Disallow use of unset variables

[virt-what.git] / virt-what.in

diff --git a/virt-what.in b/virt-what.in
index a0f7406..d62f7c8 100644 (file)
--- a/virt-what.in
+++ b/virt-what.in
@@ -26,6 +26,11 @@
 # The following resources were useful in writing this script:
 # . http://www.dmo.ca/blog/20080530151107
 
+# Do not allow unset variables, and set defaults.
+set -u
+root=''
+skip_qemu_kvm=false
+
 VERSION="@VERSION@"
 
 function fail {
@@ -43,7 +48,7 @@ function usage {
 
 # Handle the command line arguments, if any.
 
-TEMP=`getopt -o v --long help --long version --long test-root: -n 'virt-what' -- "$@"`
+TEMP=$(getopt -o v --long help --long version --long test-root: -n 'virt-what' -- "$@")
 if [ $? != 0 ]; then exit 1; fi
 eval set -- "$TEMP"
 
@@ -78,11 +83,19 @@ fi
 # Many fullvirt hypervisors give an indication through CPUID.  Use the
 # helper program to get this information.
 
-cpuid=`virt-what-cpuid-helper`
+cpuid=$(virt-what-cpuid-helper)
 
 # Check for various products in the BIOS information.
+# Note that dmidecode doesn't exist on non-PC architectures.  On these,
+# this will return an error which is ignored (error message redirected
+# into $dmi variable).
+
+dmi=$(LANG=C dmidecode 2>&1)
+
+# Architecture.
+# Note for the purpose of testing, we only call uname with -p option.
 
-dmi=`LANG=C dmidecode 2>&1`
+arch=$(uname -p)
 
 # Check for VMware.
 # cpuid check added by Chetan Loke.
@@ -100,8 +113,10 @@ if [ "$cpuid" = "Microsoft Hv" ]; then
 fi
 
 # Check for VirtualPC.
-
-if echo "$dmi" | grep -q 'Manufacturer: Microsoft Corporation'; then
+# The negative check for cpuid is to distinguish this from Hyper-V
+# which also has the same manufacturer string in the SM-BIOS data.
+if [ "$cpuid" != "Microsoft Hv" ] &&
+    echo "$dmi" | grep -q 'Manufacturer: Microsoft Corporation'; then
     echo virtualpc
 fi
 
@@ -161,13 +176,14 @@ fi
 # Check for Parallels.
 if echo "$dmi" | grep -q 'Vendor: Parallels'; then
     echo parallels
+    skip_qemu_kvm=true
 fi
 
 # Check for Xen.
 
 if [ "$cpuid" = "XenVMMXenVMM" ]; then
     echo xen; echo xen-hvm
-    is_xen=1
+    skip_qemu_kvm=true
 elif [ -f $root/proc/xen/capabilities ]; then
     echo xen
     if grep -q "control_d" $root/proc/xen/capabilities; then
@@ -175,25 +191,46 @@ elif [ -f $root/proc/xen/capabilities ]; then
     else
         echo xen-domU
     fi
-    is_xen=1
+    skip_qemu_kvm=true
 elif [ -f $root/sys/hypervisor/type ] &&
     grep -q "xen" $root/sys/hypervisor/type; then
     # Ordinary kernel with pv_ops.  There does not seem to be
     # enough information at present to tell whether this is dom0
     # or domU.  XXX
     echo xen
+elif [ "$arch" = "ia64" ]; then
+    if [ -d $root/sys/bus/xen -a ! -d $root/sys/bus/xen-backend ]; then
+        # PV-on-HVM drivers installed in a Xen guest.
+        echo xen
+        echo xen-hvm
+    else
+        # There is no virt leaf on IA64 HVM.  This is a last-ditch
+        # attempt to detect something is virtualized by using a
+        # timing attack.
+        virt-what-ia64-xen-rdtsc-test > /dev/null 2>&1
+        case "$?" in
+            0) ;; # not virtual
+            1) # Could be some sort of virt, or could just be a bit slow.
+                echo virt
+        esac
+    fi
 fi
 
 # Check for QEMU/KVM.
+#
+# Parallels exports KVMKVMKVM leaf, so skip this test if we've already
+# seen that it's Parallels.  Xen uses QEMU as the device model, so
+# skip this test if we know it is Xen.
 
-if [ ! "$is_xen" ]; then
-    # Disable this test if we know this is Xen already, because Xen
-    # uses QEMU for its device model.
-
-    if grep -q 'QEMU' $root/proc/cpuinfo; then
-       if [ "$cpuid" = "KVMKVMKVM" ]; then
-           echo kvm
-       else
+if ! $skip_qemu_kvm; then
+    if [ "$cpuid" = "KVMKVMKVM" ]; then
+       echo kvm
+    else
+        # XXX This is known to fail for qemu with the explicit -cpu
+        # option, since /proc/cpuinfo will not contain the QEMU
+        # string.  The long term fix for this would be to export
+        # another CPUID leaf for non-accelerated qemu.
+        if grep -q 'QEMU' $root/proc/cpuinfo; then
            echo qemu
        fi
     fi