Bug#844339: [PATCH v3 3/4] libvirt-daemon-system.postinst: use allocated uid/gid if possible

Use the allocated uid/gid for libvirt-qemu
when creating the user/group, if not taken.

In case it's taken, the user has been asked
to continue or abort the installation, thus
if we are here, it is OK to proceed and not
use the allocated uid/gid.

Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Signed-off-by: Guido Günther <agx@sigxcpu.org>

debian/libvirt-daemon-system.postinst

@@ -20,6 +20,10 @@ set -e
 # Source debconf library.
 . /usr/share/debconf/confmodule
 
+# Allocated UID and GID for libvirt-qemu
+LIBVIRT_QEMU_UID=64055
+LIBVIRT_QEMU_GID=64055
+
 add_users_groups()
 {
     if ! getent group libvirt >/dev/null; then
@@ -31,6 +35,13 @@ add_users_groups()
     fi
     # user and group libvirt runs qemu/kvm instances with
     if ! getent passwd libvirt-qemu >/dev/null; then
+
+        # set uid if available (expected); don't fail otherwise.
+        PARAMETER_UID=''
+        if ! getent passwd $LIBVIRT_QEMU_UID >/dev/null; then
+            PARAMETER_UID="--uid $LIBVIRT_QEMU_UID"
+        fi
+
         adduser --quiet \
             --system \
             --ingroup kvm \
@@ -40,10 +51,18 @@ add_users_groups()
             --home /var/lib/libvirt \
             --no-create-home \
             --gecos "Libvirt Qemu" \
+            $PARAMETER_UID \
             libvirt-qemu
     fi
     if ! getent group libvirt-qemu >/dev/null; then
-        addgroup --quiet --system libvirt-qemu
+
+        # set gid if available (expected); don't fail otherwise.
+        PARAMETER_GID=''
+        if ! getent group $LIBVIRT_QEMU_GID >/dev/null; then
+            PARAMETER_GID="--gid $LIBVIRT_QEMU_GID"
+        fi
+
+        addgroup --quiet --system $PARAMETER_GID libvirt-qemu
         adduser --quiet libvirt-qemu libvirt-qemu
     fi
 }