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