diff options
Diffstat (limited to 'src/basic/virt.c')
| -rw-r--r-- | src/basic/virt.c | 642 |
1 files changed, 642 insertions, 0 deletions
diff --git a/src/basic/virt.c b/src/basic/virt.c new file mode 100644 index 0000000..f63f15f --- /dev/null +++ b/src/basic/virt.c @@ -0,0 +1,642 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#if defined(__i386__) || defined(__x86_64__) +#include <cpuid.h> +#endif +#include <errno.h> +#include <stdint.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "alloc-util.h" +#include "dirent-util.h" +#include "env-util.h" +#include "fd-util.h" +#include "fileio.h" +#include "macro.h" +#include "process-util.h" +#include "stat-util.h" +#include "string-table.h" +#include "string-util.h" +#include "virt.h" + +static int detect_vm_cpuid(void) { + + /* CPUID is an x86 specific interface. */ +#if defined(__i386__) || defined(__x86_64__) + + static const struct { + const char *cpuid; + int id; + } cpuid_vendor_table[] = { + { "XenVMMXenVMM", VIRTUALIZATION_XEN }, + { "KVMKVMKVM", VIRTUALIZATION_KVM }, + { "TCGTCGTCGTCG", VIRTUALIZATION_QEMU }, + /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */ + { "VMwareVMware", VIRTUALIZATION_VMWARE }, + /* https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/tlfs */ + { "Microsoft Hv", VIRTUALIZATION_MICROSOFT }, + /* https://wiki.freebsd.org/bhyve */ + { "bhyve bhyve ", VIRTUALIZATION_BHYVE }, + { "QNXQVMBSQG", VIRTUALIZATION_QNX }, + }; + + uint32_t eax, ebx, ecx, edx; + bool hypervisor; + + /* http://lwn.net/Articles/301888/ */ + + /* First detect whether there is a hypervisor */ + if (__get_cpuid(1, &eax, &ebx, &ecx, &edx) == 0) + return VIRTUALIZATION_NONE; + + hypervisor = ecx & 0x80000000U; + + if (hypervisor) { + union { + uint32_t sig32[3]; + char text[13]; + } sig = {}; + unsigned j; + + /* There is a hypervisor, see what it is */ + __cpuid(0x40000000U, eax, ebx, ecx, edx); + + sig.sig32[0] = ebx; + sig.sig32[1] = ecx; + sig.sig32[2] = edx; + + log_debug("Virtualization found, CPUID=%s", sig.text); + + for (j = 0; j < ELEMENTSOF(cpuid_vendor_table); j ++) + if (streq(sig.text, cpuid_vendor_table[j].cpuid)) + return cpuid_vendor_table[j].id; + + return VIRTUALIZATION_VM_OTHER; + } +#endif + log_debug("No virtualization found in CPUID"); + + return VIRTUALIZATION_NONE; +} + +static int detect_vm_device_tree(void) { +#if defined(__arm__) || defined(__aarch64__) || defined(__powerpc__) || defined(__powerpc64__) + _cleanup_free_ char *hvtype = NULL; + int r; + + r = read_one_line_file("/proc/device-tree/hypervisor/compatible", &hvtype); + if (r == -ENOENT) { + _cleanup_closedir_ DIR *dir = NULL; + struct dirent *dent; + + dir = opendir("/proc/device-tree"); + if (!dir) { + if (errno == ENOENT) { + log_debug_errno(errno, "/proc/device-tree: %m"); + return VIRTUALIZATION_NONE; + } + return -errno; + } + + FOREACH_DIRENT(dent, dir, return -errno) + if (strstr(dent->d_name, "fw-cfg")) { + log_debug("Virtualization QEMU: \"fw-cfg\" present in /proc/device-tree/%s", dent->d_name); + return VIRTUALIZATION_QEMU; + } + + log_debug("No virtualization found in /proc/device-tree/*"); + return VIRTUALIZATION_NONE; + } else if (r < 0) + return r; + + log_debug("Virtualization %s found in /proc/device-tree/hypervisor/compatible", hvtype); + if (streq(hvtype, "linux,kvm")) + return VIRTUALIZATION_KVM; + else if (strstr(hvtype, "xen")) + return VIRTUALIZATION_XEN; + else + return VIRTUALIZATION_VM_OTHER; +#else + log_debug("This platform does not support /proc/device-tree"); + return VIRTUALIZATION_NONE; +#endif +} + +static int detect_vm_dmi(void) { +#if defined(__i386__) || defined(__x86_64__) || defined(__arm__) || defined(__aarch64__) + + static const char *const dmi_vendors[] = { + "/sys/class/dmi/id/product_name", /* Test this before sys_vendor to detect KVM over QEMU */ + "/sys/class/dmi/id/sys_vendor", + "/sys/class/dmi/id/board_vendor", + "/sys/class/dmi/id/bios_vendor" + }; + + static const struct { + const char *vendor; + int id; + } dmi_vendor_table[] = { + { "KVM", VIRTUALIZATION_KVM }, + { "QEMU", VIRTUALIZATION_QEMU }, + /* http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009458 */ + { "VMware", VIRTUALIZATION_VMWARE }, + { "VMW", VIRTUALIZATION_VMWARE }, + { "innotek GmbH", VIRTUALIZATION_ORACLE }, + { "Xen", VIRTUALIZATION_XEN }, + { "Bochs", VIRTUALIZATION_BOCHS }, + { "Parallels", VIRTUALIZATION_PARALLELS }, + /* https://wiki.freebsd.org/bhyve */ + { "BHYVE", VIRTUALIZATION_BHYVE }, + }; + unsigned i; + int r; + + for (i = 0; i < ELEMENTSOF(dmi_vendors); i++) { + _cleanup_free_ char *s = NULL; + unsigned j; + + r = read_one_line_file(dmi_vendors[i], &s); + if (r < 0) { + if (r == -ENOENT) + continue; + + return r; + } + + for (j = 0; j < ELEMENTSOF(dmi_vendor_table); j++) + if (startswith(s, dmi_vendor_table[j].vendor)) { + log_debug("Virtualization %s found in DMI (%s)", s, dmi_vendors[i]); + return dmi_vendor_table[j].id; + } + } +#endif + + log_debug("No virtualization found in DMI"); + + return VIRTUALIZATION_NONE; +} + +static int detect_vm_xen(void) { + + /* Check for Dom0 will be executed later in detect_vm_xen_dom0 + The presence of /proc/xen indicates some form of a Xen domain */ + if (access("/proc/xen", F_OK) < 0) { + log_debug("Virtualization XEN not found, /proc/xen does not exist"); + return VIRTUALIZATION_NONE; + } + + log_debug("Virtualization XEN found (/proc/xen exists)"); + return VIRTUALIZATION_XEN; +} + +#define XENFEAT_dom0 11 /* xen/include/public/features.h */ +#define PATH_FEATURES "/sys/hypervisor/properties/features" +/* Returns -errno, or 0 for domU, or 1 for dom0 */ +static int detect_vm_xen_dom0(void) { + _cleanup_free_ char *domcap = NULL; + char *cap, *i; + int r; + + r = read_one_line_file(PATH_FEATURES, &domcap); + if (r < 0 && r != -ENOENT) + return r; + if (r == 0) { + unsigned long features; + + /* Here, we need to use sscanf() instead of safe_atoul() + * as the string lacks the leading "0x". */ + r = sscanf(domcap, "%lx", &features); + if (r == 1) { + r = !!(features & (1U << XENFEAT_dom0)); + log_debug("Virtualization XEN, found %s with value %08lx, " + "XENFEAT_dom0 (indicating the 'hardware domain') is%s set.", + PATH_FEATURES, features, r ? "" : " not"); + return r; + } + log_debug("Virtualization XEN, found %s, unhandled content '%s'", + PATH_FEATURES, domcap); + } + + r = read_one_line_file("/proc/xen/capabilities", &domcap); + if (r == -ENOENT) { + log_debug("Virtualization XEN because /proc/xen/capabilities does not exist"); + return 0; + } + if (r < 0) + return r; + + i = domcap; + while ((cap = strsep(&i, ","))) + if (streq(cap, "control_d")) + break; + if (!cap) { + log_debug("Virtualization XEN DomU found (/proc/xen/capabilites)"); + return 0; + } + + log_debug("Virtualization XEN Dom0 ignored (/proc/xen/capabilities)"); + return 