#!/bin/sh

PROGNAME="$(basename $0)"

# ============================================================================

# ENV

# ============================================================================

CONFIGFS_ROOT="/config"

GADGET_DIR="$CONFIGFS_ROOT/usb_gadget/g1"

CONFIG_DIR="$GADGET_DIR/configs/b.1"

FUNCTION_DIR="$GADGET_DIR/functions"

UDC_CONTROL="$GADGET_DIR/UDC"

UDC_ENABLE="$(ls /sys/class/udc)"

UDC_DISABLE=""

# "charging_only"

FUNCTION_MASS_STORAGE="mass_storage.usb0"

# "developer_mode"

FUNCTION_RNDIS="rndis_bam.rndis"

# "mtp_mode"

FUNCTION_MTP="ffs.mtp"

# ============================================================================

# LOG

# ============================================================================

LOG_LEVEL=6

log_critical() { test $LOG_LEVEL -ge 2 && echo >&2 "$PROGNAME: C: $*" ; }

log_error() { test $LOG_LEVEL -ge 3 && echo >&2 "$PROGNAME: E: $*" ; }

log_warning() { test $LOG_LEVEL -ge 4 && echo >&2 "$PROGNAME: W: $*" ; }

log_notice() { test $LOG_LEVEL -ge 5 && echo >&2 "$PROGNAME: N: $*" ; }

log_info() { test $LOG_LEVEL -ge 6 && echo >&2 "$PROGNAME: I: $*" ; }

log_debug() { test $LOG_LEVEL -ge 7 && echo >&2 "$PROGNAME: D: $*" ; }

# ============================================================================

# CONFIGFS

# ============================================================================

configfs_validate() {

log_debug "Validate ConfigFS mountpoint"

mountpoint -q $CONFIGFS_ROOT || exit 1

test -d "$GADGET_DIR" || exit 1

test -f "$UDC_CONTROL" || exit 1

test -d "$CONFIG_DIR" || exit 1

test -d "$FUNCTION_DIR" || exit 1

}

# ============================================================================

# UDC

# ============================================================================

udc_control() {

local prev="$(cat $UDC_CONTROL)"

local next="$1"

if [ "$prev" != "$next" ]; then

echo > "$UDC_CONTROL" "$next"

fi

}

udc_disable() {

log_debug "Disable UDC"

udc_control "$UDC_DISABLE"

}

udc_enable() {

log_debug "Enable UDC"

udc_control "$UDC_ENABLE"

}

# ============================================================================

# FUNCTION

# ============================================================================

function_register() {

log_debug "Register function: $1"

test -d "$FUNCTION_DIR/$1" || mkdir "$FUNCTION_DIR/$1"

}

function_activate() {

log_debug "Activate function: $1"

test -h "$CONFIG_DIR/$1" || ln -s "$FUNCTION_DIR/$1" "$CONFIG_DIR/$1"

}

function_deactivate() {

log_debug "Deactivate function: $1"

test -h "$CONFIG_DIR/$1" && rm "$CONFIG_DIR/$1"

}

function_deactivate_all() {

local err=0

for f in $CONFIG_DIR/*; do

# symlink == function

test -h $f || continue

if ! function_deactivate $(basename $f); then

err=1

fi

done

return $err

}

function_list_active() {

log_debug "List active functions"

for f in $CONFIG_DIR/*; do

# symlink == function

test -h $f || continue

log_debug "Active function: $(basename $f)"

done

return 0

}

function_set_attr() {

local f="$1"

local k="$2"

local v="$3"

log_debug "Function $f: set $k = $v"

echo > "$FUNCTION_DIR/$f/$k" "$v"

}

# ============================================================================

# RNDIS

# ============================================================================

rndis_down() {

log_debug "Disable rndis interface"

ifconfig rndis0 down 2> /dev/null || :

}

rndis_up() {

log_debug "Enable rndis interface"

}

udhcpd_configure() {

log_debug "Configure udhcpd"

cat > /etc/udhcpd.conf <<-EOF

start 192.168.2.1

end 192.168.2.15

interface rndis0

option subnet 255.255.255.0

option lease 3600

max_leases 15

EOF

}

udhcpd_start() {

log_debug "Start udhcpd"

systemctl start udhcpd.service

}

udhcpd_stop() {

log_debug "Stop udhcpd"

systemctl stop udhcpd.service

}

# ============================================================================

# MTP

# ============================================================================

MTPD_ENV="LANG=en_GB.utf8 MSYNCD_LOGGING_LEVEL=7"

MTPD_BIN="/usr/lib/mtp/mtp_service"

MTPD_LOG="/tmp/mtpd.log"

mtp_mount() {

log_debug "Mount mtp endpoint directory"

if ! mountpoint -q /dev/mtp ; then

/bin/mount -o uid=100000,gid=100000 -t functionfs mtp /dev/mtp

fi

}

mtp_unmount() {

log_debug "Unmount mtp endpoint directory"

if mountpoint -q /dev/mtp ; then

/bin/umount /dev/mtp

fi

}

mtpd_start() {

log_debug "Start mtpd"

