src/basic/virt.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2011 Lennart Poettering
   6
   7   systemd is free software; you can redistribute it and/or modify it
   8   under the terms of the GNU Lesser General Public License as published by
   9   the Free Software Foundation; either version 2.1 of the License, or
  10   (at your option) any later version.
  11
  12   systemd is distributed in the hope that it will be useful, but
  13   WITHOUT ANY WARRANTY; without even the implied warranty of
  14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  15   Lesser General Public License for more details.
  16
  17   You should have received a copy of the GNU Lesser General Public License
  18   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  19 ***/
  20
  21 #include <errno.h>
  22 #include <stdint.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26
  27 #include "alloc-util.h"
  28 #include "dirent-util.h"
  29 #include "env-util.h"
  30 #include "fd-util.h"
  31 #include "fileio.h"
  32 #include "macro.h"
  33 #include "process-util.h"
  34 #include "stat-util.h"
  35 #include "string-table.h"
  36 #include "string-util.h"
  37 #include "virt.h"
  38
  39 static int detect_vm_cpuid(void) {
  40
  41         /* CPUID is an x86 specific interface. */
  42 #if defined(__i386__) || defined(__x86_64__)
  43
  44         static const struct {
  45                 const char *cpuid;
  46                 int id;
  47         } cpuid_vendor_table[] = {
  48                 { "XenVMMXenVMM", VIRTUALIZATION_XEN       },
  49                 { "KVMKVMKVM",    VIRTUALIZATION_KVM       },
  50                 { "TCGTCGTCGTCG", VIRTUALIZATION_QEMU      },
  51                 /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
  52                 { "VMwareVMware", VIRTUALIZATION_VMWARE    },
  53                 /* https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs */
  54                 { "Microsoft Hv", VIRTUALIZATION_MICROSOFT },
  55                 /* https://wiki.freebsd.org/bhyve */
  56                 { "bhyve bhyve ", VIRTUALIZATION_BHYVE     },
  57         };
  58
  59         uint32_t eax, ecx;
  60         bool hypervisor;
  61
  62         /* http://lwn.net/Articles/301888/ */
  63
  64 #if defined (__i386__)
  65 #define REG_a "eax"
  66 #define REG_b "ebx"
  67 #elif defined (__amd64__)
  68 #define REG_a "rax"
  69 #define REG_b "rbx"
  70 #endif
  71
  72         /* First detect whether there is a hypervisor */
  73         eax = 1;
  74         __asm__ __volatile__ (
  75                 /* ebx/rbx is being used for PIC! */
  76                 "  push %%"REG_b"         \n\t"
  77                 "  cpuid                  \n\t"
  78                 "  pop %%"REG_b"          \n\t"
  79
  80                 : "=a" (eax), "=c" (ecx)
  81                 : "0" (eax)
  82         );
  83
  84         hypervisor = !!(ecx & 0x80000000U);
  85
  86         if (hypervisor) {
  87                 union {
  88                         uint32_t sig32[3];
  89                         char text[13];
  90                 } sig = {};
  91                 unsigned j;
  92
  93                 /* There is a hypervisor, see what it is */
  94                 eax = 0x40000000U;
  95                 __asm__ __volatile__ (
  96                         /* ebx/rbx is being used for PIC! */
  97                         "  push %%"REG_b"         \n\t"
  98                         "  cpuid                  \n\t"
  99                         "  mov %%ebx, %1          \n\t"
 100                         "  pop %%"REG_b"          \n\t"
 101
 102                         : "=a" (eax), "=r" (sig.sig32[0]), "=c" (sig.sig32[1]), "=d" (sig.sig32[2])
 103                         : "0" (eax)
 104                 );
 105
 106                 log_debug("Virtualization found, CPUID=%s", sig.text);
 107
 108                 for (j = 0; j < ELEMENTSOF(cpuid_vendor_table); j ++)
 109                         if (streq(sig.text, cpuid_vendor_table[j].cpuid))
 110                                 return cpuid_vendor_table[j].id;
 111
 112                 return VIRTUALIZATION_VM_OTHER;
