Merge pull request #20 from cimryan/u/cimryan/readonlyrootfs

U/cimryan/readonlyrootfs
2026-03-01 04:30:33 +00:00 · 2018-10-16 07:41:52 -07:00
parent 78128464ab 6a3d6f34ae
commit 92f19af357
7 changed files with 263 additions and 81 deletions
--- a/GetShellWithoutMonitorOnWindows.md
+++ b/GetShellWithoutMonitorOnWindows.md
@@ -14,7 +14,7 @@
 1. Run the following commands:
    ```
    cd ~
-    wget https://raw.githubusercontent.com/cimryan/teslausb/master/windows_archive/setup-piForHeadlessConfig.ps1 -OutFile setup-piForHeadlessConfig.ps1
+    wget https://raw.githubusercontent.com/cimryan/teslausb/u/cimryan/readonlyrootfs/windows_archive/setup-piForHeadlessConfig.ps1 -OutFile setup-piForHeadlessConfig.ps1
    ./setup-piForHeadlessConfig.ps1 -Verbose
    ```
 1. Enter the single letter of the "boot" drive and press Enter.
--- a/README.md
+++ b/README.md
@@ -130,7 +130,7 @@ Now that you have a shell on the Pi you can turn the Pi into a smart USB drive.
    ```
 1. Run these commands:
    ```
-    wget https://raw.githubusercontent.com/cimryan/teslausb/master/windows_archive/setup-teslausb
+    wget https://raw.githubusercontent.com/cimryan/teslausb/u/cimryan/readonlyrootfs/windows_archive/setup-teslausb
    chmod +x setup-teslausb
    ./setup-teslausb
    ```
@@ -146,3 +146,17 @@ If you set up the Pi with a keyboard and a monitor disconnect it and connect it
 1. Eject the drives.
 1. Unplug the Pi from the PC.
 1. Plug the Pi into your Tesla.
+
+## Making changes to the system after setup
+The setup process configures the Pi with read-only file systems for the operating system but with read-write access through the USB
+ interface. This means that you'll be able to record dashcam video and add and remove music files but you won't be able to make changes 
+ to files on / or on /boot. This is to protect against corruption of the operating system when the Tesla cuts power to the Pi.
+
+To make changes to the system partitions:
+```
+ssh pi@teslausb.
+sudo -i
+mount / -o remount,rw
+mount /boot -o remount,rw
+```
+Then make whatever changes you need to. The next time the system boots the partitions will once again be read-only.
--- a/windows_archive/create-backingfiles-partition.sh
+++ b/windows_archive/create-backingfiles-partition.sh
@@ -0,0 +1,22 @@
+#!/bin/bash -eu
+
+BACKINGFILES_MOUNTPOINT="$1"
+  
+PARTITION_TABLE=$(parted -m /dev/mmcblk0 unit s print)
+ROOT_PARTITION_LINE=$(echo "$PARTITION_TABLE" | grep -e "^2:")
+LAST_ROOT_PARTITION_SECTOR=$(echo "$ROOT_PARTITION_LINE" | sed 's/s//g' | cut -d ":" -f 3)
+
+FIRST_BACKINGFILES_PARTITION_SECTOR=$(( $LAST_ROOT_PARTITION_SECTOR + 1 ))
+
+ORIGINAL_DISK_IDENTIFIER=$( fdisk -l /dev/mmcblk0 | grep -e "^Disk identifier" | sed "s/Disk identifier: 0x//" )
+
+parted -m /dev/mmcblk0 u s mkpart primary ext4 "$FIRST_BACKINGFILES_PARTITION_SECTOR" 100%
+
+NEW_DISK_IDENTIFIER=$( fdisk -l /dev/mmcblk0 | grep -e "^Disk identifier" | sed "s/Disk identifier: 0x//" )
+
+sed -i "s/${ORIGINAL_DISK_IDENTIFIER}/${NEW_DISK_IDENTIFIER}/g" /etc/fstab
+sed -i "s/${ORIGINAL_DISK_IDENTIFIER}/${NEW_DISK_IDENTIFIER}/" /boot/cmdline.txt
+
+mkfs.ext4 -F /dev/mmcblk0p3
+
+echo "/dev/mmcblk0p3 $BACKINGFILES_MOUNTPOINT ext4 auto,rw,noatime 0 2" >> /etc/fstab
--- a/windows_archive/create-backingfiles.sh
+++ b/windows_archive/create-backingfiles.sh
@@ -0,0 +1,38 @@
