Simultaneously capture XI2, evdev, and HID data from a tablet

capture.sh

#!/usr/bin/env bash

# Usage: capture.sh [limit [count]]
# Simultaneously capture HID, evdev, and Xinput events from a device.
#
#   limit         Maximum output file size in bytes (default: 0 [unlimited])
#   count         Number of output files to rotate through (default: 1)
#
# This script must be run as root in order to read all events.

set -e

trap cleanup INT QUIT TERM

function cleanup {
	echo
	echo "Archiving capture data..."
	sleep 0.1
	jobs -p | xargs kill 2>/dev/null || true
	wait

	tar cvzf record_$NOW.tar.gz record_$NOW.*.log*
	rm record_$NOW.*.log*
	echo
	echo "Files have been archived to $(pwd)/record_$NOW.tar.gz"
	echo "Please upload this file for analysis."
}

function kernelver_int {
	awk -F'[-.]' '{print $1*1000000+$2*1000+$3}' <<<$1
}

function hid_available {
	test $(kernelver_int $(uname -r)) -ge $(kernelver_int "3.17") || grep -o 7.[56789] /etc/redhat-release >/dev/null 2>/dev/null
	return $?
}

function logger {
	DEST=$1
	LOGSIZE=$2
	LOGCOUNT=$3
	NBYTES=0
	T=$(date +%s.%N)
	while IFS='' read -r TEXT; do
		if [[ "$DEST" == *".xi2.log" && "$TEXT" == "EVENT "* ]]; then
			NOW=$(date +%s.%N)
			awk -vA="$T" -vB="$NOW" 'BEGIN {print B " [" (B-A)*1000 " ms]"; exit}' >> "$DEST"
			T=$NOW
		fi
		echo "$TEXT" >> "$DEST"

		if [[ $LOGSIZE -gt 0 ]]; then
			# Calling stat to get the size every time we write a line is very slow...
			# Lets do our own accounting instead.
			NBYTES=$(($NBYTES + ${#TEXT} + 2))

			if [[ $NBYTES -gt $LOGSIZE ]]; then
				echo "Rotating $DEST..."
				for I in $(seq $(($LOGCOUNT-1)) -1 0); do
					mv -f "$DEST.$I" "$DEST.$(($I+1))" 2> /dev/null || true
				done
				mv "$DEST" "$DEST.0" || true
				rm -f "$DEST.$LOGCOUNT" 2> /dev/null || true
				NBYTES=0
			fi
		fi
	done
}


if [[ "$EUID" -ne 0 ]]; then
	echo "This command must be run as root to capture hardware and kernel logs."
	exit 1
fi

LOGLIMIT=0
LOGCOUNT=1
if [[ $# -ge 1 ]]; then
	LOGLIMIT=$1
fi
if [[ $# -ge 2 ]]; then
	LOGCOUNT=$2
fi

REC_XI2=$(command -v xinput 2> /dev/null || true)
REC_KRN=$(command -v evemu-record 2> /dev/null || command -v evtest 2>/dev/null || true)
REC_HID=$(command -v hid-recorder 2> /dev/null || true)
REC_USB=""
REC_TTY=$(command -v isdv4-serial-debugger 2>/dev/null || true)
if ! hid_available ; then
	# Can't capture HID data prior to Linux 3.17...
	REC_USB="grep"
	if ! modprobe usbmon; then
		echo "Unable to load usbmon kernel module."
		exit 1
	fi
fi

ERRMSG=""
if [[ -z "$REC_XI2" ]]; then
	ERRMSG="${ERRMSG}\n  * xinput [Try: \`apt-get install xinput\` or \`yum install xorg-x11-server-utils\`]"
fi
if [[ -z "$REC_KRN" ]]; then
	ERRMSG="${ERRMSG}\n  * evemu-record [Try: \`apt-get install evemu-tools\` or \`yum install evemu\` (may require EPEL)]"
fi
if hid_available && [[ -z "$REC_HID" ]]; then
	ERRMSG="${ERRMSG}\n  * hid-recorder [Try: \`yum install hid-replay\` (may require EPEL) or https://bentiss.github.io/hid-replay-docs/ ]"
fi
if [[ -z "$REC_TTY" ]]; then
	ERRMSG="${ERRMSG}\n  * isdv4-serial-debugger [Try: \`apt-get install xserver-xorg-input-wacom\` \`yum install xorg-x11-wacom-devel\` ]"
fi
if [[ -n "$ERRMSG" ]] ; then
	echo "The following utilities are missing and must be installed to capture logs:"
	echo "$ERRMSG"
	exit 1
fi


