add a rootfs overlay, drop to sh on exit

apps/proxy42_firmware/config/config.exs

@@ -9,8 +9,9 @@ use Mix.Config
 # to add files to the root filesystem or modify the firmware
 # archive.
 
-# config :nerves, :firmware,
-#   rootfs_additions: "config/rootfs_additions",
+
+ config :nerves, :firmware,
+   rootfs_overlay: "rootfs_overlay"
 #   fwup_conf: "config/fwup.conf"
 
 # Import target specific config. This must remain at the bottom
@@ -22,3 +23,4 @@ use Mix.Config
 config :bootloader,
   init: [:nerves_runtime],
   app: :proxy42_firmware
+

apps/proxy42_firmware/rootfs_overlay/etc/erlinit.config

@@ -0,0 +1,40 @@
+# Additional configuration for erlinit
+
+# Turn on the debug prints
+#-v
+
+# Specify the UART port that the shell should use.
+-c tty1
+
+# If more than one tty are available, always warn if the user is looking at
+# the wrong one.
+--warn-unused-tty
+
+# Use dtach to capture the iex session so that it can be redirected
+# to the app's GUI
+#-s "/usr/bin/dtach -N /tmp/iex_prompt"
+
+# Specify the user and group IDs for the Erlang VM
+#--uid 100
+#--gid 200
+
+# Uncomment to hang the board rather than rebooting when Erlang exits
+#--hang-on-exit
+
+# Optionally run a program if the Erlang VM exits
+--run-on-exit /bin/sh
+
+# Enable UTF-8 filename handling in Erlang and custom inet configuration
+-e LANG=en_US.UTF-8;LANGUAGE=en;ERL_INETRC=/etc/erl_inetrc
+
+# Mount the application partition
+# See http://www.linuxfromscratch.org/lfs/view/6.3/chapter08/fstab.html about
+# ignoring warning the Linux kernel warning about using UTF8 with vfat.
+-m /dev/mmcblk0p3:/root:vfat::
+
+# Erlang release search path
+-r /srv/erlang
+
+# Assign a unique hostname based on the board id
+-d "/usr/bin/boardid -b rpi -n 4"
+-n nerves-%.4s