if (streq(hvtype, "xen"))
 268                 return VIRTUALIZATION_XEN;
 269         else
 270                 return VIRTUALIZATION_VM_OTHER;
 271 }
 272
 273 static int detect_vm_uml(void) {
 274         _cleanup_free_ char *cpuinfo_contents = NULL;
 275         int r;
 276
 277         /* Detect User-Mode Linux by reading /proc/cpuinfo */
 278         r = read_full_file("/proc/cpuinfo", &cpuinfo_contents, NULL);
 279         if (r < 0)
 280                 return r;
 281
 282         if (strstr(cpuinfo_contents, "\nvendor_id\t: User Mode Linux\n")) {
 283                 log_debug("UML virtualization found in /proc/cpuinfo");
 284                 return VIRTUALIZATION_UML;
 285         }
 286
 287         log_debug("No virtualization found in /proc/cpuinfo.");
 288         return VIRTUALIZATION_NONE;
 289 }
 290
 291 static int detect_vm_zvm(void) {
 292
 293 #if defined(__s390__)
 294         _cleanup_free_ char *t = NULL;
 295         int r;
 296
 297         r = get_proc_field("/proc/sysinfo", "VM00 Control Program", WHITESPACE, &t);
 298         if (r == -ENOENT)
 299                 return VIRTUALIZATION_NONE;
 300         if (r < 0)
 301                 return r;
 302
 303         log_debug("Virtualization %s found in /proc/sysinfo", t);
 304         if (streq(t, "z/VM"))
 305                 return VIRTUALIZATION_ZVM;
 306         else
 307                 return VIRTUALIZATION_KVM;
 308 #else
 309         log_debug("This platform does not support /proc/sysinfo");
 310         return VIRTUALIZATION_NONE;
 311 #endif
 312 }
 313
 314 /* Returns a short identifier for the various VM implementations */
 315 int detect_vm(void) {
 316         static thread_local int cached_found = _VIRTUALIZATION_INVALID;
 317         int r;
 318
 319         if (cached_found >= 0)
 320                 return cached_found;
 321
 322         /* We have to use the correct order here:
 323          * Some virtualization technologies do use KVM hypervisor but are
 324          * expected to be detected as something else. So detect DMI first.
 325          *
 326          * An example is Virtualbox since version 5.0, which uses KVM backend.
 327          * Detection via DMI works corretly, the CPU ID would find KVM
 328          * only. */
 329         r = detect_vm_dmi();
 330         if (r < 0)
 331                 return r;
 332         if (r != VIRTUALIZATION_NONE)
 333                 goto finish;
 334
 335         r = detect_vm_cpuid();
 336         if (r < 0)
 337                 return r;
 338         if (r != VIRTUALIZATION_NONE)
 339                 goto finish;
 340
 341         /* x86 xen will most likely be detected by cpuid. If not (most likely
 342          * because we're not an x86 guest), then we should try the xen capabilities
 343          * file next. If that's not found, then we check for the high-level
 344          * hypervisor sysfs file:
 345          *
 346          * https://bugs.freedesktop.org/show_bug.cgi?id=77271 */
 347
 348         r = detect_vm_xen();
 349         if (r < 0)
 350                 return r;
 351         if (r != VIRTUALIZATION_NONE)
 352                 goto finish;
 353
 354         r = detect_vm_hypervisor();
 355         if (r < 0)
 356                 return r;
 357         if (r != VIRTUALIZATION_NONE)
 358                 goto finish;
 359
 360         r = detect_vm_device_tree();
 361         if (r < 0)
 362                 return r;
 363         if (r != VIRTUALIZATION_NONE)
 364                 goto finish;
 365
 366         r = detect_vm_uml();
 367         if (r < 0)
 368                 return r;
 369         if (r != VIRTUALIZATION_NONE)
 370                 goto finish;
 371
 372         r = detect_vm_zvm();
 373         if (r < 0)
 374                 return r;
 375
 376 finish:
 377         /* x86 xen Dom0 is detected as XEN in hypervisor and maybe others.
