Hi.
I try to configure postfix to check content per content_filter
my main.cf:

alias_database=hash:/usr/local/etc/postfix/aliases
alias_maps =hash:/usr/local/etc/postfix/aliases
command_directory = /usr/local/sbin
config_directory=/usr/local/etc/postfix
daemon_directory = /usr/local/libexec/postfix

debugger_command =
PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
xxgdb $daemon_directory/$process_name $process_id & sleep 5

debug_peer_level = 3

default_destination_concurrency_limit = 10
disable_vrfy_command = yes

# header_checks = mysql:/usr/local/etc/postfix/mysql_virtual_header_maps.cf
header_checks = regexp:/usr/local/etc/postfix/header_checks

# header_checks = mysql:/usr/local/etc/postfix/mysql_virtual_header_maps.cf, re gexp:/usr/local/etc/postfix/header_checks,

# hash_queue_depth = 1
# hash_queue_names = incoming, active,deferred,bounce,defer,flush,hold

home_mailbox=Maildir/

inet_interfaces = all
local_destination_concurrency_limit = 2
mail_name=Postfix
mail_owner = postfix
mail_spool_directory = /var/mail
mailbox_size_limit = 102400000
mailq_path = /usr/local/bin/mailq
manpage_directory = /usr/local/man
maximal_queue_lifetime=3d
# message_size_limit = 51200000
message_size_limit = 0
mydomain=abc.kom.pl
myhostname = 78-tor-7.acn.waw.pl
myorigin = $myhostname
mynetworks = 192.168.1.0/24, 127.0.0.1
newaliases_path = /usr/local/bin/newaliases
queue_directory = /var/spool/postfix
queue_run_delay=30m
readme_directory = no
relay_domains = 127.0.0.0/8
sample_directory = /usr/local/etc/postfix
sendmail_path = /usr/local/sbin/sendmail
setgid_group = maildrop
smtpd_banner = Fuck you yellow Taiwanese spammer!
broken_sasl_auth_clients = yes

smtpd_client_restrictions =
reject_unknown_sender_domain,
reject_rbl_client rbl.rafi.pl.eu.org

smtpd_error_sleep_time = 3

smtpd_hard_error_limit = 5

smtpd_recipient_limit=10

smtpd_recipient_restrictions =
permit_mynetworks,
permit_sasl_authenticated,
reject_unauth_destination
# check_recipient_access mysql:/usr/local/etc/postfix/mysql-virt-userspam.cf,

smtpd_sasl_auth_enable = yes

smtpd_sasl_local_domain =

smtpd_sasl_security_options = noanonymous

smtpd_sender_restrictions = reject_unknown_sender_domain

smtpd_soft_error_limit = 3

unknown_local_recipient_reject_code = 450

virtual_alias_maps=mysql:/usr/local/etc/postfix/mysql_virtual_alias_maps.cf

virtual_gid_maps=static:125

virtual_mailbox_base=/usr/local/virtual

virtual_mailbox_domains=mysql:/usr/local/etc/postfix/mysql_virtual_domains_maps. cf

virtual_mailbox_maps=mysql:/usr/local/etc/postfix/mysql_virtual_mailbox_maps.cf

virtual_mailbox_limit=102200000

# virtual_transport=courier
virtual_transport=virtual

transport_maps=mysql:/usr/local/etc/postfix/mysql_virtual_transport.cf

virtual_uid_maps=static:125

# dodane

virtual_create_maildirsize = yes

virtual_mailbox_extended = yes
virtual_maildir_extended = yes

virtual_mailbox_limit_maps = mysql:/usr/local/etc/postfix/mysql_virtual_mailbox_ limit_maps.cf

virtual_mailbox_limit_override = yes

virtual_mailbox_limit_message = Użytkownik przekroczył rozmiar swojej skrzynki. Prosimy spróbować później. / User quota is exceed. Please try again later.
virtual_maildir_limit_message = Użytkownik przekroczył rozmiar swojej skrzynki. Prosimy spróbować później. / User quota is exceed. Please try again later.

virtual_overquota_bounce = yes

virtual_mailbox_limit_inbox = yes


debug_peer_level = 2

html_directory = no

hash_queue_names= incoming, active, deffered, bounce, defer, flush, hold
hash_queue_depth=1


reject_non_fqdn_hostname = yes
# reject_unknown_hostname = yes
reject_invalid_hostname = yes
# reject_naked_ip_address = yes
smtpd_helo_required = yes
smtpd_delay_reject = yes
smtpd_helo_restrictions =
permit_mynetworks,
check_helo_access hash:/usr/local/etc/postfix/helo_access,
permit

# reject_invalid_hostname, permit
body_checks=regexp:/usr/local/etc/postfix/body_checks

content_filter=filter


my master.cf:

smtp inet n - n - - smtpd
-o content_filter=filter:dummy
filter unix - n n - 10 pipe
flags=Rq user=filter argv=/test/spamnowy/filter -f ${sender} -- ${recipient}
#
#smtps inet n - n - - smtpd
# -o smtpd_tls_wrappermode=yes -o smtpd_sasl_auth_enable=yes
#submission inet n - n - - smtpd
# -o smtpd_enforce_tls=yes -o smtpd_sasl_auth_enable=yes
#628 inet n - n - - qmqpd
pickup fifo n - n 60 1 pickup
cleanup unix n - n - 0 cleanup
qmgr fifo n - n 300 1 qmgr
#qmgr fifo n - n 300 1 nqmgr
#tlsmgr fifo - - n 300 1 tlsmgr
rewrite unix - - n - - trivial-rewrite
bounce unix - - n - 0 bounce
defer unix - - n - 0 bounce
flush unix n - n 1000? 0 flush
proxymap unix - - n - - proxymap
smtp unix - - n - - smtp
-o content_filter=filter:dummy
relay unix - - n - - smtp
# -o smtp_helo_timeout=5 -o smtp_connect_timeout=5
showq unix n - n - - showq
error unix - - n - - error
local unix - n n - - local
virtual unix - n n - - virtual

and my filter in /test/spamnowy/

#!/bin/sh

# Simple shell-based filter. It is meant to be invoked as follows:
# /path/to/script -f sender recipients...

# Localize these.
INSPECT_DIR=/var/spool/filter
SENDMAIL="/usr/sbin/sendmail -i"

# Exit codes from <sysexits.h>
EX_TEMPFAIL=75
EX_UNAVAILABLE=69

# Clean up when done or when aborting.
trap "rm -f in.$$" 0 1 2 3 15

# Start processing.
cd $INSPECT_DIR || {
echo $INSPECT_DIR does not exists; exit $EX_TEMPFAIL; }

cat > in.$$ || {
echo Cannot save mail to file; exit $EX_TEMPFAIL; }

# Specify your content filter here.
# filter < in.$$ || {
# echo Message content rejected; exit $EX_UNAVAILABLE; }

$SENDMAIL "$@" < in.$$

exit $?

when postfix receive mail message loops in queue and is not deliver to mailbox.
Why and how to fix it?