<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"> <HTML ><HEAD ><link rel='stylesheet' type='text/css' href='manpage.css'> <!-- $Id: maildrop.sgml,v 1.6 2004/07/27 01:36:41 mrsam Exp $ --> <!-- Copyright 1998 - 2002 Double Precision, Inc. See COPYING for --> <!-- distribution information. --> <meta name="MSSmartTagsPreventParsing" content="TRUE"> <link rel="icon" href="icon.gif" type="image/gif" /> <TITLE >maildrop</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><H1 ><A NAME="MAILDROP" ></A >maildrop</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN10" ></A ><H2 >Name</H2 >maildrop -- mail delivery filter/agent</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN13" ></A ><H2 >Synopsis</H2 ><P ><B CLASS="COMMAND" >maildrop</B > [option...] [-d <VAR CLASS="REPLACEABLE" >user</VAR >] [<VAR CLASS="REPLACEABLE" >arg</VAR >...]</P ><P ><B CLASS="COMMAND" >maildrop</B > [option...] [<VAR CLASS="REPLACEABLE" >filename</VAR >] [<VAR CLASS="REPLACEABLE" >arg</VAR >...]</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN28" ></A ><H2 >DESCRIPTION</H2 ><P ><B CLASS="COMMAND" >maildrop</B > is a replacement local mail delivery agent that includes a mail filtering language. The system administrator can either replace the existing mail delivery agent with <B CLASS="COMMAND" >maildrop</B >, or users may run <B CLASS="COMMAND" >maildrop</B > using the 'forward to program' mechanism of the existing mail delivery agent.</P ><P ><B CLASS="COMMAND" >maildrop</B > first reads the E-mail message on standard input. Trailing carriage return characters are automatically stripped. An E-mail message consists of header lines, followed by a blank line, followed by the contents of the message. The message may contain an mbox-style <TT CLASS="LITERAL" >From_</TT > line before the first header line. If the message does not contain a <TT CLASS="LITERAL" >From_</TT > line, <B CLASS="COMMAND" >maildrop</B > will create one (if needed).</P ><P >If the file <TT CLASS="FILENAME" >/etc/maildrop/maildroprc</TT > exists, mail delivery or mail filtering instructions are read from that file. <B CLASS="COMMAND" >maildrop</B >'s delivery/filtering instructions may direct <B CLASS="COMMAND" >maildrop</B > to save the message in specific mailbox, discard it, return it to sender, or forward it to a different E-mail address.</P ><P >If <TT CLASS="FILENAME" >/etc/maildrop/maildroprc</TT > does not exist, or its mail delivery instructions do not completely dispose of this message, <B CLASS="COMMAND" >maildrop</B > then reads the mail delivery instructions from <TT CLASS="FILENAME" >$HOME/.mailfilter</TT >. If it doesn't exist, or its mail delivery instructions do not completely dispose of the message, <B CLASS="COMMAND" >maildrop</B > then saves the E-mail message in the default mailbox.</P ><P ><B CLASS="COMMAND" >maildrop</B > knows how to deliver mail to an standard mailbox files; it also knows how to deliver to maildirs. A <TT CLASS="LITERAL" >maildir</TT > is a directory-based mail format used by the <TT CLASS="APPLICATION" ><A HREF="http://www.courier-mta.org" TARGET="_top" >Courier</A ></TT > and <TT CLASS="APPLICATION" ><A HREF="http://www.qmail.org" TARGET="_top" >Qmail</A ></TT > mail servers. Many other mail servers also know how to read maildirs. When delivering to mailbox files, <B CLASS="COMMAND" >maildrop</B > will lock the mailbox for the duration of the delivery.</P ><P >At least one mail program writes an empty line before a From_ header when saving a message into a file. <B CLASS="COMMAND" >maildrop</B > ignores empty lines at the beginning of messages. Therefore, <B CLASS="COMMAND" >maildrop</B > requires that every message must have at least one header line.