src/basic/virt.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2011 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <string.h>
  23 #include <errno.h>
  24 #include <unistd.h>
  25
  26 #include "util.h"
  27 #include "process-util.h"
  28 #include "virt.h"
  29 #include "fileio.h"
  30
  31 static int detect_vm_cpuid(void) {
  32
  33         /* Both CPUID and DMI are x86 specific interfaces... */
  34 #if defined(__i386__) || defined(__x86_64__)
  35
  36         static const struct {
  37                 const char *cpuid;
  38                 int id;
  39         } cpuid_vendor_table[] = {
  40                 { "XenVMMXenVMM", VIRTUALIZATION_XEN       },
  41                 { "KVMKVMKVM",    VIRTUALIZATION_KVM       },
  42                 /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
  43                 { "VMwareVMware", VIRTUALIZATION_VMWARE    },
  44                 /* http://msdn.microsoft.com/en-us/library/ff542428.aspx */
  45                 { "Microsoft Hv", VIRTUALIZATION_MICROSOFT },
  46         };
  47
  48         uint32_t eax, ecx;
  49         bool hypervisor;
  50
  51         /* http://lwn.net/Articles/301888/ */
  52
  53 #if defined (__i386__)
  54 #define REG_a "eax"
  55 #define REG_b "ebx"
  56 #elif defined (__amd64__)
  57 #define REG_a "rax"
  58 #define REG_b "rbx"
  59 #endif
  60
  61         /* First detect whether there is a hypervisor */
  62         eax = 1;
  63         __asm__ __volatile__ (
  64                 /* ebx/rbx is being used for PIC! */
  65                 "  push %%"REG_b"         \n\t"
  66                 "  cpuid                  \n\t"
  67                 "  pop %%"REG_b"          \n\t"
  68
  69                 : "=a" (eax), "=c" (ecx)
  70                 : "0" (eax)
  71         );
  72
  73         hypervisor = !!(ecx & 0x80000000U);
  74
  75         if (hypervisor) {
  76                 union {
  77                         uint32_t sig32[3];
  78                         char text[13];
  79                 } sig = {};
  80                 unsigned j;
  81
  82                 /* There is a hypervisor, see what it is */
  83                 eax = 0x40000000U;
  84                 __asm__ __volatile__ (
  85                         /* ebx/rbx is being used for PIC! */
  86                         "  push %%"REG_b"         \n\t"
  87                         "  cpuid                  \n\t"
  88                         "  mov %%ebx, %1          \n\t"
  89                         "  pop %%"REG_b"          \n\t"
  90
  91                         : "=a" (eax), "=r" (sig.sig32[0]), "=c" (sig.sig32[1]), "=d" (sig.sig32[2])
  92                         : "0" (eax)
  93                 );
  94
  95                 for (j = 0; j < ELEMENTSOF(cpuid_vendor_table); j ++)
  96                         if (streq(sig.text, cpuid_vendor_table[j].cpuid))
  97                                 return cpuid_vendor_table[j].id;
  98
  99                 return VIRTUALIZATION_VM_OTHER;
 100         }
 101 #endif
 102
 103         return VIRTUALIZATION_NONE;
 104 }
 105
 106 static int detect_vm_device_tree(void) {
 107 #if defined(__arm__) || defined(__aarch64__) || defined(__powerpc__) || defined(__powerpc64__)
 108         _cleanup_free_ char *hvtype = NULL;
 109         int r;
 110
 111         r = read_one_line_file("/proc/device-tree/hypervisor/compatible", &hvtype);
 112         if (r == -ENOENT) {
 113                 _cleanup_closedir_ DIR *dir = NULL;
 114                 struct dirent *dent;
 115
 116                 dir = opendir("/proc/device-tree");
 117                 if (!dir) {
 118                         if (errno == ENOENT)
 119                                 return VIRTUALIZATION_NONE;
 120                         return -errno;
 121                 }
 122
 123                 FOREACH_DIRENT(dent, dir, return -errno)
 124                         if (strstr(dent->d_name, "fw-cfg"))
 125                                 return VIRTUALIZATION_QEMU;
 126
 127                 return VIRTUALIZATION_NONE;
 128         } else if (r < 0)
 129                 return r;
 130
 131         if (streq(hvtype, "linux,kvm"))
 132                 return VIRTUALIZATION_KVM;
 133         else if (strstr(hvtype, "xen"))
 134                 return VIRTUALIZATION_XEN;
 135         else
 136                 return VIRTUALIZATION_VM_OTHER;
 137 #else
 138         return VIRTUALIZATION_NONE;
 139 #endif
 140 }
 141
 142 static int detect_vm_dmi(void) {
 143
 144         /* Both CPUID and DMI are x86 specific interfaces... */
 145 #if defined(__i386__) || defined(__x86_64__)
 146
 147         static const char *const dmi_vendors[] = {
 148                 "/sys/class/dmi/id/sys_vendor",
 149                 "/sys/class/dmi/id/board_vendor",
 150                 "/sys/class/dmi/id/bios_vendor"
 151         };
 152
 153         static const struct {
 154                 const char *vendor;