+#!/bin/bash -eu
+
+CAM_PERCENT="$1"
+BACKINGFILES_MOUNTPOINT="$2"
+
+G_MASS_STORAGE_CONF_FILE_NAME=/etc/modprobe.d/g_mass_storage.conf
+
+function add_drive () {
+  local name="$1"
+  local label="$2"
+  local size="$3"
+
+  local filename="$4"
+  echo "Allocating ${size}K for $filename..."
+  fallocate -l "$size"K "$filename"
+  mkfs.vfat "$filename" -F 32 -n "$label"
+
+  local mountpoint=/mnt/"$name"
+
+  mkdir "$mountpoint"
+  echo "$filename $mountpoint vfat noauto,users,umask=000 0 0" >> /etc/fstab
+}
+
+FREE_1K_BLOCKS="$(df --output=avail --block-size=1K /backingfiles/ | tail -n 1)"
+
+CAM_DISK_SIZE="$(( $FREE_1K_BLOCKS * $CAM_PERCENT / 100 ))"
+CAM_DISK_FILE_NAME="$BACKINGFILES_MOUNTPOINT/cam_disk.bin"
+add_drive "cam" "CAM" "$CAM_DISK_SIZE" "$CAM_DISK_FILE_NAME"
+
+if [ "$CAM_PERCENT" -lt 100 ]
+then
+  MUSIC_DISK_SIZE="$(df --output=avail --block-size=1K /backingfiles/ | tail -n 1)"
+  MUSIC_DISK_FILE_NAME="$BACKINGFILES_MOUNTPOINT/music_disk.bin"
+  add_drive "music" "MUSIC" "$MUSIC_DISK_SIZE" "$MUSIC_DISK_FILE_NAME"
+  echo "options g_mass_storage file=$CAM_DISK_FILE_NAME,$MUSIC_DISK_FILE_NAME removable=1,1 ro=0,0 stall=0 iSerialNumber=123456" > "$G_MASS_STORAGE_CONF_FILE_NAME"
+else
+  echo "options g_mass_storage file=$CAM_DISK_FILE_NAME removable=1 ro=0 stall=0 iSerialNumber=123456" > "$G_MASS_STORAGE_CONF_FILE_NAME"
+fi
--- a/windows_archive/make-root-fs-readonly.sh
+++ b/windows_archive/make-root-fs-readonly.sh
@@ -0,0 +1,49 @@
+#!/bin/bash
+
+# Adapted from https://github.com/adafruit/Raspberry-Pi-Installer-Scripts/blob/master/read-only-fs.sh
+
+function append_cmdline_txt_param() {
+  local toAppend="$1"
+  sed -i "s/\'/ ${toAppend}/g" /boot/cmdline.txt >/dev/null
+}
+
+echo "Updating package index files..."
+apt-get update
+echo "Removing unwanted packages..."
+apt-get remove -y --force-yes --purge triggerhappy logrotate dphys-swapfile fake-hwclock
+apt-get -y --force-yes autoremove --purge
+# Replace log management with busybox (use logread if needed)
+echo "Installing ntp and busybox-syslogd..."
+apt-get -y --force-yes install ntp busybox-syslogd; dpkg --purge rsyslog
+echo "Configuring system..."
+  
+# Add fastboot, noswap and/or ro to end of /boot/cmdline.txt
+append_cmdline_txt_param fastboot
+append_cmdline_txt_param noswap
+append_cmdline_txt_param ro
+
+# Move /var/spool to /tmp
+rm -rf /var/spool
+ln -s /tmp /var/spool
+
+# Change spool permissions in var.conf (rondie/Margaret fix)
+sed -i "s/spool\s*0755/spool 1777/g" /usr/lib/tmpfiles.d/var.conf >/dev/null
+
+# Move dhcpd.resolv.conf to tmpfs
+touch /tmp/dhcpcd.resolv.conf
+rm /etc/resolv.conf
+ln -s /tmp/dhcpcd.resolv.conf /etc/resolv.conf
+
+# Update /etc/fstab
+# make /boot read-only
+# make / read-only
+# tmpfs /var/log tmpfs nodev,nosuid 0 0
+# tmpfs /var/tmp tmpfs nodev,nosuid 0 0
+# tmpfs /tmp     tmpfs nodev,nosuid 0 0
+sed -i -r "s@(/boot\s+vfat\s+\S+)@\1,ro@" /etc/fstab
+sed -i -r "s@(/\s+ext4\s+\S+)@\1,ro@" /etc/fstab
+echo "" >> /etc/fstab
+echo "tmpfs /var/log tmpfs nodev,nosuid 0 0" >> /etc/fstab
+echo "tmpfs /var/tmp tmpfs nodev,nosuid 0 0" >> /etc/fstab
+echo "tmpfs /tmp    tmpfs nodev,nosuid 0 0" >> /etc/fstab
+
--- a/windows_archive/setup-piForHeadlessConfig.ps1
+++ b/windows_archive/setup-piForHeadlessConfig.ps1
@@ -23,7 +23,7 @@ Write-Verbose "Updating $configPath ..."

