diff --git a/usr/libexec/security-misc/apt-get-update b/usr/libexec/security-misc/apt-get-update
index 3086e55..fecfe4f 100755
--- a/usr/libexec/security-misc/apt-get-update
+++ b/usr/libexec/security-misc/apt-get-update
@@ -4,10 +4,10 @@
 ## See the file COPYING for copying conditions.
 
 write_pid_file() {
-  safe-rm -rf /tmp/security-misc-apt-get-update-pid;
-  install -m644 /dev/null /tmp/security-misc-apt-get-update-pid \
-     || exit 1
-  echo "$$" > /tmp/security-misc-apt-get-update-pid
+  [[ -z "${TMP:-}" ]] && error "TMP is unset"
+  safe-rm -rf "$TMP/security-misc-apt-get-update-pid";
+  install -m644 /dev/null "$TMP/security-misc-apt-get-update-pid" || exit 1
+  echo "$$" | sponge -- "$TMP/security-misc-apt-get-update-pid"
 }
 
 sigterm_trap() {