misternfs/nfs_mount.sh

294 lines
8.0 KiB
Bash
Executable File

#!/usr/bin/env bash
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# Copyright 2022 Oliver "RealLarry" Jaksch
# You can download the latest version of this script from:
# https://github.com/MiSTer-devel/CIFS_MiSTer
# Version 1.1 - 2022-12-25 - Cosmetics
# Version 1.0 - 2021-12-29 - First commit
#========= USER OPTIONS =========
# You can edit these user options or make an ini file with the same
# name as the script, i.e. nfs_mount.ini, containing the same options.
# Your NFS Server, i.e. your NAS name or it's IP address.
SERVER=""
# The path to mount from your NFS server, for example "/storage/games"
SERVER_PATH=""
# The number of seconds to wait before considering the server unreachable
SERVER_TIMEOUT="60"
# Wake up the server from above by using WOL (Wake On LAN)
WOL="no"
MAC="FFFFFFFFFFFF"
SERVER_MAC="00:11:22:33:44:55"
# Optional additional mount options.
MOUNT_OPTIONS="noatime"
# "yes" for automounting NFS shares at boot time;
# it will create start/kill scripts in /etc/network/if-up.d and /etc/network/if-down.d.
MOUNT_AT_BOOT="yes"
#=========NO USER-SERVICEABLE PARTS BELOW THIS LINE=====
#=========FUNCTION LIBRARY==============================
# Are we running as root?
function as_root() {
if [ "$(id -u)" != "0" ]; then
/usr/bin/logger "This script must be run as root. Please run again with sudo or as root user. Exiting."
exit 1
fi
}
# Check for existing NFS mounts
function no_existing_nfs() {
if mount | grep -q nfs; then
/usr/bin/logger "Found mounted NFS filesystems. Aborting."
exit 1
fi
}
# Load script configuration from an INI file.
# ..which isn't really an INI file but just a list of Bash vars
function load_ini() {
local SCRIPT_PATH="$(realpath "$0")"
local INI_FILE=${SCRIPT_PATH%.*}.ini
if [ -e "$INI_FILE" ]; then
eval "$(cat $INI_FILE | tr -d '\r')"
fi
}
# Check if we have an IPv4 address on any of the interfaces that is
# not a local loopback (127.0.0.0/8) or link-local (169.254.0.0/16) adddress.
function has_ip_address() {
local start_time=$(date +%s)
while [[ $(($(date +%s) - $start_time)) -lt 30 ]]; do
ip addr show | grep 'inet ' | grep -vE '127.|169.254.' >/dev/null 2>&1
if [[ $? -eq 0 ]]; then
return 0
fi
sleep 1
done
/usr/bin/logger "Failed to obtain an IP address within the time limit. Exiting."
exit 1
}
# Check if the script's configuration is minimally viable
function viable_config() {
if [ -z "$SERVER" ] || [ -z "$SERVER_PATH" ]; then
/usr/bin/logger "SERVER and SERVER_PATH must be set. Exiting."
exit 1
fi
}
# Wake-up the NFS server using WOL
function wake_up_nfs() {
if [ "${WOL}" == "yes" ]; then
for REP in {1..16}; do
MAC+=$(echo ${SERVER_MAC})
done
echo -n "${MAC}" | xxd -r -u -p | socat - UDP-DATAGRAM:255.255.255.255:9,broadcast
fi
}
# Wait for the NFS server to be up
function wait_for_nfs() {
local PORTS=(2049 111)
local START=$(date +%s)
local ELAPSED=0
while [ $ELAPSED -lt $SERVER_TIMEOUT ]; do
for PORT in "${PORTS[@]}"; do
if nc -z "$SERVER" "$PORT" >/dev/null 2>&1; then
/usr/bin/logger "NFS server $SERVER is up."
return 0
fi
done
sleep 1
ELAPSED=$(($(date +%s) - $START))
done
/usr/bin/logger "Timeout while waiting for NFS server $SERVER."