</P ><P >This is the general mail delivery behavior. There are minor differences in behavior depending on <B CLASS="COMMAND" >maildrop</B > delivery mode, which is determined based on how <B CLASS="COMMAND" >maildrop</B > was started. <B CLASS="COMMAND" >maildrop</B > uses three different primary operating modes:</P ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT >Manual mode</DT ><DD ><P >A file containing filtering instructions - <VAR CLASS="REPLACEABLE" >filename</VAR > is specified as an argument to the <B CLASS="COMMAND" >maildrop</B > command. <B CLASS="COMMAND" >maildrop</B > reads this <VAR CLASS="REPLACEABLE" >filename</VAR > (after <TT CLASS="FILENAME" >/etc/maildrop/maildroprc</TT >) and follows the instructions in it. Unless the message is explicitly forwarded, bounced, deleted, or delivered to a specific mailbox, it will be delivered to the user's system mailbox.</P ></DD ><DT >Delivery mode</DT ><DD ><P ><B CLASS="COMMAND" >maildrop</B > is the mail server's mail delivery agent. <B CLASS="COMMAND" >maildrop</B > runs in delivery mode when no <VAR CLASS="REPLACEABLE" >filename</VAR > is specified on the command line. <B CLASS="COMMAND" >maildrop</B > changes the current directory to the user's home directory, then reads <TT CLASS="FILENAME" >/etc/maildrop/maildroprc</TT >, then <TT CLASS="FILENAME" >$HOME/.mailfilter</TT >.</P ></DD ><DT >Embedded mode</DT ><DD ><P ><B CLASS="COMMAND" >maildrop</B > functions as a part of another application. The embedded mode is used by the <TT CLASS="APPLICATION" ><A HREF="http://www.courier-mta.org" TARGET="_top" >Courier</A ></TT > mail server to integrate mail filtering directly into the process of receiving mail from a remote mail relay, thus rejecting unwanted mail before it is even accepted for local mail delivery. Embedded mode is used when either the -m, or the -M, option is specified, and is described below. See below for a more extensive description of the embedded mode.</P ></DD ></DL ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN90" ></A ><H2 >SECURITY</H2 ><P >It is safe to install <B CLASS="COMMAND" >maildrop</B > as a root setuid program. <TT CLASS="APPLICATION" ><A HREF="http://www.courier-mta.org" TARGET="_top" >Courier</A ></TT > installs <B CLASS="COMMAND" >maildrop</B > as a root setuid program by default, in order to be able to use <B CLASS="COMMAND" >maildrop</B > in embedded mode. If root runs <B CLASS="COMMAND" >maildrop</B > (or it is setuided to root) the <VAR CLASS="OPTION" >-d</VAR > option may be used to specify the message's recipient. <B CLASS="COMMAND" >maildrop</B > immediately resets its userid to the one specified by the <VAR CLASS="OPTION" >-d</VAR > option. The user's <TT CLASS="FILENAME" >$HOME/.mailfilter</TT > is read (if it exists), and the message is delivered to the indicated user.</P ><P >The system administrator can configure <B CLASS="COMMAND" >maildrop</B > to restrict the <VAR CLASS="OPTION" >-d</VAR > option for everyone except the mail system itself.</P ><P >If in delivery mode the user's home directory has the sticky bit set, <B CLASS="COMMAND" >maildrop</B > immediately terminates with an exit code of <SPAN CLASS="ERRORCODE" >EX_TEMPFAIL</SPAN >, without doing anything. Mail servers interpret the <SPAN CLASS="ERRORCODE" >EX_TEMPFAIL</SPAN > exit code as a request to reschedule the message for another delivery attempt later. Setting the sticky bit allows <TT CLASS="FILENAME" >$HOME/.mailfilter</TT > to be edited while temporarily holding all incoming mail.</P ><P ><B CLASS="COMMAND" >maildrop</B > also terminates with <SPAN CLASS="ERRORCODE" >EX_TEMPFAIL</SPAN > if the user's home directory has world write permissions.</P ><P ><B CLASS="COMMAND" >maildrop</B > immediately terminates with <SPAN CLASS="ERRORCODE" >EX_TEMPFAIL</SPAN > if the <TT CLASS="FILENAME" >filename</TT > is not owned by the user, or if it has any group or world permissions. This includes read permissions. The permissions on <TT CLASS="FILENAME" >$HOME/.mailfilter</TT > may only include read and write privileges to the user.