* Location Logging
This document was created by Steven Baltakatei Sandoval on
-<2020-06-29 Mon 12:14> under a [[https://creativecommons.org/licenses/by-sa/4.0/][Creative Commons BY-SA 4.0 license]]. It
-was updated by Steven Baltakatei Sandoval on <2020-06-29 Mon 18:39>.
+~2020-06-29T12:14Z~ under a [[https://creativecommons.org/licenses/by-sa/4.0/][Creative Commons BY-SA 4.0 license]]. It
+was updated by Steven Baltakatei Sandoval on ~2020-06-30T19:44Z~
+#+TITLE: Ninfacyzga-01 Manual
+#+AUTHOR: Steven Baltakatei Sandoval
+#+EMAIL: baltakatei@gmail.com
** Narrative
Ninfacyzga-01 records (logs) its position in time and space using a
[[https://en.wikipedia.org/wiki/Satellite_navigation_device][GPS receiver]]. The NMEA location data produced by the receiver is
the bech32 public key string produced by ~age-keygen~ for convenience.
Help information for ~age~ is available by running ~$ age --help~.
-***** Encryption
+***** Encryption Commands
Files may be encrypted to several recipients using a command similar to:
#+BEGIN_EXAMPLE
timeout "60s" gpspipe -r | gpsbabel -i nmea -f - -o gpx -F | age \
bech32-formatted public key strings.
-***** Decryption
+***** Decryption Commands
Files may be decrypted using a command similar to:
#+BEGIN_EXAMPLE
possible.
**** Software Setup
-
***** Install Executables
Install Raspbian 10 Buster onto an SD card image. See the Raspberry Pi
Place ~age~ binary (the one compiled for ARM CPU architecture for
Linux) in ~$HOME/.local/bin~.
+***** Disable Swap File
+Since standard Raspbian 10 (Buster) install involves copying
+unencrypted file system image to SD card which is mounted by the
+Raspberry Pi, system memory may be written to disk in the form of a
+Swap file as described [[https://ideaheap.com/2013/07/stopping-sd-card-corruption-on-a-raspberry-pi/][here]]. In order to reduce the chance that
+location log data is ever written to disk, swap file functionality
+must be disabled[fn:ideaheap_20130731_disableswap].
+
+Raspbian 10 uses dphys-swapfile to manage a swap file. It may be
+disabled persistently[fn:rpf_20190702_disableswappersist] by running
+the following command:
+
+: sudo systemctl disable dphys-swapfile.service
+
+To view the status of the swap file in Raspbian 10, run ~free -m~:
+
+#+BEGIN_EXAMPLE
+pi@ninfacyzga-01:~$ free -m
+ total used free shared buff/cache available
+Mem: 432 86 36 21 309 268
+Swap: 99 0 99
+#+END_EXAMPLE
+
+After disabling the swap file and rebooting:
+
+#+BEGIN_EXAMPLE
+pi@ninfacyzga-01:~$ free -m
+ total used free shared buff/cache available
+Mem: 432 89 214 3 128 289
+Swap: 0 0 0
+#+END_EXAMPLE
+
+[fn:ideaheap_20130731_disableswap] Explanation:
+https://ideaheap.com/2013/07/stopping-sd-card-corruption-on-a-raspberry-pi/
+
+[fn:rpf_20190702_disableswappersist] Persistant disabling of swap in
+Raspbian 10 Buster:
+https://www.raspberrypi.org/forums/viewtopic.php?p=1490692&sid=5c596a124b7805d6b10dab8d3d7caf16#p1490692
+
***** Automatic Start Configuration
Edit the user cron job list with ~$ crontab -e~ to add the following
lines:
#+BEGIN_EXAMPLE
-0 * * * * /bin/bash /path/to/bkgpslog --output $HOME/Sync/example_dir
+0 * * * * /bin/bash ~/bkgpslog --output ~/dir
-@reboot /bin/bash /path/to/bkgpslog --output $HOME/Sync/example_dir
+@reboot /bin/bash ~/bkgpslog --output ~/dir
#+END_EXAMPLE
-The first line will run ~bkgpslog~ at the start of every hour.
+The first line will run ~bkgpslog~ at the start of every hour and save
+output files to the ~dir~ directory in your home folder.
The second line will run ~bkgpslog~ when the system starts up.
+~/bin/bash~ tells ~cron~ to run ~bkgpslog~ with Bash.
+
+If encryption and compression are required, then the appropriate
+options must be added. The lines that must be added via ~$ crontab -e~
+may resemble:
+
+#+BEGIN_EXAMPLE
+0 * * * * /bin/bash ~/bkgpslog -c -e -r age1z2...qkv6p -o ~/dir
+
+@reboot /bin/bash ~/bkgpslog -c -e -r age1z2...qkv6p -o ~/dir
+#+END_EXAMPLE
+
+The ~age1z2...qkv6p~ is an ~age~ public key string. Please see the
+[[*Key Generation][Key Generation]] section for an explanation.
+
+The options are:
+
+: -c : tells bkgpslog to compress output
+: -e : tells bkgpslog log to encrypt output
+: -r : tells bkgpslog to interpret the next argument as a pubkey string
+: -o : tells bkgpslog to write output files to the directory represented
+: by the next argument
+
***** Log Transfer Configuration
Log files may be shared to other machines via ~syncthing~. See [[https://docs.syncthing.net/][this]]
manual for how to set up a shared folder and add Ninfacyzga-01 as a
#+BEGIN_EXAMPLE
$ umask # Gets current umask
0022 # Note: This is the default umask for Raspbian 10
-$ umask 066 # Sets umask so key.txt will have no permissions except for owner (you)
+$ umask 066 # So key.txt will have no perms except for owner (you)
$ umask # Confirm umask set to 066
0066
$ age-keygen > key.txt
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