1; +} + +static int detect_vm_hypervisor(void) { + _cleanup_free_ char *hvtype = NULL; + int r; + + r = read_one_line_file("/sys/hypervisor/type", &hvtype); + if (r == -ENOENT) + return VIRTUALIZATION_NONE; + if (r < 0) + return r; + + log_debug("Virtualization %s found in /sys/hypervisor/type", hvtype); + + if (streq(hvtype, "xen")) + return VIRTUALIZATION_XEN; + else + return VIRTUALIZATION_VM_OTHER; +} + +static int detect_vm_uml(void) { + _cleanup_fclose_ FILE *f = NULL; + int r; + + /* Detect User-Mode Linux by reading /proc/cpuinfo */ + f = fopen("/proc/cpuinfo", "re"); + if (!f) { + if (errno == ENOENT) { + log_debug("/proc/cpuinfo not found, assuming no UML virtualization."); + return VIRTUALIZATION_NONE; + } + return -errno; + } + + for (;;) { + _cleanup_free_ char *line = NULL; + const char *t; + + r = read_line(f, LONG_LINE_MAX, &line); + if (r < 0) + return r; + if (r == 0) + break; + + t = startswith(line, "vendor_id\t: "); + if (t) { + if (startswith(t, "User Mode Linux")) { + log_debug("UML virtualization found in /proc/cpuinfo"); + return VIRTUALIZATION_UML; + } + + break; + } + } + + log_debug("UML virtualization not found in /proc/cpuinfo."); + return VIRTUALIZATION_NONE; +} + +static int detect_vm_zvm(void) { + +#if defined(__s390__) + _cleanup_free_ char *t = NULL; + int r; + + r = get_proc_field("/proc/sysinfo", "VM00 Control Program", WHITESPACE, &t); + if (r == -ENOENT) + return VIRTUALIZATION_NONE; + if (r < 0) + return r; + + log_debug("Virtualization %s found in /proc/sysinfo", t); + if (streq(t, "z/VM")) + return VIRTUALIZATION_ZVM; + else + return VIRTUALIZATION_KVM; +#else + log_debug("This platform does not support /proc/sysinfo"); + return VIRTUALIZATION_NONE; +#endif +} + +/* Returns a short identifier for the various VM implementations */ +int detect_vm(void) { + static thread_local int cached_found = _VIRTUALIZATION_INVALID; + bool other = false; + int r, dmi; + + if (cached_found >= 0) + return cached_found; + + /* We have to use the correct order here: + * + * → First, try to detect Oracle Virtualbox, even if it uses KVM, as well as Xen even if it cloaks as Microsoft + * Hyper-V. + * + * → Second, try to detect from CPUID, this will report KVM for whatever software is used even if info in DMI is + * overwritten. + * + * → Third, try to detect from DMI. */ + + dmi = detect_vm_dmi(); + if (IN_SET(dmi, VIRTUALIZATION_ORACLE, VIRTUALIZATION_XEN)) { + r = dmi; + goto finish; + } + + r = detect_vm_cpuid(); + if (r < 0) + return r; + if (r == VIRTUALIZATION_VM_OTHER) + other = true; + else if (r != VIRTUALIZATION_NONE) + goto finish; + + /* Now, let's get back to DMI */ + if (dmi < 0) + return dmi; + if (dmi == VIRTUALIZATION_VM_OTHER) + other = true; + else if (dmi != VIRTUALIZATION_NONE) { + r = dmi; + goto finish; + } + + /* x86 xen will most likely be detected by cpuid. If not (most likely + * because we're not an x86 guest), then we should try the /proc/xen + * directory next. If that's not found, then we check for the high-level + * hypervisor sysfs file. + */ + + r = detect_vm_xen(); + if (r < 0) + return r; + if (r == VIRTUALIZATION_VM_OTHER) + other = true; + else if (r != VIRTUALIZATION_NONE) + goto finish; + + r = detect_vm_hypervisor(); + if (r < 0) + return r; + if (r == VIRTUALIZATION_VM_OTHER) + other = true; + else if (r != VIRTUALIZATION_NONE) + goto finish; + + r = detect_vm_device_tree(); + if (r < 0) + return r; + if (r == VIRTUALIZATION_VM_OTHER) + other = true; + else if (r != VIRTUALIZATION_NONE) + goto finish; + + r = detect_vm_uml(); + if (r < 0) + return r; + if (r == VIRTUALIZATION_VM_OTHER) + other = true; + else if (r != VIRTUALIZATION_NONE) + goto finish; + + r = detect_vm_zvm(); + if (r < 0) + return r; + +finish: + /* x86 xen Dom0 is detected as XEN in hypervisor and maybe others. + * In order to detect the Dom0 as not virtualization we need to + * double-check it */ + if (r == VIRTUALIZATION_XEN) { + int dom0; + + dom0 = detect_vm_xen_dom0(); + if (dom0 < 0) + return dom0; + if (dom0 > 0) + r = VIRTUALIZATION_NONE; + } else if (r == VIRTUALIZATION_NONE && other) + r = VIRTUALIZATION_VM_OTHER; + + cached_found = r; + log_debug("Found VM virtualization %s", virtualization_to_string(r)); + return r; +} + +int detect_container(void) { + + static const struct { + const char *value; + int id; + } value_table[] = { + { "lxc", VIRTUALIZATION_LXC }, + { "lxc-libvirt", VIRTUALIZATION_LXC_LIBVIRT }, + { "systemd-nspawn", VIRTUALIZATION_SYSTEMD_NSPAWN }, + { "docker", VIRTUALIZATION_DOCKER }, + { "rkt", VIRTUALIZATION_RKT }, + }; + + static thread_local int cached_found = _VIRTUALIZATION_INVALID; + _cleanup_free_ char *m = NULL; + const char *e = NULL; + unsigned j; + int r; + + if (cached_found >= 0) + return cached_found; + + /* /proc/vz exists in container and outside of the container, /proc/bc only outside of the container. */ + if (access("/proc/vz", F_OK) >= 0 && + access("/proc/bc", F_OK) < 0) { + r = VIRTUALIZATION_OPENVZ; + goto finish; + } + + if (getpid_cached() == 1) { + /* If we are PID 1 we can just check our own environment variable, and that's authoritative. */ + + e = getenv("container"); + if (isempty(e)) { + r = VIRTUALIZATION_NONE; + goto finish; + } + + goto translate_name; + } + + /* Otherwise, PID 1 might have dropped this information into a file in /run. This is better than accessing + * /proc/1/environ, since we don't need CAP_SYS_PTRACE for that. */ + r = read_one_line_file("/run/systemd/container", &m); + if (r >= 0) { + e = m; + goto translate_name; + } + if (r != -ENOENT) + return log_debug_errno(r, "Failed to read /run/systemd/container: %m"); + + /* Fallback for cases where PID 1 was not systemd (for example, cases where init=/bin/sh is used. */ + r = getenv_for_pid(1, "container", &m); + if (r > 0) { + e = m; + goto translate_name; + } + if (r < 0) /* This only works if we have CAP_SYS_PTRACE, hence let's better ignore failures here */ + log_debug_errno(r, "Failed to read $container of PID 1, ignoring: %m"); + + /* Interestingly /proc/1/sched actually shows the host's PID for what we see as PID 1. Hence, if the PID shown + * there is not 1, we know we are in a PID namespace. and hence a container. */ + r = read_one_line_file("/proc/1/sched", &m); + if (r >= 0) { + const char *t; + + t = strrchr(m, '('); + if (!t) + return -EIO; + + if (!startswith(t, "(1,")) { + r = VIRTUALIZATION_CONTAINER_OTHER; + goto finish; + } + } else if (r != -ENOENT) + return r; + + /* If that didn't work, give up, assume no container manager. */ + r = VIRTUALIZATION_NONE; + goto finish; + +translate_name: + for (j = 0; j < ELEMENTSOF(value_table); j++) + if (streq(e, value_table[j].value)) { + r = value_table[j].id; + goto finish; + } + + r = VIRTUALIZATION_CONTAINER_OTHER; + +finish: + log_debug("Found container