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 "env-util.h"
  29 #include "fd-util.h"
  30 #include "fileio.h"
  31 #include "macro.h"
  32 #include "process-util.h"
  33 #include "stat-util.h"
  34 #include "string-table.h"
  35 #include "string-util.h"
  36 #include "virt.h"
  37
  38 #if 0 /// UNNEEDED by elogind
  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                 for (j = 0; j < ELEMENTSOF(dmi_vendor_table); j++)
 205                         if (startswith(s, dmi_vendor_table[j].vendor)) {
 206                                 log_debug("Virtualization %s found in DMI (%s)", s, dmi_vendors[i]);
 207                                 return dmi_vendor_table[j].id;
 208                         }
 209         }
 210 #endif
 211
 212         log_debug("No virtualization found in DMI");
 213
 214         return VIRTUALIZATION_NONE;
 215 }
 216
 217 static int detect_vm_xen(void) {
 218
 219         /* Check for Dom0 will be executed later in detect_vm_xen_dom0
 220            The presence of /proc/xen indicates some form of a Xen domain */
 221         if (access("/proc/xen", F_OK) < 0) {
 222                 log_debug("Virtualization XEN not found, /proc/xen does not exist");
 223                 return VIRTUALIZATION_NONE;
 224         }
 225
 226         log_debug("Virtualization XEN found (/proc/xen exists)");
 227         return VIRTUALIZATION_XEN;
 228 }
 229
 230 static bool detect_vm_xen_dom0(void) {
 231         _cleanup_free_ char *domcap = NULL;
 232         char *cap, *i;
 233         int r;
 234
 235         r = read_one_line_file("/proc/xen/capabilities", &domcap);
 236         if (r == -ENOENT) {
 237                 log_debug("Virtualization XEN not found, /proc/xen/capabilities does not exist");
 238                 return false;
 239         }
 240         if (r < 0)
 241                 return r;
 242
 243         i = domcap;
 244         while ((cap = strsep(&i, ",")))
 245                 if (streq(cap, "control_d"))
 246                         break;
 247         if (!cap) {
 248                 log_debug("Virtualization XEN DomU found (/proc/xen/capabilites)");
 249                 return false;
 250         }
 251
 252         log_debug("Virtualization XEN Dom0 ignored (/proc/xen/capabilities)");
 253         return true;
 254 }
 255
 256 static int detect_vm_hypervisor(void) {
 257         _cleanup_free_ char *hvtype = NULL;
 258         int r;
 259
 260         r = read_one_line_file("/sys/hypervisor/type", &hvtype);
 261         if (r == -ENOENT)
 262                 return VIRTUALIZATION_NONE;
 263         if (r < 0)
 264                 return r;
 265
 266         log_debug("Virtualization %s found in /sys/hypervisor/type", hvtype);
 267
 268         if (streq(hvtype, "xen"))
 269                 return VIRTUALIZATION_XEN;
 270         else
 271                 return VIRTUALIZATION_VM_OTHER;
 272 }
 273
 274 static int detect_vm_uml(void) {
 275         _cleanup_free_ char *cpuinfo_contents = NULL;
 276         int r;
 277
 278         /* Detect User-Mode Linux by reading /proc/cpuinfo */
 279         r = read_full_file("/proc/cpuinfo", &cpuinfo_contents, NULL);
 280         if (r < 0)
 281                 return r;
 282
 283         if (strstr(cpuinfo_contents, "\nvendor_id\t: User Mode Linux\n")) {
 284                 log_debug("UML virtualization found in /proc/cpuinfo");
 285                 return VIRTUALIZATION_UML;
 286         }
 287
 288         log_debug("No virtualization found in /proc/cpuinfo.");
 289         return VIRTUALIZATION_NONE;
 290 }
 291
 292 static int detect_vm_zvm(void) {
 293
 294 #if defined(__s390__)
 295         _cleanup_free_ char *t = NULL;
 296         int r;
 297
 298         r = get_proc_field("/proc/sysinfo", "VM00 Control Program", WHITESPACE, &t);
 299         if (r == -ENOENT)
 300                 return VIRTUALIZATION_NONE;
 301         if (r < 0)
 302                 return r;
 303
 304         log_debug("Virtualization %s found in /proc/sysinfo", t);
 305         if (streq(t, "z/VM"))
 306                 return VIRTUALIZATION_ZVM;
 307         else
 308                 return VIRTUALIZATION_KVM;
 309 #else
 310         log_debug("This platform does not support /proc/sysinfo");
 311         return VIRTUALIZATION_NONE;
 312 #endif
 313 }
 314
 315 /* Returns a short identifier for the various VM implementations */
 316 int detect_vm(void) {
 317         static thread_local int cached_found = _VIRTUALIZATION_INVALID;
 318         int r, dmi;
 319         bool other = false;
 320
 321         if (cached_found >= 0)
 322                 return cached_found;
 323
 324         /* We have to use the correct order here:
 325          *
 326          * -> First try to detect Oracle Virtualbox, even if it uses KVM.