</P ><P >When using the special embedded mode (see below) <B CLASS="COMMAND" >maildrop</B > immediately terminates with the exit code set to <SPAN CLASS="ERRORCODE" >EX_TEMPFAIL</SPAN > if <TT CLASS="FILENAME" >$HOME/.mailfilters</TT > is not owned by the user, or if it has any group or world permissions.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN123" ></A ><H2 >TEMPORARY FILES</H2 ><P ><B CLASS="COMMAND" >maildrop</B > is heavily optimized and tries to use as little resources as possible. <B CLASS="COMMAND" >maildrop</B > reads smalle messages into memory, then filters and/or delivers the message directly from memory. For larger messages, <B CLASS="COMMAND" >maildrop</B > accesses the message directly from the file. If the standard input is not a file, <B CLASS="COMMAND" >maildrop</B > writes the message to a temporary file, then accesses the message from the temporary file. The temporary file is automatically removed when the message is delivered.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN130" ></A ><H2 >OPTIONS</H2 ><A NAME="OPTIONS" ></A ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT >-A "<VAR CLASS="REPLACEABLE" >Header: value</VAR >"</DT ><DD ><P >Adds an additional header to the message. Specifying <I CLASS="EMPHASIS" >-A "Foo: Bar"</I > effectively adds this header to the message being delivered.</P ><P >The mail transport agent usually adds additional headers when delivering a message to a local mailbox. The way it's usually done is by the mail transport agent sending the message using a pipe to the local delivery agent - such as <B CLASS="COMMAND" >maildrop</B > - and adding some additional headers in the process. Because <B CLASS="COMMAND" >maildrop</B > receives the message from a pipe, <B CLASS="COMMAND" >maildrop</B > must either save the message in memory or write the message into a temporary file.</P ><P >The <VAR CLASS="OPTION" >-A</VAR > option enables the file containing the message to be provided to <B CLASS="COMMAND" >maildrop</B > directly, as standard input, and the additional headers specified on the command line. Because the standard input is a file, <B CLASS="COMMAND" >maildrop</B > will not need a temporary file. Multiple <VAR CLASS="OPTION" >-A</VAR > options may be specified.</P ></DD ><DT >-d <VAR CLASS="REPLACEABLE" >user</VAR ></DT ><DD ><P >Run <B CLASS="COMMAND" >maildrop</B > in delivery mode for this user ID.</P ><P >The system administrator may optionally restrict the <VAR CLASS="OPTION" >-d</VAR > option to be available to the mail system only, so it may not be available to you. In all cases, the <VAR CLASS="OPTION" >-d</VAR > option is allowed if <VAR CLASS="REPLACEABLE" >user</VAR > is the same user who is running <B CLASS="COMMAND" >maildrop</B >. Also, for the <VAR CLASS="OPTION" >-d</VAR > option to work at all, <B CLASS="COMMAND" >maildrop</B > must be executed by root, or <B CLASS="COMMAND" >maildrop</B > must be a root-owned program with the setuid bit set. Absence of a <TT CLASS="FILENAME" >filename</TT > on <B CLASS="COMMAND" >maildrop</B >'s command line implies the <VAR CLASS="OPTION" >-d</VAR > option for the user running <B CLASS="COMMAND" >maildrop</B >.</P ><P >If <VAR CLASS="OPTION" >-d</VAR > is not specified, the first argument following all the options is a name of the file containing filtering instructions. The remaining arguments, if any, are assigned to the variables <VAR CLASS="VARNAME" >$1</VAR >, <VAR CLASS="VARNAME" >$2</VAR >, and so on (see <A HREF="maildropfilter.html#environment" TARGET="_top" >"Environment"</A > and <A HREF="maildropfilter.html#varsubst" TARGET="_top" >"Variable substitution"</A >).</P ></DD ><DT >-f <VAR CLASS="REPLACEABLE" >address</VAR ></DT ><DD ><P >Sets the FROM variable (message envelope sender) to <VAR CLASS="REPLACEABLE" >address</VAR >. The system administrator may optionally disable the <VAR CLASS="OPTION" >-f</VAR > option for users, so it may not be available to you.