 Write-Verbose "Updating $cmdlinePath ..."
 $cmdlinetxtContent = gc -Raw $cmdlinePath
-$cmdlinetxtContent.Replace("rootwait", "rootwait modules-load=dwc2,g_ether") | Out-File -FilePath $cmdlinePath -Encoding utf8
+$cmdlinetxtContent.Replace("rootwait", "rootwait modules-load=dwc2,g_ether").Replace(" init=/usr/lib/raspi-config/init_resize.sh", "") | Out-File -FilePath $cmdlinePath -Encoding utf8

 Write-Verbose "Enabling SSH ..."
 [System.IO.File]::CreateText($sshPath).Dispose()
--- a/windows_archive/setup-teslausb
+++ b/windows_archive/setup-teslausb
@@ -1,6 +1,8 @@
 #!/bin/bash -eu

-if [ "$(whoami)" != "root" ]
+BRANCH=u/cimryan/readonlyrootfs
+
+if ! [ $(id -u) = 0 ]
 then
  echo "STOP: Run sudo -i."
  exit 1
@@ -15,13 +17,9 @@ function check_variable () {
  fi
 }

-check_variable "archiveserver"
-check_variable "sharename"
-check_variable "shareuser"
-check_variable "sharepassword"
-check_variable "campercent"
-
-serverunreachable=false
+function check_archive_server_reachable () {
+  echo "Verifying that the archive server $archiveserver is reachable..."
+  local serverunreachable=false
  ping -c 1 -w 1 "$archiveserver" 1>/dev/null 2>&1 || serverunreachable=true
  
  if [ "$serverunreachable" = true ]
@@ -30,57 +28,87 @@ then
    exit 1
  fi
  
-archiveserverip="$(getent hosts $archiveserver | cut -d' ' -f1)"
+  echo "The archive server is reachable."
+}

-available_space="$(($(df --output=avail / | tail -1) - 1000000))"
+function check_available_space () {
+  echo "Verifying that there is sufficient space available on the MicroSD card..."
  
-if [ "$available_space" -lt 0 ]
+  local available_space="$( parted -m /dev/mmcblk0 u b print free | tail -1 | cut -d ":" -f 4 | sed 's/B//g' )"
+
+  if [ "$available_space" -lt  4294967296 ]
  then
    echo "STOP: The MicroSD card is too small."
    exit 1
  fi
  
-function add_drive () {
-  local name="$1"
-  local label="$2"
-  local size="$3"
-
-  local filename="$4"
-  fallocate -l "$size"K "$filename"
-  mkfs.vfat "$filename" -F 32 -n "$label"
-
-  local mountpoint=/mnt/"$name"
-
-  mkdir "$mountpoint"
-  echo "$filename $mountpoint vfat noauto,users,umask=000 0 0" >> /etc/fstab
+  echo "There is sufficient space available."
 }

-pushd ~
+function get_ancillary_setup_scripts () {
+  pushd /tmp
+  wget https://raw.githubusercontent.com/cimryan/teslausb/"$BRANCH"/windows_archive/create-backingfiles-partition.sh
+  chmod +x ./create-backingfiles-partition.sh
+  wget https://raw.githubusercontent.com/cimryan/teslausb/"$BRANCH"/windows_archive/create-backingfiles.sh
+  chmod +x ./create-backingfiles.sh
+  wget https://raw.githubusercontent.com/cimryan/teslausb/"$BRANCH"/windows_archive/make-root-fs-readonly.sh
+  chmod +x ./make-root-fs-readonly.sh
+  popd
+}

+function fix_cmdline_txt_modules_load () 
+{
+  echo "Fixing the modules-load parameter in /boot/cmdline.txt..."
  cp /boot/cmdline.txt ~
  cat ~/cmdline.txt | sed 's/[[:space:]]\+modules-load=[^ [:space:]]\+//' | sed 's/rootwait/rootwait modules-load=dwc2/' > /boot/cmdline.txt
  rm ~/cmdline.txt
+  echo "Fixed cmdline.txt."
+}