 327          * -> Second try to detect from cpuid, this will report KVM for
 328          *    whatever software is used even if info in dmi is overwritten.
 329          * -> Third try to detect from dmi. */
 330
 331         dmi = detect_vm_dmi();
 332         if (dmi == VIRTUALIZATION_ORACLE) {
 333                 r = dmi;
 334                 goto finish;
 335         }
 336
 337         r = detect_vm_cpuid();
 338         if (r < 0)
 339                 return r;
 340         if (r != VIRTUALIZATION_NONE) {
 341                 if (r == VIRTUALIZATION_VM_OTHER)
 342                         other = true;
 343                 else
 344                         goto finish;
 345         }
 346
 347         r = dmi;
 348         if (r < 0)
 349                 return r;
 350         if (r != VIRTUALIZATION_NONE) {
 351                 if (r == VIRTUALIZATION_VM_OTHER)
 352                         other = true;
 353                 else
 354                         goto finish;
 355         }
 356
 357         /* x86 xen will most likely be detected by cpuid. If not (most likely
 358          * because we're not an x86 guest), then we should try the /proc/xen
 359          * directory next. If that's not found, then we check for the high-level
 360          * hypervisor sysfs file.
 361          */
 362
 363         r = detect_vm_xen();
 364         if (r < 0)
 365                 return r;
 366         if (r != VIRTUALIZATION_NONE) {
 367                 if (r == VIRTUALIZATION_VM_OTHER)
 368                         other = true;
 369                 else
 370                         goto finish;
 371         }
 372
 373         r = detect_vm_hypervisor();
 374         if (r < 0)
 375                 return r;
 376         if (r != VIRTUALIZATION_NONE) {
 377                 if (r == VIRTUALIZATION_VM_OTHER)
 378                         other = true;
 379                 else
 380                         goto finish;
 381         }
 382
 383         r = detect_vm_device_tree();
 384         if (r < 0)
 385                 return r;
 386         if (r != VIRTUALIZATION_NONE) {
 387                 if (r == VIRTUALIZATION_VM_OTHER)
 388                         other = true;
 389                 else
 390                         goto finish;
 391         }
 392
 393         r = detect_vm_uml();
 394         if (r < 0)
 395                 return r;
 396         if (r != VIRTUALIZATION_NONE) {
 397                 if (r == VIRTUALIZATION_VM_OTHER)
 398                         other = true;
 399                 else
 400                         goto finish;
 401         }
 402
 403         r = detect_vm_zvm();
 404         if (r < 0)
 405                 return r;
 406
 407 finish:
 408         /* x86 xen Dom0 is detected as XEN in hypervisor and maybe others.
 409          * In order to detect the Dom0 as not virtualization we need to
 410          * double-check it */
 411         if (r == VIRTUALIZATION_XEN && detect_vm_xen_dom0())
 412                 r = VIRTUALIZATION_NONE;
 413         else if (r == VIRTUALIZATION_NONE && other)
 414                 r = VIRTUALIZATION_VM_OTHER;
 415
 416         cached_found = r;
 417         log_debug("Found VM virtualization %s", virtualization_to_string(r));
 418         return r;
 419 }
 420 #endif // 0
 421
 422 int detect_container(void) {
 423
 424         static const struct {
 425                 const char *value;
 426                 int id;
 427         } value_table[] = {
 428                 { "lxc",            VIRTUALIZATION_LXC            },
 429                 { "lxc-libvirt",    VIRTUALIZATION_LXC_LIBVIRT    },
 430                 { "systemd-nspawn", VIRTUALIZATION_SYSTEMD_NSPAWN },
 431                 { "docker",         VIRTUALIZATION_DOCKER         },
 432                 { "rkt",            VIRTUALIZATION_RKT            },
 433         };
 434
 435         static thread_local int cached_found = _VIRTUALIZATION_INVALID;
 436         _cleanup_free_ char *m = NULL;
 437         const char *e = NULL;
 438         unsigned j;
 439         int r;
 440
 441         if (cached_found >= 0)
 442                 return cached_found;
 443
 444         /* /proc/vz exists in container and outside of the container, /proc/bc only outside of the container. */
 445         if (access("/proc/vz", F_OK) >= 0 &&
 446             access("/proc/bc", F_OK) < 0) {
 447                 r = VIRTUALIZATION_OPENVZ;
 448                 goto finish;