 113         }
 114 #endif
 115         log_debug("No virtualization found in CPUID");
 116
 117         return VIRTUALIZATION_NONE;
 118 }
 119
 120 static int detect_vm_device_tree(void) {
 121 #if defined(__arm__) || defined(__aarch64__) || defined(__powerpc__) || defined(__powerpc64__)
 122         _cleanup_free_ char *hvtype = NULL;
 123         int r;
 124
 125         r = read_one_line_file("/proc/device-tree/hypervisor/compatible", &hvtype);
 126         if (r == -ENOENT) {
 127                 _cleanup_closedir_ DIR *dir = NULL;
 128                 struct dirent *dent;
 129
 130                 dir = opendir("/proc/device-tree");
 131                 if (!dir) {
 132                         if (errno == ENOENT) {
 133                                 log_debug_errno(errno, "/proc/device-tree: %m");
 134                                 return VIRTUALIZATION_NONE;
 135                         }
 136                         return -errno;
 137                 }
 138
 139                 FOREACH_DIRENT(dent, dir, return -errno)
 140                         if (strstr(dent->d_name, "fw-cfg")) {
 141                                 log_debug("Virtualization QEMU: \"fw-cfg\" present in /proc/device-tree/%s", dent->d_name);
 142                                 return VIRTUALIZATION_QEMU;
 143                         }
 144
 145                 log_debug("No virtualization found in /proc/device-tree/*");
 146                 return VIRTUALIZATION_NONE;
 147         } else if (r < 0)
 148                 return r;
 149
 150         log_debug("Virtualization %s found in /proc/device-tree/hypervisor/compatible", hvtype);
 151         if (streq(hvtype, "linux,kvm"))
 152                 return VIRTUALIZATION_KVM;
 153         else if (strstr(hvtype, "xen"))
 154                 return VIRTUALIZATION_XEN;
 155         else
 156                 return VIRTUALIZATION_VM_OTHER;
 157 #else
 158         log_debug("This platform does not support /proc/device-tree");
 159         return VIRTUALIZATION_NONE;
 160 #endif
 161 }
 162
 163 static int detect_vm_dmi(void) {
 164 #if defined(__i386__) || defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)
 165
 166         static const char *const dmi_vendors[] = {
 167                 "/sys/class/dmi/id/product_name", /* Test this before sys_vendor to detect KVM over QEMU */
 168                 "/sys/class/dmi/id/sys_vendor",
 169                 "/sys/class/dmi/id/board_vendor",
 170                 "/sys/class/dmi/id/bios_vendor"
 171         };
 172
 173         static const struct {
 174                 const char *vendor;
 175                 int id;
 176         } dmi_vendor_table[] = {
 177                 { "KVM",           VIRTUALIZATION_KVM       },
 178                 { "QEMU",          VIRTUALIZATION_QEMU      },
 179                 /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
 180                 { "VMware",        VIRTUALIZATION_VMWARE    },
 181                 { "VMW",           VIRTUALIZATION_VMWARE    },
 182                 { "innotek GmbH",  VIRTUALIZATION_ORACLE    },
 183                 { "Xen",           VIRTUALIZATION_XEN       },
 184                 { "Bochs",         VIRTUALIZATION_BOCHS     },
 185                 { "Parallels",     VIRTUALIZATION_PARALLELS },
 186                 /* https://wiki.freebsd.org/bhyve */
 187                 { "BHYVE",         VIRTUALIZATION_BHYVE     },
 188         };
 189         unsigned i;
 190         int r;
 191
 192         for (i = 0; i < ELEMENTSOF(dmi_vendors); i++) {
 193                 _cleanup_free_ char *s = NULL;
 194                 unsigned j;
 195
 196                 r = read_one_line_file(dmi_vendors[i], &s);
 197                 if (r < 0) {
 198                         if (r == -ENOENT)
 199                                 continue;
 200
 201                         return r;
 202                 }
 203
 204
 205
 206                 for (j = 0; j < ELEMENTSOF(dmi_vendor_table); j++)
 207                         if (startswith(s, dmi_vendor_table[j].vendor)) {
 208                                 log_debug("Virtualization %s found in DMI (%s)", s, dmi_vendors[i]);