(/bin/su - nemo -c "$MTPD_ENV $MTPD_BIN" 2>$MTPD_LOG) &

local seen=0

for i in $(seq 10); do

sleep 0.333

if killall -0 "$MTPD_BIN" ; then

seen=$((seen+1))

test "$seen" -ge 3 && return 0

else

log_debug "Wait for mtpd ..."

fi

done

log_warning "Could not start mtpd"

return 1

}

mtpd_stop() {

log_debug "Stop mtpd"

/usr/bin/killall "$MTPD_BIN" || :

}

# ============================================================================

# USB_MODE

# ============================================================================

# -- undefined --

usb_mode_enter_undefined() {

log_debug "ENTER UNKNOWN MODE"

# same as enter undefined...

udc_disable

function_deactivate_all

}

usb_mode_leave_undefined() {

log_debug "LEAVE UNKNOWN MODE"

udc_disable

function_deactivate_all

}

# -- charging_only --

usb_mode_enter_charging_only() {

log_debug "ENTER CHARGING_ONLY"

function_register $FUNCTION_MASS_STORAGE

function_activate $FUNCTION_MASS_STORAGE

udc_enable

}

usb_mode_leave_charging_only() {

log_debug "LEAVE CHARGING_ONLY"

udc_disable

function_deactivate_all

}

# -- developer_mode --

usb_mode_enter_developer_mode() {

log_debug "ENTER DEVELOPER_MODE"

function_register $FUNCTION_RNDIS

function_set_attr $FUNCTION_RNDIS wceis 1

function_activate $FUNCTION_RNDIS

udc_enable

sleep 0.5

rndis_up

sleep 0.5

udhcpd_configure

udhcpd_start

}

usb_mode_leave_developer_mode() {

log_debug "LEAVE DEVELOPER_MODE"

udhcpd_stop

rndis_down

udc_disable

function_deactivate_all

}

# -- mtp_mode --

usb_mode_enter_mtp_mode() {

log_debug "ENTER MTP_MODE"

function_register $FUNCTION_MTP

function_activate $FUNCTION_MTP

mtp_mount

mtpd_start

udc_enable

}

usb_mode_leave_mtp_mode() {

log_debug "LEAVE MTP_MODE"

udc_disable

mtpd_stop

mtp_unmount

function_deactivate_all

}

# -- mode switch --

usb_mode_enter() {

case $1 in

mtp_mode)

usb_mode_enter_mtp_mode

;;

developer_mode)

usb_mode_enter_developer_mode

;;

charging_only)

usb_mode_enter_charging_only

;;

undefined)

usb_mode_enter_undefined

;;

*)

log_warning "Unknown mode: $1"

usb_mode_enter_undefined

;;

esac

}

usb_mode_leave() {

case $1 in

mtp_mode)

usb_mode_leave_mtp_mode

;;

developer_mode)

usb_mode_leave_developer_mode

;;

charging_only)

usb_mode_leave_charging_only

;;

undefined)

usb_mode_leave_undefined

;;

*)

log_warning "Unknown mode: $1"

usb_mode_leave_undefined

;;

esac

}

usb_mode_switch() {

configfs_validate

local next="$1"

local curr="$(cat /tmp/usb-mode)"

test ! -z "$curr" || curr="undefined"

if [ "$curr" != "$next" ]; then

log_info "SWITCH FROM: $curr TO: $next"

usb_mode_leave "$curr"

echo > /tmp/usb-mode "$next"

usb_mode_enter "$next"

else

log_info "ALREADY IN: $next"

fi

}

# ============================================================================

# MAIN

# ============================================================================

# try to guess if we were executed or sourced

if [ "$PROGNAME" = "set_usb_mode.sh" ]; then

TARGET_MODE="$1"

case $TARGET_MODE in

cha*)

TARGET_MODE="charging_only"

;;

dev*)

TARGET_MODE="developer_mode"

;;

mtp*)

TARGET_MODE="mtp_mode"

;;

und*)

TARGET_MODE="undefined"

;;

-v|--verbose)

LOG_LEVEL=$((LOG_LEVEL+1))

;;

-q|--quiet)

LOG_LEVEL=$((LOG_LEVEL-1))

;;

-s|--silent)

LOG_LEVEL=0

;;

-h|--help|--usage)

cat <<-EOF

Usage:

$PROGNAME <mode>

Valid modes are:

- charging_only

- developer_mode

- mtp_mode

- undefined

EOF

exit 0

;;

*)

cat >&2 <<-EOF

unknown option: ${TARGET_MODE:-<nothing>}

(Use $PROGNAME --usage to show help)

EOF

exit 1

;;

esac

usb_mode_switch "$TARGET_MODE"

fi