Protect user db with flock

target/bin/addmailuser

@@ -22,13 +22,20 @@ escape() {
 [ -z "$USER" ] && { usage; errex "no username specified"; }
 expr index "$USER" "@" >/dev/null || { usage; errex "username must include the domain"; }
 
-grep -qi "^$(escape "$USER")|" $DATABASE 2>/dev/null &&
-	errex "User \"$USER\" already exists"
+# Protect config file with lock to avoid race conditions
+touch $DATABASE
+( 
+  flock -e 200
 
-if [ -z "$PASSWD" ]; then
-	read -s -p "Enter Password: " PASSWD
-	echo
-	[ -z "$PASSWD" ] && errex "Password must not be empty"
-fi
-HASH="$(doveadm pw -s SHA512-CRYPT -u "$USER" -p "$PASSWD")"
-echo "$USER|$HASH" >> $DATABASE
+  grep -qi "^$(escape "$USER")|" $DATABASE 2>/dev/null &&
+    errex "User \"$USER\" already exists"
+
+  if [ -z "$PASSWD" ]; then
+    read -s -p "Enter Password: " PASSWD
+    echo
+    [ -z "$PASSWD" ] && errex "Password must not be empty"
+  fi
+
+  HASH="$(doveadm pw -s SHA512-CRYPT -u "$USER" -p "$PASSWD")"
+  echo "$USER|$HASH" >> $DATABASE
+) 200<$DATABASE

target/bin/delmailuser

@@ -33,25 +33,31 @@ shift $((OPTIND-1))
 [ -z "$@" ] && { usage; errex "No user specifed"; }
 [ -s "$DATABASE" ] || exit 0
 
-for USER in "$@"; do
-	#very simple plausibility check
-	[[ "$USER" != *"@"*"."* ]] && errex "No valid address: $USER"
-	MAILARR=(${USER//@/ })
-	# XXX $USER must not contain /s and other syntactic characters
-	USER=$(escape "$USER")
-	sed -i "/^"$USER"|/d" $DATABASE
-	[ $? != 0 ] && errex "$USER couldn't be deleted in $DATABASE. $?"
-	# Delete all aliases where the user is the only recipient( " $USER$" )
-	# Delete user only for all aliases that deliver to multiple recipients ( ",$USER" "$USER," )
-	sed -i -e "/ "$USER"$/d" \
-				 -e "s/,"$USER"//g" \
-				 -e "s/"$USER",//g" $ALIAS_DATABASE
-	[ $? = 0 ] && echo "$USER and potential aliases deleted." || errex "Aliases for $USER couldn't be deleted in $ALIAS_DATABASE. $?"
-	if [ "$MAILDEL" != "y" ]; then
-	  read -p "Do you want to delete the maildir as well(all mails will be removed)?(y/n) " MAILDEL
-		echo
-	fi
-	[ "$MAILDEL" != "y" ] && errex "Leaving the maildir untouched. If you want to delete it at a later point use \"sudo docker exec mail rm -R /var/mail/${MAILARR[1]}/${MAILARR[0]}\""
-	rm -r -f /var/mail/${MAILARR[1]}/${MAILARR[0]}
-	[ $? = 0 ] && echo "Maildir deleted." || errex "Maildir couldn't be deleted: $?"
-done
+# Protect config file with lock to avoid race conditions
+(
+  flock -e 200
+
+  for USER in "$@"; do
+    # very simple plausibility check
+    [[ "$USER" != *"@"*"."* ]] && errex "No valid address: $USER"
+    MAILARR=(${USER//@/ })
+    # XXX $USER must not contain /s and other syntactic characters
+    USER=$(escape "$USER")
+    sed -i "/^"$USER"|/d" $DATABASE
+    [ $? != 0 ] && errex "$USER couldn't be deleted in $DATABASE. $?"
+    # Delete all aliases where the user is the only recipient( " $USER$" )
+    # Delete user only for all aliases that deliver to multiple recipients ( ",$USER" "$USER," )
+    sed -i -e "/ "$USER"$/d" \
+        -e "s/,"$USER"//g" \
+        -e "s/"$USER",//g" $ALIAS_DATABASE
+    [ $? = 0 ] && echo "$USER and potential aliases deleted." || errex "Aliases for $USER couldn't be deleted in $ALIAS_DATABASE. $?"
+    if [ "$MAILDEL" != "y" ]; then
+      read -p "Do you want to delete the maildir as well(all mails will be removed)?(y/n) " MAILDEL
+      echo
+    fi
+    [ "$MAILDEL" != "y" ] && errex "Leaving the maildir untouched. If you want to delete it at a later point use \"sudo docker exec mail rm -R /var/mail/${MAILARR[1]}/${MAILARR[0]}\""
+    rm -r -f /var/mail/${MAILARR[1]}/${MAILARR[0]}
+    [ $? = 0 ] && echo "Maildir deleted." || errex "Maildir couldn't be deleted: $?"
+  done
+
+) 200<$DATABASE

