Fixed su quoting usage, as outlined here:

http://lists.debian.org/debian-devel-announce/2006/03/msg00003.html

ChangeLog

 version 0.9.4 -- unreleased
     handler changes
-	mysql, pgsql, svn: fixed inversed vsname emptyness check
 	mysql:
 	 . Fixed improper use of $vuserhome (Debian: #351083)
 	 . Fixed erroneous removal of tmpfile when it didn't exit
+	 . Fixed inversed vsname emptiness check
+	 . Fixed su quote usage to be more posixy
+	pgsql:
+	 . Fixed inversed vsname emptiness check
+	 . Fixed su quote usage to be more posixy
+	svn:
+	 . Fixed inversed vsname emptiness check
 	rdiff:
 	 . Fixed improper include/exclude symlink dereference
 	dup:

examples/example.rdiff

@@ -86,7 +86,7 @@ directory = /backups
 host = backuphost
 
 # make the files owned by this user. you must be able to
-# `su -c ssh backupuser@backhost` without specifying a password.
+# `su -c "ssh backupuser@backhost"` without specifying a password.
 # only use if "[dest] type = remote"
 user = backupuser
 

handlers/mysql

@@ -179,7 +179,7 @@ then
 	else
 		execstr="$MYSQLHOTCOPY --quiet --allowold --regexp /.\*/./.\*/ $hotdir"
 	fi
-	debug "su $user -c '$execstr'"
+	debug 'su $user -c "$execstr"'
 	if [ ! $test ]
 	then
 		output=`su $user -c "$execstr" 2>&1`
@@ -202,7 +202,7 @@ then
 		else
 			execstr="$MYSQLHOTCOPY --allowold $db $hotdir"
 		fi
-		debug "su $user -c '$execstr'"
+		debug 'su $user -c "$execstr"'
 		if [ ! $test ]
 		then
 			output=`su $user -c "$execstr" 2>&1`
@@ -230,7 +230,7 @@ then
     then
 	if [ $usevserver = yes ]
 	then
-	    debug "echo show databases | $VSERVER $vsname exec su $user -c $MYSQL $defaultsfile | grep -v Database"
+	    debug 'echo show databases | $VSERVER $vsname exec su $user -c "$MYSQL $defaultsfile" | grep -v Database'
 	    databases=`echo 'show databases' | $VSERVER $vsname exec su $user -c "$MYSQL $defaultsfile" | grep -v Database`
 	    if [ $? -ne 0 ]
 	    then
@@ -253,7 +253,7 @@ fi
 		else
 			execstr="$MYSQLDUMP $defaultsfile --lock-tables --complete-insert --add-drop-table --quick --quote-names $ignore $db > $dumpdir/${db}.sql"
 		fi
-		debug "su $user -c '$execstr'"
+		debug 'su $user -c "$execstr"'
 		if [ ! $test ]
 		then
 			output=`su $user -c "$execstr" 2>&1`

handlers/pgsql

@@ -72,9 +72,9 @@ chmod 700 $vroot$backupdir
 # if $databases = all, use pg_dumpall
 if [ "$databases" == "all" ]; then
     if [ $usevserver = yes ]; then
-	execstr="$VSERVER $vsname exec su - postgres -c $PGSQLDUMPALL > $backupdir/${vsname}.sql"
+	execstr='$VSERVER $vsname exec su - postgres -c "$PGSQLDUMPALL > $backupdir/${vsname}.sql"'
     else
-	execstr="su - postgres -c $PGSQLDUMPALL > $backupdir/${localhost}-all.sql"
+	execstr='su - postgres -c "$PGSQLDUMPALL > $backupdir/${localhost}-all.sql"'
     fi
     debug "$execstr"
     if [ ! $test ]; then
@@ -94,9 +94,9 @@ else
     for db in $databases; do
 	if [ $usevserver = yes ]
 	    then
-	    execstr="$VSERVER $vsname exec su - postgres -c $PGSQLDUMP $db > $backupdir/${db}.sql"
+	    execstr='$VSERVER $vsname exec su - postgres -c "$PGSQLDUMP $db > $backupdir/${db}.sql"'
 	else
-	    execstr="su - postgres -c $PGSQLDUMP $db > $backupdir/${db}.sql"
+	    execstr='su - postgres -c "$PGSQLDUMP $db > $backupdir/${db}.sql"'
 	fi
 	debug "$execstr"
 	if [ ! $test ]; then