virtualization %s.", virtualization_to_string(r)); + cached_found = r; + return r; +} + +int detect_virtualization(void) { + int r; + + r = detect_container(); + if (r == 0) + r = detect_vm(); + + return r; +} + +static int userns_has_mapping(const char *name) { + _cleanup_fclose_ FILE *f = NULL; + _cleanup_free_ char *buf = NULL; + size_t n_allocated = 0; + ssize_t n; + uint32_t a, b, c; + int r; + + f = fopen(name, "re"); + if (!f) { + log_debug_errno(errno, "Failed to open %s: %m", name); + return errno == ENOENT ? false : -errno; + } + + n = getline(&buf, &n_allocated, f); + if (n < 0) { + if (feof(f)) { + log_debug("%s is empty, we're in an uninitialized user namespace", name); + return true; + } + + return log_debug_errno(errno, "Failed to read %s: %m", name); + } + + r = sscanf(buf, "%"PRIu32" %"PRIu32" %"PRIu32, &a, &b, &c); + if (r < 3) + return log_debug_errno(errno, "Failed to parse %s: %m", name); + + if (a == 0 && b == 0 && c == UINT32_MAX) { + /* The kernel calls mappings_overlap() and does not allow overlaps */ + log_debug("%s has a full 1:1 mapping", name); + return false; + } + + /* Anything else implies that we are in a user namespace */ + log_debug("Mapping found in %s, we're in a user namespace", name); + return true; +} + +int running_in_userns(void) { + _cleanup_free_ char *line = NULL; + int r; + + r = userns_has_mapping("/proc/self/uid_map"); + if (r != 0) + return r; + + r = userns_has_mapping("/proc/self/gid_map"); + if (r != 0) + return r; + + /* "setgroups" file was added in kernel v3.18-rc6-15-g9cc46516dd. It is also + * possible to compile a kernel without CONFIG_USER_NS, in which case "setgroups" + * also does not exist. We cannot distinguish those two cases, so assume that + * we're running on a stripped-down recent kernel, rather than on an old one, + * and if the file is not found, return false. + */ + r = read_one_line_file("/proc/self/setgroups", &line); + if (r < 0) { + log_debug_errno(r, "/proc/self/setgroups: %m"); + return r == -ENOENT ? false : r; + } + + truncate_nl(line); + r = streq(line, "deny"); + /* See user_namespaces(7) for a description of this "setgroups" contents. */ + log_debug("/proc/self/setgroups contains \"%s\", %s user namespace", line, r ? "in" : "not in"); + return r; +} + +int running_in_chroot(void) { + int r; + + if (getenv_bool("SYSTEMD_IGNORE_CHROOT") > 0) + return 0; + + r = files_same("/proc/1/root", "/", 0); + if (r < 0) + return r; + + return r == 0; +} + +static const char *const virtualization_table[_VIRTUALIZATION_MAX] = { + [VIRTUALIZATION_NONE] = "none", + [VIRTUALIZATION_KVM] = "kvm", + [VIRTUALIZATION_QEMU] = "qemu", + [VIRTUALIZATION_BOCHS] = "bochs", + [VIRTUALIZATION_XEN] = "xen", + [VIRTUALIZATION_UML] = "uml", + [VIRTUALIZATION_VMWARE] = "vmware", + [VIRTUALIZATION_ORACLE] = "oracle", + [VIRTUALIZATION_MICROSOFT] = "microsoft", + [VIRTUALIZATION_ZVM] = "zvm", + [VIRTUALIZATION_PARALLELS] = "parallels", + [VIRTUALIZATION_BHYVE] = "bhyve", + [VIRTUALIZATION_QNX] = "qnx", + [VIRTUALIZATION_VM_OTHER] = "vm-other", + + [VIRTUALIZATION_SYSTEMD_NSPAWN] = "systemd-nspawn", + [VIRTUALIZATION_LXC_LIBVIRT] = "lxc-libvirt", + [VIRTUALIZATION_LXC] = "lxc", + [VIRTUALIZATION_OPENVZ] = "openvz", + [VIRTUALIZATION_DOCKER] = "docker", + [VIRTUALIZATION_RKT] = "rkt", + [VIRTUALIZATION_CONTAINER_OTHER] = "container-other", +}; + +DEFINE_STRING_TABLE_LOOKUP(virtualization, int); |