Refactor TBB firefox start into exec_firefox() library function.

That way one only has to remember to always call firefox with
exec_firefox(), and not to set LD_LIBRARY_PATH. As an example, this
was forgotten for Tor Launcher, which also was fixed.

config/chroot_local-includes/usr/bin/tor-launcher

@@ -2,7 +2,7 @@
 
 set -e
 
-# Import the TBB_INSTALL variable
+# Import exec_firefox()
 . /usr/local/lib/tails-shell-library/tor-browser.sh
 
 # The Tor Browser hardcodes the default profile dir to ../.. from the
@@ -27,4 +27,4 @@ EOF
     ln -s /var/lib/tails-user-session/browser-locale.js \
           "${HOME}"/.tor-launcher/TorBrowser/Data/Browser/profile.default/preferences/locale.js
 fi
-exec "${TBB_INSTALL}"/Browser/firefox --app "${HOME}"/.tor-launcher/tor-launcher-standalone/application.ini
+exec_firefox -app "${HOME}"/.tor-launcher/tor-launcher-standalone/application.ini

config/chroot_local-includes/usr/local/bin/tor-browser

@@ -11,7 +11,7 @@ export TEXTDOMAIN
 
 PROFILE="${HOME}/.tor-browser/profile.default"
 
-# Import the TBB_INSTALL variable
+# Import exec_firefox()
 . /usr/local/lib/tails-shell-library/tor-browser.sh
 
 ask_for_confirmation() {
@@ -43,10 +43,7 @@ start_browser() {
 
     unset SESSION_MANAGER
 
-    LD_LIBRARY_PATH="${TBB_INSTALL}"/Browser
-    export LD_LIBRARY_PATH
-
-    exec "${TBB_INSTALL}"/Browser/firefox -allow-remote --class "Tor Browser" -profile "${PROFILE}" "${@}"
+    exec_firefox -allow-remote --class "Tor Browser" -profile "${PROFILE}" "${@}"
 }
 
 

config/chroot_local-includes/usr/local/lib/tails-shell-library/tor-browser.sh

@@ -3,3 +3,9 @@
 TBB_INSTALL=/usr/local/lib/tor-browser
 TBB_PROFILE=/etc/tor-browser/profile
 TBB_EXT="${TBB_INSTALL}/extensions"
+
+exec_firefox() {
+    LD_LIBRARY_PATH="${TBB_INSTALL}"/Browser
+    export LD_LIBRARY_PATH
+    exec "${TBB_INSTALL}"/Browser/firefox "${@}"
+}

config/chroot_local-includes/usr/local/sbin/unsafe-browser

@@ -214,7 +214,10 @@ run_browser_in_chroot () {
     echo "* Starting Unsafe Browser"
 
     sudo -u ${SUDO_USER} xhost +SI:localuser:${CLEARNET_USER} 2>/dev/null
-    chroot ${CHROOT} sudo -u ${CLEARNET_USER} LD_LIBRARY_PATH="${TBB_INSTALL}"/Browser "${TBB_INSTALL}"/Browser/firefox -DISPLAY=:0.0 -profile /home/clearnet/.tor-browser/profile.default
+    chroot ${CHROOT} sudo -u ${CLEARNET_USER} /bin/sh -c \
+        '. /usr/local/lib/tails-shell-library/tor-browser.sh && \
+         exec_firefox -DISPLAY=:0.0 \
+                      -profile /home/clearnet/.tor-browser/profile.default'
     sudo -u ${SUDO_USER} xhost -SI:localuser:${CLEARNET_USER} 2>/dev/null
 }