exit 1
}
# Install the mount-at-boot scripts
function install_mount_at_boot() {
# Enable strict error checking
set -euo pipefail
# Check if MOUNT_AT_BOOT is set to "yes"
if [ "${MOUNT_AT_BOOT:-}" != "yes" ]; then
return 0
fi
# Remount root filesystem read-write if it's currently read-only
if mount | grep -q "on / .*[(,]ro[,$]"; then
mount -o remount,rw /
readonly ROOTFS_REMOUNTED="yes"
fi
# Set up scripts to run on network interface up/down events
SCRIPT_PATH="$(realpath "$0")"
SCRIPT_NAME="$(basename "${SCRIPT_PATH%.*}")"
NET_UP_SCRIPT="/etc/network/if-up.d/${SCRIPT_NAME}"
NET_DOWN_SCRIPT="/etc/network/if-down.d/${SCRIPT_NAME}"
# Ensure directories for scripts exist and have appropriate permissions
mkdir -p /etc/network/if-up.d /etc/network/if-down.d
chmod 755 /etc/network /etc/network/if-up.d /etc/network/if-down.d
# Create network interface up script
cat >"${NET_UP_SCRIPT}" <<EOF
#!/bin/bash
${SCRIPT_PATH} &
EOF
chmod 755 "${NET_UP_SCRIPT}"
# Create network interface down script
cat >"${NET_DOWN_SCRIPT}" <<EOF
#!/bin/bash
umount -a -t nfs4
EOF
chmod 755 "${NET_DOWN_SCRIPT}"
# Remount root filesystem read-only if it was remounted earlier
if [ "${ROOTFS_REMOUNTED:-}" == "yes" ]; then
mount -o remount,ro /
fi
return 0
}
# Remove the mount-at-boot script
function remove_mount_at_boot() {
RO_ROOT="no"
if [ "${MOUNT_AT_BOOT}" != "yes" ]; then
local ORIGINAL_SCRIPT_PATH="$0"
local NET_UP_SCRIPT="/etc/network/if-up.d/$(basename ${ORIGINAL_SCRIPT_PATH%.*})"
local NET_DOWN_SCRIPT="/etc/network/if-down.d/$(basename ${ORIGINAL_SCRIPT_PATH%.*})"
# We need to write to the root filesystem so remount it
# read-write if it's currently read-only.
if mount | grep -q "on / .*[(,]ro[,$]"; then
RO_ROOT="yes"
mount / -o remount,rw
fi
if [ -f "${NET_UP_SCRIPT}" ]; then
rm "${NET_UP_SCRIPT}"
fi
if [ -f "${NET_DOWN_SCRIPT}" ]; then
rm "${NET_DOWN_SCRIPT}"
fi
sync
# If we remounted the rootfs because it was read-only, we now
# undo our remount action and revert the mount to how we found it.
if [ "${RO_ROOT}" == "yes" ]; then
mount / -o remount,ro
fi
return 0
fi
}
# Perform the actual mount operation supporting only NFSv4 for now
function mount_nfs() {
set -e
local ORIGINAL_SCRIPT_PATH="$0"
local SCRIPT_NAME="${ORIGINAL_SCRIPT_PATH##*/}"
SCRIPT_NAME="${SCRIPT_NAME%.*}"
if ! mkdir -p "/tmp/${SCRIPT_NAME}" >/dev/null 2>&1; then
/usr/bin/logger "Error: failed to create directory /tmp/${SCRIPT_NAME}"
exit 1
fi
if ! /usr/bin/busybox mount -t nfs4 "${SERVER}:${SERVER_PATH}" "/tmp/${SCRIPT_NAME}" -o "${MOUNT_OPTIONS}"; then
/usr/bin/logger "Error: failed to mount NFS share ${SERVER}:${SERVER_PATH} to /tmp/${SCRIPT_NAME}"
exit 1
fi
find "/tmp/${SCRIPT_NAME}" -mindepth 1 -maxdepth 1 -type d | while read -r LDIR; do
LDIR="${LDIR##*/}"
if [ -d "/media/fat/${LDIR}" ] && ! mount | grep -qx "/media/fat/${LDIR}"; then
if ! mount -o bind "/tmp/${SCRIPT_NAME}/${LDIR}" "/media/fat/${LDIR}"; then
/usr/bin/logger "Error: failed to mount directory /tmp/${SCRIPT_NAME}/${LDIR} to /media/fat/${LDIR}"
exit 1
fi
fi
done
}
#=========BUSINESS LOGIC================================
#
# This part just calls the functions we define above
# in a sequence. To keep things excruciatingly easy
# to follow, any and all config checks are done *inside*
# the functions themselves.
#
# Each of these steps will exit if things are not OK.
#
#=======================================================
# Ensure we are the root user
as_root
# Load configuration from the .ini file if we have one.
load_ini
# Only cause changes if the configuration is viable..
viable_config
# ..and our network seems to be working.
has_ip_address
# We wake up the NFS-server if needed
wake_up_nfs
# ..and give it time to actually get dressed.
wait_for_nfs
# Install/update the scripts to run at every reboot
install_mount_at_boot
# ..or remove them if that's what the user wants.
remove_mount_at_boot
# Only ensure we haven't already got NFS filesystems present
no_existing_nfs
# Finally, we mount the NFS filesystem and be done with it.
mount_nfs
exit 0