Fix package name encoding issues in apt_get_download

Replace direct `apt-get download` with curl approach to handle package names
containing special characters. The `apt-get download` command encodes special
characters in package names but doesn't decode them when saving files to disk,
causing filename issues. This change uses `apt-get --print-uris` to get the
download URL, then uses `curl -fLJO` to download with proper filename handling.

Signed-off-by: Suraj Deshmukh <suraj.deshmukh@microsoft.com>

Author: surajssd

parts/linux/cloud-init/artifacts/cse_helpers.sh

@@ -517,14 +517,24 @@ apt_get_download() {
   retries=$1; wait_sleep=$2; shift && shift;
   local ret=0
   pushd $APT_CACHE_DIR || return 1
-  for i in $(seq 1 $retries); do
+  for i in $(seq 1 "$retries"); do
     dpkg --configure -a --force-confdef
     wait_for_apt_locks
-    apt-get -o Dpkg::Options::=--force-confold download -y "${@}" && break
-    if [ $i -eq $retries ]; then ret=1; else sleep $wait_sleep; fi
+
+    # Pull the first quoted URL from --print-uris
+    url="$(apt-get --print-uris -o Dpkg::Options::=--force-confold download -y -- "$@" \
+           | awk -F"'" 'NR==1 && $2 {print $2}')"
+    if [ -n "$url" ]; then
+      # This avoids issues with the naming in the package. `apt-get download`
+      # encodes the package names with special characters and does not decode
+      # them when saving to disk, but `curl -J` handles the names correctly.
+      if curl -fLJO -- "$url"; then ret=0; break; fi
+    fi
+
+    if [ "$i" -eq "$retries" ]; then ret=1; else sleep "$wait_sleep"; fi
   done
   popd || return 1
-  return $ret
+  return "$ret"
 }
 
 getCPUArch() {

parts/linux/cloud-init/artifacts/ubuntu/cse_install_ubuntu.sh

@@ -193,7 +193,9 @@ downloadPkgFromVersion() {
     downloadDir="${3:-"/opt/${packageName}/downloads"}"
     mkdir -p ${downloadDir}
     apt_get_download 20 30 ${packageName}=${packageVersion} || exit $ERR_APT_INSTALL_TIMEOUT
-    cp -al ${APT_CACHE_DIR}${packageName}_${packageVersion}* ${downloadDir}/ || exit $ERR_APT_INSTALL_TIMEOUT
+    # Strip epoch (e.g., 1:4.4.1-1 -> 4.4.1-1)
+    version_no_epoch="${packageVersion#*:}"
+    cp -al "${APT_CACHE_DIR}/${packageName}_${version_no_epoch}"* "${downloadDir}/" || exit $ERR_APT_INSTALL_TIMEOUT
     echo "Succeeded to download ${packageName} version ${packageVersion}"
 }