#!/bin/sh
# Copyright (C) 2016 Velocloud Inc
# Copyright (C) 2016 Aleksander Morgado <aleksander@aleksander.es>

################################################################################

. /lib/functions.sh
. /lib/netifd/netifd-proto.sh

################################################################################
# Runtime state

MODEMMANAGER_RUNDIR="/var/run/modemmanager"
MODEMMANAGER_PID_FILE="${MODEMMANAGER_RUNDIR}/modemmanager.pid"
MODEMMANAGER_CDCWDM_CACHE="${MODEMMANAGER_RUNDIR}/cdcwdm.cache"
MODEMMANAGER_MONITOR_CACHE="${MODEMMANAGER_RUNDIR}/monitor.cache"
MODEMMANAGER_EVENTS_CACHE="${MODEMMANAGER_RUNDIR}/events.cache"

################################################################################
# Common logging

mm_log() {
	local level="$1"; shift

	[ "${level}" = "debug" ] && return
	logger -p "daemon.${level}" -t "ModemManager[$$]" "hotplug: $*"
}

################################################################################
# Receives as input argument the full sysfs path of the device
# Returns the physical device sysfs path
#
# NOTE: this method only works when the device exists, i.e. it cannot be used
# on removal hotplug events

mm_find_physdev_sysfs_path() {
	local tmp_path="$1"

	while true; do
		tmp_path=$(dirname "${tmp_path}")

		# avoid infinite loops iterating
		[ -z "${tmp_path}" ] || [ "${tmp_path}" = "/" ] && return

		# For USB devices, the physical device will be that with a idVendor
		# and idProduct pair of files
		[ -f "${tmp_path}"/idVendor ] && [ -f "${tmp_path}"/idProduct ] && {
			tmp_path=$(readlink -f "$tmp_path")
			echo "${tmp_path}"
			return
		}

		# For PCI devices, the physical device will be that with a vendor
		# and device pair of files
		[ -f "${tmp_path}"/vendor ] && [ -f "${tmp_path}"/device ] && {
			tmp_path=$(readlink -f "$tmp_path")
			echo "${tmp_path}"
			return
		}
	done
}

################################################################################

# Returns the cdc-wdm name retrieved from sysfs
mm_track_cdcwdm() {
	local wwan="$1"
	local cdcwdm

	cdcwdm=$(ls "/sys/class/net/${wwan}/device/usbmisc/")
	[ -n "${cdcwdm}" ] || return

	# We have to cache it for later, as we won't be able to get the
	# associated cdc-wdm device on a remove event
	echo "${wwan} ${cdcwdm}" >> "${MODEMMANAGER_CDCWDM_CACHE}"

	echo "${cdcwdm}"
}

# Returns the cdc-wdm name retrieved from the cache
mm_untrack_cdcwdm() {
	local wwan="$1"
	local cdcwdm

	# Look for the cached associated cdc-wdm device
	[ -f "${MODEMMANAGER_CDCWDM_CACHE}" ] || return

	cdcwdm=$(awk -v wwan="${wwan}" '!/^#/ && $0 ~ wwan { print $2 }' "${MODEMMANAGER_CDCWDM_CACHE}")
	[ -n "${cdcwdm}" ] || return

	# Remove from cache
	sed -i "/${wwan} ${cdcwdm}/d" "${MODEMMANAGER_CDCWDM_CACHE}"

	echo "${cdcwdm}"
}

# Callback for config_foreach()
mm_get_modem_config_foreach_cb() {
	local cfg="$1"
	local sysfspath="$2"

	local dev
	dev=$(uci_get network "${cfg}" device)
	[ "${dev}" = "${sysfspath}" ] || return 0

	echo "${cfg}"
}

# Returns the name of the interface configured for this device
mm_get_modem_config() {
	local sysfspath="$1"

	# Look for configuration for the given sysfs path
	config_load network
	config_foreach mm_get_modem_config_foreach_cb interface "${sysfspath}"
}

################################################################################
# Event reporting

# Receives as input the action, the device name and the subsystem
mm_report_event() {
	local action="$1"
	local name="$2"
	local subsystem="$3"
	local sysfspath="$4"

	# Do not save virtual devices
	local virtual result
	virtual="$(echo "$sysfspath" | cut -d'/' -f4)"
	[ "$virtual" = "virtual" ] && {
		mm_log "debug" "sysfspath is a virtual device ($sysfspath)"
		case "$name" in
			"qmapmux"*)
				mm_log "debug" "rmnet netdevice $name"
				;;
			"qmimux"*)
				mm_log "debug" "qmi_wwan qmap netdevice $name"
				;;
			"mbimmux"*)
				mm_log "debug" "mbim vlan netdevice $name"
				;;
			*)
				return
				;;
		esac
	}