 209                                 return dmi_vendor_table[j].id;
 210                         }
 211         }
 212 #endif
 213
 214         log_debug("No virtualization found in DMI");
 215
 216         return VIRTUALIZATION_NONE;
 217 }
 218
 219 static int detect_vm_xen(void) {
 220
 221         /* Check for Dom0 will be executed later in detect_vm_xen_dom0
 222            The presence of /proc/xen indicates some form of a Xen domain */
 223         if (access("/proc/xen", F_OK) < 0) {
 224                 log_debug("Virtualization XEN not found, /proc/xen does not exist");
 225                 return VIRTUALIZATION_NONE;
 226         }
 227
 228         log_debug("Virtualization XEN found (/proc/xen exists)");
 229         return VIRTUALIZATION_XEN;
 230 }
 231
 232 static bool detect_vm_xen_dom0(void) {
 233         _cleanup_free_ char *domcap = NULL;
 234         char *cap, *i;
 235         int r;
 236
 237         r = read_one_line_file("/proc/xen/capabilities", &domcap);
 238         if (r == -ENOENT) {
 239                 log_debug("Virtualization XEN not found, /proc/xen/capabilities does not exist");
 240                 return false;
 241         }
 242         if (r < 0)
 243                 return r;
 244
 245         i = domcap;
 246         while ((cap = strsep(&i, ",")))
 247                 if (streq(cap, "control_d"))
 248                         break;
 249         if (!cap) {
 250                 log_debug("Virtualization XEN DomU found (/proc/xen/capabilites)");
 251                 return false;
 252         }
 253
 254         log_debug("Virtualization XEN Dom0 ignored (/proc/xen/capabilities)");
 255         return true;
 256 }
 257
 258 static int detect_vm_hypervisor(void) {
 259         _cleanup_free_ char *hvtype = NULL;
 260         int r;
 261
 262         r = read_one_line_file("/sys/hypervisor/type", &hvtype);
 263         if (r == -ENOENT)
 264                 return VIRTUALIZATION_NONE;
 265         if (r < 0)
 266                 return r;
 267
 268         log_debug("Virtualization %s found in /sys/hypervisor/type", hvtype);
 269
 270         if (streq(hvtype, "xen"))
 271                 return VIRTUALIZATION_XEN;
 272         else
 273                 return VIRTUALIZATION_VM_OTHER;
 274 }
 275
 276 static int detect_vm_uml(void) {
 277         _cleanup_free_ char *cpuinfo_contents = NULL;
 278         int r;
 279
 280         /* Detect User-Mode Linux by reading /proc/cpuinfo */
 281         r = read_full_file("/proc/cpuinfo", &cpuinfo_contents, NULL);
 282         if (r < 0)
 283                 return r;
 284
 285         if (strstr(cpuinfo_contents, "\nvendor_id\t: User Mode Linux\n")) {
 286                 log_debug("UML virtualization found in /proc/cpuinfo");
 287                 return VIRTUALIZATION_UML;
 288         }
 289
 290         log_debug("No virtualization found in /proc/cpuinfo.");
 291         return VIRTUALIZATION_NONE;
 292 }
 293
 294 static int detect_vm_zvm(void) {
 295
 296 #if defined(__s390__)
 297         _cleanup_free_ char *t = NULL;
 298         int r;
 299
 300         r = get_proc_field("/proc/sysinfo", "VM00 Control Program", WHITESPACE, &t);
 301         if (r == -ENOENT)
 302                 return VIRTUALIZATION_NONE;
 303         if (r < 0)
 304                 return r;
 305
 306         log_debug("Virtualization %s found in /proc/sysinfo", t);
 307         if (streq(t, "z/VM"))
 308                 return VIRTUALIZATION_ZVM;
 309         else
 310                 return VIRTUALIZATION_KVM;
 311 #else
 312         log_debug("This platform does not support /proc/sysinfo");
 313         return VIRTUALIZATION_NONE;
 314 #endif
 315 }
 316
 317 /* Returns a short identifier for the various VM implementations */
 318 int detect_vm(void) {
 319         static thread_local int cached_found = _VIRTUALIZATION_INVALID;
 320         int r, dmi;
 321         bool other = false;
 322
 323         if (cached_found >= 0)
 324                 return cached_found;
 325
 326         /* We have to use the correct order here:
 327          *
 328          * -> First try to detect Oracle Virtualbox, even if it uses KVM.