</P ></DD ><DT >-m</DT ><DD ><P >Run <B CLASS="COMMAND" >maildrop</B > in embedded mode. It's possible to use both the <VAR CLASS="OPTION" >-m</VAR >, and the <VAR CLASS="OPTION" >-d</VAR > options, but it doesn't make much sense to do so. Even if you really wanted to run your message through someone else's <TT CLASS="FILENAME" >.mailfilter</TT >, that <TT CLASS="FILENAME" >.mailfilter</TT > probably has at least one instruction which is not allowed in the embedded mode.</P ><P >The <TT CLASS="FILENAME" >filename</TT > argument to <B CLASS="COMMAND" >maildrop</B > should be specified. <TT CLASS="FILENAME" >filename</TT > is a file that includes filtering instructions to be processed in embedded mode. The <TT CLASS="FILENAME" >-m</TT > option is used for debugging filter files which are later placed in <TT CLASS="FILENAME" >$HOME/.mailfilters</TT >, and used with the <VAR CLASS="OPTION" >-M</VAR > option.</P ></DD ><DT >-M <VAR CLASS="REPLACEABLE" >filterfile</VAR ></DT ><DD ><A NAME="MOPTION" ></A ><P >Run <B CLASS="COMMAND" >maildrop</B > in a special embedded mode. The <VAR CLASS="OPTION" >-d</VAR > option is implied when <VAR CLASS="OPTION" >-M</VAR > is used, and if absent it defaults to the userid running <B CLASS="COMMAND" >maildrop</B >.</P ><P >All the requirements for the <VAR CLASS="OPTION" >-d</VAR > option apply. <B CLASS="COMMAND" >maildrop</B > must either be executed by root, or the <B CLASS="COMMAND" >maildrop</B > program must be owned by root with the setuid bit set. <B CLASS="COMMAND" >maildrop</B > immediately gives up root privileges by changing its user ID to the one specified by <VAR CLASS="OPTION" >-d</VAR >, then reads <TT CLASS="FILENAME" >$HOME/.mailfilters/<VAR CLASS="REPLACEABLE" >filterfile</VAR ></TT >. For security reasons the name of the file may not begin with a slash or include periods. <B CLASS="COMMAND" >maildrop</B > is very paranoid: both <TT CLASS="FILENAME" >$HOME/.mailfilters</TT >, and <TT CLASS="FILENAME" >$HOME/.mailfilters/<VAR CLASS="REPLACEABLE" >filterfile</VAR ></TT > must be owned by the user, and may not have any group or world permissions.</P ><P >The <VAR CLASS="OPTION" >-M</VAR > option allows for some friendly cooperation between the user running the application, and the user who provides a filter for the embedded mode. The user running the application can use someone else's canned filter and be assured that the filter is not going to run amok and start sending mail or create files all over the place. The user who provides the filter can be assured that the environment variables are clean, and that there are no surprises.</P ><P ><B CLASS="COMMAND" >maildrop</B > supports the concept of "default" filter files. If the file specified by the <B CLASS="COMMAND" >-M</B > option cannot be found in <TT CLASS="FILENAME" >$HOME/.mailfilters</TT >, <B CLASS="COMMAND" >maildrop</B > will try to open <TT CLASS="FILENAME" >$HOME/.mailfilters/<VAR CLASS="REPLACEABLE" >filterfileprefix</VAR >-default</TT >. <VAR CLASS="REPLACEABLE" >filterfileprefix</VAR > is the initial part of <VAR CLASS="REPLACEABLE" >filterfile</VAR > up until the last '-' character in <VAR CLASS="REPLACEABLE" >filterfile</VAR >.</P ><P >If <TT CLASS="FILENAME" >$HOME/.mailfilters/<VAR CLASS="REPLACEABLE" >filterfileprefix</VAR >-default</TT > does not exist, and there are any other dashes left in <VAR CLASS="REPLACEABLE" >filterfileprefix</VAR >, maildrop removes the last dash and everything following it, then tries again.</P ><P >As a last resort <B CLASS="COMMAND" >maildrop</B > tries to open <TT CLASS="FILENAME" >$HOME/.mailfilters/default</TT >.