 449         }
 450
 451         if (getpid_cached() == 1) {
 452                 /* If we are PID 1 we can just check our own environment variable, and that's authoritative. */
 453
 454                 e = getenv("container");
 455                 if (isempty(e)) {
 456                         r = VIRTUALIZATION_NONE;
 457                         goto finish;
 458                 }
 459
 460                 goto translate_name;
 461         }
 462
 463         /* Otherwise, PID 1 might have dropped this information into a file in /run. This is better than accessing
 464          * /proc/1/environ, since we don't need CAP_SYS_PTRACE for that. */
 465         r = read_one_line_file("/run/systemd/container", &m);
 466         if (r >= 0) {
 467                 e = m;
 468                 goto translate_name;
 469         }
 470         if (r != -ENOENT)
 471                 return log_debug_errno(r, "Failed to read /run/systemd/container: %m");
 472
 473         /* Fallback for cases where PID 1 was not systemd (for example, cases where init=/bin/sh is used. */
 474         r = getenv_for_pid(1, "container", &m);
 475         if (r > 0) {
 476                 e = m;
 477                 goto translate_name;
 478         }
 479         if (r < 0) /* This only works if we have CAP_SYS_PTRACE, hence let's better ignore failures here */
 480                 log_debug_errno(r, "Failed to read $container of PID 1, ignoring: %m");
 481
 482         /* Interestingly /proc/1/sched actually shows the host's PID for what we see as PID 1. Hence, if the PID shown
 483          * there is not 1, we know we are in a PID namespace. and hence a container. */
 484         r = read_one_line_file("/proc/1/sched", &m);
 485         if (r >= 0) {
 486                 const char *t;
 487
 488                 t = strrchr(m, '(');
 489                 if (!t)
 490                         return -EIO;
 491
 492                 if (!startswith(t, "(1,")) {
 493                         r = VIRTUALIZATION_CONTAINER_OTHER;
 494                         goto finish;
 495                 }
 496         } else if (r != -ENOENT)
 497                 return r;
 498
 499         /* If that didn't work, give up, assume no container manager. */
 500         r = VIRTUALIZATION_NONE;
 501         goto finish;
 502
 503 translate_name:
 504         for (j = 0; j < ELEMENTSOF(value_table); j++)
 505                 if (streq(e, value_table[j].value)) {
 506                         r = value_table[j].id;
 507                         goto finish;
 508                 }
 509
 510         r = VIRTUALIZATION_CONTAINER_OTHER;
 511
 512 finish:
 513         log_debug("Found container virtualization %s.", virtualization_to_string(r));
 514         cached_found = r;
 515         return r;
 516 }
 517
 518 #if 0 /// UNNEEDED by elogind
 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 #endif // 0
 599
 600 int running_in_chroot(void) {
 601         int ret;
 602
 603 #if 0 /// elogind does not allow to ignore chroots, we are never init!
 604         if (getenv_bool("SYSTEMD_IGNORE_CHROOT") > 0)
 605                 return 0;
 606 #endif // 0
 607
 608         ret = files_same("/proc/1/root", "/", 0);
 609         if (ret < 0)
 610                 return ret;
 611
 612         return ret == 0;
 613 }
 614
 615 static const char *const virtualization_table[_VIRTUALIZATION_MAX] = {
 616         [VIRTUALIZATION_NONE] = "none",
 617         [VIRTUALIZATION_KVM] = "kvm",
 618         [VIRTUALIZATION_QEMU] = "qemu",
 619         [VIRTUALIZATION_BOCHS] = "bochs",
 620         [VIRTUALIZATION_XEN] = "xen",
 621         [VIRTUALIZATION_UML] = "uml",
 622         [VIRTUALIZATION_VMWARE] = "vmware",
 623         [VIRTUALIZATION_ORACLE] = "oracle",
 624         [VIRTUALIZATION_MICROSOFT] = "microsoft",
 625         [VIRTUALIZATION_ZVM] = "zvm",
 626         [VIRTUALIZATION_PARALLELS] = "parallels",
 627         [VIRTUALIZATION_BHYVE] = "bhyve",
 628         [VIRTUALIZATION_VM_OTHER] = "vm-other",
 629
 630         [VIRTUALIZATION_SYSTEMD_NSPAWN] = "systemd-nspawn",
 631         [VIRTUALIZATION_LXC_LIBVIRT] = "lxc-libvirt",
 632         [VIRTUALIZATION_LXC] = "lxc",
 633         [VIRTUALIZATION_OPENVZ] = "openvz",
 634         [VIRTUALIZATION_DOCKER] = "docker",
 635         [VIRTUALIZATION_RKT] = "rkt",
 636         [VIRTUALIZATION_CONTAINER_OTHER] = "container-other",
 637 };
 638
 639 DEFINE_STRING_TABLE_LOOKUP(virtualization, int);