DEV_X11=""
DEV_EVDEV=""
DEV_HID=""
DEV_USB=""
DEV_TTY=""

xinput list
while [[ "x$DEV_X11" == "x" ]]; do
	echo -ne "\nID number of the device to record: "
	read DEV_X11
	if ! xinput list $DEV_X11 > /dev/null 2>&1; then
		echo "Unknown device ID."
		DEV_X11=""
	fi
done


DEV_EVDEV=$(xinput list-props "$DEV_X11" | awk 'BEGIN {OFS=FS="\t"} /^\tDevice Node/ {$1=$2="";print substr($0,4,length()-4)}')
if [[ -c "$DEV_EVDEV" ]]; then
	echo "Found evdev device node: $DEV_EVDEV"
else
	echo "Unknown device node: $DEV_EVDEV"
	exit 1
fi


SYSFS_PATH=$(readlink -e "/sys/$(udevadm info -q path "$DEV_EVDEV")" 2>/dev/null || true)
if [[ -n "$SYSFS_PATH" ]]; then
	echo "Found evdev sysfs at $SYSFS_PATH"
else
	echo "Unable to locate sysfs path from $(udevadm info -q path "$DEV_EVDEV")"
	exit 1
fi

HIDRAW_PATH=$(readlink -e "$SYSFS_PATH/device/device/hidraw" 2>/dev/null || true)
USBBUS_PATH=$(readlink -e "$SYSFS_PATH/../../../../../busnum" 2>/dev/null || true)
USBDEV_PATH=$(readlink -e "$SYSFS_PATH/../../../../../devnum" 2>/dev/null || true)
TTYDEV_PATH=$(ls "$SYSFS_PATH/../../../../serio*" 2>/dev/null || true)

if [[ -n "$HIDRAW_PATH" ]]; then
	echo "Found hidraw sysfs at $HIDRAW_PATH"
	DEV_HID="/dev/$(ls $HIDRAW_PATH)"
	if [[ -c "$DEV_HID" ]]; then
		echo "Found hidraw device node: $DEV_HID"
	else
		echo "Unknown hidraw device node: $DEV_HID"
		exit 1
	fi
elif [[ -n "$USBBUS_PATH" && -n "$USBDEV_PATH" ]]; then
	echo "Found usb bus sysfs at $USBBUS_PATH"
	echo "Found usb dev sysfs at $USBDEV_PATH"
	BUS=$(cat "$USBBUS_PATH")
	DEV=$(cat "$USBDEV_PATH")
	DEV_USB=$(printf "%d:%03d" $BUS $DEV)

	echo "Found USB bus/device: $DEV_USB"
	if ! test -f /sys/kernel/debug/usb/usbmon/0u; then
		echo "Unable to locate usbmon character device"
		exit 1
	fi
elif [[ -n "$TTYDEV_PATH" ]]; then
	echo "Found tty sysfs at $TTYDEV_PATH"
	DEV_TTY="/dev/"$(basename $(readlink -f "$SYSFS_PATH/../../../.."))
	if [[ -c "$DEV_TTY" ]]; then
		echo "Found TTY device node: $DEV_TTY"
	else
		echo "Unknown TTY device node: $DEV_TTY"
		exit 1
	fi
else
	echo "Unable to find a hardware device from $SYSFS_PATH"
	exit 1
fi


cd /tmp
NOW=$(date +%s)

echo
echo "Capturing events into temporary files..."

if [[ $LOGLIMIT -gt 0 ]]; then
	echo "(Limiting to $LOGLIMIT bytes across $LOGCOUNT files)"
fi

$REC_XI2 test-xi2 --root "$DEV_X11" | logger record_$NOW.xi2.log $LOGLIMIT $LOGCOUNT &
echo "    XI2:   $(pwd)/record_$NOW.xi2.log"

$REC_KRN "$DEV_EVDEV" | logger record_$NOW.evemu.log $LOGLIMIT $LOGCOUNT &
echo "    evdev: $(pwd)/record_$NOW.evemu.log"

if [[ -n "$DEV_HID" ]] ; then
	$REC_HID "$DEV_HID" | logger record_$NOW.hid.log $LOGLIMIT $LOGCOUNT &
	echo "    HW:    $(pwd)/record_$NOW.hid.log"
elif [[ -n "$DEV_USB" ]] ; then
	$REC_USB ":$DEV_USB:" /sys/kernel/debug/usb/usbmon/0u | logger record_$NOW.usb.log $LOGLIMIT $LOGCOUNT &
	echo "    HW:    $(pwd)/record_$NOW.usb.log"
elif [[ -n "$DEV_TTY" ]] ; then
	$REC_TTY "$DEV_TTY" | logger record_$NOW.tty.log $LOGLIMIT $LOGCOUNT &
	echo "    HW:    $(pwd)/record_$NOW.tty.log"
fi

echo
echo "Press CTRL+C to stop recording."
wait