</P ><P >For example, if the parameter to the <VAR CLASS="OPTION" >-M</VAR > option is <I CLASS="EMPHASIS" >mailfilter-lists-maildrop</I >, <B CLASS="COMMAND" >maildrop</B > will try to open the following files, in order: <A NAME="AEN241" ></A ><BLOCKQUOTE CLASS="BLOCKQUOTE" ><P CLASS="LITERALLAYOUT" ><TT CLASS="FILENAME" >$HOME/.mailfilters/mailfilter-lists-maildrop</TT ><br> <TT CLASS="FILENAME" >$HOME/.mailfilters/mailfilter-lists-maildrop-default</TT ><br> <TT CLASS="FILENAME" >$HOME/.mailfilters/mailfilter-lists-default</TT ><br> <TT CLASS="FILENAME" >$HOME/.mailfilters/mailfilter-default</TT ><br> <TT CLASS="FILENAME" >$HOME/.mailfilters/default</TT ></P ></BLOCKQUOTE ></P ><P >Note that <B CLASS="COMMAND" >maildrop</B > looks for -default files ONLY if <VAR CLASS="OPTION" >-M</VAR > is used.</P ></DD ><DT >-D <VAR CLASS="REPLACEABLE" >uuu/ggg</VAR ></DT ><DD ><P >This option is reserved for use by the version of <B CLASS="COMMAND" >maildrop</B > that comes integrated with the <TT CLASS="APPLICATION" ><A HREF="http://www.courier-mta.org" TARGET="_top" >Courier mail server</A ></TT >.</P ></DD ><DT >-V <VAR CLASS="REPLACEABLE" >level</VAR ></DT ><DD ><P >Initialize the <VAR CLASS="VARNAME" >VERBOSE</VAR > variable to <VAR CLASS="REPLACEABLE" >level</VAR >. Because <B CLASS="COMMAND" >maildrop</B > parses the entire before running it, this option is used to produce debugging output in the parsing phase. Otherwise, if <TT CLASS="FILENAME" >filename</TT > has syntax errors, then no debugging output is possible because the <VAR CLASS="VARNAME" >VERBOSE</VAR > variable is not yet set.</P ><P ><VAR CLASS="OPTION" >-V</VAR > is ignored when <B CLASS="COMMAND" >maildrop</B > runs in delivery mode.</P ></DD ><DT >-w <VAR CLASS="REPLACEABLE" >N</VAR ></DT ><DD ><P >The <VAR CLASS="OPTION" >-w N</VAR > option places a warning message into the maildir if the maildir has a quota setting, and after the message was successfully delivered the maildir was at least <VAR CLASS="REPLACEABLE" >N</VAR > percent full. The warning message is copied verbatim from <TT CLASS="FILENAME" >/etc/quotawarnmsg</TT > with the addition of the "<TT CLASS="LITERAL" >Date:</TT >" and "<TT CLASS="LITERAL" >Message-Id:</TT >" headers. The warning is repeated every 24 hours (at least), until the maildir drops below <VAR CLASS="REPLACEABLE" >N</VAR > percent full.</P ></DD ></DL ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN283" ></A ><H2 >DELIVERY MODE</H2 ><P >If a <TT CLASS="FILENAME" >filename</TT > is not specified on the command line, or if the <VAR CLASS="OPTION" >-d</VAR > option is used, <B CLASS="COMMAND" >maildrop</B > will run in delivery mode. In delivery mode, <B CLASS="COMMAND" >maildrop</B > changes to the home directory of the user specified by the <VAR CLASS="OPTION" >-d</VAR > option (or the user who is running <B CLASS="COMMAND" >maildrop</B > if the <VAR CLASS="OPTION" >-d</VAR > option was not given) and reads <TT CLASS="FILENAME" >$HOME/.mailfilter</TT > for filtering instructions. <TT CLASS="FILENAME" >$HOME/.mailfilter</TT > must be owned by the user, and have no group or global permissions (<B CLASS="COMMAND" >maildrop</B > terminates if it does).</P ><P >If <TT CLASS="FILENAME" >$HOME/.mailfilter</TT > does not exist, <B CLASS="COMMAND" >maildrop</B > will simply deliver the message to the user's mailbox.</P ><P >If the file <TT CLASS="FILENAME" >/etc/maildrop/maildroprc</TT > exists, <B CLASS="COMMAND" >maildrop</B > reads filtering instructions from this file first, before reading <TT CLASS="FILENAME" >$HOME/.mailfilter</TT >. This allows the system administrator to provide global filtering instructions for all users.</P ><DIV CLASS="NOTE" ><P ></P ><TABLE CLASS="NOTE" WIDTH="100%" BORDER="0" ><TR ><TD WIDTH="25" ALIGN="CENTER" VALIGN="TOP" >NOTE:</TD ><TD ALIGN="LEFT" VALIGN="TOP" ><P ><TT CLASS="FILENAME" >/etc/maildrop/maildroprc</TT > is read only in delivery mode.