 378          * In order to detect the Dom0 as not virtualization we need to
 379          * double-check it */
 380         if (r == VIRTUALIZATION_XEN && detect_vm_xen_dom0())
 381                 r = VIRTUALIZATION_NONE;
 382
 383         cached_found = r;
 384         log_debug("Found VM virtualization %s", virtualization_to_string(r));
 385         return r;
 386 }
 387
 388 int detect_container(void) {
 389
 390         static const struct {
 391                 const char *value;
 392                 int id;
 393         } value_table[] = {
 394                 { "lxc",            VIRTUALIZATION_LXC            },
 395                 { "lxc-libvirt",    VIRTUALIZATION_LXC_LIBVIRT    },
 396                 { "systemd-nspawn", VIRTUALIZATION_SYSTEMD_NSPAWN },
 397                 { "docker",         VIRTUALIZATION_DOCKER         },
 398                 { "rkt",            VIRTUALIZATION_RKT            },
 399         };
 400
 401         static thread_local int cached_found = _VIRTUALIZATION_INVALID;
 402         _cleanup_free_ char *m = NULL;
 403         const char *e = NULL;
 404         unsigned j;
 405         int r;
 406
 407         if (cached_found >= 0)
 408                 return cached_found;
 409
 410         /* /proc/vz exists in container and outside of the container,
 411          * /proc/bc only outside of the container. */
 412         if (access("/proc/vz", F_OK) >= 0 &&
 413             access("/proc/bc", F_OK) < 0) {
 414                 r = VIRTUALIZATION_OPENVZ;
 415                 goto finish;
 416         }
 417
 418         if (getpid() == 1) {
 419                 /* If we are PID 1 we can just check our own
 420                  * environment variable */
 421
 422                 e = getenv("container");
 423                 if (isempty(e)) {
 424                         r = VIRTUALIZATION_NONE;
 425                         goto finish;
 426                 }
 427         } else {
 428
 429                 /* Otherwise, PID 1 dropped this information into a
 430                  * file in /run. This is better than accessing
 431                  * /proc/1/environ, since we don't need CAP_SYS_PTRACE
 432                  * for that. */
 433
 434                 r = read_one_line_file("/run/systemd/container", &m);
 435                 if (r == -ENOENT) {
 436
 437                         /* Fallback for cases where PID 1 was not
 438                          * systemd (for example, cases where
 439                          * init=/bin/sh is used. */
 440
 441                         r = getenv_for_pid(1, "container", &m);
 442                         if (r <= 0) {
 443
 444                                 /* If that didn't work, give up,
 445                                  * assume no container manager.
 446                                  *
 447                                  * Note: This means we still cannot
 448                                  * detect containers if init=/bin/sh
 449                                  * is passed but privileges dropped,
 450                                  * as /proc/1/environ is only readable
 451                                  * with privileges. */
 452
 453                                 r = VIRTUALIZATION_NONE;
 454                                 goto finish;
 455                         }
 456                 }
 457                 if (r < 0)
 458                         return r;
 459
 460                 e = m;
 461         }
 462
 463         for (j = 0; j < ELEMENTSOF(value_table); j++)
 464                 if (streq(e, value_table[j].value)) {
 465                         r = value_table[j].id;
 466                         goto finish;
 467                 }
 468
 469         r = VIRTUALIZATION_CONTAINER_OTHER;
 470
 471 finish:
 472         log_debug("Found container virtualization %s", virtualization_to_string(r));
 473         cached_found = r;
 474         return r;
 475 }
 476
 477 int detect_virtualization(void) {
 478         int r;
 479
 480         r = detect_container();
 481         if (r == 0)
 482                 r = detect_vm();
 483
 484         return r;
 485 }
 486
 487 int running_in_chroot(void) {
 488         int ret;
 489
 490         ret = files_same("/proc/1/root", "/");
 491         if (ret < 0)
 492                 return ret;
 493
 494         return ret == 0;
 495 }
 496
 497 static const char *const virtualization_table[_VIRTUALIZATION_MAX] = {
 498         [VIRTUALIZATION_NONE] = "none",
 499         [VIRTUALIZATION_KVM] = "kvm",
 500         [VIRTUALIZATION_QEMU] = "qemu",
 501         [VIRTUALIZATION_BOCHS] = "bochs",
 502         [VIRTUALIZATION_XEN] = "xen",
 503         [VIRTUALIZATION_UML] = "uml",
 504         [VIRTUALIZATION_VMWARE] = "vmware",
 505         [VIRTUALIZATION_ORACLE] = "oracle",
 506         [VIRTUALIZATION_MICROSOFT] = "microsoft",
 507         [VIRTUALIZATION_ZVM] = "zvm",
 508         [VIRTUALIZATION_PARALLELS] = "parallels",
 509         [VIRTUALIZATION_BHYVE] = "bhyve",
 510         [VIRTUALIZATION_VM_OTHER] = "vm-other",
 511
 512         [VIRTUALIZATION_SYSTEMD_NSPAWN] = "systemd-nspawn",
 513         [VIRTUALIZATION_LXC_LIBVIRT] = "lxc-libvirt",
 514         [VIRTUALIZATION_LXC] = "lxc",
 515         [VIRTUALIZATION_OPENVZ] = "openvz",
 516         [VIRTUALIZATION_DOCKER] = "docker",
 517         [VIRTUALIZATION_RKT] = "rkt",
 518         [VIRTUALIZATION_CONTAINER_OTHER] = "container-other",
 519 };
 520
 521 DEFINE_STRING_TABLE_LOOKUP(virtualization, int);