 155                 int id;
 156         } dmi_vendor_table[] = {
 157                 { "QEMU",          VIRTUALIZATION_QEMU      },
 158                 /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */
 159                 { "VMware",        VIRTUALIZATION_VMWARE    },
 160                 { "VMW",           VIRTUALIZATION_VMWARE    },
 161                 { "innotek GmbH",  VIRTUALIZATION_ORACLE    },
 162                 { "Xen",           VIRTUALIZATION_XEN       },
 163                 { "Bochs",         VIRTUALIZATION_BOCHS     },
 164                 { "Parallels",     VIRTUALIZATION_PARALLELS },
 165         };
 166         unsigned i;
 167         int r;
 168
 169         for (i = 0; i < ELEMENTSOF(dmi_vendors); i++) {
 170                 _cleanup_free_ char *s = NULL;
 171                 unsigned j;
 172
 173                 r = read_one_line_file(dmi_vendors[i], &s);
 174                 if (r < 0) {
 175                         if (r == -ENOENT)
 176                                 continue;
 177
 178                         return r;
 179                 }
 180
 181                 for (j = 0; j < ELEMENTSOF(dmi_vendor_table); j++)
 182                         if (startswith(s, dmi_vendor_table[j].vendor))
 183                                 return dmi_vendor_table[j].id;
 184         }
 185 #endif
 186
 187         return VIRTUALIZATION_NONE;
 188 }
 189
 190 static int detect_vm_xen(void) {
 191         _cleanup_free_ char *domcap = NULL;
 192         char *cap, *i;
 193         int r;
 194
 195         r = read_one_line_file("/proc/xen/capabilities", &domcap);
 196         if (r == -ENOENT)
 197                 return VIRTUALIZATION_NONE;
 198
 199         i = domcap;
 200         while ((cap = strsep(&i, ",")))
 201                 if (streq(cap, "control_d"))
 202                         break;
 203
 204         return cap ? VIRTUALIZATION_NONE : VIRTUALIZATION_XEN;
 205 }
 206
 207 static int detect_vm_hypervisor(void) {
 208         _cleanup_free_ char *hvtype = NULL;
 209         int r;
 210
 211         r = read_one_line_file("/sys/hypervisor/type", &hvtype);
 212         if (r == -ENOENT)
 213                 return VIRTUALIZATION_NONE;
 214         if (r < 0)
 215                 return r;
 216
 217         if (streq(hvtype, "xen"))
 218                 return VIRTUALIZATION_XEN;
 219         else
 220                 return VIRTUALIZATION_VM_OTHER;
 221 }
 222
 223 static int detect_vm_uml(void) {
 224         _cleanup_free_ char *cpuinfo_contents = NULL;
 225         int r;
 226
 227         /* Detect User-Mode Linux by reading /proc/cpuinfo */
 228         r = read_full_file("/proc/cpuinfo", &cpuinfo_contents, NULL);
 229         if (r < 0)
 230                 return r;
 231         if (strstr(cpuinfo_contents, "\nvendor_id\t: User Mode Linux\n"))
 232                 return VIRTUALIZATION_UML;
 233
 234         return VIRTUALIZATION_NONE;
 235 }
 236
 237 static int detect_vm_zvm(void) {
 238
 239 #if defined(__s390__)
 240         _cleanup_free_ char *t = NULL;
 241         int r;
 242
 243         r = get_proc_field("/proc/sysinfo", "VM00 Control Program", WHITESPACE, &t);
 244         if (r == -ENOENT)
 245                 return VIRTUALIZATION_NONE;
 246         if (r < 0)
 247                 return r;
 248
 249         if (streq(t, "z/VM"))
 250                 return VIRTUALIZATION_ZVM;
 251         else
 252                 return VIRTUALIZATION_KVM;
 253 #else
 254         return VIRTUALIZATION_NONE;
 255 #endif
 256 }
 257
 258 /* Returns a short identifier for the various VM implementations */
 259 int detect_vm(void) {
 260         static thread_local int cached_found = _VIRTUALIZATION_INVALID;
 261         int r;
 262
 263         if (cached_found >= 0)
 264                 return cached_found;
 265
 266         /* Try xen capabilities file first, if not found try
 267          * high-level hypervisor sysfs file:
 268          *
 269          * https://bugs.freedesktop.org/show_bug.cgi?id=77271 */
 270
 271         r = detect_vm_xen();
 272         if (r < 0)
 273                 return r;
 274         if (r != VIRTUALIZATION_NONE)
 275                 goto finish;
 276
 277         r = detect_vm_dmi();
 278         if (r < 0)
 279                 return r;
 280         if (r != VIRTUALIZATION_NONE)
 281                 goto finish;
 282
 283         r = detect_vm_cpuid();
 284         if (r < 0)
 285                 return r;
 286         if (r != VIRTUALIZATION_NONE)
 287                 goto finish;
 288
 289         r = detect_vm_hypervisor();
 290         if (r < 0)
 291                 return r;
 292         if (r != VIRTUALIZATION_NONE)
 293                 goto finish;
 294
 295         r = detect_vm_device_tree();
 296         if (r < 0)
 297                 return r;
 298         if (r != VIRTUALIZATION_NONE)
 299                 goto finish;
 300
 301         r = detect_vm_uml();
 302         if (r < 0)