</P ></TD ></TR ></TABLE ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN306" ></A ><H2 >VIRTUAL ACCOUNTS</H2 ><P >The <VAR CLASS="OPTION" >-d</VAR > option can also specify a name of a virtual account or mailbox. See <A HREF="makeuserdb.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >makeuserdb</SPAN >(1)</SPAN ></A > for more information.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN314" ></A ><H2 >EMBEDDED MODE</H2 ><A NAME="EMBEDDED" ></A ><P >The embedded mode is used when <B CLASS="COMMAND" >maildrop</B >'s filtering abilities are desired, but no actual mail delivery is needed. In embedded mode <B CLASS="COMMAND" >maildrop</B > is executed by another application, and <A HREF="#options" TARGET="_top" >is passed the -m or the -M option.</A > <B CLASS="COMMAND" >maildrop</B > reads the message, then runs the filtering rules specified in <TT CLASS="FILENAME" >filename</TT >.</P ><P ><TT CLASS="FILENAME" >filename</TT > may contain any filtering instructions EXCEPT the following: <P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT >` ... `</DT ><DD ><P >Text strings delimited by back-tick characters (run shell command) are not allowed.</P ></DD ><DT ><A HREF="maildropfilter.html#cc" TARGET="_top" >cc</A ></DT ><DD ><P >The <B CLASS="COMMAND" >cc</B > command is not allowed in embedded mode.</P ></DD ><DT ><A HREF="maildropfilter.html#dotlock" TARGET="_top" >dotlock</A ></DT ><DD ><P >The <B CLASS="COMMAND" >dotlock</B > command is not allowed in embedded mode.</P ></DD ><DT ><A HREF="maildropfilter.html#flock" TARGET="_top" >flock</A ></DT ><DD ><P >The <B CLASS="COMMAND" >flock</B > command is not allowed in embedded mode.</P ></DD ><DT ><A HREF="maildropgdbm.html" TARGET="_top" >gdbmopen</A ></DT ><DD ><P >In embedded mode, GDBM databases may be opened only for reading.</P ></DD ><DT ><A HREF="maildropfilter.html#log" TARGET="_top" >log</A ></DT ><DD ><P >The <B CLASS="COMMAND" >log</B > command is not allowed in embedded mode.</P ></DD ><DT ><A HREF="maildropfilter.html#log" TARGET="_top" >logfile</A ></DT ><DD ><P >The <B CLASS="COMMAND" >logfile</B > command is not allowed in embedded mode.</P ></DD ><DT ><A HREF="maildropfilter.html#to" TARGET="_top" >to</A ></DT ><DD ><P >The <B CLASS="COMMAND" >to</B > command is not allowed in embedded mode.</P ></DD ><DT ><A HREF="maildropfilter.html#xfilter" TARGET="_top" >xfilter</A ></DT ><DD ><P >The <B CLASS="COMMAND" >xfilter</B > command is not allowed in embedded mode.</P ></DD ></DL ></DIV ></P ><P >Normally when the <TT CLASS="FILENAME" >filename</TT > does not explicitly delivers a message, <B CLASS="COMMAND" >maildrop</B > will deliver the message to the user's default mailbox. This is also disabled in embedded mode.</P ><P >The <TT CLASS="FILENAME" >filename</TT > may communicate with the parent application by using the <A HREF="maildropfilter.html#echo" TARGET="_top" >echo</A > statement and the <VAR CLASS="VARNAME" >EXITCODE</VAR > environment variable.</P ><DIV CLASS="REFSECT2" ><A NAME="AEN384" ></A ><H3 ><TT CLASS="FILENAME" >/etc/maildrop/maildroprcs</TT ></H3 ><P >If <B CLASS="COMMAND" >maildrop</B > encounters an <A HREF="maildropfilter.html#include" TARGET="_top" >include</A > statement where the filename starts with <TT CLASS="FILENAME" >/etc/maildrop/maildroprcs/</TT >, the normal restrictions for the embedded mode are suspended while executing the filter file in the <TT CLASS="FILENAME" >/etc/maildrop/maildroprcs</TT > directory. The restrictions are also suspended for any additional filter files that are included from <TT CLASS="FILENAME" >/etc/maildrop/maildroprcs</TT >. The restrictions resume once <B CLASS="COMMAND" >maildrop</B > finishes executing the file from <TT CLASS="FILENAME" >/etc/maildrop/maildroprcs</TT >.</P ><P >This allows the system administrator to have a controlled environment for running external commands (via the backticks, or the <A HREF="maildropfilter.html#xfilter" TARGET="_top" >xfilter</A > command).