target/bin/listmailuser

@@ -10,4 +10,9 @@ errex() {
 [ -f $DATABASE ] || errex "No postfix-accounts.cf file"
 [ -s $DATABASE ] || errex "Empty postfix-accounts.cf - no users have been added"
 
-awk -F '|' '{ print $1; }' $DATABASE
+# Lock database even though we are only reading
+(
+  flock -e 200
+  awk -F '|' '{ print $1; }' $DATABASE
+) 200<$DATABASE
+

target/bin/updatemailuser

@@ -27,7 +27,13 @@ if [ -z "$PASSWD" ]; then
 	[ -z "$PASSWD" ] && errex "Password must not be empty"
 fi
 HASH="$(doveadm pw -s SHA512-CRYPT -u "$USER" -p "$PASSWD")"
-grep -qi "^$(escape "$USER")|" $DATABASE 2>/dev/null ||
-	errex "User \"$USER\" does not exist"
 
-sed -i "s ^"$USER"|.* "$USER"|"$HASH" " $DATABASE
+# Protect config file with lock to avoid race conditions
+(
+  flock -e 200
+
+  grep -qi "^$(escape "$USER")|" $DATABASE 2>/dev/null ||
+    errex "User \"$USER\" does not exist"
+
+  sed -i "s ^"$USER"|.* "$USER"|"$HASH" " $DATABASE
+) 200<$DATABASE

target/check-for-changes.sh

@@ -37,8 +37,7 @@ for file in postfix-accounts.cf postfix-virtual.cf postfix-aliases.cf; do
 done
 
 # Wait to make sure server is up before we start
-# Plus the files have just been generated, no hurry to process changes
-sleep 20
+sleep 10
 
 # Run forever
 while true; do
@@ -46,7 +45,7 @@ while true; do
 # recreate logdate
 log_date=$(date +"%Y-%m-%d %H:%M:%S ")
 
-# Get chksum and check it.
+# Get chksum and check it, no need to lock config yet
 chksum=$(sha512sum -c --ignore-missing $CHKSUM_FILE)
 
 if [[ $chksum == *"FAIL"* ]]; then
@@ -57,6 +56,11 @@ if [[ $chksum == *"FAIL"* ]]; then
         # Also note that changes are performed in place and are not atomic
         # We should fix that and write to temporary files, stop, swap and start
 
+        # Lock configuration while working
+        # Not fixing indentation yet to reduce diff (fix later in separate commit)
+        (
+          flock -e 200
+
 	#regen postix aliases.
 	echo "root: ${PM_ADDRESS}" > /etc/aliases
 	if [ -f /tmp/docker-mailserver/postfix-aliases.cf ]; then
@@ -195,6 +199,8 @@ if [[ $chksum == *"FAIL"* ]]; then
 
 	echo "${log_date} Update checksum"
 	sha512sum ${cf_files[@]/#/--tag } >$CHKSUM_FILE
+
+        ) 200<postfix-accounts.cf # end lock
 fi
 
 sleep 1