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