 329          * -> Second try to detect from cpuid, this will report KVM for
 330          *    whatever software is used even if info in dmi is overwritten.
 331          * -> Third try to detect from dmi. */
 332
 333         dmi = detect_vm_dmi();
 334         if (dmi == VIRTUALIZATION_ORACLE) {
 335                 r = dmi;
 336                 goto finish;
 337         }
 338
 339         r = detect_vm_cpuid();
 340         if (r < 0)
 341                 return r;
 342         if (r != VIRTUALIZATION_NONE) {
 343                 if (r == VIRTUALIZATION_VM_OTHER)
 344                         other = true;
 345                 else
 346                         goto finish;
 347         }
 348
 349         r = dmi;
 350         if (r < 0)
 351                 return r;
 352         if (r != VIRTUALIZATION_NONE) {
 353                 if (r == VIRTUALIZATION_VM_OTHER)
 354                         other = true;
 355                 else
 356                         goto finish;
 357         }
 358
 359         /* x86 xen will most likely be detected by cpuid. If not (most likely
 360          * because we're not an x86 guest), then we should try the /proc/xen
 361          * directory next. If that's not found, then we check for the high-level
 362          * hypervisor sysfs file.
 363          */
 364
 365         r = detect_vm_xen();
 366         if (r < 0)
 367                 return r;
 368         if (r != VIRTUALIZATION_NONE) {
 369                 if (r == VIRTUALIZATION_VM_OTHER)
 370                         other = true;
 371                 else
 372                         goto finish;
 373         }
 374
 375         r = detect_vm_hypervisor();
 376         if (r < 0)
 377                 return r;
 378         if (r != VIRTUALIZATION_NONE) {
 379                 if (r == VIRTUALIZATION_VM_OTHER)
 380                         other = true;
 381                 else
 382                         goto finish;
 383         }
 384
 385         r = detect_vm_device_tree();
 386         if (r < 0)
 387                 return r;
 388         if (r != VIRTUALIZATION_NONE) {
 389                 if (r == VIRTUALIZATION_VM_OTHER)
 390                         other = true;
 391                 else
 392                         goto finish;
 393         }
 394
 395         r = detect_vm_uml();
 396         if (r < 0)
 397                 return r;
 398         if (r != VIRTUALIZATION_NONE) {
 399                 if (r == VIRTUALIZATION_VM_OTHER)
 400                         other = true;
 401                 else
 402                         goto finish;
 403         }
 404
 405         r = detect_vm_zvm();
 406         if (r < 0)
 407                 return r;
 408
 409 finish:
 410         /* x86 xen Dom0 is detected as XEN in hypervisor and maybe others.