	# Track/untrack events in cache
	case "${action}" in
		"add")
			# On add events, store event details in cache (if not exists yet)
			grep -qs "${name},${subsystem}" "${MODEMMANAGER_EVENTS_CACHE}" || \
				echo "${action},${name},${subsystem},${sysfspath}" >> "${MODEMMANAGER_EVENTS_CACHE}"
			;;
		"remove")
			# On remove events, remove old events from cache (match by subsystem+name)
			sed -i "/${name},${subsystem}/d" "${MODEMMANAGER_EVENTS_CACHE}"
			;;
	esac

	# Report the event
	mm_log "debug" "Report event: action=${action}, name=${name}, subsystem=${subsystem}"
	result=$(mmcli --report-kernel-event="action=${action},name=${name},subsystem=${subsystem}" 2>&1)
	if [ "$?" -ne "0" ]; then
		mm_log "error" "Couldn't report kernel event: ${result}"
	fi
}

mm_report_event_from_cache_line() {
	local event_line="$1"

	local action name subsystem sysfspath
	action=$(echo "${event_line}" | awk -F ',' '{ print $1 }')
	name=$(echo "${event_line}" | awk -F ',' '{ print $2 }')
	subsystem=$(echo "${event_line}" | awk -F ',' '{ print $3 }')
	sysfspath=$(echo "${event_line}" | awk -F ',' '{ print $4 }')

	mm_log "debug" "cached event found: action=${action}, name=${name}, subsystem=${subsystem}, sysfspath=${sysfspath}"
	mm_report_event "${action}" "${name}" "${subsystem}" "${sysfspath}"
}

mm_report_events_from_cache() {
	local n=60
	local step=1
	local mmrunning=0

	# Wait for ModemManager to be available in the bus
	while [ $n -ge 0 ]; do
		sleep $step
		mm_log "info" "checking if ModemManager is available..."

		if ! mmcli -L >/dev/null 2>&1
		then
			mm_log "info" "ModemManager not yet available"
		else
			mmrunning=1
			break
		fi
		n=$((n-step))
	done

	[ ${mmrunning} -eq 1 ] || {
		mm_log "error" "couldn't report initial kernel events: ModemManager not running"
		return
	}

	# Remove the sysfs cache
	rm -f "${MODEMMANAGER_SYSFS_CACHE}"

	# Report cached kernel events
	while IFS= read -r event_line; do
		mm_report_event_from_cache_line "${event_line}"
	done < ${MODEMMANAGER_EVENTS_CACHE}
}

# This method expects as first argument a list of key-value pairs, as returned by mmcli --output-keyvalue
# The second argument must be exactly the name of the field to read
#
# Sample output:
#     $ mmcli -m 0 -K
#     modem.dbus-path                                 : /org/freedesktop/ModemManager1/Modem/0
#     modem.generic.device-identifier                 : ed6eff2e3e0f90463da1c2a755b2acacd1335752
#     modem.generic.manufacturer                      : Dell Inc.
#     modem.generic.model                             : DW5821e Snapdragon X20 LTE
#     modem.generic.revision                          : T77W968.F1.0.0.4.0.GC.009\n026
#     modem.generic.carrier-configuration             : GCF
#     modem.generic.carrier-configuration-revision    : 08E00009
#     modem.generic.hardware-revision                 : DW5821e Snapdragon X20 LTE
#     ....
modemmanager_get_field() {
	local list=$1
	local field=$2
	local value=""

	[ -z "${list}" ] || [ -z "${field}" ] && return

	# there is always at least a whitespace after each key, and we use that as part of the
	# key matching we do (e.g. to avoid getting 'modem.generic.state-failed-reason' as a result
	# when grepping for 'modem.generic.state'.
	line=$(echo "${list}" | grep "${field} ")
	value=$(echo ${line#*:})

	# not found?
	[ -n "${value}" ] || return 2

	# only print value if set
	[ "${value}" != "--" ] && echo "${value}"
	return 0
}

# build a comma-separated list of values from the list
modemmanager_get_multivalue_field() {
	local list=$1
	local field=$2
	local value=""
	local length idx item

	[ -z "${list}" ] || [ -z "${field}" ] && return

	length=$(modemmanager_get_field "${list}" "${field}.length")
	[ -n "${length}" ] || return 0
	[ "$length" -ge 1 ] || return 0

	idx=1
	while [ $idx -le "$length" ]; do
		item=$(modemmanager_get_field "${list}" "${field}.value\[$idx\]")
		[ -n "${item}" ] && [ "${item}" != "--" ] && {
			[ -n "${value}" ] && value="${value}, "
			value="${value}${item}"
		}
		idx=$((idx + 1))
	done

	# nothing built?
	[ -n "${value}" ] || return 2

	# only print value if set
	echo "${value}"
	return 0
}