</P ><P >The name of the file may not contain any periods (so that a creative individual can't write <I CLASS="EMPHASIS" >include "/etc/maildrop/maildroprcs/../../home/user/recipe"</I >).</P ><P >Before executing the commands in the <TT CLASS="FILENAME" >/etc/maildrop/maildroprcs</TT > file, <B CLASS="COMMAND" >maildrop</B > automatically resets the following variables to their initial values: <VAR CLASS="VARNAME" >DEFAULT</VAR >, <VAR CLASS="VARNAME" >HOME</VAR >, <VAR CLASS="VARNAME" >LOCKEXT</VAR >, <VAR CLASS="VARNAME" >LOCKSLEEP</VAR >, <VAR CLASS="VARNAME" >LOCKTIMEOUT</VAR >, <VAR CLASS="VARNAME" >LOCKREFRESH</VAR >, <VAR CLASS="VARNAME" >LOGNAME</VAR >, <VAR CLASS="VARNAME" >PATH</VAR >, <VAR CLASS="VARNAME" >SENDMAIL</VAR >, and <VAR CLASS="VARNAME" >SHELL</VAR >. Please note that the previous values of these variables (if they were changed) will NOT be restored once <B CLASS="COMMAND" >maildrop</B > finishes executing the commands from <TT CLASS="FILENAME" >/etc/maildrop/maildroprcs</TT >.</P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN414" ></A ><H2 >WATCHDOG TIMER</H2 ><P ><B CLASS="COMMAND" >maildrop</B > has a watchdog timer that attempts to abort runaway filtering. If filtering is not complete within a predefined time interval (defined by the system administrator, usually five minutes), <B CLASS="COMMAND" >maildrop</B > terminates.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN419" ></A ><H2 >FILES</H2 ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><TT CLASS="FILENAME" >/etc/passwd</TT ></DT ><DD ><P >Sets user's home directory, and related variables. If NIS/YP is install, that will be used as well.</P ></DD ><DT ><TT CLASS="FILENAME" >/etc/maildrop/maildroprc</TT ></DT ><DD ><P >Global filtering instructions for delivery mode.</P ></DD ><DT ><TT CLASS="FILENAME" >/var/spool/mail</TT ></DT ><DD ><P >System mailbox (actual directory defined by the system administrator).</P ></DD ><DT ><TT CLASS="FILENAME" >/usr/lib/sendmail</TT ></DT ><DD ><P >Program to forward mail (exact program defined by the system administrator).</P ></DD ><DT ><TT CLASS="FILENAME" >$HOME/.mailfilter</TT ></DT ><DD ><P >Filtering instructions in delivery mode.</P ></DD ><DT ><TT CLASS="FILENAME" >$HOME/.mailfilters</TT ></DT ><DD ><P >Directory containing files used in special embedded mode.</P ></DD ></DL ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN452" ></A ><H2 >SEE ALSO</H2 ><P ><A HREF="lockmail.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >lockmail</SPAN >(1)</SPAN ></A >, <A HREF="maildropfilter.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >maildropfilter</SPAN >(7)</SPAN ></A >, <A HREF="makedat.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >makedat</SPAN >(1)</SPAN ></A >, <A HREF="maildropgdbm.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >maildropgdbm</SPAN >(7)</SPAN ></A >, <A HREF="maildropex.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >maildropex</SPAN >(7)</SPAN ></A >, <A HREF="reformail.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >reformail</SPAN >(1)</SPAN ></A >, <A HREF="makeuserdb.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >makeuserdb</SPAN >(1)</SPAN ></A >, <A HREF="makemime.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >makemime</SPAN >(1)</SPAN ></A >, <A HREF="reformime.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >reformime</SPAN >(1)</SPAN ></A >, <SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >egrep</SPAN >(1)</SPAN >, <SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >grep</SPAN >(1)</SPAN >, , <A HREF="courier.html" TARGET="_top" ><SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >courier</SPAN >(8)</SPAN ></A >, <SPAN CLASS="CITEREFENTRY" ><SPAN CLASS="REFENTRYTITLE" >sendmail</SPAN >(8)</SPAN >, <A HREF="http://www.qmail.org" TARGET="_top" >http://www.qmail.org</A >.</P ></DIV ></BODY ></HTML >