 411          * In order to detect the Dom0 as not virtualization we need to
 412          * double-check it */
 413         if (r == VIRTUALIZATION_XEN && detect_vm_xen_dom0())
 414                 r = VIRTUALIZATION_NONE;
 415         else if (r == VIRTUALIZATION_NONE && other)
 416                 r = VIRTUALIZATION_VM_OTHER;
 417
 418         cached_found = r;
 419         log_debug("Found VM virtualization %s", virtualization_to_string(r));
 420         return r;
 421 }
 422
 423 int detect_container(void) {
 424
 425         static const struct {
 426                 const char *value;
 427                 int id;
 428         } value_table[] = {
 429                 { "lxc",            VIRTUALIZATION_LXC            },
 430                 { "lxc-libvirt",    VIRTUALIZATION_LXC_LIBVIRT    },
 431                 { "systemd-nspawn", VIRTUALIZATION_SYSTEMD_NSPAWN },
 432                 { "docker",         VIRTUALIZATION_DOCKER         },
 433                 { "rkt",            VIRTUALIZATION_RKT            },
 434         };
 435
 436         static thread_local int cached_found = _VIRTUALIZATION_INVALID;
 437         _cleanup_free_ char *m = NULL;
 438         const char *e = NULL;
 439         unsigned j;
 440         int r;
 441
 442         if (cached_found >= 0)
 443                 return cached_found;
 444
 445         /* /proc/vz exists in container and outside of the container, /proc/bc only outside of the container. */
 446         if (access("/proc/vz", F_OK) >= 0 &&
 447             access("/proc/bc", F_OK) < 0) {
 448                 r = VIRTUALIZATION_OPENVZ;
 449                 goto finish;
 450         }
 451
 452         if (getpid_cached() == 1) {
 453                 /* If we are PID 1 we can just check our own environment variable, and that's authoritative. */
 454
 455                 e = getenv("container");
 456                 if (isempty(e)) {
 457                         r = VIRTUALIZATION_NONE;
 458                         goto finish;
 459                 }
 460
 461                 goto translate_name;
 462         }
 463
 464         /* Otherwise, PID 1 might have dropped this information into a file in /run. This is better than accessing
 465          * /proc/1/environ, since we don't need CAP_SYS_PTRACE for that. */
 466         r = read_one_line_file("/run/systemd/container", &m);
 467         if (r >= 0) {
 468                 e = m;
 469                 goto translate_name;
 470         }
 471         if (r != -ENOENT)
 472                 return log_debug_errno(r, "Failed to read /run/systemd/container: %m");
 473
 474         /* Fallback for cases where PID 1 was not systemd (for example, cases where init=/bin/sh is used. */
 475         r = getenv_for_pid(1, "container", &m);
 476         if (r > 0) {
 477                 e = m;
 478                 goto translate_name;
 479         }
 480         if (r < 0) /* This only works if we have CAP_SYS_PTRACE, hence let's better ignore failures here */
 481                 log_debug_errno(r, "Failed to read $container of PID 1, ignoring: %m");
 482
 483         /* Interestingly /proc/1/sched actually shows the host's PID for what we see as PID 1. Hence, if the PID shown
 484          * there is not 1, we know we are in a PID namespace. and hence a container. */
 485         r = read_one_line_file("/proc/1/sched", &m);
 486         if (r >= 0) {
 487                 const char *t;
 488
 489                 t = strrchr(m, '(');
 490                 if (!t)
 491                         return -EIO;
 492
 493                 if (!startswith(t, "(1,")) {
 494                         r = VIRTUALIZATION_CONTAINER_OTHER;
 495                         goto finish;
 496                 }
 497         } else if (r != -ENOENT)
 498                 return r;
 499
 500         /* If that didn't work, give up, assume no container manager. */
 501         r = VIRTUALIZATION_NONE;
 502         goto finish;
 503
 504 translate_name:
 505         for (j = 0; j < ELEMENTSOF(value_table); j++)
 506                 if (streq(e, value_table[j].value)) {
 507                         r = value_table[j].id;
 508                         goto finish;
 509                 }
 510
 511         r = VIRTUALIZATION_CONTAINER_OTHER;
 512
 513 finish:
 514         log_debug("Found container virtualization %s.", virtualization_to_string(r));
 515         cached_found = r;
 516         return r;
 517 }
 518
 519 int detect_virtualization(void) {