+BACKINGFILES_MOUNTPOINT=/backingfiles
+
+function create_usb_drive_backing_files () {
+  mkdir "$BACKINGFILES_MOUNTPOINT"
+  /tmp/create-backingfiles-partition.sh "$BACKINGFILES_MOUNTPOINT"
+  
+  echo "Mounting the partition for the backing files..."
+  mount /backingfiles
+  echo "Mounted the partition for the backing files."
+  
+  /tmp/create-backingfiles.sh "$campercent" "$BACKINGFILES_MOUNTPOINT" 
+}
+
+function configure_archive () {
+  echo "Configuring the archive..."
  mkdir /mnt/archive
-
-echo "" >> /etc/fstab
-echo "//$archiveserverip/$sharename /mnt/archive cifs vers=3,credentials=/root/.teslaCamArchiveCredentials,iocharset=utf8,file_mode=0777,dir_mode=0777 0" >> /etc/fstab
+  local archive_server_ip_address="$(getent hosts $archiveserver | cut -d' ' -f1)"
+  echo "//$archive_server_ip_address/$sharename /mnt/archive cifs vers=3,credentials=/root/.teslaCamArchiveCredentials,iocharset=utf8,file_mode=0777,dir_mode=0777 0" >> /etc/fstab
  
  echo "username=$shareuser" > /root/.teslaCamArchiveCredentials
  echo "password=$sharepassword" >> /root/.teslaCamArchiveCredentials
+  echo "Configured the archive."
+}

+function configure_archive_scripts () {
+  echo "Configuring the archive scripts..."
  mkdir /root/bin

-wget https://raw.githubusercontent.com/cimryan/teslausb/master/windows_archive/archiveloop
+  pushd ~  
+  wget https://raw.githubusercontent.com/cimryan/teslausb/"$BRANCH"/windows_archive/archiveloop
  sed s/ARCHIVE_HOST_NAME=archiveserver/ARCHIVE_HOST_NAME=$archiveserver/ ~/archiveloop > /root/bin/archiveloop
  rm ~/archiveloop
  chmod +x /root/bin/archiveloop
-
-pushd /root/bin
-wget https://raw.githubusercontent.com/cimryan/teslausb/master/windows_archive/archive-teslacam-clips
-chmod +x archive-teslacam-clips
  popd
  
+  pushd /root/bin
+  wget https://raw.githubusercontent.com/cimryan/teslausb/"$BRANCH"/windows_archive/archive-teslacam-clips
+  chmod +x archive-teslacam-clips
+  popd
+  echo "Configured the archive scripts."
+}
+
+function configure_rc_local () {
+  echo "Configuring /etc/rc.local to run the archive scripts at startup..."
  echo "#!/bin/bash -eu" > ~/rc.local
  tail -n +2 /etc/rc.local | sed '$d' >> ~/rc.local
 cat << 'EOF' >> ~/rc.local
@@ -99,24 +127,55 @@ EOF

  cat ~/rc.local > /etc/rc.local
  rm ~/rc.local
+  echo "Configured rc.local."
+}

-cam_disk_size="$(( $available_space * $campercent / 100 ))"
-cam_disk_file_name="/cam_disk.bin"
-add_drive "cam" "CAM" "$cam_disk_size" "$cam_disk_file_name"
-
-if [ "$campercent" -lt 100 ]
-then
-  musicpercent="$(( 100 - $campercent ))"
-  music_disk_size="$(( $available_space * $musicpercent / 100 ))"
-  music_disk_file_name="/music_disk.bin"
-  add_drive "music" "MUSIC" "$music_disk_size" "$music_disk_file_name"
-  echo "options g_mass_storage file=$cam_disk_file_name,$music_disk_file_name removable=1,1 ro=0,0 stall=0 iSerialNumber=123456" > /etc/modprobe.d/g_mass_storage.conf
-else
-  echo "options g_mass_storage file=$cam_disk_file_name removable=1 ro=0 stall=0 iSerialNumber=123456" > /etc/modprobe.d/g_mass_storage.conf
-fi
+function configure_hostname () {
+  echo "Configuring the hostname..."
  
+  local new_host_name="teslausb"
  cp /etc/hosts ~
-sed s/raspberrypi/teslausb/g ~/hosts > /etc/hosts
+  sed "s/raspberrypi/$new_host_name/g" ~/hosts > /etc/hosts
  
  cp /etc/hostname ~
-sed s/raspberrypi/teslausb/g ~/hostname > /etc/hostname
+  sed "s/raspberrypi/$new_host_name/g" ~/hostname > /etc/hostname
+  echo "Configured the hostname."
+}
+
+function make_root_fs_readonly () {
+  /tmp/make-root-fs-readonly.sh
+}
+
+echo "Verifying environment variables..."
+
+check_variable "archiveserver"
+check_variable "sharename"
+check_variable "shareuser"
+check_variable "sharepassword"
+check_variable "campercent"
+
+check_archive_server_reachable
+
+check_available_space
+
+get_ancillary_setup_scripts
+
+pushd ~
+
+configure_archive_scripts
+
+fix_cmdline_txt_modules_load
+
+echo "" >> /etc/fstab
+
+create_usb_drive_backing_files
+
+configure_archive
+
+configure_rc_local
+
+configure_hostname
+
+make_root_fs_readonly
+
+echo "All done."