From: Phillip Berndt <phillip.berndt@googlemail.com>
Date: Thu, 28 Jul 2016 17:35:17 +0000 (+0200)
Subject: Improve detection of $DISPLAY session owner
X-Git-Tag: 1.0~18
X-Git-Url: https://git.donarmstrong.com/?p=deb_pkgs%2Fautorandr.git;a=commitdiff_plain;h=d0fb527ffd0c2a491fe5318af46104e9c607b5b1

Improve detection of $DISPLAY session owner

This closes bug #39.
---

diff --git a/contrib/pm-utils/40autorandr b/contrib/pm-utils/40autorandr
index 4d59012..ab02263 100755
--- a/contrib/pm-utils/40autorandr
+++ b/contrib/pm-utils/40autorandr
@@ -8,28 +8,95 @@ AUTORANDR="autorandr -c --default default"
 # Work around #44: Long user names in w
 export PROCPS_USERLEN=32
 
+find_user() {
+	# Determine user owning the display session from $1
+	D="$1"
+
+	# Prefer loginctl over all others, see bug #49
+	if [ -x "`which loginctl`" ]; then
+		# Based on http://unix.stackexchange.com/questions/203844/how-to-find-out-the-current-active-xserver-display-number/204498
+		# by SO user intelfx
+		user="$(
+		loginctl list-sessions --no-legend | while read id uid user seat; do
+			 loginctl show-session -p Display -p Active "$id" | while IFS='=' read property value; do
+				case "$property" in
+					Active)
+						if [ "$value" != "yes" ]; then
+							continue
+						fi
+						;;
+					Display)
+						if [ -n "$value" -a "$value" = "$D" ]; then
+							echo $user
+						fi
+						;;
+				esac
+			done
+		done
+		)"
+		user=
+		if [ -n "$user" ]; then
+			echo $user
+			return 0
+		fi
+	fi
+
+	# Prefer w to who, see bug #39
+	if [ -x "`which w`" ]; then
+		user="`w -h | awk -vD="$D" '$2 ~ ":"D"(.[0-9])?$" || $3 ~ ":"D"(.[0-9])?$" {print $1}' | head -n1`"
+
+		if [ -z "$user" ];	then
+			# This fallback checks if there is exactly one user (except
+			# root) logged in an interactive session and assumes the
+			# session belongs to him. See bug #39.
+			user="`w -hu | awk '/^\w+/ && $1 !~ "root" { users[$1]=$1; } ENDFILE { if(asort(users) == 1) for(u in users) print users[u]; }'`"
+		fi
+	else
+		user="`who --all | awk -vD="$D" '$3 ~ ":"D"(.[0-9])?$" {print $1}' | head -1`"
+
+		if [ -z "$user" ];	then
+			# Same fallback as above; see bug #39.
+			user="`who -u | awk '/^\w+/ && $1 !~ "root" { users[$1]=$1; } ENDFILE { if(asort(users) == 1) for(u in users) print users[u]; }'`"
+		fi
+	fi
+
+	user=
+	if [ -n "$user" ]; then
+		echo $user
+		return 0
+	fi
+
+	# If none of the above worked, check if there is only one user owning
+	# processes in $DISPLAY except root
+	#
+	# This code should be optimized somehow, but keep in mind that not all
+	# systems symlink sh -> bash!
+	OUTPUT="$(
+		for p in /proc/*; do
+			[ -d $p ] || continue
+			d="$(awk -v RS='\0' -F= '$1=="DISPLAY" {print $2}' $p/environ 2>/dev/null)"
+			if [ "$d" = "$D" ]; then
+				stat -c %U $p
+			fi
+		done | sort | uniq | grep -v root | nl | head -n1
+	)"
+	count=$(echo $OUTPUT | awk '{print $1}')
+	user=$(echo $OUTPUT | awk '{print $2}')
+
+	if [ "$count" -eq 1 ]; then
+		echo $user
+		return 0
+	fi
+
+	return 1
+}
+
 detect_display()
 {
 	for X in /tmp/.X11-unix/X*; do
 		D="${X##/tmp/.X11-unix/X}"
-		# Prefer w to who, see bug #39
-		if [ -x "`which w`" ]; then
-			user="`w -h | awk -vD="$D" '$2 ~ ":"D"(.[0-9])?$" || $3 ~ ":"D"(.[0-9])?$" {print $1}' | head -n1`"
-
-			if [ -z "$user" ];	then
-				# This fallback checks if there is exactly one user (except
-				# root) logged in an interactive session and assumes the
-				# session belongs to him. See bug #39.
-				user="`w -hu | awk '/^\w+/ && $1 !~ "root" { users[$1]=$1; } ENDFILE { if(asort(users) == 1) for(u in users) print users[u]; }'`"
-			fi
-		else
-			user="`who --all | awk -vD="$D" '$3 ~ ":"D"(.[0-9])?$" {print $1}' | head -1`"
 
-			if [ -z "$user" ];	then
-				# Same fallback as above; see bug #39.
-				user="`who -u | awk '/^\w+/ && $1 !~ "root" { users[$1]=$1; } ENDFILE { if(asort(users) == 1) for(u in users) print users[u]; }'`"
-			fi
-		fi
+		user="$(find_user "$D")"
 
 		if [ x"$user" != x"" ]; then
 			logger "autorandr: Changing display configuration for display :$D, user '$user'"