1 files changed, 30 insertions, 21 deletions

diff --git a/src/basic/virt.c b/src/basic/virt.c
index 88357a9..0970350 100644
--- a/src/basic/virt.c
+++ b/src/basic/virt.c
@@ -21,6 +21,7 @@
 #include "stat-util.h"
 #include "string-table.h"
 #include "string-util.h"
+#include "uid-range.h"
 #include "virt.h"
 
 enum {
@@ -446,7 +447,7 @@ static Virtualization detect_vm_zvm(void) {
 /* Returns a short identifier for the various VM implementations */
 Virtualization detect_vm(void) {
         static thread_local Virtualization cached_found = _VIRTUALIZATION_INVALID;
-        bool other = false;
+        bool other = false, hyperv = false;
         int xen_dom0 = 0;
         Virtualization v, dmi;
 
@@ -455,12 +456,12 @@ Virtualization detect_vm(void) {
 
         /* We have to use the correct order here:
          *
-         * → First, try to detect Oracle Virtualbox, Amazon EC2 Nitro, Parallels, and Google Compute Engine, even if they use KVM,
-         *   as well as Xen even if it cloaks as Microsoft Hyper-V. Attempt to detect uml at this stage also
-         *   since it runs as a user-process nested inside other VMs. Also check for Xen now, because Xen PV
-         *   mode does not override CPUID when nested inside another hypervisor.
+         * → First, try to detect Oracle Virtualbox, Amazon EC2 Nitro, Parallels, and Google Compute Engine,
+         *   even if they use KVM, as well as Xen, even if it cloaks as Microsoft Hyper-V. Attempt to detect
+         *   UML at this stage too, since it runs as a user-process nested inside other VMs. Also check for
+         *   Xen now, because Xen PV mode does not override CPUID when nested inside another hypervisor.
          *
-         * → Second, try to detect from CPUID, this will report KVM for whatever software is used even if
+         * → 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. */
@@ -503,7 +504,12 @@ Virtualization detect_vm(void) {
         v = detect_vm_cpuid();
         if (v < 0)
                 return v;
-        if (v == VIRTUALIZATION_VM_OTHER)
+        if (v == VIRTUALIZATION_MICROSOFT)
+                /* QEMU sets the CPUID string to hyperv's, in case it provides hyperv enlightenments. Let's
+                 * hence not return Microsoft here but just use the other mechanisms first to make a better
+                 * decision. */
+                hyperv = true;
+        else if (v == VIRTUALIZATION_VM_OTHER)
                 other = true;
         else if (v != VIRTUALIZATION_NONE)
                 goto finish;
@@ -544,8 +550,15 @@ Virtualization detect_vm(void) {
                 return v;
 
 finish:
-        if (v == VIRTUALIZATION_NONE && other)
-                v = VIRTUALIZATION_VM_OTHER;
+        /* None of the checks above gave us a clear answer, hence let's now use fallback logic: if hyperv
+         * enlightenments are available but the VMM wasn't recognized as anything yet, it's probably
+         * Microsoft. */
+        if (v == VIRTUALIZATION_NONE) {
+                if (hyperv)
+                        v = VIRTUALIZATION_MICROSOFT;
+                else if (other)
+                        v = VIRTUALIZATION_VM_OTHER;
+        }
 
         cached_found = v;
         log_debug("Found VM virtualization %s", virtualization_to_string(v));
@@ -818,7 +831,7 @@ Virtualization detect_virtualization(void) {
 
 static int userns_has_mapping(const char *name) {
         _cleanup_fclose_ FILE *f = NULL;
-        uid_t a, b, c;
+        uid_t base, shift, range;
         int r;
 
         f = fopen(name, "re");
@@ -827,26 +840,22 @@ static int userns_has_mapping(const char *name) {
                 return errno == ENOENT ? false : -errno;
         }
 
-        errno = 0;
-        r = fscanf(f, UID_FMT " " UID_FMT " " UID_FMT "\n", &a, &b, &c);
-        if (r == EOF) {
-                if (ferror(f))
-                        return log_debug_errno(errno_or_else(EIO), "Failed to read %s: %m", name);
-
-                log_debug("%s is empty, we're in an uninitialized user namespace", name);
+        r = uid_map_read_one(f, &base, &shift, &range);
+        if (r == -ENOMSG) {
+                log_debug("%s is empty, we're in an uninitialized user namespace.", name);
                 return true;
         }
-        if (r != 3)
-                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG), "Failed to parse %s: %m", name);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to read %s: %m", name);
 
-        if (a == 0 && b == 0 && c == UINT32_MAX) {
+        if (base == 0 && shift == 0 && range == 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);
+        log_debug("Mapping found in %s, we're in a user namespace.", name);
         return true;
 }