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