Restart Tor if bootstrapping stalls for more than 20 seconds

Will-fix: #9516

config/chroot_local-includes/etc/NetworkManager/dispatcher.d/20-time.sh

@@ -175,7 +175,7 @@ maybe_set_time_from_tor_consensus() {
 	date -us "${vmid}" 1>/dev/null
 
 	# Tor is unreliable with picking a circuit after time change
-	restart-tor
+	service tor restart
 }
 
 tor_cert_valid_after() {

config/chroot_local-includes/usr/local/sbin/restart-tor

@@ -2,13 +2,52 @@
 
 set -e
 
+# Import try_for()
+. /usr/local/lib/tails-shell-library/common.sh
+
+# Import tor_bootstrap_progress()
+. /usr/local/lib/tails-shell-library/tor.sh
+
+# The Tor log is removed to ensure `tor_bootstrap_progress`'s output will be
+# accurate.
+clear_tor_log() {
+   rm -f /var/log/tor/log
+}
+
+clear_tor_log
 service tor restart
 
-# The main point of this script is to make sure that if vidalia is
-# running, and Tor is restarted, then we also restart Vidalia. This is
-# because Vidalia doesn't re-connect to Tor automatically, so the user
-# has to restart it to be able to control Tor again. Also, any options
-# set by Vidalia will be lost since they weren't written to torrc.
+# There are two main points to this script:
+#   * restarting Tor if bootstrapping stalls for more than 20 seconds
+#   * making sure that if vidalia is running it is restarted if Tor is restarted.
+#     This is needed because Vidalia doesn't re-connect to Tor automatically,
+#     so the user has to restart it to be able to control Tor again. Also, any
+#     options  set by Vidalia will be lost since they weren't written to torrc.
+
+bootstrap_progress=0
+last_bootstrap_change=$(date +%s)
+
+maybe_restart_tor() {
+  local new_bootstrap_progress=$(tor_bootstrap_progress)
+  if [ $new_bootstrap_progress -eq 100 ]; then
+      return 0
+  elif [ $new_bootstrap_progress -gt $bootstrap_progress ]; then
+     bootstrap_progress=$new_bootstrap_progress
+     last_bootstrap_change=$(date +%s)
+     return 1
+  elif [ $(expr $(date +%s) - $last_bootstrap_change) -ge 20 ]; then
+     clear_tor_log
+     service tor restart
+     bootstrap_progress=0
+     last_bootstrap_change=$(date +%s)
+     return 1
+  else
+     return 1
+  fi
+}
+
+try_for 270 maybe_restart_tor
+
 if pgrep "\<vidalia\>" >/dev/null; then
     killall -SIGKILL vidalia
     # Since Tor just restarted we wait for a while until the