 520         int r;
 521
 522         r = detect_container();
 523         if (r == 0)
 524                 r = detect_vm();
 525
 526         return r;
 527 }
 528
 529 static int userns_has_mapping(const char *name) {
 530         _cleanup_fclose_ FILE *f = NULL;
 531         _cleanup_free_ char *buf = NULL;
 532         size_t n_allocated = 0;
 533         ssize_t n;
 534         uint32_t a, b, c;
 535         int r;
 536
 537         f = fopen(name, "re");
 538         if (!f) {
 539                 log_debug_errno(errno, "Failed to open %s: %m", name);
 540                 return errno == ENOENT ? false : -errno;
 541         }
 542
 543         n = getline(&buf, &n_allocated, f);
 544         if (n < 0) {
 545                 if (feof(f)) {
 546                         log_debug("%s is empty, we're in an uninitialized user namespace", name);
 547                         return true;
 548                 }
 549
 550                 return log_debug_errno(errno, "Failed to read %s: %m", name);
 551         }
 552
 553         r = sscanf(buf, "%"PRIu32" %"PRIu32" %"PRIu32, &a, &b, &c);
 554         if (r < 3)
 555                 return log_debug_errno(errno, "Failed to parse %s: %m", name);
 556
 557         if (a == 0 && b == 0 && c == UINT32_MAX) {
 558                 /* The kernel calls mappings_overlap() and does not allow overlaps */
 559                 log_debug("%s has a full 1:1 mapping", name);
 560                 return false;
 561         }
 562
 563         /* Anything else implies that we are in a user namespace */
 564         log_debug("Mapping found in %s, we're in a user namespace", name);
 565         return true;
 566 }
 567
 568 int running_in_userns(void) {
 569         _cleanup_free_ char *line = NULL;
 570         int r;
 571
 572         r = userns_has_mapping("/proc/self/uid_map");
 573         if (r != 0)
 574                 return r;
 575
 576         r = userns_has_mapping("/proc/self/gid_map");
 577         if (r != 0)
 578                 return r;
 579
 580         /* "setgroups" file was added in kernel v3.18-rc6-15-g9cc46516dd. It is also
 581          * possible to compile a kernel without CONFIG_USER_NS, in which case "setgroups"
 582          * also does not exist. We cannot distinguish those two cases, so assume that
 583          * we're running on a stripped-down recent kernel, rather than on an old one,
 584          * and if the file is not found, return false.
 585          */
 586         r = read_one_line_file("/proc/self/setgroups", &line);
 587         if (r < 0) {
 588                 log_debug_errno(r, "/proc/self/setgroups: %m");
 589                 return r == -ENOENT ? false : r;
 590         }
 591
 592         truncate_nl(line);
 593         r = streq(line, "deny");
 594         /* See user_namespaces(7) for a description of this "setgroups" contents. */
 595         log_debug("/proc/self/setgroups contains \"%s\", %s user namespace", line, r ? "in" : "not in");
 596         return r;
 597 }
 598
 599 int running_in_chroot(void) {
 600         int ret;
 601
 602         if (getenv_bool("SYSTEMD_IGNORE_CHROOT") > 0)
 603                 return 0;
 604
 605         ret = files_same("/proc/1/root", "/", 0);
 606         if (ret < 0)
 607                 return ret;
 608
 609         return ret == 0;
 610 }
 611
 612 static const char *const virtualization_table[_VIRTUALIZATION_MAX] = {
 613         [VIRTUALIZATION_NONE] = "none",
 614         [VIRTUALIZATION_KVM] = "kvm",
 615         [VIRTUALIZATION_QEMU] = "qemu",
 616         [VIRTUALIZATION_BOCHS] = "bochs",
 617         [VIRTUALIZATION_XEN] = "xen",
 618         [VIRTUALIZATION_UML] = "uml",
 619         [VIRTUALIZATION_VMWARE] = "vmware",
 620         [VIRTUALIZATION_ORACLE] = "oracle",
 621         [VIRTUALIZATION_MICROSOFT] = "microsoft",
 622         [VIRTUALIZATION_ZVM] = "zvm",
 623         [VIRTUALIZATION_PARALLELS] = "parallels",
 624         [VIRTUALIZATION_BHYVE] = "bhyve",
 625         [VIRTUALIZATION_VM_OTHER] = "vm-other",
 626
 627         [VIRTUALIZATION_SYSTEMD_NSPAWN] = "systemd-nspawn",
 628         [VIRTUALIZATION_LXC_LIBVIRT] = "lxc-libvirt",
 629         [VIRTUALIZATION_LXC] = "lxc",
 630         [VIRTUALIZATION_OPENVZ] = "openvz",
 631         [VIRTUALIZATION_DOCKER] = "docker",
 632         [VIRTUALIZATION_RKT] = "rkt",
 633         [VIRTUALIZATION_CONTAINER_OTHER] = "container-other",
 634 };
 635
 636 DEFINE_STRING_TABLE_LOOKUP(virtualization, int);