Cleanup yum downloading

Using "yum --downloadonly" breaks the abstraction of
"install-packages" because it downloads to the yum cache.  It also
acts funny if the package is already there.

Add an argument to "-d" which is the directory to download to.  dnf
has "download" built in, and for the old case use yumdownloader which
acts about the same.  Ensure it is installed, since it comes in
yum-utils.

Also a slight cleanup of the getopt parsing so it's easier to have the
required argument for -d

Thus we can remove most of the stuff in 15-remove-grub.  The check for
centos6 and it's lack of grub2 is clarified.  All the stuff about
having to remove the package, purging the cache etc so yum gets the
right thing is no longer relevant.  The long section of commented out
code at the end is also removed for clarity.

I tested this with an F21, F22 & centos (6) build

Change-Id: Id1e430e7d050a0b99ac449e2ea435e06cda1c4e6

elements/redhat-common/pre-install.d/15-remove-grub

@@ -5,35 +5,17 @@ fi
 set -eu
 set -o pipefail
 
-GRUBNAME=$(which grub-install) || echo "trying grub2-install"
-if [ -z "$GRUBNAME" ]; then
-    GRUBNAME=$(which grub2-install)
-fi
-if [ -z "$GRUBNAME" ] || [ $($GRUBNAME --version | grep -c "0.97") -ne 0 ]; then
-    echo "No GRUB2 found. No need to remove"
+# grub2 isn't available on rhel6/centos6; they are setup to use
+# extlinux.  skip this
+# you would think we could match on $DISTRO or something else; but
+# we can't because the rhel/centos elements are a bit mixed up;
+# centos-minimal for example sets distro to "centos".  so the best
+# check is just for the original "grub-install" script
+if [ -f /sbin/grub-install ]; then
     exit 0
-else
-# Must manually remove grub2 here, otherwise the download below does not work.
-    yum remove -y grub2
 fi
 
-# Remove all old versions of grub2 from the yum cache and then ensure the
-# latest version is in the cache.
-basearch=$(cat /etc/yum/vars/basearch)
-find /tmp/yum/$basearch -regex ".*/grub2-[0-9].*\.rpm" -exec rm -f {} +
-install-packages -d grub2
-
-# Copy grub2 rpm out of mounted yum cache for install during finalise
-mkdir -p /tmp/grub
-cp $(find /tmp/yum/$basearch -regex ".*/grub2-[0-9].*\.rpm") /tmp/grub
+# download the latest grub2 package and setup the install script which
+# will be called later by vm/finalise.d/51-bootloader
+install-packages -d /tmp/grub grub2
 echo "rpm -i /tmp/grub/*.rpm" > /tmp/grub/install
-
-#GRUB_CFG=/boot/grub2/grub.cfg
-
-#[ -f "$GRUB_CFG" ]
-
-# Update the config to have the search UUID of the image being built.
-# When partition staging is moved to a separate stage, this will need to happen
-# there. This generates a non-UUID config, which is irrelevant for booting with
-# hypervisor kernel + ramdisk, and fixed up by 51-grub for vm images.
-#GRUB_DISABLE_LINUX_UUID=true grub2-mkconfig -o $GRUB_CFG

elements/yum/bin/install-packages

@@ -33,27 +33,37 @@ function show_options () {
     echo
     echo "Options:"
     echo "    -u          -- update all packages"
-    echo "    -d          -- download the packages only"
+    echo "    -d dir      -- download the packages to directory"
     echo "    -e          -- erase/remove packages"
-    echo "    -m          -- use custom element package map (Example: -m nova)"
+    echo "    -m map      -- use custom element package map (Example: -m nova)"
     exit 0
 }
 
-TEMP=$(getopt -o hudem: -n $SCRIPTNAME -- "$@")
-if [ $? != 0 ] ; then echo "Terminating..." >&2 ; exit 1 ; fi
-eval set -- "$TEMP"
-
-while true ; do
-    case "$1" in
-        -u) ${YUM} -y update; exit 0;;
-        -d) EXTRA_ARGS="--downloadonly"; shift;;
-        -e) ACTION="erase"; shift;;
-        -m) MAP_ELEMENT=$2; shift 2;;
-        -h) show_options;;
-        --) shift; break ;;
-        *) echo "Error: unsupported option $1."; exit 1;;
+while getopts "hud:em:" opt; do
+    case "$opt" in
+        u)
+            ${YUM} -y update;
+            exit 0
+            ;;
+        d)
+            ACTION="download"
+            DOWNLOAD_PATH=$OPTARG
+            ;;
+        e)
+            ACTION="erase"
+            ;;
+        m)
+            MAP_ELEMENT=$OPTARG
+            ;;
+        h)
+            show_options
+            ;;
+        *)
+            exit 1
+            ;;
     esac
 done
+shift $((OPTIND-1))
 
 
 # Packages that aren't available in the distro but requested for installation
@@ -87,15 +97,39 @@ if [ -n "$WHITELIST" ]; then
     else
         PKGS=$(map-packages $WHITELIST)
     fi
+
     if [ -z "${PKGS}" ]; then
         echo "Not running install-packages $ACTION with empty packages list"
-    else
+        exit 0
+    fi
+
     echo "Running install-packages ${ACTION}. Package list: $PKGS"
+
+    if [ "$ACTION" == "download" ]; then
+        mkdir -p $DOWNLOAD_PATH
+        if [ ${YUM} == "dnf" ]; then
+            dnf download --destdir=$DOWNLOAD_PATH $PKGS
+        else
+            # note; you don't want to use yum --download only here.
+            # Firstly that only puts things in the yum cache
+            # directory, and secondly it acts funny if old versions
+            # are already in the cache.
+            if [ ! -f /usr/bin/yumdownloader ]; then
+                yum install -y yum-utils
+            fi
+            yumdownloader --destdir=$DOWNLOAD_PATH $PKGS
+        fi
+        exit 0
+    fi
+
     ${YUM} -v -y $ACTION $EXTRA_ARGS $PKGS
+
+    # probably not the right place for this; but python-pip package on
+    # fedora/rh calls pip "pip-python" while the rest of the work
+    # expects it to be just called "pip"
     for pkg in "$@"; do
         if [ "$pkg" = "python-pip" ] ; then
             alternatives --install /usr/bin/pip pip /usr/bin/pip-python 10
         fi
     done
 fi
-fi