 303                 return r;
 304         if (r != VIRTUALIZATION_NONE)
 305                 goto finish;
 306
 307         r = detect_vm_zvm();
 308         if (r < 0)
 309                 return r;
 310
 311 finish:
 312         cached_found = r;
 313         return r;
 314 }
 315
 316 int detect_container(void) {
 317
 318         static const struct {
 319                 const char *value;
 320                 int id;
 321         } value_table[] = {
 322                 { "lxc",            VIRTUALIZATION_LXC            },
 323                 { "lxc-libvirt",    VIRTUALIZATION_LXC_LIBVIRT    },
 324                 { "systemd-nspawn", VIRTUALIZATION_SYSTEMD_NSPAWN },
 325                 { "docker",         VIRTUALIZATION_DOCKER         },
 326         };
 327
 328         static thread_local int cached_found = _VIRTUALIZATION_INVALID;
 329         _cleanup_free_ char *m = NULL;
 330         const char *e = NULL;
 331         unsigned j;
 332         int r;
 333
 334         if (cached_found >= 0)
 335                 return cached_found;
 336
 337         /* /proc/vz exists in container and outside of the container,
 338          * /proc/bc only outside of the container. */
 339         if (access("/proc/vz", F_OK) >= 0 &&
 340             access("/proc/bc", F_OK) < 0) {
 341                 r = VIRTUALIZATION_OPENVZ;
 342                 goto finish;
 343         }
 344
 345         if (getpid() == 1) {
 346                 /* If we are PID 1 we can just check our own
 347                  * environment variable */
 348
 349                 e = getenv("container");
 350                 if (isempty(e)) {
 351                         r = VIRTUALIZATION_NONE;
 352                         goto finish;
 353                 }
 354         } else {
 355
 356                 /* Otherwise, PID 1 dropped this information into a
 357                  * file in /run. This is better than accessing
 358                  * /proc/1/environ, since we don't need CAP_SYS_PTRACE
 359                  * for that. */
 360
 361                 r = read_one_line_file("/run/systemd/container", &m);
 362                 if (r == -ENOENT) {
 363
 364                         /* Fallback for cases where PID 1 was not
 365                          * systemd (for example, cases where
 366                          * init=/bin/sh is used. */
 367
 368                         r = getenv_for_pid(1, "container", &m);
 369                         if (r <= 0) {
 370
 371                                 /* If that didn't work, give up,
 372                                  * assume no container manager.
 373                                  *
 374                                  * Note: This means we still cannot
 375                                  * detect containers if init=/bin/sh
 376                                  * is passed but privileges dropped,
 377                                  * as /proc/1/environ is only readable
 378                                  * with privileges. */
 379
 380                                 r = VIRTUALIZATION_NONE;
 381                                 goto finish;
 382                         }
 383                 }
 384                 if (r < 0)
 385                         return r;
 386
 387                 e = m;
 388         }
 389
 390         for (j = 0; j < ELEMENTSOF(value_table); j++)
 391                 if (streq(e, value_table[j].value)) {
 392                         r = value_table[j].id;
 393                         goto finish;
 394                 }
 395
 396         r = VIRTUALIZATION_NONE;
 397
 398 finish:
 399         cached_found = r;
 400         return r;
 401 }
 402
 403 int detect_virtualization(void) {
 404         int r;
 405
 406         r = detect_container();
 407         if (r != 0)
 408                 return r;
 409
 410         return detect_vm();
 411 }
 412
 413 static const char *const virtualization_table[_VIRTUALIZATION_MAX] = {
 414         [VIRTUALIZATION_NONE] = "none",
 415         [VIRTUALIZATION_KVM] = "kvm",
 416         [VIRTUALIZATION_QEMU] = "qemu",
 417         [VIRTUALIZATION_BOCHS] = "bochs",
 418         [VIRTUALIZATION_XEN] = "xen",
 419         [VIRTUALIZATION_UML] = "uml",
 420         [VIRTUALIZATION_VMWARE] = "vmware",
 421         [VIRTUALIZATION_ORACLE] = "oracle",
 422         [VIRTUALIZATION_MICROSOFT] = "microsoft",
 423         [VIRTUALIZATION_ZVM] = "zvm",
 424         [VIRTUALIZATION_PARALLELS] = "parallels",
 425         [VIRTUALIZATION_VM_OTHER] = "vm-other",
 426
 427         [VIRTUALIZATION_SYSTEMD_NSPAWN] = "systemd-nspawn",
 428         [VIRTUALIZATION_LXC_LIBVIRT] = "lxc-libvirt",
 429         [VIRTUALIZATION_LXC] = "lxc",
 430         [VIRTUALIZATION_OPENVZ] = "openvz",
 431         [VIRTUALIZATION_DOCKER] = "docker",
 432         [VIRTUALIZATION_CONTAINER_OTHER] = "container-other",
 433 };
 434
 435 DEFINE_STRING_TABLE_LOOKUP(virtualization, int);